Effects of a Problem-based Structure of Physics Contents on Conceptual Learning and the Ability to Solve Problems

NASA Astrophysics Data System (ADS)

Becerra-Labra, Carlos; Gras-Martí, Albert; Martínez Torregrosa, Joaquín

2012-05-01

A model of teaching/learning is proposed based on a 'problem-based structure' of the contents of the course, in combination with a training in paper and pencil problem solving that emphasizes discussion and quantitative analysis, rather than formulae plug-in. The aim is to reverse the high failure and attrition rate among engineering undergraduates taking physics. A number of tests and questionnaires were administered to a group of students following a traditional lecture-based instruction, as well as to another group that was following an instruction scheme based on the proposed approach and the teaching materials developed ad hoc. The results show that students following the new method can develop scientific reasoning habits in problem-solving skills, and show gains in conceptual learning, attitudes and interests, and that the effects of this approach on learning are noticeable several months after the course is over.

Examining the Critical Thinking Dispositions and the Problem Solving Skills of Computer Engineering Students

ERIC Educational Resources Information Center

Özyurt, Özcan

2015-01-01

Problem solving is an indispensable part of engineering. Improving critical thinking dispositions for solving engineering problems is one of the objectives of engineering education. In this sense, knowing critical thinking and problem solving skills of engineering students is of importance for engineering education. This study aims to determine…

Robust fault detection of turbofan engines subject to adaptive controllers via a Total Measurable Fault Information Residual (ToMFIR) technique.

PubMed

Chen, Wen; Chowdhury, Fahmida N; Djuric, Ana; Yeh, Chih-Ping

2014-09-01

This paper provides a new design of robust fault detection for turbofan engines with adaptive controllers. The critical issue is that the adaptive controllers can depress the faulty effects such that the actual system outputs remain the pre-specified values, making it difficult to detect faults/failures. To solve this problem, a Total Measurable Fault Information Residual (ToMFIR) technique with the aid of system transformation is adopted to detect faults in turbofan engines with adaptive controllers. This design is a ToMFIR-redundancy-based robust fault detection. The ToMFIR is first introduced and existing results are also summarized. The Detailed design process of the ToMFIRs is presented and a turbofan engine model is simulated to verify the effectiveness of the proposed ToMFIR-based fault-detection strategy. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

Rocket Engine Oscillation Diagnostics

NASA Technical Reports Server (NTRS)

Nesman, Tom; Turner, James E. (Technical Monitor)

2002-01-01

Rocket engine oscillating data can reveal many physical phenomena ranging from unsteady flow and acoustics to rotordynamics and structural dynamics. Because of this, engine diagnostics based on oscillation data should employ both signal analysis and physical modeling. This paper describes an approach to rocket engine oscillation diagnostics, types of problems encountered, and example problems solved. Determination of design guidelines and environments (or loads) from oscillating phenomena is required during initial stages of rocket engine design, while the additional tasks of health monitoring, incipient failure detection, and anomaly diagnostics occur during engine development and operation. Oscillations in rocket engines are typically related to flow driven acoustics, flow excited structures, or rotational forces. Additional sources of oscillatory energy are combustion and cavitation. Included in the example problems is a sampling of signal analysis tools employed in diagnostics. The rocket engine hardware includes combustion devices, valves, turbopumps, and ducts. Simple models of an oscillating fluid system or structure can be constructed to estimate pertinent dynamic parameters governing the unsteady behavior of engine systems or components. In the example problems it is shown that simple physical modeling when combined with signal analysis can be successfully employed to diagnose complex rocket engine oscillatory phenomena.

A model for the space shuttle main engine high pressure oxidizer turbopump shaft seal system

NASA Technical Reports Server (NTRS)

Paxson, Daniel E.

1990-01-01

A simple static model is presented which solves for the flow properties of pressure, temperature, and mass flow in the Space Shuttle Main Engine pressure Oxidizer Turbopump Shaft Seal Systems. This system includes the primary and secondary turbine seals, the primary and secondary turbine drains, the helium purge seals and feed line, the primary oxygen drain, and the slinger/labyrinth oxygen seal pair. The model predicts the changes in flow variables that occur during and after failures of the various seals. Such information would be particularly useful in a post flight situation where processing of sensor information using this model could identify a particular seal that had experienced excessive wear. Most of the seals in the system are modeled using simple one dimensional equations which can be applied to almost any seal provided that the fluid is gaseous. A failure is modeled as an increase in the clearance between the shaft and the seal. Thus, the model does not attempt to predict how the failure process actually occurs (e.g., wear, seal crack initiation). The results presented were obtained using a FORTRAN implementation of the model running on a VAX computer. Solution for the seal system properties is obtained iteratively; however, a further simplified implementation (which does not include the slinger/labyrinth combination) was also developed which provides fast and reasonable results for most engine operating conditions. Results from the model compare favorably with the limited redline data available.

A TAPS Interactive Multimedia Package to Solve Engineering Dynamics Problem

ERIC Educational Resources Information Center

Sidhu, S. Manjit; Selvanathan, N.

2005-01-01

Purpose: To expose engineering students to using modern technologies, such as multimedia packages, to learn, visualize and solve engineering problems, such as in mechanics dynamics. Design/methodology/approach: A multimedia problem-solving prototype package is developed to help students solve an engineering problem in a step-by-step approach. A…

The errors of metacognitive evaluation on metacognitive failure of students in mathematical problem solving

NASA Astrophysics Data System (ADS)

Huda, Nizlel; Sutawidjaja, Akbar; Subanji; Rahardjo, Swasono

2018-04-01

Metacognitive activity is very important in mathematical problems solving. Metacognitive activity consists of metacognitive awareness, metacognitive evaluation and metacognitive regulation. This study aimed to reveal the errors of metacognitive evaluation in students’ metacognitive failure in solving mathematical problems. 20 students taken as research subjects were grouped into three groups: the first group was students who experienced one metacognitive failure, the second group was students who experienced two metacognitive failures and the third group was students who experienced three metacognitive failures. One person was taken from each group as the reasearch subject. The research data was collected from worksheets done using think aload then followed by interviewing the research subjects based on the results’ of subject work. The findings in this study were students who experienced metacognitive failure in solving mathematical problems tends to miscalculate metacognitive evaluation in considering the effectiveness and limitations of their thinking and the effectiveness of their chosen strategy of completion.

The Rapidly Evolving Concept of Whole Heart Engineering

PubMed Central

Dal Sasso, Eleonora; Menabò, Roberta; Di Lisa, Fabio; Gerosa, Gino

2017-01-01

Whole heart engineering represents an incredible journey with as final destination the challenging aim to solve end-stage cardiac failure with a biocompatible and living organ equivalent. Its evolution started in 2008 with rodent organs and is nowadays moving closer to clinical application thanks to scaling-up strategies to human hearts. This review will offer a comprehensive examination on the important stages to be reached for the bioengineering of the whole heart, by describing the approaches of organ decellularization, repopulation, and maturation so far applied and the novel technologies of potential interest. In addition, it will carefully address important demands that still need to be satisfied in order to move to a real clinical translation of the whole bioengineering heart concept. PMID:29250121

Educational Effects of Practical Education Using a Debate Exercise on Engineering Ethics

NASA Astrophysics Data System (ADS)

Takanokura, Masato; Hayashi, Shigeo

The educational effects of practical education using a debate exercise are investigated using questionnaires. For the group-work composed of discussion and debate, students understand thoroughly various engineering ethical topics, such as factors preventing ethical decision-making. Students enhance their abilities to make a rational and logical decision by themselves such as a judgment based on correct information. Mutual evaluation by students through group interaction elevates positive educational effects. However, students answer fewer questions related to the understanding of professional duties and cooperate social responsibility because of the group-work using failure cases. Students also show less progress in their abilities to communicate with others and to express their opinions to audiences. A more suitable number of group members solves the latter problem.

Challenges of constructing salt cavern gas storage in China

NASA Astrophysics Data System (ADS)

Xia, Yan; Yuan, Guangjie; Ban, Fansheng; Zhuang, Xiaoqian; Li, Jingcui

2017-11-01

After more than ten years of research and engineering practice in salt cavern gas storage, the engineering technology of geology, drilling, leaching, completion, operation and monitoring system has been established. With the rapid growth of domestic consumption of natural gas, the requirement of underground gas storage is increasing. Because high-quality rock salt resources about 1000m depth are relatively scarce, the salt cavern gas storages will be built in deep rock salt. According to the current domestic conventional construction technical scheme, construction in deep salt formations will face many problems such as circulating pressure increasing, tubing blockage, deformation failure, higher completion risk and so on, caused by depth and the complex geological conditions. Considering these difficulties, the differences between current technical scheme and the construction scheme of twin well and big hole are analyzed, and the results show that the technical scheme of twin well and big hole have obvious advantages in reducing the circulating pressure loss, tubing blockage and failure risk, and they can be the alternative schemes to solve the technical difficulties of constructing salt cavern gas storages in the deep rock salt.

On a New Approach to Education about Ethics for Engineers at Meijou University

NASA Astrophysics Data System (ADS)

Fukaya, Minoru; Morimoto, Tsukasa; Kimura, Noritsugu

We propose a new approach to education of so called “engineering ethics”. This approach has two important elements in its teaching system. One is “problem-solving learning”, and the other is “discussion ability”. So far, engineering ethics started at the ethical standpoint. But we put the viewpoint of problem-solving learning at the educational base of engineering ethics. Because many problems have complicated structures, so if we want to solve them, we should discuss each other. Problem-solving ability and discussion ability, they help engineers to solve the complex problems in their social everyday life. Therefore, Meijo University names engineering ethics “ethics for engineers”. At Meijou University about 1300 students take classes in both ethics for engineers and environmental ethics for one year.

UQTools: The Uncertainty Quantification Toolbox - Introduction and Tutorial

NASA Technical Reports Server (NTRS)

Kenny, Sean P.; Crespo, Luis G.; Giesy, Daniel P.

2012-01-01

UQTools is the short name for the Uncertainty Quantification Toolbox, a software package designed to efficiently quantify the impact of parametric uncertainty on engineering systems. UQTools is a MATLAB-based software package and was designed to be discipline independent, employing very generic representations of the system models and uncertainty. Specifically, UQTools accepts linear and nonlinear system models and permits arbitrary functional dependencies between the system s measures of interest and the probabilistic or non-probabilistic parametric uncertainty. One of the most significant features incorporated into UQTools is the theoretical development centered on homothetic deformations and their application to set bounding and approximating failure probabilities. Beyond the set bounding technique, UQTools provides a wide range of probabilistic and uncertainty-based tools to solve key problems in science and engineering.

How To Solve Problems. For Success in Freshman Physics, Engineering, and Beyond. Third Edition.

ERIC Educational Resources Information Center

Scarl, Donald

To expertly solve engineering and science problems one needs to know science and engineering as well as have a tool kit of problem-solving methods. This book is about problem-solving methods: it presents the methods professional problem solvers use, explains why these methods have evolved, and shows how a student can make these methods his/her…

Measurement of Plastic Stress and Strain for Analytical Method Verification (MSFC Center Director's Discretionary Fund Project No. 93-08)

NASA Technical Reports Server (NTRS)

Price, J. M.; Steeve, B. E.; Swanson, G. R.

1999-01-01

The analytical prediction of stress, strain, and fatigue life at locations experiencing local plasticity is full of uncertainties. Much of this uncertainty arises from the material models and their use in the numerical techniques used to solve plasticity problems. Experimental measurements of actual plastic strains would allow the validity of these models and solutions to be tested. This memorandum describes how experimental plastic residual strain measurements were used to verify the results of a thermally induced plastic fatigue failure analysis of a space shuttle main engine fuel pump component.

Failure of engineering artifacts: a life cycle approach.

PubMed

Del Frate, Luca

2013-09-01

Failure is a central notion both in ethics of engineering and in engineering practice. Engineers devote considerable resources to assure their products will not fail and considerable progress has been made in the development of tools and methods for understanding and avoiding failure. Engineering ethics, on the other hand, is concerned with the moral and social aspects related to the causes and consequences of technological failures. But what is meant by failure, and what does it mean that a failure has occurred? The subject of this paper is how engineers use and define this notion. Although a traditional definition of failure can be identified that is shared by a large part of the engineering community, the literature shows that engineers are willing to consider as failures also events and circumstance that are at odds with this traditional definition. These cases violate one or more of three assumptions made by the traditional approach to failure. An alternative approach, inspired by the notion of product life cycle, is proposed which dispenses with these assumptions. Besides being able to address the traditional cases of failure, it can deal successfully with the problematic cases. The adoption of a life cycle perspective allows the introduction of a clearer notion of failure and allows a classification of failure phenomena that takes into account the roles of stakeholders involved in the various stages of a product life cycle.

Ferrographic and spectrometer oil analysis from a failed gas turbine engine

NASA Technical Reports Server (NTRS)

Jones, W. R., Jr.

1982-01-01

An experimental gas turbine engine was destroyed as a result of the combustion of its titanium components. It was concluded that a severe surge may have caused interference between rotating and stationary compressor that either directly or indirectly ignited the titanium components. Several engine oil samples (before and after the failure) were analyzed with a Ferrograph, a plasma, an atomic absorption, and an emission spectrometer to see if this information would aid in the engine failure diagnosis. The analyses indicated that a lubrication system failure was not a causative factor in the engine failure. Neither an abnormal wear mechanism nor a high level of wear debris was detected in the engine oil sample taken just prior to the test in which the failure occurred. However, low concentrations (0.2 to 0.5 ppm) of titanium were evident in this sample and samples taken earlier. After the failure, higher titanium concentrations ( 2 ppm) were detected in oil samples taken from different engine locations. Ferrographic analysis indicated that most of the titanium was contained in spherical metallic debris after the failure. The oil analyses eliminated a lubrication system bearing or shaft seal failure as the cause of the engine failure.

Issues and Strategies in Solving Multidisciplinary Optimization Problems

NASA Technical Reports Server (NTRS)

Patnaik, Surya

2013-01-01

Optimization research at NASA Glenn Research Center has addressed the design of structures, aircraft and airbreathing propulsion engines. The accumulated multidisciplinary design activity is collected under a testbed entitled COMETBOARDS. Several issues were encountered during the solution of the problems. Four issues and the strategies adapted for their resolution are discussed. This is followed by a discussion on analytical methods that is limited to structural design application. An optimization process can lead to an inefficient local solution. This deficiency was encountered during design of an engine component. The limitation was overcome through an augmentation of animation into optimization. Optimum solutions obtained were infeasible for aircraft and airbreathing propulsion engine problems. Alleviation of this deficiency required a cascading of multiple algorithms. Profile optimization of a beam produced an irregular shape. Engineering intuition restored the regular shape for the beam. The solution obtained for a cylindrical shell by a subproblem strategy converged to a design that can be difficult to manufacture. Resolution of this issue remains a challenge. The issues and resolutions are illustrated through a set of problems: Design of an engine component, Synthesis of a subsonic aircraft, Operation optimization of a supersonic engine, Design of a wave-rotor-topping device, Profile optimization of a cantilever beam, and Design of a cylindrical shell. This chapter provides a cursory account of the issues. Cited references provide detailed discussion on the topics. Design of a structure can also be generated by traditional method and the stochastic design concept. Merits and limitations of the three methods (traditional method, optimization method and stochastic concept) are illustrated. In the traditional method, the constraints are manipulated to obtain the design and weight is back calculated. In design optimization, the weight of a structure becomes the merit function with constraints imposed on failure modes and an optimization algorithm is used to generate the solution. Stochastic design concept accounts for uncertainties in loads, material properties, and other parameters and solution is obtained by solving a design optimization problem for a specified reliability. Acceptable solutions can be produced by all the three methods. The variation in the weight calculated by the methods was found to be modest. Some variation was noticed in designs calculated by the methods. The variation may be attributed to structural indeterminacy. It is prudent to develop design by all three methods prior to its fabrication. The traditional design method can be improved when the simplified sensitivities of the behavior constraint is used. Such sensitivity can reduce design calculations and may have a potential to unify the traditional and optimization methods. Weight versus reliability traced out an inverted-S-shaped graph. The center of the graph corresponded to mean valued design. A heavy design with weight approaching infinity could be produced for a near-zero rate of failure. Weight can be reduced to a small value for a most failure-prone design. Probabilistic modeling of load and material properties remained a challenge.

Teaching Problem-Solving Skills to Nuclear Engineering Students

ERIC Educational Resources Information Center

Waller, E.; Kaye, M. H.

2012-01-01

Problem solving is an essential skill for nuclear engineering graduates entering the workforce. Training in qualitative and quantitative aspects of problem solving allows students to conceptualise and execute solutions to complex problems. Solutions to problems in high consequence fields of study such as nuclear engineering require rapid and…

Enhanced and Conventional Project-Based Learning in an Engineering Design Module

ERIC Educational Resources Information Center

Chua, K. J.; Yang, W. M.; Leo, H. L.

2014-01-01

Engineering education focuses chiefly on students' ability to solve problems. While most engineering students are proficient in solving paper questions, they may not be proficient at providing optimal solutions to pragmatic project-based problems that require systematic learning strategy, innovation, problem-solving, and execution. The…

Failure is an option: Reactions to failure in elementary engineering design projects

NASA Astrophysics Data System (ADS)

Johnson, Matthew M.

Recent reform documents in science education have called for teachers to use epistemic practices of science and engineering researchers to teach disciplinary content (NRC, 2007; NRC, 2012; NGSS Lead States, 2013). Although this creates challenges for classroom teachers unfamiliar with engineering, it has created a need for high quality research about how students and teachers engage in engineering activities to improve curriculum development and teaching pedagogy. While framers of the Next Generation Science Standards (NRC, 2012; NGSS Lead States 2013) focused on the similarities of the practices of science researchers and engineering designers, some have proposed that engineering has a unique set of epistemic practices, including improving from failure (Cunningham & Carlsen, 2014; Cunningham & Kelly, in review). While no one will deny failures occur in science, failure in engineering is thought of in fundamentally different ways. In the study presented here, video data from eight classes of elementary students engaged in one of two civil engineering units were analyzed using methods borrowed from psychology, anthropology, and sociolinguistics to investigate: 1) the nature of failure in elementary engineering design; 2) the ways in which teachers react to failure; and 3) how the collective actions of students and teachers support or constrain improvement in engineering design. I propose new ways of considering the types and causes of failure, and note three teacher reactions to failure: the manager, the cheerleader, and the strategic partner. Because the goal of iteration in engineering is improvement, I also studied improvement. Students only systematically improve when they have the opportunity, productive strategies, and fair comparisons between prototypes. I then investigate the use of student engineering journals to assess learning from the process of improvement after failure. After discussion, I consider implications from this work as well as future research to advance our understanding in this area.

Ferrographic and spectrographic analysis of oil sampled before and after failure of a jet engine

NASA Technical Reports Server (NTRS)

Jones, W. R., Jr.

1980-01-01

An experimental gas turbine engine was destroyed as a result of the combustion of its titanium components. Several engine oil samples (before and after the failure) were analyzed with a Ferrograph as well as plasma, atomic absorption, and emission spectrometers. The analyses indicated that a lubrication system failure was not a causative factor in the engine failure. Neither an abnormal wear mechanism, nor a high level of wear debris was detected in the oil sample from the engine just prior to the test in which the failure occurred. However, low concentrations of titanium were evident in this sample and samples taken earlier. After the failure, higher titanium concentrations were detected in oil samples taken from different engine locations. Ferrographic analysis indicated that most of the titanium was contained in spherical metallic debris after the failure.

Turbofan engine demonstration of sensor failure detection

NASA Technical Reports Server (NTRS)

Merrill, Walter C.; Delaat, John C.; Abdelwahab, Mahmood

1991-01-01

In the paper, the results of a full-scale engine demonstration of a sensor failure detection algorithm are presented. The algorithm detects, isolates, and accommodates sensor failures using analytical redundancy. The experimental hardware, including the F100 engine, is described. Demonstration results were obtained over a large portion of a typical flight envelope for the F100 engine. They include both subsonic and supersonic conditions at both medium and full, nonafter burning, power. Estimated accuracy, minimum detectable levels of sensor failures, and failure accommodation performance for an F100 turbofan engine control system are discussed.

Convergence and translation: attitudes to inter-professional learning and teaching of creative problem-solving among medical and engineering students and staff.

PubMed

Spoelstra, Howard; Stoyanov, Slavi; Burgoyne, Louise; Bennett, Deirdre; Sweeney, Catherine; Drachsler, Hendrik; Vanderperren, Katrien; Van Huffel, Sabine; McSweeney, John; Shorten, George; O'Flynn, Siun; Cantillon-Murphy, Padraig; O'Tuathaigh, Colm

2014-01-22

Healthcare worldwide needs translation of basic ideas from engineering into the clinic. Consequently, there is increasing demand for graduates equipped with the knowledge and skills to apply interdisciplinary medicine/engineering approaches to the development of novel solutions for healthcare. The literature provides little guidance regarding barriers to, and facilitators of, effective interdisciplinary learning for engineering and medical students in a team-based project context. A quantitative survey was distributed to engineering and medical students and staff in two universities, one in Ireland and one in Belgium, to chart knowledge and practice in interdisciplinary learning and teaching, and of the teaching of innovation. We report important differences for staff and students between the disciplines regarding attitudes towards, and perceptions of, the relevance of interdisciplinary learning opportunities, and the role of creativity and innovation. There was agreement across groups concerning preferred learning, instructional styles, and module content. Medical students showed greater resistance to the use of structured creativity tools and interdisciplinary teams. The results of this international survey will help to define the optimal learning conditions under which undergraduate engineering and medicine students can learn to consider the diverse factors which determine the success or failure of a healthcare engineering solution.

Convergence and translation: attitudes to inter-professional learning and teaching of creative problem-solving among medical and engineering students and staff

PubMed Central

2014-01-01

Background Healthcare worldwide needs translation of basic ideas from engineering into the clinic. Consequently, there is increasing demand for graduates equipped with the knowledge and skills to apply interdisciplinary medicine/engineering approaches to the development of novel solutions for healthcare. The literature provides little guidance regarding barriers to, and facilitators of, effective interdisciplinary learning for engineering and medical students in a team-based project context. Methods A quantitative survey was distributed to engineering and medical students and staff in two universities, one in Ireland and one in Belgium, to chart knowledge and practice in interdisciplinary learning and teaching, and of the teaching of innovation. Results We report important differences for staff and students between the disciplines regarding attitudes towards, and perceptions of, the relevance of interdisciplinary learning opportunities, and the role of creativity and innovation. There was agreement across groups concerning preferred learning, instructional styles, and module content. Medical students showed greater resistance to the use of structured creativity tools and interdisciplinary teams. Conclusions The results of this international survey will help to define the optimal learning conditions under which undergraduate engineering and medicine students can learn to consider the diverse factors which determine the success or failure of a healthcare engineering solution. PMID:24450310

Engineering design: A cognitive process approach

NASA Astrophysics Data System (ADS)

Strimel, Greg Joseph

The intent of this dissertation was to identify the cognitive processes used by advanced pre-engineering students to solve complex engineering design problems. Students in technology and engineering education classrooms are often taught to use an ideal engineering design process that has been generated mostly by educators and curriculum developers. However, the review of literature showed that it is unclear as to how advanced pre-engineering students cognitively navigate solving a complex and multifaceted problem from beginning to end. Additionally, it was unclear how a student thinks and acts throughout their design process and how this affects the viability of their solution. Therefore, Research Objective 1 was to identify the fundamental cognitive processes students use to design, construct, and evaluate operational solutions to engineering design problems. Research Objective 2 was to determine identifiers within student cognitive processes for monitoring aptitude to successfully design, construct, and evaluate technological solutions. Lastly, Research Objective 3 was to create a conceptual technological and engineering problem-solving model integrating student cognitive processes for the improved development of problem-solving abilities. The methodology of this study included multiple forms of data collection. The participants were first given a survey to determine their prior experience with engineering and to provide a description of the subjects being studied. The participants were then presented an engineering design challenge to solve individually. While they completed the challenge, the participants verbalized their thoughts using an established "think aloud" method. These verbalizations were captured along with participant observational recordings using point-of-view camera technology. Additionally, the participant design journals, design artifacts, solution effectiveness data, and teacher evaluations were collected for analysis to help achieve the research objectives of this study. Two independent coders then coded the video/audio recordings and the additional design data using Halfin's (1973) 17 mental processes for technological problem-solving. The results of this study indicated that the participants employed a wide array of mental processes when solving engineering design challenges. However, the findings provide a general analysis of the number of times participants employed each mental process, as well as the amount of time consumed employing the various mental processes through the different stages of the engineering design process. The results indicated many similarities between the students solving the problem, which may highlight voids in current technology and engineering education curricula. Additionally, the findings showed differences between the processes employed by participants that created the most successful solutions and the participants who developed the least effective solutions. Upon comparing and contrasting these processes, recommendations for instructional strategies to enhance a student's capability for solving engineering design problems were developed. The results also indicated that students, when left without teacher intervention, use a simplified and more natural process to solve design challenges than the 12-step engineering design process reported in much of the literature. Lastly, these data indicated that students followed two different approaches to solving the design problem. Some students employed a sequential and logical approach, while others employed a nebulous, solution centered trial-and-error approach to solving the problem. In this study the participants who were more sequential had better performing solutions. Examining these two approaches and the student cognition data enabled the researcher to generate a conceptual engineering design model for the improved teaching and development of engineering design problem solving.

Ferrographic and spectrometer oil analysis from a failed gas turbine engine

NASA Technical Reports Server (NTRS)

Jones, W. R., Jr.

1983-01-01

An experimental gas turbine engine was destroyed as a result of the combustion of its titanium components. It was concluded that a severe surge may have caused interference between rotating and stationary compressor parts that either directly or indirectly ignited the titanium components. Several engine oil samples (before and after the failure) were analyzed with a Ferrograph, and with plasma, atomic absorption, and emission spectrometers to see if this information would aid in the engine failure diagnosis. The analyses indicated that a lubrication system failure was not a causative factor in the engine failure. Neither an abnormal wear mechanism nor a high level of wear debris was detected in the engine oil sample taken just prior to the test in which the failure occurred. However, low concentrations (0.2 to 0.5 ppm) of titanium were evident in this sample and samples taken earlier. After the failure, higher titanium concentrations (2 ppm) were detected in oil samples taken from different engine locations. Ferrographic analysis indicated that most of the titanium was contained in spherical metallic debris after the failure. The oil analyses eliminated a lubrication system bearing or shaft seal failure as the cause of the engine failure. Previously announced in STAR as N83-12433

Lox/Gox related failures during Space Shuttle Main Engine development

NASA Technical Reports Server (NTRS)

Cataldo, C. E.

1981-01-01

Specific rocket engine hardware and test facility system failures are described which were caused by high pressure liquid and/or gaseous oxygen reactions. The failures were encountered during the development and testing of the space shuttle main engine. Failure mechanisms are discussed as well as corrective actions taken to prevent or reduce the potential of future failures.

Air/Oil Seals R and D at AlliedSignal

NASA Technical Reports Server (NTRS)

Ullah, M. Rifat

2006-01-01

AlliedSignal aerospace company is committed to significantly improving the reliabilities of air/oil seals in their gas turbine engines. One motivation for this is that aircraft cabin air quality can be affected by the performance of mainshaft air/oil seals. In the recent past, coking related failure modes have been the focus of air/oil seal R&D at AlliedSignal. Many significant advances have been made to combat coke related failures, with some more work continuing in this area. This years R&D begins to address other commin failure modes. Among them, carbon seal "blistering" has been a chronic problem facing the sealing industry for many decades. AlliedSignal has launched an aggressive effort this year to solve this problem for our aerospace rated carbon seals in a short (one to two year) timeframe. Work also continues in developing more user-friendly tools and data for seal analysis & design. Innovations in seal cooling continue. Nominally non-contacting hydropad sealing concept is being developed for aerospace applications. Finally, proprietary work is in planning stages for development of a seal with the aggressive aim of zero oil leakage.

Factors that Affect Operational Reliability of Turbojet Engines

NASA Technical Reports Server (NTRS)

1956-01-01

The problem of improving operational reliability of turbojet engines is studied in a series of papers. Failure statistics for this engine are presented, the theory and experimental evidence on how engine failures occur are described, and the methods available for avoiding failure in operation are discussed. The individual papers of the series are Objectives, Failure Statistics, Foreign-Object Damage, Compressor Blades, Combustor Assembly, Nozzle Diaphrams, Turbine Buckets, Turbine Disks, Rolling Contact Bearings, Engine Fuel Controls, and Summary Discussion.

Weighted Fuzzy Risk Priority Number Evaluation of Turbine and Compressor Blades Considering Failure Mode Correlations

NASA Astrophysics Data System (ADS)

Gan, Luping; Li, Yan-Feng; Zhu, Shun-Peng; Yang, Yuan-Jian; Huang, Hong-Zhong

2014-06-01

Failure mode, effects and criticality analysis (FMECA) and Fault tree analysis (FTA) are powerful tools to evaluate reliability of systems. Although single failure mode issue can be efficiently addressed by traditional FMECA, multiple failure modes and component correlations in complex systems cannot be effectively evaluated. In addition, correlated variables and parameters are often assumed to be precisely known in quantitative analysis. In fact, due to the lack of information, epistemic uncertainty commonly exists in engineering design. To solve these problems, the advantages of FMECA, FTA, fuzzy theory, and Copula theory are integrated into a unified hybrid method called fuzzy probability weighted geometric mean (FPWGM) risk priority number (RPN) method. The epistemic uncertainty of risk variables and parameters are characterized by fuzzy number to obtain fuzzy weighted geometric mean (FWGM) RPN for single failure mode. Multiple failure modes are connected using minimum cut sets (MCS), and Boolean logic is used to combine fuzzy risk priority number (FRPN) of each MCS. Moreover, Copula theory is applied to analyze the correlation of multiple failure modes in order to derive the failure probabilities of each MCS. Compared to the case where dependency among multiple failure modes is not considered, the Copula modeling approach eliminates the error of reliability analysis. Furthermore, for purpose of quantitative analysis, probabilities importance weight from failure probabilities are assigned to FWGM RPN to reassess the risk priority, which generalize the definition of probability weight and FRPN, resulting in a more accurate estimation than that of the traditional models. Finally, a basic fatigue analysis case drawn from turbine and compressor blades in aeroengine is used to demonstrate the effectiveness and robustness of the presented method. The result provides some important insights on fatigue reliability analysis and risk priority assessment of structural system under failure correlations.

Promoting Collaborative Problem-Solving Skills in a Course on Engineering Grand Challenges

ERIC Educational Resources Information Center

Zou, Tracy X. P.; Mickleborough, Neil C.

2015-01-01

The ability to solve problems with people of diverse backgrounds is essential for engineering graduates. A course on engineering grand challenges was designed to promote collaborative problem-solving (CPS) skills. One unique component is that students need to work both within their own team and collaborate with the other team to tackle engineering…

The Problem-Solving Process in Physics as Observed When Engineering Students at University Level Work in Groups

ERIC Educational Resources Information Center

Gustafsson, Peter; Jonsson, Gunnar; Enghag, Margareta

2015-01-01

The problem-solving process is investigated for five groups of students when solving context-rich problems in an introductory physics course included in an engineering programme. Through transcripts of their conversation, the paths in the problem-solving process have been traced and related to a general problem-solving model. All groups exhibit…

Learning from Engineering Failures: A Case Study of the Deepwater Horizon

ERIC Educational Resources Information Center

Rose, Mary Annette; Hunt, Brian

2012-01-01

Natural catastrophes and engineering failures provide timely, motivating, and conceptually rich backdrops for learning. Engineering educators have long embraced case studies of engineering failures as a sound pedagogical strategy for meeting several learning standards, such as "design within realistic constraints", and teaching failure…

Problem Solving and Engineering Design, Introducing Bachelor Students to Engineering Practice at K. U. Leuven

ERIC Educational Resources Information Center

Heylen, Christel; Smet, Marc; Buelens, Hermans; Sloten, Jos Vander

2007-01-01

A present-day engineer has a large scientific knowledge; he is a team-player, eloquent communicator and life-long learner. At the Katholieke Universiteit Leuven, the course "Problem Solving and Engineering Design" introduces engineering students from the first semester onwards into real engineering practice and teamwork. Working in small…

Euler Flow Computations on Non-Matching Unstructured Meshes

NASA Technical Reports Server (NTRS)

Gumaste, Udayan

1999-01-01

Advanced fluid solvers to predict aerodynamic performance-coupled treatment of multiple fields are described. The interaction between the fluid and structural components in the bladed regions of the engine is investigated with respect to known blade failures caused by either flutter or forced vibrations. Methods are developed to describe aeroelastic phenomena for internal flows in turbomachinery by accounting for the increased geometric complexity, mutual interaction between adjacent structural components and presence of thermal and geometric loading. The computer code developed solves the full three dimensional aeroelastic problem of-stage. The results obtained show that flow computations can be performed on non-matching finite-volume unstructured meshes with second order spatial accuracy.

Current Status of Hybrid Bearing Damage Detection

NASA Technical Reports Server (NTRS)

Dempsey, Paula J.; Certo, Joseph M.; Morales, Wilfredo

2004-01-01

Advances in material development and processing have led to the introduction of ceramic hybrid bearings for many applications. The introduction of silicon nitride hybrid bearings into the high pressure oxidizer turbopump, on the space shuttle main engine, led NASA to solve a highly persistent and troublesome bearing problem. Hybrid bearings consist of ceramic balls and steel races. The majority of hybrid bearings utilize Si3N4 balls. The aerospace industry is currently studying the use of hybrid bearings and naturally the failure modes of these bearings become an issue in light of the limited data available. In today s turbine engines and helicopter transmissions, the health of the bearings is detected by the properties of the debris found in the lubrication line when damage begins to occur. Current oil debris sensor technology relies on the magnetic properties of the debris to detect damage. Since the ceramic rolling elements of hybrid bearings have no metallic properties, a new sensing system must be developed to indicate the system health if ceramic components are to be safely implemented in aerospace applications. The ceramic oil debris sensor must be capable of detecting ceramic and metallic component damage with sufficient reliability and forewarning to prevent a catastrophic failure. The objective of this research is to provide a background summary on what is currently known about hybrid bearing failure modes and to report preliminary results on the detection of silicon nitride debris, in oil, using a commercial particle counter.

14 CFR 25.367 - Unsymmetrical loads due to engine failure.

Code of Federal Regulations, 2013 CFR

2013-01-01

... the engine compressor from the turbine or from loss of the turbine blades are considered to be... § 25.367 Unsymmetrical loads due to engine failure. (a) The airplane must be designed for the unsymmetrical loads resulting from the failure of the critical engine. Turbopropeller airplanes must be designed...

14 CFR 25.367 - Unsymmetrical loads due to engine failure.

Code of Federal Regulations, 2010 CFR

2010-01-01

... the engine compressor from the turbine or from loss of the turbine blades are considered to be... § 25.367 Unsymmetrical loads due to engine failure. (a) The airplane must be designed for the unsymmetrical loads resulting from the failure of the critical engine. Turbopropeller airplanes must be designed...

14 CFR 25.367 - Unsymmetrical loads due to engine failure.

Code of Federal Regulations, 2011 CFR

2011-01-01

... the engine compressor from the turbine or from loss of the turbine blades are considered to be... § 25.367 Unsymmetrical loads due to engine failure. (a) The airplane must be designed for the unsymmetrical loads resulting from the failure of the critical engine. Turbopropeller airplanes must be designed...

Failing to Learn: Towards a Unified Design Approach for Failure-Based Learning

ERIC Educational Resources Information Center

Tawfik, Andrew A.; Rong, Hui; Choi, Ikseon

2015-01-01

To date, many instructional systems are designed to support learners as they progress through a problem-solving task. Often these systems are designed in accordance with instructional design models that progress the learner efficiently through the problem-solving process. However, theories from various fields have discussed failure as a strategic…

Grand challenges for biological engineering

PubMed Central

Yoon, Jeong-Yeol; Riley, Mark R

2009-01-01

Biological engineering will play a significant role in solving many of the world's problems in medicine, agriculture, and the environment. Recently the U.S. National Academy of Engineering (NAE) released a document "Grand Challenges in Engineering," covering broad realms of human concern from sustainability, health, vulnerability and the joy of living. Biological engineers, having tools and techniques at the interface between living and non-living entities, will play a prominent role in forging a better future. The 2010 Institute of Biological Engineering (IBE) conference in Cambridge, MA, USA will address, in part, the roles of biological engineering in solving the challenges presented by the NAE. This letter presents a brief outline of how biological engineers are working to solve these large scale and integrated problems of our society. PMID:19772647

76 FR 8661 - Airworthiness Directives; Lycoming Engines, Fuel Injected Reciprocating Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-15

... engine models requiring inspections. We are proposing this AD to prevent failure of the fuel injector... repetitive inspection compliance time. We issued that AD to prevent failure of the fuel injector fuel lines... engine models requiring inspection. We are issuing this AD to prevent failure of the fuel injector fuel...

General Monte Carlo reliability simulation code including common mode failures and HARP fault/error-handling

NASA Technical Reports Server (NTRS)

Platt, M. E.; Lewis, E. E.; Boehm, F.

1991-01-01

A Monte Carlo Fortran computer program was developed that uses two variance reduction techniques for computing system reliability applicable to solving very large highly reliable fault-tolerant systems. The program is consistent with the hybrid automated reliability predictor (HARP) code which employs behavioral decomposition and complex fault-error handling models. This new capability is called MC-HARP which efficiently solves reliability models with non-constant failures rates (Weibull). Common mode failure modeling is also a specialty.

Developing Creativity and Problem-Solving Skills of Engineering Students: A Comparison of Web- and Pen-and-Paper-Based Approaches

ERIC Educational Resources Information Center

Valentine, Andrew; Belski, Iouri; Hamilton, Margaret

2017-01-01

Problem-solving is a key engineering skill, yet is an area in which engineering graduates underperform. This paper investigates the potential of using web-based tools to teach students problem-solving techniques without the need to make use of class time. An idea generation experiment involving 90 students was designed. Students were surveyed…

Pre-Engineering Program. Introduction to Engineering. Advanced Engineering.

ERIC Educational Resources Information Center

Henrico County Public Schools, Glen Allen, VA. Virginia Vocational Curriculum and Resource Center.

This guide contains information and hands-on activities to guide students through the problem-solving process needed in engineering (problem solving, presentation, and impact analysis) and information to help the instructor manage the program or courses in Virginia. Following an introduction, the guide contains a program description that supplies…

An improved approach for flight readiness certification: Methodology for failure risk assessment and application examples. Volume 2: Software documentation

NASA Technical Reports Server (NTRS)

Moore, N. R.; Ebbeler, D. H.; Newlin, L. E.; Sutharshana, S.; Creager, M.

1992-01-01

An improved methodology for quantitatively evaluating failure risk of spaceflight systems to assess flight readiness and identify risk control measures is presented. This methodology, called Probabilistic Failure Assessment (PFA), combines operating experience from tests and flights with engineering analysis to estimate failure risk. The PFA methodology is of particular value when information on which to base an assessment of failure risk, including test experience and knowledge of parameters used in engineering analyses of failure phenomena, is expensive or difficult to acquire. The PFA methodology is a prescribed statistical structure in which engineering analysis models that characterize failure phenomena are used conjointly with uncertainties about analysis parameters and/or modeling accuracy to estimate failure probability distributions for specific failure modes, These distributions can then be modified, by means of statistical procedures of the PFA methodology, to reflect any test or flight experience. Conventional engineering analysis models currently employed for design of failure prediction are used in this methodology. The PFA methodology is described and examples of its application are presented. Conventional approaches to failure risk evaluation for spaceflight systems are discussed, and the rationale for the approach taken in the PFA methodology is presented. The statistical methods, engineering models, and computer software used in fatigue failure mode applications are thoroughly documented.

An improved approach for flight readiness certification: Methodology for failure risk assessment and application examples, volume 1

NASA Technical Reports Server (NTRS)

Moore, N. R.; Ebbeler, D. H.; Newlin, L. E.; Sutharshana, S.; Creager, M.

1992-01-01

An improved methodology for quantitatively evaluating failure risk of spaceflight systems to assess flight readiness and identify risk control measures is presented. This methodology, called Probabilistic Failure Assessment (PFA), combines operating experience from tests and flights with engineering analysis to estimate failure risk. The PFA methodology is of particular value when information on which to base an assessment of failure risk, including test experience and knowledge of parameters used in engineering analyses of failure phenomena, is expensive or difficult to acquire. The PFA methodology is a prescribed statistical structure in which engineering analysis models that characterize failure phenomena are used conjointly with uncertainties about analysis parameters and/or modeling accuracy to estimate failure probability distributions for specific failure modes. These distributions can then be modified, by means of statistical procedures of the PFA methodology, to reflect any test or flight experience. Conventional engineering analysis models currently employed for design of failure prediction are used in this methodology. The PFA methodology is described and examples of its application are presented. Conventional approaches to failure risk evaluation for spaceflight systems are discussed, and the rationale for the approach taken in the PFA methodology is presented. The statistical methods, engineering models, and computer software used in fatigue failure mode applications are thoroughly documented.

Software Performs Complex Design Analysis

NASA Technical Reports Server (NTRS)

2008-01-01

Designers use computational fluid dynamics (CFD) to gain greater understanding of the fluid flow phenomena involved in components being designed. They also use finite element analysis (FEA) as a tool to help gain greater understanding of the structural response of components to loads, stresses and strains, and the prediction of failure modes. Automated CFD and FEA engineering design has centered on shape optimization, which has been hindered by two major problems: 1) inadequate shape parameterization algorithms, and 2) inadequate algorithms for CFD and FEA grid modification. Working with software engineers at Stennis Space Center, a NASA commercial partner, Optimal Solutions Software LLC, was able to utilize its revolutionary, one-of-a-kind arbitrary shape deformation (ASD) capability-a major advancement in solving these two aforementioned problems-to optimize the shapes of complex pipe components that transport highly sensitive fluids. The ASD technology solves the problem of inadequate shape parameterization algorithms by allowing the CFD designers to freely create their own shape parameters, therefore eliminating the restriction of only being able to use the computer-aided design (CAD) parameters. The problem of inadequate algorithms for CFD grid modification is solved by the fact that the new software performs a smooth volumetric deformation. This eliminates the extremely costly process of having to remesh the grid for every shape change desired. The program can perform a design change in a markedly reduced amount of time, a process that would traditionally involve the designer returning to the CAD model to reshape and then remesh the shapes, something that has been known to take hours, days-even weeks or months-depending upon the size of the model.

Reusable Rocket Engine Maintenance Study

NASA Technical Reports Server (NTRS)

Macgregor, C. A.

1982-01-01

Approximately 85,000 liquid rocket engine failure reports, obtained from 30 years of developing and delivering major pump feed engines, were reviewed and screened and reduced to 1771. These were categorized into 16 different failure modes. Failure propagation diagrams were established. The state of the art of engine condition monitoring for in-flight sensors and between flight inspection technology was determined. For the 16 failure modes, the potential measurands and diagnostic requirements were identified, assessed and ranked. Eight areas are identified requiring advanced technology development.

Challenges for Engineering Design, Construction, and Maintenance of Infrastructure in Afghanistan

DTIC Science & Technology

2010-11-01

applied engineering expertise that collectively can solve challenging infra- structure problems. USACE-ERDC’s researchers and engineers are field...Development Center (ERDC) possesses a unique combination of basic research and applied engineering expertise that collectively can solve challenging...restoration, and other projects. The USACE Engineer Research and Development Center (ERDC) possesses a unique combination of basic research and applied

STS-51 pad abort. OV103-engine 2033 (ME-2) fuel flowmeter sensor open circuit

NASA Technical Reports Server (NTRS)

1993-01-01

The STS-51 initial launch attempt of Discovery (OV-103) was terminated on KSC launch pad 39B on 12 Aug. 1993 at 9:12 AM E.S.T. due to a sensor redundancy failure in the liquid hydrogen system of ME-2 (Engine 2033). The event description and time line are summarized. Propellant loading was initiated on 12 Aug. 1993 at 12:00 AM EST. All space shuttle main engine (SSME) chill parameters and Launch Commit Criteria (LCC) were nominal. At engine start plus 1.34 seconds a Failure Identification (FID) was posted against Engine 2033 for exceeding the 1800 spin intra-channel (A1-A2) Fuel Flowrate sensor channel qualification limit. The engine was shut down at 1.50 seconds followed by Engines 2032 and 2030. All shut down sequences were nominal and the mission was safely aborted. SSME Avionics hardware and software performed nominally during the incident. A review of vehicle data table (VDT) data and controller software logic revealed no failure indications other than the single FID 111-101, Fuel Flowrate Intra-Channel Test Channel A disqualification. Software logic was executed according to requirements and there was no anomalous controller software operation. Immediately following the abort, a Rocketdyne/NASA failure investigation team was assembled. The team successfully isolated the failure cause to an open circuit in a Fuel Flowrate Sensor. This type of failure has occurred eight previous times in ground testing. The sensor had performed acceptably on three previous flights of the engine and SSME flight history shows 684 combined fuel flow rate sensor channel flights without failure. The disqualification of an Engine 2 (SSME No. 2033) Fuel Flowrate sensor channel was a result of an instrumentation failure and not engine performance. All other engine operations were nominal. This disqualification resulted in an engine shutdown and safe sequential shutdown of all three engines prior to ignition of the solid boosters.

Adaptive Failure Compensation for Aircraft Tracking Control Using Engine Differential Based Model

NASA Technical Reports Server (NTRS)

Liu, Yu; Tang, Xidong; Tao, Gang; Joshi, Suresh M.

2006-01-01

An aircraft model that incorporates independently adjustable engine throttles and ailerons is employed to develop an adaptive control scheme in the presence of actuator failures. This model captures the key features of aircraft flight dynamics when in the engine differential mode. Based on this model an adaptive feedback control scheme for asymptotic state tracking is developed and applied to a transport aircraft model in the presence of two types of failures during operation, rudder failure and aileron failure. Simulation results are presented to demonstrate the adaptive failure compensation scheme.

Using the Space Glove to Teach Spatial Thinking

NASA Technical Reports Server (NTRS)

Lord, Peter

2008-01-01

The challenge of extending students' skills in spatial thinking to astronomical scales was the central focus of our K-8 curriculum development. When the project's lead teacher requested a curriculum that cumulatively built on each prior year's learning in a spiral fashion, I knew exactly what the school was asking for. Second and third graders began by noticing the cyclical patters that the sun, moon, and stars make in the sky. Fourth graders explored the phases of the moon by taking turns modeling and sketching them in their classroom and then comparing them to the real sky. Sixth !graders used real telescopes to observe a moving model of our solar system and walked a scale model of the planets' orbits. The curriculum is designed to expand students' capacity to visualize space in a hierarchical fashion that asks them to imagine themselves from a broader number of spatial perspectives through hands-on activities. The "situational awareness" Peter's story describes is a hallmark of high-performance engineering and innovation. Keeping in mind the potential outcomes of multiple paths of pursuit from multiple perspectives while keeping track of their relative merits and performance requirements is a demanding spatial task. What made it possible for Peter to transform the failure of his first glove into triumph was the mental space in which that failure provided exactly the information needed for a new breakthrough. In at least two cases, Peter could immediately "see" the full implications of what his hands were telling him. He tells the story of how putting his hands in a Phase VI astronaut glove instantly transformed his understanding of the glove challenge. Six months into his development, the failure of circumferentially wrapped cords to produce a sufficiently flexible glove again forced him to abandon his assumptions. His situational awareness was so clear and compelling it became a gut-level response. Peter's finely developed spatial skills enabled him to almost instinctively focus his full energy on a carefully constructed set of experiments. The finger's ability to sense pressure, force, and work gave him the immediate feedback required to solve this one central problem. Once properly understood, his failure quickly led to the magical "Aha!" moment of discovery; the rest is history. Just as children need opportunities to develop hands-on understanding, engineers need to explore new possibilities through incremental hands-on failure. High-performance innovation is all about learning to make maximum use of thinking spatially to direct this process. Peter Homer's glove also reminds us that efficient engineering decisions need to be made as close to the hardware as possible. Whether we're doing hands-on education or hands-on engineering, it is when we trust in our ability to "feel our way" through failure that we reach our highest potential.

A Further Study of Productive Failure in Mathematical Problem Solving: Unpacking the Design Components

ERIC Educational Resources Information Center

Kapur, Manu

2011-01-01

This paper replicates and extends my earlier work on productive failure in mathematical problem solving (Kapur, doi:10.1007/s11251-009-9093-x, 2009). One hundred and nine, seventh-grade mathematics students taught by the same teacher from a Singapore school experienced one of three learning designs: (a) traditional lecture and practice (LP), (b)…

The Use of Probabilistic Methods to Evaluate the Systems Impact of Component Design Improvements on Large Turbofan Engines

NASA Technical Reports Server (NTRS)

Packard, Michael H.

2002-01-01

Probabilistic Structural Analysis (PSA) is now commonly used for predicting the distribution of time/cycles to failure of turbine blades and other engine components. These distributions are typically based on fatigue/fracture and creep failure modes of these components. Additionally, reliability analysis is used for taking test data related to particular failure modes and calculating failure rate distributions of electronic and electromechanical components. How can these individual failure time distributions of structural, electronic and electromechanical component failure modes be effectively combined into a top level model for overall system evaluation of component upgrades, changes in maintenance intervals, or line replaceable unit (LRU) redesign? This paper shows an example of how various probabilistic failure predictions for turbine engine components can be evaluated and combined to show their effect on overall engine performance. A generic model of a turbofan engine was modeled using various Probabilistic Risk Assessment (PRA) tools (Quantitative Risk Assessment Software (QRAS) etc.). Hypothetical PSA results for a number of structural components along with mitigation factors that would restrict the failure mode from propagating to a Loss of Mission (LOM) failure were used in the models. The output of this program includes an overall failure distribution for LOM of the system. The rank and contribution to the overall Mission Success (MS) is also given for each failure mode and each subsystem. This application methodology demonstrates the effectiveness of PRA for assessing the performance of large turbine engines. Additionally, the effects of system changes and upgrades, the application of different maintenance intervals, inclusion of new sensor detection of faults and other upgrades were evaluated in determining overall turbine engine reliability.

USAF Evaluation of an Automated Adaptive Flight Training System

DTIC Science & Technology

1975-10-01

system. C. What is the most effective wav to utilize the system in ^jierational training’ Student opinion for this question JS equally divided...None Utility hydraulic failure Flap failure left engine failure Right engine failure Stah 2 aug failure No g\\ ro approach procedure, no MIDI

An improved approach for flight readiness certification: Methodology for failure risk assessment and application examples. Volume 3: Structure and listing of programs

NASA Technical Reports Server (NTRS)

Moore, N. R.; Ebbeler, D. H.; Newlin, L. E.; Sutharshana, S.; Creager, M.

1992-01-01

An improved methodology for quantitatively evaluating failure risk of spaceflight systems to assess flight readiness and identify risk control measures is presented. This methodology, called Probabilistic Failure Assessment (PFA), combines operating experience from tests and flights with engineering analysis to estimate failure risk. The PFA methodology is of particular value when information on which to base an assessment of failure risk, including test experience and knowledge of parameters used in engineering analyses of failure phenomena, is expensive or difficult to acquire. The PFA methodology is a prescribed statistical structure in which engineering analysis models that characterize failure phenomena are used conjointly with uncertainties about analysis parameters and/or modeling accuracy to estimate failure probability distributions for specific failure modes. These distributions can then be modified, by means of statistical procedures of the PFA methodology, to reflect any test or flight experience. Conventional engineering analysis models currently employed for design of failure prediction are used in this methodology. The PFA methodology is described and examples of its application are presented. Conventional approaches to failure risk evaluation for spaceflight systems are discussed, and the rationale for the approach taken in the PFA methodology is presented. The statistical methods, engineering models, and computer software used in fatigue failure mode applications are thoroughly documented.

A fuzzy case based reasoning tool for model based approach to rocket engine health monitoring

NASA Technical Reports Server (NTRS)

Krovvidy, Srinivas; Nolan, Adam; Hu, Yong-Lin; Wee, William G.

1992-01-01

In this system we develop a fuzzy case based reasoner that can build a case representation for several past anomalies detected, and we develop case retrieval methods that can be used to index a relevant case when a new problem (case) is presented using fuzzy sets. The choice of fuzzy sets is justified by the uncertain data. The new problem can be solved using knowledge of the model along with the old cases. This system can then be used to generalize the knowledge from previous cases and use this generalization to refine the existing model definition. This in turn can help to detect failures using the model based algorithms.

75 FR 63060 - Airworthiness Directives; PIAGGIO AERO INDUSTRIES S.p.A. Model PIAGGIO P-180 Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-14

... failure of engine oil dipsticks, installed on Pratt & Whitney Canada (P&WC) PT6A66 and PT6A66B engines... subsequent corrosion, can cause incorrect reading of the engine oil low level on the Refuel/Ground Test Panel. If left uncorrected, this situation could lead to in-flight engine failure(s). We are issuing this AD...

Integrating Cost Engineering and Project Management in a Junior Engineering Economics Course and a Senior Capstone Project Design Course

ERIC Educational Resources Information Center

Tickles, Virginia C.; Li, Yadong; Walters, Wilbur L.

2013-01-01

Much criticism exists concerning a lack of focus on real-world problem-solving in the science, technology, engineering and mathematics (STEM) infrastructures. Many of these critics say that current educational infrastructures are incapable in preparing future scientists and engineers to solve the complex and multidisciplinary problems this society…

Happy software developers solve problems better: psychological measurements in empirical software engineering

PubMed Central

Wang, Xiaofeng; Abrahamsson, Pekka

2014-01-01

For more than thirty years, it has been claimed that a way to improve software developers’ productivity and software quality is to focus on people and to provide incentives to make developers satisfied and happy. This claim has rarely been verified in software engineering research, which faces an additional challenge in comparison to more traditional engineering fields: software development is an intellectual activity and is dominated by often-neglected human factors (called human aspects in software engineering research). Among the many skills required for software development, developers must possess high analytical problem-solving skills and creativity for the software construction process. According to psychology research, affective states—emotions and moods—deeply influence the cognitive processing abilities and performance of workers, including creativity and analytical problem solving. Nonetheless, little research has investigated the correlation between the affective states, creativity, and analytical problem-solving performance of programmers. This article echoes the call to employ psychological measurements in software engineering research. We report a study with 42 participants to investigate the relationship between the affective states, creativity, and analytical problem-solving skills of software developers. The results offer support for the claim that happy developers are indeed better problem solvers in terms of their analytical abilities. The following contributions are made by this study: (1) providing a better understanding of the impact of affective states on the creativity and analytical problem-solving capacities of developers, (2) introducing and validating psychological measurements, theories, and concepts of affective states, creativity, and analytical-problem-solving skills in empirical software engineering, and (3) raising the need for studying the human factors of software engineering by employing a multidisciplinary viewpoint. PMID:24688866

Happy software developers solve problems better: psychological measurements in empirical software engineering.

PubMed

Graziotin, Daniel; Wang, Xiaofeng; Abrahamsson, Pekka

2014-01-01

For more than thirty years, it has been claimed that a way to improve software developers' productivity and software quality is to focus on people and to provide incentives to make developers satisfied and happy. This claim has rarely been verified in software engineering research, which faces an additional challenge in comparison to more traditional engineering fields: software development is an intellectual activity and is dominated by often-neglected human factors (called human aspects in software engineering research). Among the many skills required for software development, developers must possess high analytical problem-solving skills and creativity for the software construction process. According to psychology research, affective states-emotions and moods-deeply influence the cognitive processing abilities and performance of workers, including creativity and analytical problem solving. Nonetheless, little research has investigated the correlation between the affective states, creativity, and analytical problem-solving performance of programmers. This article echoes the call to employ psychological measurements in software engineering research. We report a study with 42 participants to investigate the relationship between the affective states, creativity, and analytical problem-solving skills of software developers. The results offer support for the claim that happy developers are indeed better problem solvers in terms of their analytical abilities. The following contributions are made by this study: (1) providing a better understanding of the impact of affective states on the creativity and analytical problem-solving capacities of developers, (2) introducing and validating psychological measurements, theories, and concepts of affective states, creativity, and analytical-problem-solving skills in empirical software engineering, and (3) raising the need for studying the human factors of software engineering by employing a multidisciplinary viewpoint.

40 CFR 1065.410 - Maintenance limits for stabilized test engines.

Code of Federal Regulations, 2013 CFR

2013-07-01

... engineering grade tools to identify bad engine components. Any equipment, instruments, or tools used for... no longer use it as an emission-data engine. Also, if your test engine has a major mechanical failure... your test engine has a major mechanical failure that requires you to take it apart, you may no longer...

40 CFR 1065.410 - Maintenance limits for stabilized test engines.

Code of Federal Regulations, 2012 CFR

2012-07-01

... engineering grade tools to identify bad engine components. Any equipment, instruments, or tools used for... no longer use it as an emission-data engine. Also, if your test engine has a major mechanical failure... your test engine has a major mechanical failure that requires you to take it apart, you may no longer...

The Effect of Modified Control Limits on the Performance of a Generic Commercial Aircraft Engine

NASA Technical Reports Server (NTRS)

Csank, Jeffrey T.; May, Ryan D.; Gou, Ten-Huei; Litt, Jonathan S.

2012-01-01

This paper studies the effect of modifying the control limits of an aircraft engine to obtain additional performance. In an emergency situation, the ability to operate an engine above its normal operating limits and thereby gain additional performance may aid in the recovery of a distressed aircraft. However, the modification of an engine s limits is complex due to the risk of an engine failure. This paper focuses on the tradeoff between enhanced performance and risk of either incurring a mechanical engine failure or compromising engine operability. The ultimate goal is to increase the engine performance, without a large increase in risk of an engine failure, in order to increase the probability of recovering the distressed aircraft. The control limit modifications proposed are to extend the rotor speeds, temperatures, and pressures to allow more thrust to be produced by the engine, or to increase the rotor accelerations and allow the engine to follow a fast transient. These modifications do result in increased performance; however this study indicates that these modifications also lead to an increased risk of engine failure.

The Problem Solving Studio: An Apprenticeship Environment for Aspiring Engineers

ERIC Educational Resources Information Center

Le Doux, Joseph M.; Waller, Alisha A.

2016-01-01

This paper describes the problem-solving studio (PSS) learning environment. PSS was designed to teach students how to solve difficult analytical engineering problems without resorting to rote memorization of algorithms, while at the same time developing their deep conceptual understanding of the course topics. There are several key features of…

Intelligent on-line fault tolerant control for unanticipated catastrophic failures.

PubMed

Yen, Gary G; Ho, Liang-Wei

2004-10-01

As dynamic systems become increasingly complex, experience rapidly changing environments, and encounter a greater variety of unexpected component failures, solving the control problems of such systems is a grand challenge for control engineers. Traditional control design techniques are not adequate to cope with these systems, which may suffer from unanticipated dynamic failures. In this research work, we investigate the on-line fault tolerant control problem and propose an intelligent on-line control strategy to handle the desired trajectories tracking problem for systems suffering from various unanticipated catastrophic faults. Through theoretical analysis, the sufficient condition of system stability has been derived and two different on-line control laws have been developed. The approach of the proposed intelligent control strategy is to continuously monitor the system performance and identify what the system's current state is by using a fault detection method based upon our best knowledge of the nominal system and nominal controller. Once a fault is detected, the proposed intelligent controller will adjust its control signal to compensate for the unknown system failure dynamics by using an artificial neural network as an on-line estimator to approximate the unexpected and unknown failure dynamics. The first control law is derived directly from the Lyapunov stability theory, while the second control law is derived based upon the discrete-time sliding mode control technique. Both control laws have been implemented in a variety of failure scenarios to validate the proposed intelligent control scheme. The simulation results, including a three-tank benchmark problem, comply with theoretical analysis and demonstrate a significant improvement in trajectory following performance based upon the proposed intelligent control strategy.

Apparatus for sensor failure detection and correction in a gas turbine engine control system

NASA Technical Reports Server (NTRS)

Spang, H. A., III; Wanger, R. P. (Inventor)

1981-01-01

A gas turbine engine control system maintains a selected level of engine performance despite the failure or abnormal operation of one or more engine parameter sensors. The control system employs a continuously updated engine model which simulates engine performance and generates signals representing real time estimates of the engine parameter sensor signals. The estimate signals are transmitted to a control computational unit which utilizes them in lieu of the actual engine parameter sensor signals to control the operation of the engine. The estimate signals are also compared with the corresponding actual engine parameter sensor signals and the resulting difference signals are utilized to update the engine model. If a particular difference signal exceeds specific tolerance limits, the difference signal is inhibited from updating the model and a sensor failure indication is provided to the engine operator.

A Designer’s Guide to Human Performance Modelling (La Modelisation des Performances Humaines: Manuel du Concepteur).

DTIC Science & Technology

1998-12-01

failure detection, monitoring, and decision making.) moderator function. Originally, the output from these One of the best known OCM implementations, the...imposed by the tasks themselves, the information and equipment provided, the task environment, operator skills and experience, operator strategies , the...problem-solving situation, including the toward failure.) knowledge necessary to generate the right problem- solving strategies , the attention that

Failure detection and correction for turbofan engines

NASA Technical Reports Server (NTRS)

Corley, R. C.; Spang, H. A., III

1977-01-01

In this paper, a failure detection and correction strategy for turbofan engines is discussed. This strategy allows continuing control of the engines in the event of a sensor failure. An extended Kalman filter is used to provide the best estimate of the state of the engine based on currently available sensor outputs. Should a sensor failure occur the control is based on the best estimate rather than the sensor output. The extended Kalman filter consists of essentially two parts, a nonlinear model of the engine and up-date logic which causes the model to track the actual engine. Details on the model and up-date logic are presented. To allow implementation, approximations are made to the feedback gain matrix which result in a single feedback matrix which is suitable for use over the entire flight envelope. The effect of these approximations on stability and response is discussed. Results from a detailed nonlinear simulation indicate that good control can be maintained even under multiple failures.

Solving Nonlinear Differential Equations in the Engineering Curriculum

ERIC Educational Resources Information Center

Auslander, David M.

1977-01-01

Described is the Dynamic System Simulation Language (SIM) mini-computer system utilized at the University of California, Los Angeles. It is used by engineering students for solving nonlinear differential equations. (SL)

Multicast backup reprovisioning problem for Hamiltonian cycle-based protection on WDM networks

NASA Astrophysics Data System (ADS)

Din, Der-Rong; Huang, Jen-Shen

2014-03-01

As networks grow in size and complexity, the chance and the impact of failures increase dramatically. The pre-allocated backup resources cannot provide 100% protection guarantee when continuous failures occur in a network. In this paper, the multicast backup re-provisioning problem (MBRP) for Hamiltonian cycle (HC)-based protection on WDM networks for the link-failure case is studied. We focus on how to recover the protecting capabilities of Hamiltonian cycle against the subsequent link-failures on WDM networks for multicast transmissions, after recovering the multicast trees affected by the previous link-failure. Since this problem is a hard problem, an algorithm, which consists of several heuristics and a genetic algorithm (GA), is proposed to solve it. The simulation results of the proposed method are also given. Experimental results indicate that the proposed algorithm can solve this problem efficiently.

Problem Solving Method Based on E-Learning System for Engineering Education

ERIC Educational Resources Information Center

Khazaal, Hasan F.

2015-01-01

Encouraging engineering students to handle advanced technology with multimedia, as well as motivate them to have the skills of solving the problem, are the missions of the teacher in preparing students for a modern professional career. This research proposes a scenario of problem solving in basic electrical circuits based on an e-learning system…

Toward Teaching Methods that Develop Learning and Enhance Problem Solving Skills in Engineering Students

ERIC Educational Resources Information Center

Loji, K.

2012-01-01

Problem solving skills and abilities are critical in life and more specifically in the engineering field. Unfortunately, significant numbers of South African students who are accessing higher education lack problem solving skills and this results in poor academic performance jeopardizing their progress especially from first to second year. On the…

Process Inquiry: Analysis of Oral Problem-Solving Skills in Mathematics of Engineering Students

ERIC Educational Resources Information Center

Trance, Naci John C.

2013-01-01

This paper presents another effort in determining the difficulty of engineering students in terms of solving word problems. Students were presented with word problems in algebra. Then, they were asked to solve the word problems orally; that is, before they presented their written solutions, they were required to explain how they understood the…

Engineering management of large scale systems

NASA Technical Reports Server (NTRS)

Sanders, Serita; Gill, Tepper L.; Paul, Arthur S.

1989-01-01

The organization of high technology and engineering problem solving, has given rise to an emerging concept. Reasoning principles for integrating traditional engineering problem solving with system theory, management sciences, behavioral decision theory, and planning and design approaches can be incorporated into a methodological approach to solving problems with a long range perspective. Long range planning has a great potential to improve productivity by using a systematic and organized approach. Thus, efficiency and cost effectiveness are the driving forces in promoting the organization of engineering problems. Aspects of systems engineering that provide an understanding of management of large scale systems are broadly covered here. Due to the focus and application of research, other significant factors (e.g., human behavior, decision making, etc.) are not emphasized but are considered.

Efficacy of an Online Resource for Teaching Interpersonal Problem Solving Skills to Women Graduate Students in Engineering

ERIC Educational Resources Information Center

Bekki, Jennifer M.; Bernstein, Bianca; Fabert, Natalie; Gildar, Natalie; Way, Amy

2014-01-01

Interpersonal problem solving skills allow engineers to prevent interpersonal difficulties more effectively and to manage conflict, both of which are critical to successful participation on teams. This research provides evidence that the "Career"WISE online learning environment can improve those skills among women in engineering graduate…

14 CFR 23.367 - Unsymmetrical loads due to engine failure.

Code of Federal Regulations, 2010 CFR

2010-01-01

... the engine compressor from the turbine or from loss of the turbine blades are considered to be... be designed for the unsymmetrical loads resulting from the failure of the critical engine including...

14 CFR 23.367 - Unsymmetrical loads due to engine failure.

Code of Federal Regulations, 2013 CFR

2013-01-01

... the engine compressor from the turbine or from loss of the turbine blades are considered to be... be designed for the unsymmetrical loads resulting from the failure of the critical engine including...

Analysis of middle bearing failure in rotor jet engine using tip-timing and tip-clearance techniques

NASA Astrophysics Data System (ADS)

Rzadkowski, R.; Rokicki, E.; Piechowski, L.; Szczepanik, R.

2016-08-01

The reported problem is the failure of the middle bearing in an aircraft rotor engine. Tip-timing and tip-clearance and variance analyses are carried out on a compressor rotor blade in the seventh stage above the middle bearing. The experimental analyses concern both an aircraft engine with a middle bearing in good working order and an engine with a damaged middle bearing. A numerical analysis of seventh stage blade free vibration is conducted to explain the experimental results. This appears to be an effective method of predicting middle bearing failure. The results show that variance first increases in the initial stages of bearing failure, but then starts to decrease and stabilize, and then again decrease shortly before complete bearing failure.

Reverse engineering of aircraft wing data using a partial differential equation surface model

NASA Astrophysics Data System (ADS)

Huband, Jacalyn Mann

Reverse engineering is a multi-step process used in industry to determine a production representation of an existing physical object. This representation is in the form of mathematical equations that are compatible with computer-aided design and computer-aided manufacturing (CAD/CAM) equipment. The four basic steps to the reverse engineering process are data acquisition, data separation, surface or curve fitting, and CAD/CAM production. The surface fitting step determines the design representation of the object, and thus is critical to the success or failure of the reverse engineering process. Although surface fitting methods described in the literature are used to model a variety of surfaces, they are not suitable for reversing aircraft wings. In this dissertation, we develop and demonstrate a new strategy for reversing a mathematical representation of an aircraft wing. The basis of our strategy is to take an aircraft design model and determine if an inverse model can be derived. A candidate design model for this research is the partial differential equation (PDE) surface model, proposed by Bloor and Wilson and used in the Rapid Airplane Parameter Input Design (RAPID) tool at the NASA-LaRC Geolab. There are several basic mathematical problems involved in reversing the PDE surface model: (i) deriving a computational approximation of the surface function; (ii) determining a radial parametrization of the wing; (iii) choosing mathematical models or classes of functions for representation of the boundary functions; (iv) fitting the boundary data points by the chosen boundary functions; and (v) simultaneously solving for the axial parameterization and the derivative boundary functions. The study of the techniques to solve the above mathematical problems has culminated in a reverse PDE surface model and two reverse PDE surface algorithms. One reverse PDE surface algorithm recovers engineering design parameters for the RAPID tool from aircraft wing data and the other generates a PDE surface model with spline boundary functions from an arbitrary set of grid points. Our numerical tests show that the reverse PDE surface model and the reverse PDE surface algorithms can be used for the reverse engineering of aircraft wing data.

Requirements: Towards an understanding on why software projects fail

NASA Astrophysics Data System (ADS)

Hussain, Azham; Mkpojiogu, Emmanuel O. C.

2016-08-01

Requirement engineering is at the foundation of every successful software project. There are many reasons for software project failures; however, poorly engineered requirements process contributes immensely to the reason why software projects fail. Software project failure is usually costly and risky and could also be life threatening. Projects that undermine requirements engineering suffer or are likely to suffer from failures, challenges and other attending risks. The cost of project failures and overruns when estimated is very huge. Furthermore, software project failures or overruns pose a challenge in today's competitive market environment. It affects the company's image, goodwill, and revenue drive and decreases the perceived satisfaction of customers and clients. In this paper, requirements engineering was discussed. Its role in software projects success was elaborated. The place of software requirements process in relation to software project failure was explored and examined. Also, project success and failure factors were also discussed with emphasis placed on requirements factors as they play a major role in software projects' challenges, successes and failures. The paper relied on secondary data and empirical statistics to explore and examine factors responsible for the successes, challenges and failures of software projects in large, medium and small scaled software companies.

Engineering-Based Problem Solving in the Middle School: Design and Construction with Simple Machines

ERIC Educational Resources Information Center

English, Lyn D.; Hudson, Peter; Dawes, Les

2013-01-01

Incorporating engineering concepts into middle school curriculum is seen as an effective way to improve students' problem-solving skills. A selection of findings is reported from a science, technology, engineering and mathematics (STEM)-based unit in which students in the second year (grade 8) of a three-year longitudinal study explored…

Barriers to the Implementation of Project Lead the Way as Perceived by Indiana High School Principals

ERIC Educational Resources Information Center

Shields, C. J.

2007-01-01

Technology education (TE) has come to encompass many facets of curriculum, ranging from industrial arts (IA) to integrating problem-solving and engineering concepts into the curriculum. For technology educators who have chosen the pre-engineering problem-solving route there is a pre-engineering curriculum called Project Lead The Way (PLTW), that…

Estimation of probability of failure for damage-tolerant aerospace structures

NASA Astrophysics Data System (ADS)

Halbert, Keith

The majority of aircraft structures are designed to be damage-tolerant such that safe operation can continue in the presence of minor damage. It is necessary to schedule inspections so that minor damage can be found and repaired. It is generally not possible to perform structural inspections prior to every flight. The scheduling is traditionally accomplished through a deterministic set of methods referred to as Damage Tolerance Analysis (DTA). DTA has proven to produce safe aircraft but does not provide estimates of the probability of failure of future flights or the probability of repair of future inspections. Without these estimates maintenance costs cannot be accurately predicted. Also, estimation of failure probabilities is now a regulatory requirement for some aircraft. The set of methods concerned with the probabilistic formulation of this problem are collectively referred to as Probabilistic Damage Tolerance Analysis (PDTA). The goal of PDTA is to control the failure probability while holding maintenance costs to a reasonable level. This work focuses specifically on PDTA for fatigue cracking of metallic aircraft structures. The growth of a crack (or cracks) must be modeled using all available data and engineering knowledge. The length of a crack can be assessed only indirectly through evidence such as non-destructive inspection results, failures or lack of failures, and the observed severity of usage of the structure. The current set of industry PDTA tools are lacking in several ways: they may in some cases yield poor estimates of failure probabilities, they cannot realistically represent the variety of possible failure and maintenance scenarios, and they do not allow for model updates which incorporate observed evidence. A PDTA modeling methodology must be flexible enough to estimate accurately the failure and repair probabilities under a variety of maintenance scenarios, and be capable of incorporating observed evidence as it becomes available. This dissertation describes and develops new PDTA methodologies that directly address the deficiencies of the currently used tools. The new methods are implemented as a free, publicly licensed and open source R software package that can be downloaded from the Comprehensive R Archive Network. The tools consist of two main components. First, an explicit (and expensive) Monte Carlo approach is presented which simulates the life of an aircraft structural component flight-by-flight. This straightforward MC routine can be used to provide defensible estimates of the failure probabilities for future flights and repair probabilities for future inspections under a variety of failure and maintenance scenarios. This routine is intended to provide baseline estimates against which to compare the results of other, more efficient approaches. Second, an original approach is described which models the fatigue process and future scheduled inspections as a hidden Markov model. This model is solved using a particle-based approximation and the sequential importance sampling algorithm, which provides an efficient solution to the PDTA problem. Sequential importance sampling is an extension of importance sampling to a Markov process, allowing for efficient Bayesian updating of model parameters. This model updating capability, the benefit of which is demonstrated, is lacking in other PDTA approaches. The results of this approach are shown to agree with the results of the explicit Monte Carlo routine for a number of PDTA problems. Extensions to the typical PDTA problem, which cannot be solved using currently available tools, are presented and solved in this work. These extensions include incorporating observed evidence (such as non-destructive inspection results), more realistic treatment of possible future repairs, and the modeling of failure involving more than one crack (the so-called continuing damage problem). The described hidden Markov model / sequential importance sampling approach to PDTA has the potential to improve aerospace structural safety and reduce maintenance costs by providing a more accurate assessment of the risk of failure and the likelihood of repairs throughout the life of an aircraft.

Teaching problem solving: Don't forget the problem solver(s)

NASA Astrophysics Data System (ADS)

Ranade, Saidas M.; Corrales, Angela

2013-05-01

The importance of intrapersonal and interpersonal intelligences has long been known but educators have debated whether to and how to incorporate those topics in an already crowded engineering curriculum. In 2010, the authors used the classroom as a laboratory to observe the usefulness of including selected case studies and exercises from the fields of neurology, artificial intelligence, cognitive sciences and social psychology in a new problem-solving course. To further validate their initial findings, in 2012, the authors conducted an online survey of engineering students and engineers. The main conclusion is that engineering students will benefit from learning more about the impact of emotions, culture, diversity and cognitive biases when solving problems. Specifically, the work shows that an augmented problem-solving curriculum needs to include lessons on labelling emotions and cognitive biases, 'evidence-based' data on the importance of culture and diversity and additional practice on estimating conditional probability.

Modeling Marrow Failure and MDS for Novel Therapeutics

DTIC Science & Technology

2017-03-01

predisposition syndrome Shwachman-Diamond syndrome (SDS) into which a deletion of the MDS-associated region of 7q has been genomically engineered . We...associated region of 7q has been genomically engineered . We will perform functional genomic screens to identify genes and molecular pathways with...disease arising from marrow failure. 2. Keywords Bone marrow failure, clonal evolution, induced pluripotent stem cells, genomic engineering 3

Analysis of Gas Turbine Engine Failure Modes.

DTIC Science & Technology

1974-01-01

failure due to factors ex- ternal (foreign to the power plant. Because in practice it is virtually impossible to distinguish accurately between the two, all...45 55 APPEN’DIX E WHEN DISCO ’=RED z z J-79 ENGINE AND HIGH FAILURE COMPONENTS H z Compressor R or242 Copeo R F4 -C H C s SeH UPi 0. 0- H U 4 C, Engine

Rotor burst protection program: Statistics on aircraft gas turbine engine rotor failures that occurred in US commercial aviation during 1975

NASA Technical Reports Server (NTRS)

Delucia, R. A.; Mangano, G. J.

1977-01-01

Statistics on gas turbine rotor failures that have occurred in U.S. commercial aviation during 1975 are presented. The compiled data were analyzed to establish: (1) The incidence of rotor failures and the number of contained and uncontained rotor bursts; (2) The distribution of rotor bursts with respect to engine rotor component; i.e., fan, compressor or turbine; (3) The type of rotor fragment (disk, rim or blade) typically generated at burst; (4) The cause of failure; (5) The type of engines involved; and (6) The flight condition at the time of failure.

[Action-oriented versus state-oriented reactions to experimenter-induced failures].

PubMed

Brunstein, J C

1989-01-01

The present study assessed different effects of action-oriented versus state-oriented styles of coping with failure on achievement-related performance and cognition. In a learned helplessness experiment, students were exposed to an academic failure situation and were then tested on a series of problem-solving tasks, either immediately after the pretreatment or after a delay of 24 hours. Performance and cognitive concomitants were measured during both experimental periods. Results demonstrated that action orientation was associated with self-immunizing cognitions during helplessness training. Action-oriented participants improved their performance level even after repeated failure feedbacks. Moreover, action-oriented students assigned to the delayed test condition responded with increased striving for success and showed performance increments, even in comparison with control subjects. In contrast, state-oriented participants developed symptoms of helplessness and showed impaired performance during failure inductions. In later tests on problem-solving tasks, state-oriented groups responded with increased fear of failure. Independent of immediate or delayed test conditions, they soon lapsed into new performance decrements.

Perspectives on Failure in the Classroom by Elementary Teachers New to Teaching Engineering

ERIC Educational Resources Information Center

Lottero-Perdue, Pamela S.; Parry, Elizabeth A.

2017-01-01

This mixed methods study examines perspectives on failure in the classroom by elementary teachers new to teaching engineering. The study participants included 254 teachers in third, fourth, and fifth grade who responded to survey questions about failure, as well as a subset of 38 of those teachers who participated in interviews about failure. The…

Reliability analysis of forty-five strain-gage systems mounted on the first fan stage of a YF-100 engine

NASA Technical Reports Server (NTRS)

Holanda, R.; Frause, L. M.

1977-01-01

The reliability of 45 state-of-the-art strain gage systems under full scale engine testing was investigated. The flame spray process was used to install 23 systems on the first fan rotor of a YF-100 engine; the others were epoxy cemented. A total of 56 percent of the systems failed in 11 hours of engine operation. Flame spray system failures were primarily due to high gage resistance, probably caused by high stress levels. Epoxy system failures were principally erosion failures, but only on the concave side of the blade. Lead-wire failures between the blade-to-disk jump and the control room could not be analyzed.

Conceptual Comparison of Population Based Metaheuristics for Engineering Problems

PubMed Central

Green, Paul

2015-01-01

Metaheuristic algorithms are well-known optimization tools which have been employed for solving a wide range of optimization problems. Several extensions of differential evolution have been adopted in solving constrained and nonconstrained multiobjective optimization problems, but in this study, the third version of generalized differential evolution (GDE) is used for solving practical engineering problems. GDE3 metaheuristic modifies the selection process of the basic differential evolution and extends DE/rand/1/bin strategy in solving practical applications. The performance of the metaheuristic is investigated through engineering design optimization problems and the results are reported. The comparison of the numerical results with those of other metaheuristic techniques demonstrates the promising performance of the algorithm as a robust optimization tool for practical purposes. PMID:25874265

Conceptual comparison of population based metaheuristics for engineering problems.

PubMed

Adekanmbi, Oluwole; Green, Paul

2015-01-01

Metaheuristic algorithms are well-known optimization tools which have been employed for solving a wide range of optimization problems. Several extensions of differential evolution have been adopted in solving constrained and nonconstrained multiobjective optimization problems, but in this study, the third version of generalized differential evolution (GDE) is used for solving practical engineering problems. GDE3 metaheuristic modifies the selection process of the basic differential evolution and extends DE/rand/1/bin strategy in solving practical applications. The performance of the metaheuristic is investigated through engineering design optimization problems and the results are reported. The comparison of the numerical results with those of other metaheuristic techniques demonstrates the promising performance of the algorithm as a robust optimization tool for practical purposes.

Facilitating Open-Ended Problem Solving: Training Engineering TAs To Facilitate Open-Ended Problem Solving.

ERIC Educational Resources Information Center

Streveler, Ruth A.; King, Robert H.

2000-01-01

Describes and evaluates a four-session training program for Multidisciplinary Engineering Laboratory (MEL) teaching assistants at the Colorado School of Mines. The sessions focus attention on student development approaches to learning. (EV)

Reconstruction of structure and function in tissue engineering of solid organs: Toward simulation of natural development based on decellularization.

PubMed

Zheng, Chen-Xi; Sui, Bing-Dong; Hu, Cheng-Hu; Qiu, Xin-Yu; Zhao, Pan; Jin, Yan

2018-04-27

Failure of solid organs, such as the heart, liver, and kidney, remains a major cause of the world's mortality due to critical shortage of donor organs. Tissue engineering, which uses elements including cells, scaffolds, and growth factors to fabricate functional organs in vitro, is a promising strategy to mitigate the scarcity of transplantable organs. Within recent years, different construction strategies that guide the combination of tissue engineering elements have been applied in solid organ tissue engineering and have achieved much progress. Most attractively, construction strategy based on whole-organ decellularization has become a popular and promising approach, because the overall structure of extracellular matrix can be well preserved. However, despite the preservation of whole structure, the current constructs derived from decellularization-based strategy still perform partial functions of solid organs, due to several challenges, including preservation of functional extracellular matrix structure, implementation of functional recellularization, formation of functional vascular network, and realization of long-term functional integration. This review overviews the status quo of solid organ tissue engineering, including both advances and challenges. We have also put forward a few techniques with potential to solve the challenges, mainly focusing on decellularization-based construction strategy. We propose that the primary concept for constructing tissue-engineered solid organs is fabricating functional organs based on intact structure via simulating the natural development and regeneration processes. Copyright © 2018 John Wiley & Sons, Ltd.

Adaptive Failure Compensation for Aircraft Flight Control Using Engine Differentials: Regulation

NASA Technical Reports Server (NTRS)

Yu, Liu; Xidong, Tang; Gang, Tao; Joshi, Suresh M.

2005-01-01

The problem of using engine thrust differentials to compensate for rudder and aileron failures in aircraft flight control is addressed in this paper in a new framework. A nonlinear aircraft model that incorporates engine di erentials in the dynamic equations is employed and linearized to describe the aircraft s longitudinal and lateral motion. In this model two engine thrusts of an aircraft can be adjusted independently so as to provide the control flexibility for rudder or aileron failure compensation. A direct adaptive compensation scheme for asymptotic regulation is developed to handle uncertain actuator failures in the linearized system. A design condition is specified to characterize the system redundancy needed for failure compensation. The adaptive regulation control scheme is applied to the linearized model of a large transport aircraft in which the longitudinal and lateral motions are coupled as the result of using engine thrust differentials. Simulation results are presented to demonstrate the effectiveness of the adaptive compensation scheme.

Propulsion and Energetics Panel Working Group 11 on Aircraft Fire Safety. Volume 2. Main Report

DTIC Science & Technology

1979-11-01

which make burning metal particles a potent igni- tion source and extinguishment of bulk metal fires a difficult task. In the latter case, the difficulty...aircraft to fires induced by uncon- tained engine failures and internal engine metal fires . With respect to the uncontained engine failure current engine

77 FR 74123 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-13

... Deutschland Ltd & Co KG Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of... Rolls-Royce Deutschland Ltd & Co KG (RRD) models Tay 620-15 and Tay 650-15 turbofan engines. This... proposing this AD to prevent failure of the LPC rotor disc assembly, uncontained engine failure, and damage...

Elementary students' engagement in failure-prone engineering design tasks

NASA Astrophysics Data System (ADS)

Andrews, Chelsea Joy

Although engineering education has been practiced at the undergraduate level for over a century, only fairly recently has the field broadened to include the elementary level; the pre-college division of the American Society of Engineering Education was established in 2003. As a result, while recent education standards require engineering in elementary schools, current studies are still filling in basic research on how best to design and implement elementary engineering activities. One area in need of investigation is how students engage with physical failure in design tasks. In this dissertation, I explore how upper elementary students engage in failure-prone engineering design tasks in an out-of-school environment. In a series of three empirical case studies, I look closely at how students evaluate failed tests and decide on changes to their design constructions, how their reasoning evolves as they repeatedly encounter physical failure, and how students and facilitators co-construct testing norms where repetitive failure is manageable. I also briefly investigate how students' engagement differs in a task that features near-immediate success. By closely examining student groups' discourse and their interactions with their design constructions, I found that these students: are able to engage in iteration and see failure-as-feedback with minimal externally-imposed structure; seem to be designing in a more sophisticated manner, attending to multiple causal factors, after experiencing repetitive failure; and are able to manage the stress and frustration of repetitive failure, provided the co-constructed testing norms of the workshop environment are supportive of failure management. These results have both pedagogical implications, in terms of how to create and facilitate design tasks, and methodological implications--namely, I highlight the particular insights afforded by a case study approach for analyzing engagement in design tasks.

Determination of Turbine Blade Life from Engine Field Data

NASA Technical Reports Server (NTRS)

Zaretsky, Erwin V.; Litt, Jonathan S.; Hendricks, Robert C.; Soditus, Sherry M.

2013-01-01

It is probable that no two engine companies determine the life of their engines or their components in the same way or apply the same experience and safety factors to their designs. Knowing the failure mode that is most likely to occur minimizes the amount of uncertainty and simplifies failure and life analysis. Available data regarding failure mode for aircraft engine blades, while favoring low-cycle, thermal-mechanical fatigue (TMF) as the controlling mode of failure, are not definitive. Sixteen high-pressure turbine (HPT) T-1 blade sets were removed from commercial aircraft engines that had been commercially flown by a single airline and inspected for damage. Each set contained 82 blades. The damage was cataloged into three categories related to their mode of failure: (1) TMF, (2) Oxidation/erosion (O/E), and (3) Other. From these field data, the turbine blade life was determined as well as the lives related to individual blade failure modes using Johnson-Weibull analysis. A simplified formula for calculating turbine blade life and reliability was formulated. The L10 blade life was calculated to be 2427 cycles (11 077 hr). The resulting blade life attributed to O/E equaled that attributed to TMF. The category that contributed most to blade failure was Other. If there were no blade failures attributed to O/E and TMF, the overall blade L(sub 10) life would increase approximately 11 to 17 percent.

The Effect on Pupils' Science Performance and Problem-Solving Ability through Lego: An Engineering Design-Based Modeling Approach

ERIC Educational Resources Information Center

Li, Yanyan; Huang, Zhinan; Jiang, Menglu; Chang, Ting-Wen

2016-01-01

Incorporating scientific fundamentals via engineering through a design-based methodology has proven to be highly effective for STEM education. Engineering design can be instantiated for learning as they involve mental and physical stimulation and develop practical skills especially in solving problems. Lego bricks, as a set of toys based on design…

System safety in Stirling engine development

NASA Technical Reports Server (NTRS)

Bankaitis, H.

1981-01-01

The DOE/NASA Stirling Engine Project Office has required that contractors make safety considerations an integral part of all phases of the Stirling engine development program. As an integral part of each engine design subtask, analyses are evolved to determine possible modes of failure. The accepted system safety analysis techniques (Fault Tree, FMEA, Hazards Analysis, etc.) are applied in various degrees of extent at the system, subsystem and component levels. The primary objectives are to identify critical failure areas, to enable removal of susceptibility to such failures or their effects from the system and to minimize risk.

Sensor failure and multivariable control for airbreathing propulsion systems. Ph.D. Thesis - Dec. 1979 Final Report

NASA Technical Reports Server (NTRS)

Behbehani, K.

1980-01-01

A new sensor/actuator failure analysis technique for turbofan jet engines was developed. Three phases of failure analysis, namely detection, isolation, and accommodation are considered. Failure detection and isolation techniques are developed by utilizing the concept of Generalized Likelihood Ratio (GLR) tests. These techniques are applicable to both time varying and time invariant systems. Three GLR detectors are developed for: (1) hard-over sensor failure; (2) hard-over actuator failure; and (3) brief disturbances in the actuators. The probability distribution of the GLR detectors and the detectability of sensor/actuator failures are established. Failure type is determined by the maximum of the GLR detectors. Failure accommodation is accomplished by extending the Multivariable Nyquest Array (MNA) control design techniques to nonsquare system designs. The performance and effectiveness of the failure analysis technique are studied by applying the technique to a turbofan jet engine, namely the Quiet Clean Short Haul Experimental Engine (QCSEE). Single and multiple sensor/actuator failures in the QCSEE are simulated and analyzed and the effects of model degradation are studied.

Proactive risk assessment of blood transfusion process, in pediatric emergency, using the Health Care Failure Mode and Effects Analysis (HFMEA).

PubMed

Dehnavieh, Reza; Ebrahimipour, Hossein; Molavi-Taleghani, Yasamin; Vafaee-Najar, Ali; Noori Hekmat, Somayeh; Esmailzdeh, Hamid

2014-12-25

Pediatric emergency has been considered as a high risk area, and blood transfusion is known as a unique clinical measure, therefore this study was conducted with the purpose of assessing the proactive risk assessment of blood transfusion process in Pediatric Emergency of Qaem education- treatment center in Mashhad, by the Healthcare Failure Mode and Effects Analysis (HFMEA) methodology. This cross-sectional study analyzed the failure mode and effects of blood transfusion process by a mixture of quantitative-qualitative method. The proactive HFMEA was used to identify and analyze the potential failures of the process. The information of the items in HFMEA forms was collected after obtaining a consensus of experts' panel views via the interview and focus group discussion sessions. The Number of 77 failure modes were identified for 24 sub-processes enlisted in 8 processes of blood transfusion. Totally 13 failure modes were identified as non-acceptable risk (a hazard score above 8) in the blood transfusion process and were transferred to the decision tree. Root causes of high risk modes were discussed in cause-effect meetings and were classified based on the UK national health system (NHS) approved classifications model. Action types were classified in the form of acceptance (11.6%), control (74.2%) and elimination (14.2%). Recommendations were placed in 7 categories using TRIZ ("Theory of Inventive Problem Solving.") The re-engineering process for the required changes, standardizing and updating the blood transfusion procedure, root cause analysis of blood transfusion catastrophic events, patient identification bracelet, training classes and educational pamphlets for raising awareness of personnel, and monthly gathering of transfusion medicine committee have all been considered as executive strategies in work agenda in pediatric emergency.

Proactive Risk Assessment of Blood Transfusion Process, in Pediatric Emergency, Using the Health Care Failure Mode and Effects Analysis (HFMEA)

PubMed Central

Dehnavieh, Reza; Ebrahimipour, Hossein; Molavi-Taleghani, Yasamin; Vafaee-Najar, Ali; Hekmat, Somayeh Noori; Esmailzdeh, Hamid

2015-01-01

Introduction: Pediatric emergency has been considered as a high risk area, and blood transfusion is known as a unique clinical measure, therefore this study was conducted with the purpose of assessing the proactive risk assessment of blood transfusion process in Pediatric Emergency of Qaem education- treatment center in Mashhad, by the Healthcare Failure Mode and Effects Analysis (HFMEA) methodology. Methodology: This cross-sectional study analyzed the failure mode and effects of blood transfusion process by a mixture of quantitative-qualitative method. The proactive HFMEA was used to identify and analyze the potential failures of the process. The information of the items in HFMEA forms was collected after obtaining a consensus of experts’ panel views via the interview and focus group discussion sessions. Results: The Number of 77 failure modes were identified for 24 sub-processes enlisted in 8 processes of blood transfusion. Totally 13 failure modes were identified as non-acceptable risk (a hazard score above 8) in the blood transfusion process and were transferred to the decision tree. Root causes of high risk modes were discussed in cause-effect meetings and were classified based on the UK national health system (NHS) approved classifications model. Action types were classified in the form of acceptance (11.6%), control (74.2%) and elimination (14.2%). Recommendations were placed in 7 categories using TRIZ (“Theory of Inventive Problem Solving.”) Conclusion: The re-engineering process for the required changes, standardizing and updating the blood transfusion procedure, root cause analysis of blood transfusion catastrophic events, patient identification bracelet, training classes and educational pamphlets for raising awareness of personnel, and monthly gathering of transfusion medicine committee have all been considered as executive strategies in work agenda in pediatric emergency. PMID:25560332

A demonstration of an intelligent control system for a reusable rocket engine

NASA Technical Reports Server (NTRS)

Musgrave, Jeffrey L.; Paxson, Daniel E.; Litt, Jonathan S.; Merrill, Walter C.

1992-01-01

An Intelligent Control System for reusable rocket engines is under development at NASA Lewis Research Center. The primary objective is to extend the useful life of a reusable rocket propulsion system while minimizing between flight maintenance and maximizing engine life and performance through improved control and monitoring algorithms and additional sensing and actuation. This paper describes current progress towards proof-of-concept of an Intelligent Control System for the Space Shuttle Main Engine. A subset of identifiable and accommodatable engine failure modes is selected for preliminary demonstration. Failure models are developed retaining only first order effects and included in a simplified nonlinear simulation of the rocket engine for analysis under closed loop control. The engine level coordinator acts as an interface between the diagnostic and control systems, and translates thrust and mixture ratio commands dictated by mission requirements, and engine status (health) into engine operational strategies carried out by a multivariable control. Control reconfiguration achieves fault tolerance if the nominal (healthy engine) control cannot. Each of the aforementioned functionalities is discussed in the context of an example to illustrate the operation of the system in the context of a representative failure. A graphical user interface allows the researcher to monitor the Intelligent Control System and engine performance under various failure modes selected for demonstration.

Matrix Dominated Failure of Fiber-Reinforced Composite Laminates Under Static and Dynamic Loading

NASA Astrophysics Data System (ADS)

Schaefer, Joseph Daniel

Hierarchical material systems provide the unique opportunity to connect material knowledge to solving specific design challenges. Representing the quickest growing class of hierarchical materials in use, fiber-reinforced polymer composites (FRPCs) offer superior strength and stiffness-to-weight ratios, damage tolerance, and decreasing production costs compared to metals and alloys. However, the implementation of FRPCs has historically been fraught with inadequate knowledge of the material failure behavior due to incomplete verification of recent computational constitutive models and improper (or non-existent) experimental validation, which has severely slowed creation and development. Noted by the recent Materials Genome Initiative and the Worldwide Failure Exercise, current state of the art qualification programs endure a 20 year gap between material conceptualization and implementation due to the lack of effective partnership between computational coding (simulation) and experimental characterization. Qualification processes are primarily experiment driven; the anisotropic nature of composites predisposes matrix-dominant properties to be sensitive to strain rate, which necessitates extensive testing. To decrease the qualification time, a framework that practically combines theoretical prediction of material failure with limited experimental validation is required. In this work, the Northwestern Failure Theory (NU Theory) for composite lamina is presented as the theoretical basis from which the failure of unidirectional and multidirectional composite laminates is investigated. From an initial experimental characterization of basic lamina properties, the NU Theory is employed to predict the matrix-dependent failure of composites under any state of biaxial stress from quasi-static to 1000 s-1 strain rates. It was found that the number of experiments required to characterize the strain-rate-dependent failure of a new composite material was reduced by an order of magnitude, and the resulting strain-rate-dependence was applicable for a large class of materials. The presented framework provides engineers with the capability to quickly identify fiber and matrix combinations for a given application and determine the failure behavior over the range of practical loadings cases. The failure-mode-based NU Theory may be especially useful when partnered with computational approaches (which often employ micromechanics to determine constituent and constitutive response) to provide accurate validation of the matrix-dominated failure modes experienced by laminates during progressive failure.

Computational structural mechanics for engine structures

NASA Technical Reports Server (NTRS)

Chamis, C. C.

1989-01-01

The computational structural mechanics (CSM) program at Lewis encompasses: (1) fundamental aspects for formulating and solving structural mechanics problems, and (2) development of integrated software systems to computationally simulate the performance/durability/life of engine structures. It is structured to mainly supplement, complement, and whenever possible replace, costly experimental efforts which are unavoidable during engineering research and development programs. Specific objectives include: investigate unique advantages of parallel and multiprocesses for: reformulating/solving structural mechanics and formulating/solving multidisciplinary mechanics and develop integrated structural system computational simulators for: predicting structural performances, evaluating newly developed methods, and for identifying and prioritizing improved/missing methods needed. Herein the CSM program is summarized with emphasis on the Engine Structures Computational Simulator (ESCS). Typical results obtained using ESCS are described to illustrate its versatility.

Failure analysis of blots for diesel engine intercooler

NASA Astrophysics Data System (ADS)

Ren, Ping; Li, Zongquan; Wu, Jiangfei; Guo, Yibin; Li, Wanyou

2017-05-01

In diesel generating sets, it will lead to the abominable working condition if the fault couldn’t be recovered when the bolt of intercooler cracks. This paper aims at the fault of the blots of diesel generator intercooler and completes the analysis of the static strength and fatigue strength. Static intensity is checked considering blot preload and thermal stress. In order to obtain the thermal stress of the blot, thermodynamic of intercooler is calculated according to the measured temperature. Based on the measured vibration response and the finite element model, using dynamic load identification technique, equivalent excitation force of unit was solved. In order to obtain the force of bolt, the excitation force is loaded into the finite element model. By considering the thermal stress and preload as the average stress while the mechanical stress as the wave stress, fatigue strength analysis has been accomplished. Procedure of diagnosis is proposed in this paper. Finally, according to the result of intensity verification the fatigue failure is validation. Thereby, further studies are necessary to verification the result of the intensity analysis and put forward some improvement suggestion.

Sulfation in lead-acid batteries

NASA Astrophysics Data System (ADS)

Catherino, Henry A.; Feres, Fred F.; Trinidad, Francisco

Virtually, all military land vehicle systems use a lead-acid battery to initiate an engine start. The maintainability of these batteries and as a consequence, system readiness, has suffered from a lack of understanding of the reasons for battery failure. Often, the term most commonly heard for explaining the performance degradation of lead-acid batteries is the word, sulfation. Sulfation is a residual term that came into existence during the early days of lead-acid battery development. The usage is part of the legend that persists as a means for interpreting and justifying the eventual performance deterioration and failure of lead-acid batteries. The usage of this term is confined to the greater user community and, over time, has encouraged a myriad of remedies for solving sulfation problems. One can avoid the connotations associated with the all-inclusive word, sulfation by visualizing the general "sulfation" effect in terms of specific mechanistic models. Also, the mechanistic models are essential for properly understanding the operation and making proper use this battery system. It is evident that the better the model, the better the level of understanding.

Engineering education in the wake of hurricane Katrina

PubMed Central

Lima, Marybeth

2007-01-01

Living through hurricane Katrina and its aftermath and reflecting on these experiences from technical and non-technical standpoints has led me to reconsider my thoughts and philosophy on engineering education. I present three ideas regarding engineering education pedagogy that I believe will prepare future engineers for problem-solving in an increasingly complex world. They are (1) we must practice radical (to the root) engineering, (2) we must illustrate connections between engineering and public policy, and (3) we will join the charge to find sustainable solutions to problems. Ideas for bringing each of these concepts into engineering curricula through methods such as case study, practicing broad information gathering and data interpretation, and other methods inside and outside the classroom, are discussed. I believe that the consequences of not considering the root issues of problems to be solved, and of not including policy and sustainability considerations when problems to be solved are framed will lead our profession toward well meaning but insufficient utility. Hurricane Katrina convinced me that we must do better as educators to prepare our students for engineering for a sustainable world. PMID:18271988

Questioning the Role of Requirements Engineering in the Causes of Safety-Critical Software Failures

NASA Technical Reports Server (NTRS)

Johnson, C. W.; Holloway, C. M.

2006-01-01

Many software failures stem from inadequate requirements engineering. This view has been supported both by detailed accident investigations and by a number of empirical studies; however, such investigations can be misleading. It is often difficult to distinguish between failures in requirements engineering and problems elsewhere in the software development lifecycle. Further pitfalls arise from the assumption that inadequate requirements engineering is a cause of all software related accidents for which the system fails to meet its requirements. This paper identifies some of the problems that have arisen from an undue focus on the role of requirements engineering in the causes of major accidents. The intention is to provoke further debate within the emerging field of forensic software engineering.

System for Anomaly and Failure Detection (SAFD) system development

NASA Technical Reports Server (NTRS)

Oreilly, D.

1992-01-01

This task specified developing the hardware and software necessary to implement the System for Anomaly and Failure Detection (SAFD) algorithm, developed under Technology Test Bed (TTB) Task 21, on the TTB engine stand. This effort involved building two units; one unit to be installed in the Block II Space Shuttle Main Engine (SSME) Hardware Simulation Lab (HSL) at Marshall Space Flight Center (MSFC), and one unit to be installed at the TTB engine stand. Rocketdyne personnel from the HSL performed the task. The SAFD algorithm was developed as an improvement over the current redline system used in the Space Shuttle Main Engine Controller (SSMEC). Simulation tests and execution against previous hot fire tests demonstrated that the SAFD algorithm can detect engine failure as much as tens of seconds before the redline system recognized the failure. Although the current algorithm only operates during steady state conditions (engine not throttling), work is underway to expand the algorithm to work during transient condition.

Selected Systems Engineering Process Deficiencies and Their Consequences

NASA Technical Reports Server (NTRS)

Thomas, Lawrence Dale

2006-01-01

The systems engineering process is well established and well understood. While this statement could be argued in the light of the many systems engineering guidelines and that have been developed, comparative review of these respective descriptions reveal that they differ primarily in the number of discrete steps or other nuances, and are at their core essentially common. Likewise, the systems engineering textbooks differ primarily in the context for application of systems engineering or in the utilization of evolved tools and techniques, not in the basic method. Thus, failures in systems engineering cannot credibly be attributed to implementation of the wrong systems engineering process among alternatives. However, numerous systems failures can be attributed to deficient implementation of the systems engineering process. What may clearly be perceived as a system engineering deficiency in retrospect can appear to be a well considered system engineering efficiency in real time - an efficiency taken to reduce cost or meet a schedule, or more often both. Typically these efficiencies are grounded on apparently solid rationale, such as reuse of heritage hardware or software. Over time, unintended consequences of a systems engineering process deficiency may begin to be realized, and unfortunately often the consequence is system failure. This paper describes several actual cases of system failures that resulted from deficiencies in their systems engineering process implementation, including the Ariane 5 and the Hubble Space Telescope.

Selected systems engineering process deficiencies and their consequences

NASA Astrophysics Data System (ADS)

Thomas, L. Dale

2007-06-01

The systems engineering process is well established and well understood. While this statement could be argued in the light of the many systems engineering guidelines and that have been developed, comparative review of these respective descriptions reveal that they differ primarily in the number of discrete steps or other nuances, and are at their core essentially common. Likewise, the systems engineering textbooks differ primarily in the context for application of systems engineering or in the utilization of evolved tools and techniques, not in the basic method. Thus, failures in systems engineering cannot credibly be attributed to implementation of the wrong systems engineering process among alternatives. However, numerous system failures can be attributed to deficient implementation of the systems engineering process. What may clearly be perceived as a systems engineering deficiency in retrospect can appear to be a well considered system engineering efficiency in real time—an efficiency taken to reduce cost or meet a schedule, or more often both. Typically these efficiencies are grounded on apparently solid rationale, such as reuse of heritage hardware or software. Over time, unintended consequences of a systems engineering process deficiency may begin to be realized, and unfortunately often the consequence is systems failure. This paper describes several actual cases of system failures that resulted from deficiencies in their systems engineering process implementation, including the Ariane 5 and the Hubble Space Telescope.

Engineering and Computing Portal to Solve Environmental Problems

NASA Astrophysics Data System (ADS)

Gudov, A. M.; Zavozkin, S. Y.; Sotnikov, I. Y.

2018-01-01

This paper describes architecture and services of the Engineering and Computing Portal, which is considered to be a complex solution that provides access to high-performance computing resources, enables to carry out computational experiments, teach parallel technologies and solve computing tasks, including technogenic safety ones.

Developing creativity and problem-solving skills of engineering students: a comparison of web- and pen-and-paper-based approaches

NASA Astrophysics Data System (ADS)

Valentine, Andrew; Belski, Iouri; Hamilton, Margaret

2017-11-01

Problem-solving is a key engineering skill, yet is an area in which engineering graduates underperform. This paper investigates the potential of using web-based tools to teach students problem-solving techniques without the need to make use of class time. An idea generation experiment involving 90 students was designed. Students were surveyed about their study habits and reported they use electronic-based materials more than paper-based materials while studying, suggesting students may engage with web-based tools. Students then generated solutions to a problem task using either a paper-based template or an equivalent web interface. Students who used the web-based approach performed as well as students who used the paper-based approach, suggesting the technique can be successfully adopted and taught online. Web-based tools may therefore be adopted as supplementary material in a range of engineering courses as a way to increase students' options for enhancing problem-solving skills.

Determination of Turbine Blade Life from Engine Field Data

NASA Technical Reports Server (NTRS)

Zaretsky, Erwin V.; Litt, Jonathan S.; Hendricks, Robert C.; Soditus, Sherry M.

2012-01-01

It is probable that no two engine companies determine the life of their engines or their components in the same way or apply the same experience and safety factors to their designs. Knowing the failure mode that is most likely to occur minimizes the amount of uncertainty and simplifies failure and life analysis. Available data regarding failure mode for aircraft engine blades, while favoring low-cycle, thermal mechanical fatigue as the controlling mode of failure, are not definitive. Sixteen high-pressure turbine (HPT) T-1 blade sets were removed from commercial aircraft engines that had been commercially flown by a single airline and inspected for damage. Each set contained 82 blades. The damage was cataloged into three categories related to their mode of failure: (1) Thermal-mechanical fatigue, (2) Oxidation/Erosion, and (3) "Other." From these field data, the turbine blade life was determined as well as the lives related to individual blade failure modes using Johnson-Weibull analysis. A simplified formula for calculating turbine blade life and reliability was formulated. The L(sub 10) blade life was calculated to be 2427 cycles (11 077 hr). The resulting blade life attributed to oxidation/erosion equaled that attributed to thermal-mechanical fatigue. The category that contributed most to blade failure was Other. If there were there no blade failures attributed to oxidation/erosion and thermal-mechanical fatigue, the overall blade L(sub 10) life would increase approximately 11 to 17 percent.

STS-55 pad abort: Engine 2011 oxidizer preburner augmented spark igniter check valve leak

NASA Technical Reports Server (NTRS)

1993-01-01

The STS-55 initial launch attempt of Columbia (OV102) was terminated on KSC launch pad A March 22, 1993 at 9:51 AM E.S.T. due to violation of an ME-3 (Engine 2011) Launch Commit Criteria (LCC) limit exceedance. The event description and timeline are summarized. Propellant loading was initiated on 22 March, 1993 at 1:15 AM EST. All SSME chill parameters and launch commit criteria (LCC) were nominal. At engine start plus 1.44 seconds, a Failure Identification (FID) was posted against Engine 2011 for exceeding the 50 psia Oxidizer Preburner (OPB) purge pressure redline. The engine was shut down at 1.50 seconds followed by Engines 2034 and 2030. All shut down sequences were nominal and the mission was safely aborted. The OPB purge pressure redline violation and the abort profile/overlay for all three engines are depicted. SSME Avionics hardware and software performed nominally during the incident. A review of vehicle data table (VDT) data and controller software logic revealed no failure indications other than the single FID 013-414, OPB purge pressure redline exceeded. Software logic was executed according to requirements and there was no anomalous controller software operation. Immediately following the abort, a Rocketdyne/NASA failure investigation team was assembled. The team successfully isolated the failure cause to the oxidizer preburner augmented spark igniter purge check valve not being fully closed due to contamination. The source of the contaminant was traced to a cut segment from a rubber O-ring which was used in a fine clean tool during valve production prior to 1992. The valve was apparently contaminated during its fabrication in 1985. The valve had performed acceptably on four previous flights of the engine, and SSME flight history shows 780 combined check valve flights without failure. The failure of an Engine 3 (SSME No. 2011) check valve to close was sensed by onboard engine instruments even though all other engine operations were normal. This resulted in an engine shutdown and safe sequential shutdown of all three engines prior to ignition of the solid boosters.

Programmable lithography engine (ProLE) grid-type supercomputer and its applications

NASA Astrophysics Data System (ADS)

Petersen, John S.; Maslow, Mark J.; Gerold, David J.; Greenway, Robert T.

2003-06-01

There are many variables that can affect lithographic dependent device yield. Because of this, it is not enough to make optical proximity corrections (OPC) based on the mask type, wavelength, lens, illumination-type and coherence. Resist chemistry and physics along with substrate, exposure, and all post-exposure processing must be considered too. Only a holistic approach to finding imaging solutions will accelerate yield and maximize performance. Since experiments are too costly in both time and money, accomplishing this takes massive amounts of accurate simulation capability. Our solution is to create a workbench that has a set of advanced user applications that utilize best-in-class simulator engines for solving litho-related DFM problems using distributive computing. Our product, ProLE (Programmable Lithography Engine), is an integrated system that combines Petersen Advanced Lithography Inc."s (PAL"s) proprietary applications and cluster management software wrapped around commercial software engines, along with optional commercial hardware and software. It uses the most rigorous lithography simulation engines to solve deep sub-wavelength imaging problems accurately and at speeds that are several orders of magnitude faster than current methods. Specifically, ProLE uses full vector thin-mask aerial image models or when needed, full across source 3D electromagnetic field simulation to make accurate aerial image predictions along with calibrated resist models;. The ProLE workstation from Petersen Advanced Lithography, Inc., is the first commercial product that makes it possible to do these intensive calculations at a fraction of a time previously available thus significantly reducing time to market for advance technology devices. In this work, ProLE is introduced, through model comparison to show why vector imaging and rigorous resist models work better than other less rigorous models, then some applications of that use our distributive computing solution are shown. Topics covered describe why ProLE solutions are needed from an economic and technical aspect, a high level discussion of how the distributive system works, speed benchmarking, and finally, a brief survey of applications including advanced aberrations for lens sensitivity and flare studies, optical-proximity-correction for a bitcell and an application that will allow evaluation of the potential of a design to have systematic failures during fabrication.

The Effects of Successful versus Failure-Based Cases on Argumentation while Solving Decision-Making Problems

ERIC Educational Resources Information Center

Tawfik, Andrew; Jonassen, David

2013-01-01

Solving complex, ill-structured problems may be effectively supported by case-based reasoning through case libraries that provide just-in-time domain-specific principles in the form of stories. The cases not only articulate previous experiences of practitioners, but also serve as problem-solving narratives from which learners can acquire meaning.…

When Best Intentions Go Awry: The Failures of Concrete Representations to Help Solve Probability Word Problems

ERIC Educational Resources Information Center

Beitzel, Brian D.; Staley, Richard K.; DuBois, Nelson F.

2011-01-01

Previous research has cast doubt on the efficacy of utilizing external representations as an aid to solving word problems. The present study replicates previous findings that concrete representations hinder college students' ability to solve probability word problems, and extends those findings to apply to a multimedia instructional context. Our…

Models of human problem solving - Detection, diagnosis, and compensation for system failures

NASA Technical Reports Server (NTRS)

Rouse, W. B.

1983-01-01

The role of the human operator as a problem solver in man-machine systems such as vehicles, process plants, transportation networks, etc. is considered. Problem solving is discussed in terms of detection, diagnosis, and compensation. A wide variety of models of these phases of problem solving are reviewed and specifications for an overall model outlined.

Optimal landing of a helicopter in autorotation

NASA Technical Reports Server (NTRS)

Lee, A. Y. N.

1985-01-01

Gliding descent in autorotation is a maneuver used by helicopter pilots in case of engine failure. The landing of a helicopter in autorotation is formulated as a nonlinear optimal control problem. The OH-58A helicopter was used. Helicopter vertical and horizontal velocities, vertical and horizontal displacement, and the rotor angle speed were modeled. An empirical approximation for the induced veloctiy in the vortex-ring state were provided. The cost function of the optimal control problem is a weighted sum of the squared horizontal and vertical components of the helicopter velocity at touchdown. Optimal trajectories are calculated for entry conditions well within the horizontal-vertical restriction curve, with the helicopter initially in hover or forwared flight. The resultant two-point boundary value problem with path equality constraints was successfully solved using the Sequential Gradient Restoration Technique.

An Analysis of Learned Helplessness: Continuous Changes in Performance, Strategy, and Achievement Cognitions Following Failure

ERIC Educational Resources Information Center

Diener, Carol I.; Dweck, Carol S.

1978-01-01

Two studies examined the cognitive-motivational differences between helpless and mastery-oriented children by analyzing the effects of failure feedback on problem solving strategies during testing and identifying semantic differences in children's verbalizations following failure on task. Subjects were fifth graders of both sexes. (CM)

Health management system for rocket engines

NASA Technical Reports Server (NTRS)

Nemeth, Edward

1990-01-01

The functional framework of a failure detection algorithm for the Space Shuttle Main Engine (SSME) is developed. The basic algorithm is based only on existing SSME measurements. Supplemental measurements, expected to enhance failure detection effectiveness, are identified. To support the algorithm development, a figure of merit is defined to estimate the likelihood of SSME criticality 1 failure modes and the failure modes are ranked in order of likelihood of occurrence. Nine classes of failure detection strategies are evaluated and promising features are extracted as the basis for the failure detection algorithm. The failure detection algorithm provides early warning capabilities for a wide variety of SSME failure modes. Preliminary algorithm evaluation, using data from three SSME failures representing three different failure types, demonstrated indications of imminent catastrophic failure well in advance of redline cutoff in all three cases.

A Comparative Study of Optimization Algorithms for Engineering Synthesis.

DTIC Science & Technology

1983-03-01

the ADS program demonstrates the flexibility a design engineer would have in selecting an optimization algorithm best suited to solve a particular...demonstrates the flexibility a design engineer would have in selecting an optimization algorithm best suited to solve a particular problem. 4 TABLE OF...algorithm to suit a particular problem. The ADS library of design optimization algorithms was . developed by Vanderplaats in response to the first

Un-Building Blocks: A Model of Reverse Engineering and Applicable Heuristics

DTIC Science & Technology

2015-12-01

CONCLUSIONS The machine does not isolate man from the great problems of nature but plunges him more deeply into them. Antoine de Saint-Exupery— Wind ...DISTRIBUTION CODE 13. ABSTRACT (maximum 200 words) Reverse engineering is the problem -solving activity that ensues when one takes a...Douglas Moses, Vice Provost for Academic Affairs iv THIS PAGE INTENTIONALLY LEFT BLANK v ABSTRACT Reverse engineering is the problem -solving

Beam Motions under Moving Loads Solved by Finite Element Method Consistent in Spatial and Time Coordinates

DTIC Science & Technology

1980-11-01

the Applied Engineering Science, R. P. Shaw, et al.. Editors, University Press of Virginia, Charlottesville, 1980, pp. 733-741. II. SOLUTION...Dynamics Solved by Finite Element Unconstrained Variatlonal Formulations," Innovative Numerical Analysis For the Applied Engineering Science, R. P

Middle School Engineering Problem Solving Using Traditional vs. E-PBL Module Instruction

ERIC Educational Resources Information Center

Baele, Loren C.

2017-01-01

This multiple methods (Denzin, 1978) study investigated two instructional approaches, traditional module and electronic Problem-Based Learning instruction (e-PBL), used within a middle school engineering classroom focused on the variables of engagement, content knowledge, student self-assessment and teacher assessment of problem solving solutions.…

Real-time failure control (SAFD)

NASA Technical Reports Server (NTRS)

Panossian, Hagop V.; Kemp, Victoria R.; Eckerling, Sherry J.

1990-01-01

The Real Time Failure Control program involves development of a failure detection algorithm, referred as System for Failure and Anomaly Detection (SAFD), for the Space Shuttle Main Engine (SSME). This failure detection approach is signal-based and it entails monitoring SSME measurement signals based on predetermined and computed mean values and standard deviations. Twenty four engine measurements are included in the algorithm and provisions are made to add more parameters if needed. Six major sections of research are presented: (1) SAFD algorithm development; (2) SAFD simulations; (3) Digital Transient Model failure simulation; (4) closed-loop simulation; (5) SAFD current limitations; and (6) enhancements planned for.

Forensic engineering: applying materials and mechanics principles to the investigation of product failures.

PubMed

Hainsworth, S V; Fitzpatrick, M E

2007-06-01

Forensic engineering is the application of engineering principles or techniques to the investigation of materials, products, structures or components that fail or do not perform as intended. In particular, forensic engineering can involve providing solutions to forensic problems by the application of engineering science. A criminal aspect may be involved in the investigation but often the problems are related to negligence, breach of contract, or providing information needed in the redesign of a product to eliminate future failures. Forensic engineering may include the investigation of the physical causes of accidents or other sources of claims and litigation (for example, patent disputes). It involves the preparation of technical engineering reports, and may require giving testimony and providing advice to assist in the resolution of disputes affecting life or property.This paper reviews the principal methods available for the analysis of failed components and then gives examples of different component failure modes through selected case studies.

HYTESS 2: A Hypothetical Turbofan Engine Simplified Simulation with multivariable control and sensor analytical redundancy

NASA Technical Reports Server (NTRS)

Merrill, W. C.

1986-01-01

A hypothetical turbofan engine simplified simulation with a multivariable control and sensor failure detection, isolation, and accommodation logic (HYTESS II) is presented. The digital program, written in FORTRAN, is self-contained, efficient, realistic and easily used. Simulated engine dynamics were developed from linearized operating point models. However, essential nonlinear effects are retained. The simulation is representative of the hypothetical, low bypass ratio turbofan engine with an advanced control and failure detection logic. Included is a description of the engine dynamics, the control algorithm, and the sensor failure detection logic. Details of the simulation including block diagrams, variable descriptions, common block definitions, subroutine descriptions, and input requirements are given. Example simulation results are also presented.

14 CFR 27.903 - Engines.

Code of Federal Regulations, 2014 CFR

2014-01-01

... usage. (b) Engine or drive system cooling fan blade protection. (1) If an engine or rotor drive system... fan blade fails. This must be shown by showing that— (i) The fan blades are contained in case of failure; (ii) Each fan is located so that a failure will not jeopardize safety; or (iii) Each fan blade...

14 CFR 27.903 - Engines.

Code of Federal Regulations, 2012 CFR

2012-01-01

... usage. (b) Engine or drive system cooling fan blade protection. (1) If an engine or rotor drive system... fan blade fails. This must be shown by showing that— (i) The fan blades are contained in case of failure; (ii) Each fan is located so that a failure will not jeopardize safety; or (iii) Each fan blade...

14 CFR 27.903 - Engines.

Code of Federal Regulations, 2010 CFR

2010-01-01

... usage. (b) Engine or drive system cooling fan blade protection. (1) If an engine or rotor drive system... fan blade fails. This must be shown by showing that— (i) The fan blades are contained in case of failure; (ii) Each fan is located so that a failure will not jeopardize safety; or (iii) Each fan blade...

14 CFR 27.903 - Engines.

Code of Federal Regulations, 2011 CFR

2011-01-01

... usage. (b) Engine or drive system cooling fan blade protection. (1) If an engine or rotor drive system... fan blade fails. This must be shown by showing that— (i) The fan blades are contained in case of failure; (ii) Each fan is located so that a failure will not jeopardize safety; or (iii) Each fan blade...

14 CFR 27.903 - Engines.

Code of Federal Regulations, 2013 CFR

2013-01-01

... usage. (b) Engine or drive system cooling fan blade protection. (1) If an engine or rotor drive system... fan blade fails. This must be shown by showing that— (i) The fan blades are contained in case of failure; (ii) Each fan is located so that a failure will not jeopardize safety; or (iii) Each fan blade...

75 FR 69858 - Airworthiness Directives; Eurocopter France (Eurocopter) Model AS332L2 Helicopters

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-16

... MCAI AD states that a hard landing occurred during in-flight engine failure (one engine inoperative (OEI)) training. An examination revealed the failure of the right-hand main reduction gear module... freewheel unit. In case of a freewheel unit failure on one of the two MGB inputs, either inadvertently or as...

Nanomaterials for Cardiac Myocyte Tissue Engineering.

PubMed

Amezcua, Rodolfo; Shirolkar, Ajay; Fraze, Carolyn; Stout, David A

2016-07-19

Since their synthesizing introduction to the research community, nanomaterials have infiltrated almost every corner of science and engineering. Over the last decade, one such field has begun to look at using nanomaterials for beneficial applications in tissue engineering, specifically, cardiac tissue engineering. During a myocardial infarction, part of the cardiac muscle, or myocardium, is deprived of blood. Therefore, the lack of oxygen destroys cardiomyocytes, leaving dead tissue and possibly resulting in the development of arrhythmia, ventricular remodeling, and eventual heart failure. Scarred cardiac muscle results in heart failure for millions of heart attack survivors worldwide. Modern cardiac tissue engineering research has developed nanomaterial applications to combat heart failure, preserve normal heart tissue, and grow healthy myocardium around the infarcted area. This review will discuss the recent progress of nanomaterials for cardiovascular tissue engineering applications through three main nanomaterial approaches: scaffold designs, patches, and injectable materials.

Correction of engineering servicing regularity of transporttechnological machines in operational process

NASA Astrophysics Data System (ADS)

Makarova, A. N.; Makarov, E. I.; Zakharov, N. S.

2018-03-01

In the article, the issue of correcting engineering servicing regularity on the basis of actual dependability data of cars in operation is considered. The purpose of the conducted research is to increase dependability of transport-technological machines by correcting engineering servicing regularity. The subject of the research is the mechanism of engineering servicing regularity influence on reliability measure. On the basis of the analysis of researches carried out before, a method of nonparametric estimation of car failure measure according to actual time-to-failure data was chosen. A possibility of describing the failure measure dependence on engineering servicing regularity by various mathematical models is considered. It is proven that the exponential model is the most appropriate for that purpose. The obtained results can be used as a separate method of engineering servicing regularity correction with certain operational conditions taken into account, as well as for the technical-economical and economical-stochastic methods improvement. Thus, on the basis of the conducted researches, a method of engineering servicing regularity correction of transport-technological machines in the operational process was developed. The use of that method will allow decreasing the number of failures.

Strategies That Help Learning-Disabled Students Solve Verbal Mathematical Problems.

ERIC Educational Resources Information Center

Giordano, Gerard

1990-01-01

Strategies are presented for dealing with factors that can be responsible for failure in mathematical problem solving. The suggestions include personalization of verbal problems, thematic strands based on student interests, visual representation, a laboratory approach, and paraphrasing. (JDD)

Puzzles in modern biology. I. Male sterility, failure reveals design

PubMed Central

Frank, Steven A.

2016-01-01

Many human males produce dysfunctional sperm. Various plants frequently abort pollen. Hybrid matings often produce sterile males. Widespread male sterility is puzzling. Natural selection prunes reproductive failure. Puzzling failure implies something that we do not understand about how organisms are designed. Solving the puzzle reveals the hidden processes of design. PMID:28004842

Failure mode analysis to predict product reliability.

NASA Technical Reports Server (NTRS)

Zemanick, P. P.

1972-01-01

The failure mode analysis (FMA) is described as a design tool to predict and improve product reliability. The objectives of the failure mode analysis are presented as they influence component design, configuration selection, the product test program, the quality assurance plan, and engineering analysis priorities. The detailed mechanics of performing a failure mode analysis are discussed, including one suggested format. Some practical difficulties of implementation are indicated, drawn from experience with preparing FMAs on the nuclear rocket engine program.

Designing a Better Experience: A Qualitative Investigation of Student Engineering Internships

ERIC Educational Resources Information Center

Paknejad, Mohammad R.

2016-01-01

Science, Technology, Engineering and Mathematics (STEM) education play a very important role in preparing students with skills necessary to obtain better jobs, solve real-world challenges, and compete in the global economy. STEM education develops critical thinking and the ability to solve complex problems. Research showed that 8 out of 10 most…

Can I Trust This Software Package? An Exercise in Validation of Computational Results

ERIC Educational Resources Information Center

Shacham, Mordechai; Brauner, Neima; Ashurst, W. Robert; Cutlip, Michael B.

2008-01-01

Mathematical software packages such as Polymath, MATLAB, and Mathcad are currently widely used for engineering problem solving. Applications of several of these packages to typical chemical engineering problems have been demonstrated by Cutlip, et al. The main characteristic of these packages is that they provide a "problem-solving environment…

Creativity and Inspiration for Problem Solving in Engineering Education

ERIC Educational Resources Information Center

Nordstrom, Katrina; Korpelainen, Paivi

2011-01-01

Problem solving is a critical skill for engineering students and essential to development of creativity and innovativeness. Essential to such learning is an ease of communication and allowing students to address the issues at hand via the terminology, attitudes, humor and empathy, which is inherent to their frame of mind as novices, without the…

Learning on the Job: Cooperative Education, Internships and Engineering Problem-Solving Skills

ERIC Educational Resources Information Center

Yin, Alexander C.

2009-01-01

Cooperative education (co-op) and internships are forms of experiential education that allow students to complement their classroom experiences with work experience. This study examines the influence of co-op and internships on engineering problem-solving skills by answering the following research questions: (1) Does experience in cooperative…

A Coding Scheme for Analysing Problem-Solving Processes of First-Year Engineering Students

ERIC Educational Resources Information Center

Grigg, Sarah J.; Benson, Lisa C.

2014-01-01

This study describes the development and structure of a coding scheme for analysing solutions to well-structured problems in terms of cognitive processes and problem-solving deficiencies for first-year engineering students. A task analysis approach was used to assess students' problem solutions using the hierarchical structure from a…

Student Learning Outcomes from a Pilot Medical Innovations Course with Nursing, Engineering, and Biology Undergraduate Students

ERIC Educational Resources Information Center

Ludwig, Patrice M.; Nagel, Jacquelyn K.; Lewis, Erica J.

2017-01-01

Background: Preparing today's undergraduate students from science, technology, engineering, and math (STEM) and related health professions to solve wide-sweeping healthcare challenges is critical. Moreover, it is imperative that educators help students develop the capabilities needed to meet those challenges, including problem solving,…

A Language for the Analysis of Disciplinary Boundary Crossing: Insights from Engineering Problem-Solving Practice

ERIC Educational Resources Information Center

Wolff, Karin

2018-01-01

Poor graduate throughput and industry feedback on graduate inability to cope with the complex knowledge practices in twenty-first century engineering "problem solving" have placed pressure on educators to better conceptualise the theory-practice relationship, particularly in technology-dependent professions. The research draws on the…

The application of continuum damage mechanics to solve problems in geodynamics

NASA Astrophysics Data System (ADS)

Manaker, David Martin

Deformation within the Earth's lithosphere is largely controlled by the rheology of the rock. Ductile behavior in rocks is often associated with plasticity due to dislocation motion or diffusion under high pressures and temperatures. However, ductile behavior can also occur in brittle materials. An example would be cataclastic flow associated with folding at shallow crustal levels, steep subduction zones, and large-scale deformation at plate boundaries. Engineers utilize damage mechanics to model the continuum deformation of brittle materials. We utilize a modified form of damage mechanics where damage represents a reduction in frictional strength and includes a yield stress. We use this empirical approach to simulate the bending of the lithosphere. We use numerical simulations to obtain elastostatic solutions for plate bending and where the stress exceeds a yield stress, we apply damage to reduce the elastic moduli. Damage is calculated at each time step by a power-law relationship of the ratio of the yield stress to stress and the yield strain to the strain. To test our method, we apply our damage rheology to a plate deforming under applied shear, a constant bending moment, and a constant load. We simulate a wide range of behaviors from slow relaxation to instantaneous failure, over timescales that span six orders of magnitude. Stress relaxation produces elastic-perfectly plastic behavior in cases where failure does not occur. For cases of failure, we observe a rapid increase in damage leading to failure. The changes in the rate of damage accumulation in failure cases are similar to the changes in b-values of acoustic emissions observed in triaxial compression tests of fractured rock and b-value changes prior to some large earthquakes. Thus continuum damage mechanics can simulate ductile behavior due to brittle mechanisms as well as observations of laboratory experiments and seismicity.

Resilience Engineering in Critical Long Term Aerospace Software Systems: A New Approach to Spacecraft Software Safety

NASA Astrophysics Data System (ADS)

Dulo, D. A.

Safety critical software systems permeate spacecraft, and in a long term venture like a starship would be pervasive in every system of the spacecraft. Yet software failure today continues to plague both the systems and the organizations that develop them resulting in the loss of life, time, money, and valuable system platforms. A starship cannot afford this type of software failure in long journeys away from home. A single software failure could have catastrophic results for the spaceship and the crew onboard. This paper will offer a new approach to developing safe reliable software systems through focusing not on the traditional safety/reliability engineering paradigms but rather by focusing on a new paradigm: Resilience and Failure Obviation Engineering. The foremost objective of this approach is the obviation of failure, coupled with the ability of a software system to prevent or adapt to complex changing conditions in real time as a safety valve should failure occur to ensure safe system continuity. Through this approach, safety is ensured through foresight to anticipate failure and to adapt to risk in real time before failure occurs. In a starship, this type of software engineering is vital. Through software developed in a resilient manner, a starship would have reduced or eliminated software failure, and would have the ability to rapidly adapt should a software system become unstable or unsafe. As a result, long term software safety, reliability, and resilience would be present for a successful long term starship mission.

Digital implementation of the TF30-P-3 turbofan engine control

NASA Technical Reports Server (NTRS)

Cwynar, D. S.; Batterton, P. G.

1975-01-01

The standard hydromechanical control modes for TF30-P-3 engine were implemented on a digital process control computer. Programming methods are described, and a method is presented to solve stability problems associated with fast response dynamic loops contained within the exhaust nozzle control. A modification of the exhaust nozzle control to provide for either velocity or position servoactuation systems is discussed. Transient response of the digital control was evaluated by tests on a real time hybrid simulation of the TF30-P-3 engine. It is shown that the deadtime produced by the calculation time delay between sampling and final output is more significant to transient response than the effects associated with sampling rate alone. For the main fuel control, extended update and calculation times resulted in a lengthened transient response to throttle bursts from idle to intermediate with an increase in high pressure compressor stall margin. Extremely long update intervals of 250 msec could be achieved without instability. Update extension for the exhaust nozzle control resulted in a delayed response of the afterburner light-off detector and exhaust nozzle overshoot with resulting fan oversuppression. Long update times of 150 msec caused failure of the control due to a false indication by the blowout detector.

Durability Testing of Tank Track Rubber Compounds under Cyclic Loading

DTIC Science & Technology

1987-10-15

depiction of time-to-failure vs applied ( engineering ) stress for 15TP-14AX rubber compounds in creep experiments at 23"C. (After McKenna (1...behavior of the 15TP-14AX rubber was carried out at 23, 75, 125 and 175 OC. The logarithm of the time to failure vs. the applied ( engineering ) stress is...4 3I. I I 5 10 15 a/MPa Figure 3-7 Semilogarith±ic depiction of time-to--failure vs applied ( engineering ) stress for 15TP-14AX rubber compounds in

Normal people working in normal organizations with normal equipment: system safety and cognition in a mid-air collision.

PubMed

de Carvalho, Paulo Victor Rodrigues; Gomes, José Orlando; Huber, Gilbert Jacob; Vidal, Mario Cesar

2009-05-01

A fundamental challenge in improving the safety of complex systems is to understand how accidents emerge in normal working situations, with equipment functioning normally in normally structured organizations. We present a field study of the en route mid-air collision between a commercial carrier and an executive jet, in the clear afternoon Amazon sky in which 154 people lost their lives, that illustrates one response to this challenge. Our focus was on how and why the several safety barriers of a well structured air traffic system melted down enabling the occurrence of this tragedy, without any catastrophic component failure, and in a situation where everything was functioning normally. We identify strong consistencies and feedbacks regarding factors of system day-to-day functioning that made monitoring and awareness difficult, and the cognitive strategies that operators have developed to deal with overall system behavior. These findings emphasize the active problem-solving behavior needed in air traffic control work, and highlight how the day-to-day functioning of the system can jeopardize such behavior. An immediate consequence is that safety managers and engineers should review their traditional safety approach and accident models based on equipment failure probability, linear combinations of failures, rules and procedures, and human errors, to deal with complex patterns of coincidence possibilities, unexpected links, resonance among system functions and activities, and system cognition.

Neural Network-Based Sensor Validation for Turboshaft Engines

NASA Technical Reports Server (NTRS)

Moller, James C.; Litt, Jonathan S.; Guo, Ten-Huei

1998-01-01

Sensor failure detection, isolation, and accommodation using a neural network approach is described. An auto-associative neural network is configured to perform dimensionality reduction on the sensor measurement vector and provide estimated sensor values. The sensor validation scheme is applied in a simulation of the T700 turboshaft engine in closed loop operation. Performance is evaluated based on the ability to detect faults correctly and maintain stable and responsive engine operation. The set of sensor outputs used for engine control forms the network input vector. Analytical redundancy is verified by training networks of successively smaller bottleneck layer sizes. Training data generation and strategy are discussed. The engine maintained stable behavior in the presence of sensor hard failures. With proper selection of fault determination thresholds, stability was maintained in the presence of sensor soft failures.

76 FR 78863 - Airworthiness Directives; Rolls-Royce Corporation Turboshaft Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-20

... engines. This proposed AD was prompted by seven cases reported of released turbine blades and shrouds... wheels for cracks in the turbine blades. We are proposing this AD to prevent failure of 3rd or 4th stage turbine wheel blades which could cause engine failure and damage to the airplane. DATES: We must receive...

Hydraulic integration and shrub growth form linked across continental aridity gradients

Treesearch

H. Jochen Schenk; Christine M. Goedhart; Marisa Nordenstahl; Hugo I. Martinez Cabrera; Cynthia S. Jones

2008-01-01

Both engineered hydraulic systems and plant hydraulic systems are protected against failure by resistance, reparability, and redundancy. A basic rule of reliability engineering is that the level of independent redundancy should increase with increasing risk of fatal system failure. Here we show that hydraulic systems of plants function as predicted by this engineering...

Assessing the Value-Added by the Environmental Testing Process with the Aide of Physics/Engineering of Failure Evaluations

NASA Technical Reports Server (NTRS)

Cornford, S.; Gibbel, M.

1997-01-01

NASA's Code QT Test Effectiveness Program is funding a series of applied research activities focused on utilizing the principles of physics and engineering of failure and those of engineering economics to assess and improve the value-added by the various validation and verification activities to organizations.

76 FR 79051 - Airworthiness Directives; Lycoming Engines, Fuel Injected Reciprocating Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-21

... models requiring inspections. We are issuing this AD to prevent failure of the fuel injector fuel lines... to prevent failure of the fuel injector fuel lines that would allow fuel to spray into the engine... injector nozzles, and replace as necessary any fuel injector fuel line and clamp that does not meet all...

Reliability growth modeling analysis of the space shuttle main engines based upon the Weibull process

NASA Technical Reports Server (NTRS)

Wheeler, J. T.

1990-01-01

The Weibull process, identified as the inhomogeneous Poisson process with the Weibull intensity function, is used to model the reliability growth assessment of the space shuttle main engine test and flight failure data. Additional tables of percentage-point probabilities for several different values of the confidence coefficient have been generated for setting (1-alpha)100-percent two sided confidence interval estimates on the mean time between failures. The tabled data pertain to two cases: (1) time-terminated testing, and (2) failure-terminated testing. The critical values of the three test statistics, namely Cramer-von Mises, Kolmogorov-Smirnov, and chi-square, were calculated and tabled for use in the goodness of fit tests for the engine reliability data. Numerical results are presented for five different groupings of the engine data that reflect the actual response to the failures.

Reusable rocket engine turbopump condition monitoring

NASA Technical Reports Server (NTRS)

Hampson, M. E.

1984-01-01

Significant improvements in engine readiness with reductions in maintenance costs and turn-around times can be achieved with an engine condition monitoring systems (CMS). The CMS provides health status of critical engine components, without disassembly, through monitoring with advanced sensors. Engine failure reports over 35 years were categorized into 20 different modes of failure. Rotor bearings and turbine blades were determined to be the most critical in limiting turbopump life. Measurement technologies were matched to each of the failure modes identified. Three were selected to monitor the rotor bearings and turbine blades: the isotope wear detector and fiberoptic deflectometer (bearings), and the fiberoptic pyrometer (blades). Signal processing algorithms were evaluated for their ability to provide useful health data to maintenance personnel. Design modifications to the Space Shuttle Main Engine (SSME) high pressure turbopumps were developed to incorporate the sensors. Laboratory test fixtures have been designed for monitoring the rotor bearings and turbine blades in simulated turbopump operating conditions.

The effect of preignition on cylinder temperatures, pressures, power output, and piston failures

NASA Technical Reports Server (NTRS)

Corrington, Lester C; Fisher, William F

1947-01-01

An investigation was conducted using a cylinder of a V-type liquid-cooled engine to observe the behavior of the cylinder when operated under preignition conditions. Data were recorded that showed cylinder-head temperatures, time of ignition, engine speed, power output, and change in maximum cylinder pressure as a function of time as the engine entered preignition and was allowed to operate under preignition conditions for a short time. The effects of the following variables on the engine behavior during preignition were investigated: fuel-air ratio, power level, aromatic content of fuel, engine speed, mixture temperature, and preignition source. The power levels at which preignition would cause complete piston failure for the selected engine operating conditions and the types of failure encountered when using various values of clearance between the piston and cylinder barrel were determined. The fuels used had performance numbers high enough to preclude any possibility of knock throughout the test program.

Solving ordinary differential equations by electrical analogy: a multidisciplinary teaching tool

NASA Astrophysics Data System (ADS)

Sanchez Perez, J. F.; Conesa, M.; Alhama, I.

2016-11-01

Ordinary differential equations are the mathematical formulation for a great variety of problems in science and engineering, and frequently, two different problems are equivalent from a mathematical point of view when they are formulated by the same equations. Students acquire the knowledge of how to solve these equations (at least some types of them) using protocols and strict algorithms of mathematical calculation without thinking about the meaning of the equation. The aim of this work is that students learn to design network models or circuits in this way; with simple knowledge of them, students can establish the association of electric circuits and differential equations and their equivalences, from a formal point of view, that allows them to associate knowledge of two disciplines and promote the use of this interdisciplinary approach to address complex problems. Therefore, they learn to use a multidisciplinary tool that allows them to solve these kinds of equations, even students of first course of engineering, whatever the order, grade or type of non-linearity. This methodology has been implemented in numerous final degree projects in engineering and science, e.g., chemical engineering, building engineering, industrial engineering, mechanical engineering, architecture, etc. Applications are presented to illustrate the subject of this manuscript.

Engineering Education in K-12 Schools

NASA Astrophysics Data System (ADS)

Spence, Anne

2013-03-01

Engineers rely on physicists as well as other scientists and mathematicians to explain the world in which we live. Engineers take this knowledge of the world and use it to create the world that never was. The teaching of physics and other sciences as well as mathematics is critical to maintaining our national workforce. Science and mathematics education are inherently different, however, from engineering education. Engineering educators seek to enable students to develop the habits of mind critical for innovation. Through understanding of the engineering design process and how it differs from the scientific method, students can apply problem and project based learning to solve the challenges facing society today. In this talk, I will discuss the elements critical to a solid K-12 engineering education that integrates science and mathematics to solve challenges throughout the world.

Perm State University HPC-hardware and software services: capabilities for aircraft engine aeroacoustics problems solving

NASA Astrophysics Data System (ADS)

Demenev, A. G.

2018-02-01

The present work is devoted to analyze high-performance computing (HPC) infrastructure capabilities for aircraft engine aeroacoustics problems solving at Perm State University. We explore here the ability to develop new computational aeroacoustics methods/solvers for computer-aided engineering (CAE) systems to handle complicated industrial problems of engine noise prediction. Leading aircraft engine engineering company, including “UEC-Aviadvigatel” JSC (our industrial partners in Perm, Russia), require that methods/solvers to optimize geometry of aircraft engine for fan noise reduction. We analysed Perm State University HPC-hardware resources and software services to use efficiently. The performed results demonstrate that Perm State University HPC-infrastructure are mature enough to face out industrial-like problems of development CAE-system with HPC-method and CFD-solvers.

Determination of optimal trajectories for an aircraft returning to the runway following a complete loss of thrust after takeoff

NASA Astrophysics Data System (ADS)

Gordon, Craig A.

This thesis examines the ability of a small, single-engine airplane to return to the runway following an engine failure shortly after takeoff. Two sets of trajectories are examined. One set of trajectories has the airplane fly a straight climb on the runway heading until engine failure. The other set of trajectories has the airplane perform a 90° turn at an altitude of 500 feet and continue until engine failure. Various combinations of wind speed, wind direction, and engine failure times are examined. The runway length required to complete the entire flight from the beginning of the takeoff roll to wheels stop following the return to the runway after engine failure is calculated for each case. The optimal trajectories following engine failure consist of three distinct segments: a turn back toward the runway using a large bank angle and angle of attack; a straight glide; and a reversal turn to align the airplane with the runway. The 90° turn results in much shorter required runway lengths at lower headwind speeds. At higher headwind speeds, both sets of trajectories are limited by the length of runway required for the landing rollout, but the straight climb cases generally require a lower angle of attack to complete the flight. The glide back to the runway is performed at an airspeed below the best glide speed of the airplane due to the need to conserve potential energy after the completion of the turn back toward the runway. The results are highly dependent on the rate of climb of the airplane during powered flight. The results of this study can aid the pilot in determining whether or not a return to the runway could be performed in the event of an engine failure given the specific wind conditions and runway length at the time of takeoff. The results can also guide the pilot in determining the takeoff profile that would offer the greatest advantage in returning to the runway.

Theoretical Overview on the Improvement of Interest in Learning Theoretical Course for Engineering Students

ERIC Educational Resources Information Center

Xiao, Manlin; Zhang, Jianglin

2016-01-01

The phenomenon that engineering students have little interest in theoretical knowledge learning is more and more apparent. Therefore, most students fail to understand and apply theories to solve practical problems. To solve this problem, the importance of improving students' interest in the learning theoretical course is discussed firstly in this…

Adapting Experiential Learning to Develop Problem-Solving Skills in Deaf and Hard-of-Hearing Engineering Students

ERIC Educational Resources Information Center

Marshall, Matthew M.; Carrano, Andres L.; Dannels, Wendy A.

2016-01-01

Individuals who are deaf and hard-of-hearing (DHH) are underrepresented in science, technology, engineering, and mathematics (STEM) professions, and this may be due in part to their level of preparation in the development and retention of mathematical and problem-solving skills. An approach was developed that incorporates experiential learning and…

Solving mixed integer nonlinear programming problems using spiral dynamics optimization algorithm

NASA Astrophysics Data System (ADS)

Kania, Adhe; Sidarto, Kuntjoro Adji

2016-02-01

Many engineering and practical problem can be modeled by mixed integer nonlinear programming. This paper proposes to solve the problem with modified spiral dynamics inspired optimization method of Tamura and Yasuda. Four test cases have been examined, including problem in engineering and sport. This method succeeds in obtaining the optimal result in all test cases.

Student Perspectives on the Flipped-Classroom Approach and Collaborative Problem-Solving Process

ERIC Educational Resources Information Center

Karabulut-Ilgu, Aliye; Yao, Suhan; Savolainen, Peter; Jahren, Charles

2018-01-01

The flipped-classroom approach has gained increasing popularity and interest in engineering education. The purpose of this study was to investigate (a) student perspectives on the flipped-classroom approach in a transportation-engineering course and (b) how students used the in-class time dedicated to collaborative problem solving. To this end,…

Investigating and Developing Engineering Students' Mathematical Modelling and Problem-Solving Skills

ERIC Educational Resources Information Center

Wedelin, Dag; Adawi, Tom; Jahan, Tabassum; Andersson, Sven

2015-01-01

How do engineering students approach mathematical modelling problems and how can they learn to deal with such problems? In the context of a course in mathematical modelling and problem solving, and using a qualitative case study approach, we found that the students had little prior experience of mathematical modelling. They were also inexperienced…

Engineering applications of metaheuristics: an introduction

NASA Astrophysics Data System (ADS)

Oliva, Diego; Hinojosa, Salvador; Demeshko, M. V.

2017-01-01

Metaheuristic algorithms are important tools that in recent years have been used extensively in several fields. In engineering, there is a big amount of problems that can be solved from an optimization point of view. This paper is an introduction of how metaheuristics can be used to solve complex problems of engineering. Their use produces accurate results in problems that are computationally expensive. Experimental results support the performance obtained by the selected algorithms in such specific problems as digital filter design, image processing and solar cells design.

Failure Engineering Study and Accelerated Stress Test Results for the Mars Global Surveyor Spacecraft's Power Shunt Assemblies

NASA Technical Reports Server (NTRS)

Gibbel, Mark; Larson, Timothy

2000-01-01

An Engineering-of-Failure approach to designing and executing an accelerated product qualification test was performed to support a risk assessment of a "work-around" necessitated by an on-orbit failure of another piece of hardware on the Mars Global Surveyor spacecraft. The proposed work-around involved exceeding the previous qualification experience both in terms of extreme cold exposure level and in terms of demonstrated low cycle fatigue life for the power shunt assemblies. An analysis was performed to identify potential failure sites, modes and associated failure mechanisms consistent with the new use conditions. A test was then designed and executed which accelerated the failure mechanisms identified by analysis. Verification of the resulting failure mechanism concluded the effort.

Altitude-Test-Chamber Investigation of the Endurance and Performance Characteristics of the J65-W-7 Engine at a Mach Number of 2.0

NASA Technical Reports Server (NTRS)

Biermann, A.E.; Braithwaite, Willis M.

1955-01-01

An investigation of the endurance characteristics, at high Mach number, of the J65-W-7 engine was made in an altitude chamber at the Lewis laboratory. The investigation was made to determine whether this engine can be operated at flight conditions of Mach 2 at 35,000-feet altitude (inlet temperature, 250 F) as a limited-service-life engine Failure of the seventh-stage aluminum compressor blades occurred in both engines tested and was attributed to insufficient strength of the blade fastenings at the elevated temperatures. For the conditions of these tests, the results showed that it is reasonable to expect 10 to 15 minutes of satisfactory engine operation before failure. The high temperatures and pressures imposed upon the compressor housing caused no permanent deformation. In general, the performance of the engines tested was only slightly affected by the high ram conditions of this investigation. There was no discernible depreciation of performance with time prior to failure.

Some problems in mechanics of growing solids with applications to AM technologies

NASA Astrophysics Data System (ADS)

Manzhirov, A. V.

2018-04-01

Additive Manufacturing (AM) technologies are an exciting area of the modern industrial revolution and have applications in engineering, medicine, electronics, aerospace industry, etc. AM enables cost-effective production of customized geometry and parts by direct fabrication from 3D data and mathematical models. Despite much progress in AM technologies, problems of mechanical analysis for AM fabricated parts yet remain to be solved. This paper deals with three main mechanical problems: the onset of residual stresses, which occur in the AM process and can lead to failure of the parts, the distortion of the final shape of AM fabricated parts, and the development of technological solutions aimed at improving existing AM technologies and creating new ones. An approach proposed deals with the construction of adequate analytical model and effective methods for the simulation of AM processes for fabricated solid parts.

Sensor failure detection for jet engines

NASA Technical Reports Server (NTRS)

Merrill, Walter C.

1988-01-01

The use of analytical redundancy to improve gas turbine engine control system reliability through sensor failure detection, isolation, and accommodation is surveyed. Both the theoretical and application papers that form the technology base of turbine engine analytical redundancy research are discussed. Also, several important application efforts are reviewed. An assessment of the state-of-the-art in analytical redundancy technology is given.

Elementary Teachers' Reflections on Design Failures and Use of Fail Words after Teaching Engineering for Two Years

ERIC Educational Resources Information Center

Lottero-Perdue, Pamela S.; Parry, Elizabeth A.

2017-01-01

This mixed-methods study examines how teachers who have taught one or two units of the Engineering is Elementary (EiE) curriculum for two years reported on: students' responses to design failure; the ways in which they, the teachers, supported these students and used fail words (e.g. fail, failure); and the teachers' broad perspectives and…

75 FR 7996 - Airworthiness Directives; Thielert Aircraft Engines GmbH (TAE) Models TAE 125-01 and TAE 125-02...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-23

... showed that it was mainly the result of failure of the Proportional Pressure Reducing Valve (PPRV) (also... identified as the primary source of vibrations for the PPRV, and it has also been determined that failure of... TAE 125 engines. The investigations showed that it was mainly the result of failure of the PPRV due to...

76 FR 52213 - Airworthiness Directives; General Electric Company (GE) CF6-45 Series and CF6-50 Series Turbofan...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-22

... is separated from the engine. This AD was prompted by seven reports of uncontained failures of LPT... engine failure and damage to the airplane. DATES: This AD is effective September 26, 2011. ADDRESSES: You... reports of uncontained failures of LPT rotor stage 3 disks and eight reports of cracked LPT rotor stage 3...

Some challenges in designing a lunar, Martian, or microgravity CELSS.

PubMed

Salisbury, F B

1992-01-01

The design of a bioregenerative life-support system (a Controlled Ecological Life-Support System or CELSS) for long-duration stays on the moon, Mars, or in a space craft poses formidable problems in engineering and in theory. Technological (hardware) problems include: (1) Creation and control of gas composition and pressure, temperature, light, humidity, and air circulation, especially in microgravity to 1/3 xg and in the vacuum of space. Light (energy demanding), CO2 levels, and the rooting media are special problems for plants. (2) Developing specialized equipment for food preparation. (3) Equipment development for waste recycling. (4) Development of computer systems for environmental monitoring and control as well as several other functions. Problems of theory (software) include: (1) Determining crop species and cultivars (some bred especially for CELSS). (2) Optimum environments and growing and harvesting techniques for each crop. (3) Best and most efficient food-preparation techniques and required equipment. (4) Best and most efficient waste-recycling techniques and equipment. This topic includes questions about the extent of closure, resupply, and waste storage. (5) How to achieve long-term stability. (6) How to avoid catastrophic failures--and how to recover from near-catastrophic failures (for example, plant diseases). Many problems must be solved.

Some challenges in designing a lunar, Martian, or microgravity CELSS

NASA Astrophysics Data System (ADS)

Salisbury, Frank B.

The design of a bioregenerative life-support system (a Controlled Ecological Life-Support System or CELSS) for long-duration stays on the moon, Mars, or in a space craft poses formidable problems in engineering and in theory. Technological (hardware) problems include: (1) Creation and control of gas composition and pressure, temperature, light, humidity, and air circulation, especially in microgravity to 1/3xg and in the vacuum of space. Light (energy demanding), CO 2 levels, and the rooting media are special problems for plants. (2) Developing specialized equipment for food preparation. (3) Equipment development for waste recycling. (4) Development of computer systems for environmental monitoring and control as well as several other functions. Problems of theory (software) include: (1) Determining crop species and cultivars (some bred especially for CELSS). (2) Optimum environments and growing and harvesting techniques for each crop. (3) Best and most efficient food-preparation techniques and required equipment. (4) Best and most efficient waste-recycling techniques and equipment. This topic includes questions about the extent of closure, resupply, and waste storage. (5) How to achieve long-term stability. (6) How to avoid catastrophic failures-and how to recover from near-catastrophic failures (for example, plant diseases). Many problems must be solved.

Photolithography diagnostic expert systems: a systematic approach to problem solving in a wafer fabrication facility

NASA Astrophysics Data System (ADS)

Weatherwax Scott, Caroline; Tsareff, Christopher R.

1990-06-01

One of the main goals of process engineering in the semiconductor industry is to improve wafer fabrication productivity and throughput. Engineers must work continuously toward this goal in addition to performing sustaining and development tasks. To accomplish these objectives, managers must make efficient use of engineering resources. One of the tools being used to improve efficiency is the diagnostic expert system. Expert systems are knowledge based computer programs designed to lead the user through the analysis and solution of a problem. Several photolithography diagnostic expert systems have been implemented at the Hughes Technology Center to provide a systematic approach to process problem solving. This systematic approach was achieved by documenting cause and effect analyses for a wide variety of processing problems. This knowledge was organized in the form of IF-THEN rules, a common structure for knowledge representation in expert system technology. These rules form the knowledge base of the expert system which is stored in the computer. The systems also include the problem solving methodology used by the expert when addressing a problem in his area of expertise. Operators now use the expert systems to solve many process problems without engineering assistance. The systems also facilitate the collection of appropriate data to assist engineering in solving unanticipated problems. Currently, several expert systems have been implemented to cover all aspects of the photolithography process. The systems, which have been in use for over a year, include wafer surface preparation (HMDS), photoresist coat and softbake, align and expose on a wafer stepper, and develop inspection. These systems are part of a plan to implement an expert system diagnostic environment throughout the wafer fabrication facility. In this paper, the systems' construction is described, including knowledge acquisition, rule construction, knowledge refinement, testing, and evaluation. The roles played by the process engineering expert and the knowledge engineer are discussed. The features of the systems are shown, particularly the interactive quality of the consultations and the ease of system use.

Graceful Failure, Engineering, and Planning for Extremes: The Engineering for Climate Extremes Partnership (ECEP)

NASA Astrophysics Data System (ADS)

Bruyere, C. L.; Tye, M. R.; Holland, G. J.; Done, J.

2015-12-01

Graceful failure acknowledges that all systems will fail at some level and incorporates the potential for failure as a key component of engineering design, community planning, and the associated research and development. This is a fundamental component of the ECEP, an interdisciplinary partnership bringing together scientific, engineering, cultural, business and government expertise to develop robust, well-communicated predictions and advice on the impacts of weather and climate extremes in support of decision-making. A feature of the partnership is the manner in which basic and applied research and development is conducted in direct collaboration with the end user. A major ECEP focus is the Global Risk and Resilience Toolbox (GRRT) that is aimed at developing public-domain, risk-modeling and response data and planning system in support of engineering design, and community planning and adaptation activities. In this presentation I will outline the overall ECEP and GRIP activities, and expand on the 'graceful failure' concept. Specific examples for direct assessment and prediction of hurricane impacts and damage potential will be included.

On the Role of Situational Stressors in the Disruption of Global Neural Network Stability during Problem Solving.

PubMed

Liu, Mengting; Amey, Rachel C; Forbes, Chad E

2017-12-01

When individuals are placed in stressful situations, they are likely to exhibit deficits in cognitive capacity over and above situational demands. Despite this, individuals may still persevere and ultimately succeed in these situations. Little is known, however, about neural network properties that instantiate success or failure in both neutral and stressful situations, particularly with respect to regions integral for problem-solving processes that are necessary for optimal performance on more complex tasks. In this study, we outline how hidden Markov modeling based on multivoxel pattern analysis can be used to quantify unique brain states underlying complex network interactions that yield either successful or unsuccessful problem solving in more neutral or stressful situations. We provide evidence that brain network stability and states underlying synchronous interactions in regions integral for problem-solving processes are key predictors of whether individuals succeed or fail in stressful situations. Findings also suggested that individuals utilize discriminate neural patterns in successfully solving problems in stressful or neutral situations. Findings overall highlight how hidden Markov modeling can provide myriad possibilities for quantifying and better understanding the role of global network interactions in the problem-solving process and how the said interactions predict success or failure in different contexts.

Fault Tree Based Diagnosis with Optimal Test Sequencing for Field Service Engineers

NASA Technical Reports Server (NTRS)

Iverson, David L.; George, Laurence L.; Patterson-Hine, F. A.; Lum, Henry, Jr. (Technical Monitor)

1994-01-01

When field service engineers go to customer sites to service equipment, they want to diagnose and repair failures quickly and cost effectively. Symptoms exhibited by failed equipment frequently suggest several possible causes which require different approaches to diagnosis. This can lead the engineer to follow several fruitless paths in the diagnostic process before they find the actual failure. To assist in this situation, we have developed the Fault Tree Diagnosis and Optimal Test Sequence (FTDOTS) software system that performs automated diagnosis and ranks diagnostic hypotheses based on failure probability and the time or cost required to isolate and repair each failure. FTDOTS first finds a set of possible failures that explain exhibited symptoms by using a fault tree reliability model as a diagnostic knowledge to rank the hypothesized failures based on how likely they are and how long it would take or how much it would cost to isolate and repair them. This ordering suggests an optimal sequence for the field service engineer to investigate the hypothesized failures in order to minimize the time or cost required to accomplish the repair task. Previously, field service personnel would arrive at the customer site and choose which components to investigate based on past experience and service manuals. Using FTDOTS running on a portable computer, they can now enter a set of symptoms and get a list of possible failures ordered in an optimal test sequence to help them in their decisions. If facilities are available, the field engineer can connect the portable computer to the malfunctioning device for automated data gathering. FTDOTS is currently being applied to field service of medical test equipment. The techniques are flexible enough to use for many different types of devices. If a fault tree model of the equipment and information about component failure probabilities and isolation times or costs are available, a diagnostic knowledge base for that device can be developed easily.

Designing for Productive Failure

ERIC Educational Resources Information Center

Kapur, Manu; Bielaczyc, Katerine

2012-01-01

In this article, we describe the design principles undergirding "productive failure" (PF; M. Kapur, 2008). We then report findings from an ongoing program of research on PF in mathematical problem solving in 3 Singapore public schools with significantly different mathematical ability profiles, ranging from average to lower ability. In…

Tissue engineering as innovative chance for organ replacement in radical tumor surgery.

PubMed

Alberti, C

2013-03-01

Different pathological conditions such as congenital organ absence, severe organ injuries, end-stage organ failure and malignancy-related organ removal, have few effective therapeutic options a part from a whole organ transplant, that, however, often meets with a serious shortage of suitable donor organs. The purpose of this paper consists in highlighting what the novel tissue engineering approaches might help to solve such problems. EMERGING CONCEPTS: A recent approach in tissue/organ engineering, particularly to build bioartificial airways, is the procedure of decellularizing a whole donor organ to obtain a complex 3D-biomatrix-scaffold maintaining the intrinsic vascular network, that is subsequently recellularized with recipient's autologous organ-specific differentiated cells or/and stem cells, to build a potentially functional biological substitute. Such strategy has been clinically used to replace organ in trachea/broncus tumor patients. In another approach, mainly used to construct a bioartificial urinary bladder tissue, different types of either biodegradable synthetic polymers or naturally-derived matrices or even polymer/biomatrix-composite materials are used as scaffold for either cell-free or autologous cell-seeded tissue engineering procedures. So far, such technique has been mainly used to make an augmentation cystoplasty in patients with end-stage poorly compliant neuropathic bladder or in exstrophic bladder subjects. Intriguing developments in biomaterial science, nanotechnologies, stem cell biology, and further improvements in bioreactor manufacturing will allow to generate, in the near future, tissue engineered organs that, as for structure/function so the native one-like, might represent the optimum solution to replace organs in tumor surgery.

Providing a Turn for the Better

NASA Technical Reports Server (NTRS)

2004-01-01

Engineers are tasked with designing new systems every day to meet changing or unexpected technical requirements. After the tragic explosion of the Space Shuttle Challenger on January 28, 1986, NASA engineers embarked on a complete overhaul of many of their long-standing quality systems and procedures. When the official cause of the accident was determined to be an O-ring failure in the right Solid Rocket Booster, NASA's Shuttle Program initiated a thorough redesign of the rocket boosters' clevis ends, which are the O-ring's mating surfaces. One of the unique systems that NASA engineers developed as a result of this effort included a heating assembly that is coupled to the outside of the rocket boosters. When the assembly is affixed to the external surface of the boosters, the very nature of its design allows for the warming of the O-rings prior to launch. After the engineers completed the assembly's design, however, they found that it was nearly impossible to tighten the spanner nuts required for attaching the system, given the minimum amount of clearance they had in the limited and confined space. Under these circumstances, the standard wrenches typically used for tightening these types of nuts did not work, and there were no other existing devices to solve the problem. NASA engineers embraced the challenge, developing a torque wrench tool adapter that allowed for a full rotation of spanner nuts in confined spaces. The tool, which is similar to an open-ended crowfoot wrench and a fixed-face spanner wrench, contains two dowel pins that center and lock the wrench onto the nut.

Evaluation of creative problem-solving abilities in undergraduate structural engineers through interdisciplinary problem-based learning

NASA Astrophysics Data System (ADS)

McCrum, Daniel Patrick

2017-11-01

For a structural engineer, effective communication and interaction with architects cannot be underestimated as a key skill to success throughout their professional career. Structural engineers and architects have to share a common language and understanding of each other in order to achieve the most desirable architectural and structural designs. This interaction and engagement develops during their professional career but needs to be nurtured during their undergraduate studies. The objective of this paper is to present the strategies employed to engage higher order thinking in structural engineering students in order to help them solve complex problem-based learning (PBL) design scenarios presented by architecture students. The strategies employed were applied in the experimental setting of an undergraduate module in structural engineering at Queen's University Belfast in the UK. The strategies employed were active learning to engage with content knowledge, the use of physical conceptual structural models to reinforce key concepts and finally, reinforcing the need for hand sketching of ideas to promote higher order problem-solving. The strategies employed were evaluated through student survey, student feedback and module facilitator (this author) reflection. The strategies were qualitatively perceived by the tutor and quantitatively evaluated by students in a cross-sectional study to help interaction with the architecture students, aid interdisciplinary learning and help students creatively solve problems (through higher order thinking). The students clearly enjoyed this module and in particular interacting with structural engineering tutors and students from another discipline.

Group Design Problems in Engineering Design Graphics.

ERIC Educational Resources Information Center

Kelley, David

2001-01-01

Describes group design techniques used within the engineering design graphics sequence at Western Washington University. Engineering and design philosophies such as concurrent engineering place an emphasis on group collaboration for the solving of design problems. (Author/DDR)

Risk Analysis of Earth-Rock Dam Failures Based on Fuzzy Event Tree Method

PubMed Central

Fu, Xiao; Gu, Chong-Shi; Su, Huai-Zhi; Qin, Xiang-Nan

2018-01-01

Earth-rock dams make up a large proportion of the dams in China, and their failures can induce great risks. In this paper, the risks associated with earth-rock dam failure are analyzed from two aspects: the probability of a dam failure and the resulting life loss. An event tree analysis method based on fuzzy set theory is proposed to calculate the dam failure probability. The life loss associated with dam failure is summarized and refined to be suitable for Chinese dams from previous studies. The proposed method and model are applied to one reservoir dam in Jiangxi province. Both engineering and non-engineering measures are proposed to reduce the risk. The risk analysis of the dam failure has essential significance for reducing dam failure probability and improving dam risk management level. PMID:29710824

Selected Core Thinking Skills and Cognitive Strategy of an Expert and Novice Engineer

ERIC Educational Resources Information Center

Dixon, Raymond A.

2011-01-01

This exploratory study highlights certain differences in the way an expert and a novice engineer used their analyzing and generating skills while solving a fairly ill-structured design problem. The expert tends to use more inferences and elaboration when solving the design problem and the novice tend to use analysis that is focused on the…

Space Shuttle Main Engine Quantitative Risk Assessment: Illustrating Modeling of a Complex System with a New QRA Software Package

NASA Technical Reports Server (NTRS)

Smart, Christian

1998-01-01

During 1997, a team from Hernandez Engineering, MSFC, Rocketdyne, Thiokol, Pratt & Whitney, and USBI completed the first phase of a two year Quantitative Risk Assessment (QRA) of the Space Shuttle. The models for the Shuttle systems were entered and analyzed by a new QRA software package. This system, termed the Quantitative Risk Assessment System(QRAS), was designed by NASA and programmed by the University of Maryland. The software is a groundbreaking PC-based risk assessment package that allows the user to model complex systems in a hierarchical fashion. Features of the software include the ability to easily select quantifications of failure modes, draw Event Sequence Diagrams(ESDs) interactively, perform uncertainty and sensitivity analysis, and document the modeling. This paper illustrates both the approach used in modeling and the particular features of the software package. The software is general and can be used in a QRA of any complex engineered system. The author is the project lead for the modeling of the Space Shuttle Main Engines (SSMEs), and this paper focuses on the modeling completed for the SSMEs during 1997. In particular, the groundrules for the study, the databases used, the way in which ESDs were used to model catastrophic failure of the SSMES, the methods used to quantify the failure rates, and how QRAS was used in the modeling effort are discussed. Groundrules were necessary to limit the scope of such a complex study, especially with regard to a liquid rocket engine such as the SSME, which can be shut down after ignition either on the pad or in flight. The SSME was divided into its constituent components and subsystems. These were ranked on the basis of the possibility of being upgraded and risk of catastrophic failure. Once this was done the Shuttle program Hazard Analysis and Failure Modes and Effects Analysis (FMEA) were used to create a list of potential failure modes to be modeled. The groundrules and other criteria were used to screen out the many failure modes that did not contribute significantly to the catastrophic risk. The Hazard Analysis and FMEA for the SSME were also used to build ESDs that show the chain of events leading from the failure mode occurence to one of the following end states: catastrophic failure, engine shutdown, or siccessful operation( successful with respect to the failure mode under consideration).

Strategy For Yield Control And Enhancement In VLSI Wafer Manufacturing

NASA Astrophysics Data System (ADS)

Neilson, B.; Rickey, D.; Bane, R. P.

1988-01-01

In most fully utilized integrated circuit (IC) production facilities, profit is very closely linked with yield. In even the most controlled manufacturing environments, defects due to foreign material are a still major contributor to yield loss. Ideally, an IC manufacturer will have ample engineering resources to address any problem that arises. In the real world, staffing limitations require that some tasks must be left undone and potential benefits left unrealized. Therefore, it is important to prioritize problems in a manner that will give the maximum benefit to the manufacturer. When offered a smorgasbord of problems to solve, most people (engineers included) will start with what is most interesting or the most comfortable to work on. By providing a system that accurately predicts the impact of a wide variety of defect types, a rational method of prioritizing engineering effort can be made. To that effect, a program was developed to determine and rank the major yield detractors in a mixed analog/digital FET manufacturing line. The two classical methods of determining yield detractors are chip failure analysis and defect monitoring on drop in test die. Both of these methods have short comings: 1) Chip failure analysis is painstaking and very time consuming. As a result, the sample size is very small. 2) Drop in test die are usually designed for device parametric analysis rather than defect analysis. To provide enough wafer real estate to do meaningful defect analysis would render the wafer worthless for production. To avoid these problems, a defect monitor was designed that provided enough area to detect defects at the same rate or better than the NMOS product die whose yield was to be optimized. The defect monitor was comprehensive and electrically testable using such equipment as the Prometrix LM25 and other digital testers. This enabled the quick accumulation of data which could be handled statistically and mapped individually. By scaling the defect densities found on the monitors to the known sensitivities of the product wafer, the defect types were ranked by defect limiting yield. (Limiting yield is the resultant product yield if there were no other failure mechanisms other than the type being considered.) These results were then compared to the product failure analysis results to verify that the monitor was finding the same types of defects in the same proportion which were troubling our product. Finally, the major defect types were isolated and reduced using the short loop capability of the monitor.

Evaluation of lightweight material concepts for aircraft turbine engine rotor failure protection

DOT National Transportation Integrated Search

1997-07-01

Results of the evaluation of lightweight materials for aircraft turbine engine rotor failure protection are presented in this report. The program consisted of two phases. Phase 1 was an evaluation of a group of composite materials which could possibl...

Full-Authority Fault-Tolerant Electronic Engine Control System for Variable Cycle Engines.

DTIC Science & Technology

1982-04-01

single internally self-checked VLSI micro - processor . The selected configuration is an externally checked pair of com- mercially available...Electronic Engine Control FPMH Failures per Million Hours FTMP Fault Tolerant Multi- Processor FTSC Fault Tolerant Spaceborn Computer GRAMP Generalized...Removal * MTBR Mean Time Between Repair MTTF Mean Time to Failure xiii List of Abbreviations (continued) - NH High Pressure Rotor Speed O&S Operating

Engineered Heart Repair.

PubMed

Fujita, B; Zimmermann, W-H

2017-08-01

There is a pressing need for the development of advanced heart failure therapeutics. Current state-of-the-art is protection from neurohumoral overstimulation, which fails to address the underlying cause of heart failure, namely loss of cardiomyocytes. Implantation of stem cell-derived cardiomyocytes via tissue-engineered myocardium is being advanced to realize the remuscularization of the failing heart. Here, we discuss pharmacological challenges pertaining to the clinical translation of tissue-engineered heart repair with a focus on engineered heart muscle (EHM). © 2017 American Society for Clinical Pharmacology and Therapeutics.

Definition of the Engineering Method.

ERIC Educational Resources Information Center

Koen, Billy Vaughn

In an effort to more clearly define the engineering method, this document attempts to draw distinctions between engineering and science. Part I, "Some Thoughts on Engineering," discusses strategies that engineers employ to solve problems, and the characteristics of the types of engineering problems. Part II, "The Principal Rule of the Engineering…

Instructional Design Issues in a Distributed Collaborative Engineering Design (CED) Instructional Environment

ERIC Educational Resources Information Center

Koszalka, Tiffany A.; Wu, Yiyan

2010-01-01

Changes in engineering practices have spawned changes in engineering education and prompted the use of distributed learning environments. A distributed collaborative engineering design (CED) course was designed to engage engineering students in learning about and solving engineering design problems. The CED incorporated an advanced interactive…

Howard University Energy Expert Systems Institute Summer Program (EESI)

NASA Technical Reports Server (NTRS)

Momoh, James A.; Chuku, Arunsi; Abban, Joseph

1996-01-01

Howard University, under the auspices of the Center for Energy Systems and Controls runs the Energy Expert Systems Institute (EESI) summer outreach program for high school/pre-college minority students. The main objectives are to introduce precollege minority students to research in the power industry using modern state-of-the-art technology such as Expert Systems, Fuzzy Logic and Artificial Neural Networks; to involve minority students in space power management, systems and failure diagnosis; to generate interest in career options in electrical engineering; and to experience problem-solving in a teamwork environment consisting of faculty, senior research associates and graduate students. For five weeks the students are exposed not only to the exciting experience of college life, but also to the inspiring field of engineering, especially electrical engineering. The program consists of lectures in the fundamentals of engineering, mathematics, communication skills and computer skills. The projects are divided into mini and major. Topics for the 1995 mini projects were Expert Systems for the Electric Bus and Breast Cancer Detection. Topics on the major projects include Hybrid Electric Vehicle, Solar Dynamics and Distribution Automation. On the final day, designated as 'EESI Day' the students did oral presentations of their projects and prizes were awarded to the best group. The program began in the summer of 1993. The reaction from the students has been very positive. The program also arranges field trips to special places of interest such as the NASA Goddard Space Center.

Productive Failure in STEM Education

ERIC Educational Resources Information Center

Trueman, Rebecca J.

2014-01-01

Science education is criticized because it often fails to support problem-solving skills in students. Instead, the instructional methods primarily emphasize didactic models that fail to engage students and reveal how the material can be applied to solve real problems. To overcome these limitations, this study asked participants in a general…

Mechanical testing of hydrogels in cartilage tissue engineering: beyond the compressive modulus.

PubMed

Xiao, Yinghua; Friis, Elizabeth A; Gehrke, Stevin H; Detamore, Michael S

2013-10-01

Injuries to articular cartilage result in significant pain to patients and high medical costs. Unfortunately, cartilage repair strategies have been notoriously unreliable and/or complex. Biomaterial-based tissue-engineering strategies offer great promise, including the use of hydrogels to regenerate articular cartilage. Mechanical integrity is arguably the most important functional outcome of engineered cartilage, although mechanical testing of hydrogel-based constructs to date has focused primarily on deformation rather than failure properties. In addition to deformation testing, as the field of cartilage tissue engineering matures, this community will benefit from the addition of mechanical failure testing to outcome analyses, given the crucial clinical importance of the success of engineered constructs. However, there is a tremendous disparity in the methods used to evaluate mechanical failure of hydrogels and articular cartilage. In an effort to bridge the gap in mechanical testing methods of articular cartilage and hydrogels in cartilage regeneration, this review classifies the different toughness measurements for each. The urgency for identifying the common ground between these two disparate fields is high, as mechanical failure is ready to stand alongside stiffness as a functional design requirement. In comparing toughness measurement methods between hydrogels and cartilage, we recommend that the best option for evaluating mechanical failure of hydrogel-based constructs for cartilage tissue engineering may be tensile testing based on the single edge notch test, in part because specimen preparation is more straightforward and a related American Society for Testing and Materials (ASTM) standard can be adopted in a fracture mechanics context.

High Reliability Engine Control Demonstrated for Aircraft Engines

NASA Technical Reports Server (NTRS)

Guo, Ten-Huei

1999-01-01

For a dual redundant-control system, which is typical for short-haul aircraft, if a failure is detected in a control sensor, the engine control is transferred to a safety mode and an advisory is issued for immediate maintenance action to replace the failed sensor. The safety mode typically results in severely degraded engine performance. The goal of the High Reliability Engine Control (HREC) program was to demonstrate that the neural-network-based sensor validation technology can safely operate an engine by using the nominal closed-loop control during and after sensor failures. With this technology, engine performance could be maintained, and the sensor could be replaced as a conveniently scheduled maintenance action.

A Planning Approach of Engineering Characteristics Based on QFD-TRIZ Integrated

NASA Astrophysics Data System (ADS)

Liu, Shang; Shi, Dongyan; Zhang, Ying

Traditional QFD planning method compromises contradictions between engineering characteristics to achieve higher customer satisfaction. However, this compromise trade-off can not eliminate the contradictions existing among the engineering characteristics which limited the overall customer satisfaction. QFD (Quality function deployment) integrated with TRIZ (the Russian acronym of the Theory of Inventive Problem Solving) becomes hot research recently for TRIZ can be used to solve contradictions between engineering characteristics which construct the roof of HOQ (House of quality). But, the traditional QFD planning approach is not suitable for QFD integrated with TRIZ for that TRIZ requires emphasizing the contradictions between engineering characteristics at problem definition stage instead of compromising trade-off. So, a new planning approach based on QFD / TRIZ integration is proposed in this paper, which based on the consideration of the correlation matrix of engineering characteristics and customer satisfaction on the basis of cost. The proposed approach suggests that TRIZ should be applied to solve contradictions at the first step, and the correlation matrix of engineering characteristics should be amended at the second step, and at next step IFR (ideal final result) must be validated, then planning execute. An example is used to illustrate the proposed approach. The application indicated that higher customer satisfaction can be met and the contradictions between the characteristic parameters are eliminated.

On Correlated Failures in Survivable Storage Systems

DTIC Science & Technology

2002-05-01

Littlewood, D.R. Miller, “Conceptual modeling of coincident failures in multiversion software”, IEEE Transactions on Software Engineering, Volume: 15 Issue...Recovery in Multiversion Software”. IEEE Transaction on Software Engineering, Vol. 16 No.3, March 1990 [Plank1997] J. Plank “A tutorial on Reed-Solomon

14 CFR 33.75 - Safety analysis.

Code of Federal Regulations, 2013 CFR

2013-01-01

... judgment and previous experience combined with sound design and test philosophies. (4) The applicant must... STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.75 Safety analysis. (a... the effects of failures and likely combination of failures be verified by test. (c) The primary...

14 CFR 33.75 - Safety analysis.

Code of Federal Regulations, 2010 CFR

2010-01-01

... judgment and previous experience combined with sound design and test philosophies. (4) The applicant must... STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.75 Safety analysis. (a... the effects of failures and likely combination of failures be verified by test. (c) The primary...

14 CFR 33.75 - Safety analysis.

Code of Federal Regulations, 2012 CFR

2012-01-01

... judgment and previous experience combined with sound design and test philosophies. (4) The applicant must... STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.75 Safety analysis. (a... the effects of failures and likely combination of failures be verified by test. (c) The primary...

14 CFR 33.75 - Safety analysis.

Code of Federal Regulations, 2014 CFR

2014-01-01

... judgment and previous experience combined with sound design and test philosophies. (4) The applicant must... STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.75 Safety analysis. (a... the effects of failures and likely combination of failures be verified by test. (c) The primary...

Sensor failure detection for jet engines using analytical redundance

NASA Technical Reports Server (NTRS)

Merrill, W. C.

1984-01-01

Analytical redundant sensor failure detection, isolation and accommodation techniques for gas turbine engines are surveyed. Both the theoretical technology base and demonstrated concepts are discussed. Also included is a discussion of current technology needs and ongoing Government sponsored programs to meet those needs.

Piloted simulation study of the effects of an automated trim system on flight characteristics of a light twin-engine airplane with one engine inoperative

NASA Technical Reports Server (NTRS)

Stewart, E. C.; Brown, P. W.; Yenni, K. R.

1986-01-01

A simulation study was conducted to investigate the piloting problems associated with failure of an engine on a generic light twin-engine airplane. A primary piloting problem for a light twin-engine airplane after an engine failure is maintaining precise control of the airplane in the presence of large steady control forces. To address this problem, a simulated automatic trim system which drives the trim tabs as an open-loop function of propeller slipstream measurements was developed. The simulated automatic trim system was found to greatly increase the controllability in asymmetric powered flight without having to resort to complex control laws or an irreversible control system. However, the trim-tab control rates needed to produce the dramatic increase in controllability may require special design consideration for automatic trim system failures. Limited measurements obtained in full-scale flight tests confirmed the fundamental validity of the proposed control law.

Problem-Solving Rubrics Revisited: Attending to the Blending of Informal Conceptual and Formal Mathematical Reasoning

ERIC Educational Resources Information Center

Hull, Michael M.; Kuo, Eric; Gupta, Ayush; Elby, Andrew

2013-01-01

Much research in engineering and physics education has focused on improving students' problem-solving skills. This research has led to the development of step-by-step problem-solving strategies and grading rubrics to assess a student's expertise in solving problems using these strategies. These rubrics value "communication" between the…

Encouraging Students to Think Strategically when Learning to Solve Linear Equations

ERIC Educational Resources Information Center

Robson, Daphne; Abell, Walt; Boustead, Therese

2012-01-01

Students who are preparing to study science and engineering need to understand equation solving but adult students returning to study can find this difficult. In this paper, the design of an online resource, Equations2go, for helping students learn to solve linear equations is investigated. Students learning to solve equations need to consider…

Human factors and systems engineering approach to patient safety for radiotherapy.

PubMed

Rivera, A Joy; Karsh, Ben-Tzion

2008-01-01

The traditional approach to solving patient safety problems in healthcare is to blame the last person to touch the patient. But since the publication of To Err is Human, the call has been instead to use human factors and systems engineering methods and principles to solve patient safety problems. However, an understanding of the human factors and systems engineering is lacking, and confusion remains about what it means to apply their principles. This paper provides a primer on them and their applications to patient safety.

Reliability analysis of C-130 turboprop engine components using artificial neural network

NASA Astrophysics Data System (ADS)

Qattan, Nizar A.

In this study, we predict the failure rate of Lockheed C-130 Engine Turbine. More than thirty years of local operational field data were used for failure rate prediction and validation. The Weibull regression model and the Artificial Neural Network model including (feed-forward back-propagation, radial basis neural network, and multilayer perceptron neural network model); will be utilized to perform this study. For this purpose, the thesis will be divided into five major parts. First part deals with Weibull regression model to predict the turbine general failure rate, and the rate of failures that require overhaul maintenance. The second part will cover the Artificial Neural Network (ANN) model utilizing the feed-forward back-propagation algorithm as a learning rule. The MATLAB package will be used in order to build and design a code to simulate the given data, the inputs to the neural network are the independent variables, the output is the general failure rate of the turbine, and the failures which required overhaul maintenance. In the third part we predict the general failure rate of the turbine and the failures which require overhaul maintenance, using radial basis neural network model on MATLAB tool box. In the fourth part we compare the predictions of the feed-forward back-propagation model, with that of Weibull regression model, and radial basis neural network model. The results show that the failure rate predicted by the feed-forward back-propagation artificial neural network model is closer in agreement with radial basis neural network model compared with the actual field-data, than the failure rate predicted by the Weibull model. By the end of the study, we forecast the general failure rate of the Lockheed C-130 Engine Turbine, the failures which required overhaul maintenance and six categorical failures using multilayer perceptron neural network (MLP) model on DTREG commercial software. The results also give an insight into the reliability of the engine turbine under actual operating conditions, which can be used by aircraft operators for assessing system and component failures and customizing the maintenance programs recommended by the manufacturer.

Adapting Experiential Learning to Develop Problem-Solving Skills in Deaf and Hard-of-Hearing Engineering Students.

PubMed

Marshall, Matthew M; Carrano, Andres L; Dannels, Wendy A

2016-10-01

Individuals who are deaf and hard-of-hearing (DHH) are underrepresented in science, technology, engineering, and mathematics (STEM) professions, and this may be due in part to their level of preparation in the development and retention of mathematical and problem-solving skills. An approach was developed that incorporates experiential learning and best practices of STEM instruction to give first-year DHH students enrolled in a postsecondary STEM program the opportunity to develop problem-solving skills in real-world scenarios. Using an industrial engineering laboratory that provides manufacturing and warehousing environments, students were immersed in real-world scenarios in which they worked on teams to address prescribed problems encountered during the activities. The highly structured, Plan-Do-Check-Act approach commonly used in industry was adapted for the DHH student participants to document and communicate the problem-solving steps. Students who experienced the intervention realized a 14.6% improvement in problem-solving proficiency compared with a control group, and this gain was retained at 6 and 12 months, post-intervention. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

How Engineers Perceive the Importance of Ethics in Finland

ERIC Educational Resources Information Center

Taajamaa, Ville; Majanoja, Anne-Maarit; Bairaktarova, Diana; Airola, Antti; Pahikkala, Tapio; Sutinen, Erkki

2018-01-01

Success in complex and holistic engineering practices requires more than problem-solving abilities and technical competencies. Engineering education must offer proficient technical competences and also train engineers to think and act ethically. A technical "engineering-like" focus and demand have made educators and students overlook the…

Robust operative diagnosis as problem solving in a hypothesis space

NASA Technical Reports Server (NTRS)

Abbott, Kathy H.

1988-01-01

This paper describes an approach that formulates diagnosis of physical systems in operation as problem solving in a hypothesis space. Such a formulation increases robustness by: (1) incremental hypotheses construction via dynamic inputs, (2) reasoning at a higher level of abstraction to construct hypotheses, and (3) partitioning the space by grouping fault hypotheses according to the type of physical system representation and problem solving techniques used in their construction. It was implemented for a turbofan engine and hydraulic subsystem. Evaluation of the implementation on eight actual aircraft accident cases involving engine faults provided very promising results.

Engineering-Based Problem Solving Strategies in AP Calculus: An Investigation into High School Student Performance on Related Rate Free-Response Problems

ERIC Educational Resources Information Center

Thieken, John

2012-01-01

A sample of 127 high school Advanced Placement (AP) Calculus students from two schools was utilized to study the effects of an engineering design-based problem solving strategy on student performance with AP style Related Rate questions and changes in conceptions, beliefs, and influences. The research design followed a treatment-control multiple…

The Effects of Segmented Multimedia Worked Examples and Self-Explanations on Acquisition of Conceptual Knowledge and Problem-Solving Performance in an Undergraduate Engineering Course

ERIC Educational Resources Information Center

Kapli, Natalia V.

2010-01-01

The study investigated the effects of non-segmented multimedia worked examples (NS-MWE), segmented multimedia worked examples (S-MWE), and segmented multimedia worked examples enhanced with self-explanation prompts (S-MWE-SE) on acquisition of conceptual knowledge and problem solving performance in an undergraduate engineering course. In addition,…

Engineering Leadership Development Programs a Look at What Is Needed and What Is Being Done

ERIC Educational Resources Information Center

Crumpton-Young, Lesia; McCauley-Bush, Pamela; Rabelo, Luis; Meza, Katherine; Ferreras, Ana; Rodriguez, Betzaida; Millan, Angel; Miranda, David; Kelarestani, Misha

2010-01-01

"The Engineer of 2020: Visions of Engineering in the New Century," published by the National Academy of Engineering (NAE), discusses the importance of current and future engineering graduates possessing skills needed to solve business challenges. To ensure that future engineering graduates are adequately prepared, several universities and…

An Investigation in the Ames 40- by 80-Foot Wind Tunnel of a YT-56A Turboprop Engine Incorporating a Decoupler and a Controlled-Feathering Device

NASA Technical Reports Server (NTRS)

Rogallo, Vernon L.; Yaggy, Paul F.; McCloud, John L., III

1954-01-01

An investigation of a decoupler and a controlled-feathering device incorporated with the YT-56A turboprop engine has been made to determine the effectiveness of these devices in reducing the high negative thrust (drag) which accompanies power failure of this type of engine. Power failures were simulated by fuel cut-off, both without either device free to operate, and with each device free to operate singly. The investigation was made through an airspeed range from 50 to 230 mph. It was found that with neither device free to operate, the drag levels realized after power failures at airspeeds above 170 mph would impose vertical tail loads higher than those allowable for the YC-130, the airplane for which the test power package was designed. These levels were reached in approximately one second. The maximum drag realized after power failure was not appreciably altered by the use of the decoupler although the decoupler did put a limit on the duration of the peak drag. The controlled-feathering device maintained a level of essentially zero drag after power failure. The use of the decoupler in the YT-56A engine complicates windmilling air-starting procedures and makes it necessary to place operating restrictions on the engine to assure safe flight at low-power conditions,

Failure analysis of a tool steel torque shaft

NASA Technical Reports Server (NTRS)

Reagan, J. R.

1981-01-01

A low design load drive shaft used to deliver power from an experimental exhaust heat recovery system to the crankshaft of an experimental diesel truck engine failed during highway testing. An independent testing laboratory analyzed the failure by routine metallography and attributed the failure to fatigue induced by a banded microstructure. Visual examination by NASA of the failed shaft plus the knowledge of the torsional load that it carried pointed to a 100 percent ductile failure with no evidence of fatigue. Scanning electron microscopy confirmed this. Torsional test specimens were produced from pieces of the failed shaft and torsional overload testing produced identical failures to that which had occurred in the truck engine. This pointed to a failure caused by a high overload and although the microstructure was defective it was not the cause of the failure.

Probabilistic failure assessment with application to solid rocket motors

NASA Technical Reports Server (NTRS)

Jan, Darrell L.; Davidson, Barry D.; Moore, Nicholas R.

1990-01-01

A quantitative methodology is being developed for assessment of risk of failure of solid rocket motors. This probabilistic methodology employs best available engineering models and available information in a stochastic framework. The framework accounts for incomplete knowledge of governing parameters, intrinsic variability, and failure model specification error. Earlier case studies have been conducted on several failure modes of the Space Shuttle Main Engine. Work in progress on application of this probabilistic approach to large solid rocket boosters such as the Advanced Solid Rocket Motor for the Space Shuttle is described. Failure due to debonding has been selected as the first case study for large solid rocket motors (SRMs) since it accounts for a significant number of historical SRM failures. Impact of incomplete knowledge of governing parameters and failure model specification errors is expected to be important.

J-2X Abort System Development

NASA Technical Reports Server (NTRS)

Santi, Louis M.; Butas, John P.; Aguilar, Robert B.; Sowers, Thomas S.

2008-01-01

The J-2X is an expendable liquid hydrogen (LH2)/liquid oxygen (LOX) gas generator cycle rocket engine that is currently being designed as the primary upper stage propulsion element for the new NASA Ares vehicle family. The J-2X engine will contain abort logic that functions as an integral component of the Ares vehicle abort system. This system is responsible for detecting and responding to conditions indicative of impending Loss of Mission (LOM), Loss of Vehicle (LOV), and/or catastrophic Loss of Crew (LOC) failure events. As an earth orbit ascent phase engine, the J-2X is a high power density propulsion element with non-negligible risk of fast propagation rate failures that can quickly lead to LOM, LOV, and/or LOC events. Aggressive reliability requirements for manned Ares missions and the risk of fast propagating J-2X failures dictate the need for on-engine abort condition monitoring and autonomous response capability as well as traditional abort agents such as the vehicle computer, flight crew, and ground control not located on the engine. This paper describes the baseline J-2X abort subsystem concept of operations, as well as the development process for this subsystem. A strategy that leverages heritage system experience and responds to an evolving engine design as well as J-2X specific test data to support abort system development is described. The utilization of performance and failure simulation models to support abort system sensor selection, failure detectability and discrimination studies, decision threshold definition, and abort system performance verification and validation is outlined. The basis for abort false positive and false negative performance constraints is described. Development challenges associated with information shortfalls in the design cycle, abort condition coverage and response assessment, engine-vehicle interface definition, and abort system performance verification and validation are also discussed.

Stability and performance of propulsion control systems with distributed control architectures and failures

NASA Astrophysics Data System (ADS)

Belapurkar, Rohit K.

Future aircraft engine control systems will be based on a distributed architecture, in which, the sensors and actuators will be connected to the Full Authority Digital Engine Control (FADEC) through an engine area network. Distributed engine control architecture will allow the implementation of advanced, active control techniques along with achieving weight reduction, improvement in performance and lower life cycle cost. The performance of a distributed engine control system is predominantly dependent on the performance of the communication network. Due to the serial data transmission policy, network-induced time delays and sampling jitter are introduced between the sensor/actuator nodes and the distributed FADEC. Communication network faults and transient node failures may result in data dropouts, which may not only degrade the control system performance but may even destabilize the engine control system. Three different architectures for a turbine engine control system based on a distributed framework are presented. A partially distributed control system for a turbo-shaft engine is designed based on ARINC 825 communication protocol. Stability conditions and control design methodology are developed for the proposed partially distributed turbo-shaft engine control system to guarantee the desired performance under the presence of network-induced time delay and random data loss due to transient sensor/actuator failures. A fault tolerant control design methodology is proposed to benefit from the availability of an additional system bandwidth and from the broadcast feature of the data network. It is shown that a reconfigurable fault tolerant control design can help to reduce the performance degradation in presence of node failures. A T-700 turbo-shaft engine model is used to validate the proposed control methodology based on both single input and multiple-input multiple-output control design techniques.

A systems engineering approach to automated failure cause diagnosis in space power systems

NASA Technical Reports Server (NTRS)

Dolce, James L.; Faymon, Karl A.

1987-01-01

Automatic failure-cause diagnosis is a key element in autonomous operation of space power systems such as Space Station's. A rule-based diagnostic system has been developed for determining the cause of degraded performance. The knowledge required for such diagnosis is elicited from the system engineering process by using traditional failure analysis techniques. Symptoms, failures, causes, and detector information are represented with structured data; and diagnostic procedural knowledge is represented with rules. Detected symptoms instantiate failure modes and possible causes consistent with currently held beliefs about the likelihood of the cause. A diagnosis concludes with an explanation of the observed symptoms in terms of a chain of possible causes and subcauses.

Application of Weibull analysis to SSME hardware

NASA Technical Reports Server (NTRS)

Gray, L. A. B.

1986-01-01

Generally, it has been documented that the wearing of engine parts forms a failure distribution which can be approximated by a function developed by Weibull. The purpose here is to examine to what extent the Weibull distribution approximates failure data for designated engine parts of the Space Shuttle Main Engine (SSME). The current testing certification requirements will be examined in order to establish confidence levels. An examination of the failure history of SSME parts/assemblies (turbine blades, main combustion chamber, or high pressure fuel pump first stage impellers) which are limited in usage by time or starts will be done by using updated Weibull techniques. Efforts will be made by the investigator to predict failure trends by using Weibull techniques for SSME parts (turbine temperature sensors, chamber pressure transducers, actuators, and controllers) which are not severely limited by time or starts.

The Impact of Guidance during Problem-Solving Prior to Instruction on Students' Inventions and Learning Outcomes

ERIC Educational Resources Information Center

Loibl, Katharina; Rummel, Nikol

2014-01-01

Multiple studies have shown benefits of problem-solving prior to instruction (cf. Productive Failure, Invention) in comparison to direct instruction. However, students' solutions prior to instruction are usually erroneous or incomplete. In analogy to "guided" discovery learning, it might therefore be fruitful to lead students…

Design and Demonstration of Emergency Control Modes for Enhanced Engine Performance

NASA Technical Reports Server (NTRS)

Liu, Yuan; Litt, Jonathan S.; Guo, Ten-Huei

2013-01-01

A design concept is presented for developing control modes that enhance aircraft engine performance during emergency flight scenarios. The benefits of increased engine performance to overall vehicle survivability during these situations may outweigh the accompanied elevated risk of engine failure. The objective involves building control logic that can consistently increase engine performance beyond designed maximum levels based on an allowable heightened probability of failure. This concept is applied to two previously developed control modes: an overthrust mode that increases maximum engine thrust output and a faster response mode that improves thrust response to dynamic throttle commands. This paper describes the redesign of these control modes and presents simulation results demonstrating both enhanced engine performance and robust maintenance of the desired elevated risk level.

Teaching practice and effect of the curriculum design and simulation courses under the support of professional optical software

NASA Astrophysics Data System (ADS)

Lin, YuanFang; Zheng, XiaoDong; Huang, YuJia

2017-08-01

Curriculum design and simulation courses are bridges to connect specialty theories, engineering practice and experimental skills. In order to help students to have the computer aided optical system design ability adapting to developments of the times, a professional optical software-Advanced System of Analysis Program (ASAP) was used in the research teaching of curriculum design and simulation courses. The ASAP tutorials conducting, exercises both complementing and supplementing the lectures, hands-on practice in class, autonomous learning and independent design after class were bridged organically, to guide students "learning while doing, learning by doing", paying more attention to the process instead of the results. Several years of teaching practice of curriculum design and simulation courses shows that, project-based learning meets society needs of training personnel with knowledge, ability and quality. Students have obtained not only skills of using professional software, but also skills of finding and proposing questions in engineering practice, the scientific method of analyzing and solving questions with specialty knowledge, in addition, autonomous learning ability, teamwork spirit and innovation consciousness, still scientific attitude of facing failure and scientific spirit of admitting deficiency in the process of independent design and exploration.

Incipient failure detection of space shuttle main engine turbopump bearings using vibration envelope detection

NASA Technical Reports Server (NTRS)

Hopson, Charles B.

1987-01-01

The results of an analysis performed on seven successive Space Shuttle Main Engine (SSME) static test firings, utilizing envelope detection of external accelerometer data are discussed. The results clearly show the great potential for using envelope detection techniques in SSME incipient failure detection.

76 FR 64283 - Airworthiness Directives; Rolls-Royce plc (RR) Turbofan Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-18

... currently requires inspecting the intermediate-pressure (IP) compressor rotor shaft rear balance land for...-Trent 800 IP compressor rotor shafts that have been found cracked. This proposed AD would continue to... identified above could lead to IP compressor rotor shaft failure, uncontained engine failure, and damage to...

Regenerative therapy and tissue engineering for the treatment of end-stage cardiac failure

PubMed Central

Finosh, G.T.; Jayabalan, Muthu

2012-01-01

Regeneration of myocardium through regenerative therapy and tissue engineering is appearing as a prospective treatment modality for patients with end-stage heart failure. Focusing on this area, this review highlights the new developments and challenges in the regeneration of myocardial tissue. The role of various cell sources, calcium ion and cytokine on the functional performance of regenerative therapy is discussed. The evolution of tissue engineering and the role of tissue matrix/scaffold, cell adhesion and vascularisation on tissue engineering of cardiac tissue implant are also discussed. PMID:23507781

Regenerative therapy and tissue engineering for the treatment of end-stage cardiac failure: new developments and challenges.

PubMed

Finosh, G T; Jayabalan, Muthu

2012-01-01

Regeneration of myocardium through regenerative therapy and tissue engineering is appearing as a prospective treatment modality for patients with end-stage heart failure. Focusing on this area, this review highlights the new developments and challenges in the regeneration of myocardial tissue. The role of various cell sources, calcium ion and cytokine on the functional performance of regenerative therapy is discussed. The evolution of tissue engineering and the role of tissue matrix/scaffold, cell adhesion and vascularisation on tissue engineering of cardiac tissue implant are also discussed.

Investigating a Proposed Problem Solving Theory in the Context of Mathematical Problem Solving: A Multi-Case Study

ERIC Educational Resources Information Center

Mills, Nadia Monrose

2015-01-01

The ability to succeed in Science, Technology, Engineering, and Mathematics (STEM) careers is contingent on a student's ability to engage in mathematical problem solving. As a result, there has been increased focus on students' ability to think critically by providing them more with problem solving experiences in the classroom. Much research has…

A Multivariate Model of Physics Problem Solving

ERIC Educational Resources Information Center

Taasoobshirazi, Gita; Farley, John

2013-01-01

A model of expertise in physics problem solving was tested on undergraduate science, physics, and engineering majors enrolled in an introductory-level physics course. Structural equation modeling was used to test hypothesized relationships among variables linked to expertise in physics problem solving including motivation, metacognitive planning,…

Autorotation flight control system

NASA Technical Reports Server (NTRS)

Bachelder, Edward N. (Inventor); Aponso, Bimal L. (Inventor); Lee, Dong-Chan (Inventor)

2011-01-01

The present invention provides computer implemented methodology that permits the safe landing and recovery of rotorcraft following engine failure. With this invention successful autorotations may be performed from well within the unsafe operating area of the height-velocity profile of a helicopter by employing the fast and robust real-time trajectory optimization algorithm that commands control motion through an intuitive pilot display, or directly in the case of autonomous rotorcraft. The algorithm generates optimal trajectories and control commands via the direct-collocation optimization method, solved using a nonlinear programming problem solver. The control inputs computed are collective pitch and aircraft pitch, which are easily tracked and manipulated by the pilot or converted to control actuator commands for automated operation during autorotation in the case of an autonomous rotorcraft. The formulation of the optimal control problem has been carefully tailored so the solutions resemble those of an expert pilot, accounting for the performance limitations of the rotorcraft and safety concerns.

Continuous fiber ceramic matrix composites for heat engine components

NASA Technical Reports Server (NTRS)

Tripp, David E.

1988-01-01

High strength at elevated temperatures, low density, resistance to wear, and abundance of nonstrategic raw materials make structural ceramics attractive for advanced heat engine applications. Unfortunately, ceramics have a low fracture toughness and fail catastrophically because of overload, impact, and contact stresses. Ceramic matrix composites provide the means to achieve improved fracture toughness while retaining desirable characteristics, such as high strength and low density. Materials scientists and engineers are trying to develop the ideal fibers and matrices to achieve the optimum ceramic matrix composite properties. A need exists for the development of failure models for the design of ceramic matrix composite heat engine components. Phenomenological failure models are currently the most frequently used in industry, but they are deterministic and do not adequately describe ceramic matrix composite behavior. Semi-empirical models were proposed, which relate the failure of notched composite laminates to the stress a characteristic distance away from the notch. Shear lag models describe composite failure modes at the micromechanics level. The enhanced matrix cracking stress occurs at the same applied stress level predicted by the two models of steady state cracking. Finally, statistical models take into consideration the distribution in composite failure strength. The intent is to develop these models into computer algorithms for the failure analysis of ceramic matrix composites under monotonically increasing loads. The algorithms will be included in a postprocessor to general purpose finite element programs.

Mechanical Testing of Hydrogels in Cartilage Tissue Engineering: Beyond the Compressive Modulus

PubMed Central

Xiao, Yinghua; Friis, Elizabeth A.; Gehrke, Stevin H.

2013-01-01

Injuries to articular cartilage result in significant pain to patients and high medical costs. Unfortunately, cartilage repair strategies have been notoriously unreliable and/or complex. Biomaterial-based tissue-engineering strategies offer great promise, including the use of hydrogels to regenerate articular cartilage. Mechanical integrity is arguably the most important functional outcome of engineered cartilage, although mechanical testing of hydrogel-based constructs to date has focused primarily on deformation rather than failure properties. In addition to deformation testing, as the field of cartilage tissue engineering matures, this community will benefit from the addition of mechanical failure testing to outcome analyses, given the crucial clinical importance of the success of engineered constructs. However, there is a tremendous disparity in the methods used to evaluate mechanical failure of hydrogels and articular cartilage. In an effort to bridge the gap in mechanical testing methods of articular cartilage and hydrogels in cartilage regeneration, this review classifies the different toughness measurements for each. The urgency for identifying the common ground between these two disparate fields is high, as mechanical failure is ready to stand alongside stiffness as a functional design requirement. In comparing toughness measurement methods between hydrogels and cartilage, we recommend that the best option for evaluating mechanical failure of hydrogel-based constructs for cartilage tissue engineering may be tensile testing based on the single edge notch test, in part because specimen preparation is more straightforward and a related American Society for Testing and Materials (ASTM) standard can be adopted in a fracture mechanics context. PMID:23448091

Using hybrid expert system approaches for engineering applications

NASA Technical Reports Server (NTRS)

Allen, R. H.; Boarnet, M. G.; Culbert, C. J.; Savely, R. T.

1987-01-01

In this paper, the use of hybrid expert system shells and hybrid (i.e., algorithmic and heuristic) approaches for solving engineering problems is reported. Aspects of various engineering problem domains are reviewed for a number of examples with specific applications made to recently developed prototype expert systems. Based on this prototyping experience, critical evaluations of and comparisons between commercially available tools, and some research tools, in the United States and Australia, and their underlying problem-solving paradigms are made. Characteristics of the implementation tool and the engineering domain are compared and practical software engineering issues are discussed with respect to hybrid tools and approaches. Finally, guidelines are offered with the hope that expert system development will be less time consuming, more effective, and more cost-effective than it has been in the past.

Impact of an Engineering Case Study in a High School Pre-Engineering Course

ERIC Educational Resources Information Center

Rutz, Eugene; Shafer, Michelle

2011-01-01

Students at an all-girls high school who were enrolled in an introduction to engineering course were presented an engineering case study to determine if the case study affected their attitudes toward engineering and their abilities to solve engineering problems. A case study on power plants was implemented during a unit on electrical engineering.…

Comparative study on the mechanical mechanism of confined concrete supporting arches in underground engineering.

PubMed

Lv, Zhijin; Qin, Qian; Jiang, Bei; Luan, Yingcheng; Yu, Hengchang

2018-01-01

In order to solve the supporting problem in underground engineering with high stress, square steel confined concrete (SQCC) supporting method is adopted to enhance the control on surrounding rocks, and the control effect is remarkable. The commonly used cross section shapes of confined concrete arch are square and circular. At present, designers have no consensus on which kind is more proper. To search for the answer, this paper makes an analysis on the mechanical properties of the two shapes of the cross-sections. A full-scale indoor comparative test was carried out on the commonly used straight-wall semi-circular SQCC arch and circular steel confined concrete arch (CCC arch). This test is based on self-developed full-scale test system for confined concrete arch. Our research, combining with the numerical analysis, shows: (1) SQCC arch is consistent with CCC arch in the deformation and failure mode. The largest damages parts are at the legs of both of them. (2) The SQCC arch's bearing capability is 1286.9 kN, and the CCC arch's ultimate bearing capability is 1072.4kN. Thus, the SQCC arch's bearing capability is 1.2 times that of the CCC arch. (3) The arches are subjected to combined compression and bending, bending moment is the main reason for the arch failure. The section moment of inertia of SQCC arch is 1.26 times of that of CCC arch, and the former is better than the latter in bending performance. The ultimate bearing capacity is positively correlated with the size of the moment of inertia. Based on the above research, the engineering suggestions are as follows: (1) To improve the bearing capacity of the arch, the cross-sectional shape of the chamber should be optimized and the arch bearing mode changed accordingly. (2) The key damaged positions, such as the arch leg, should be reinforced, optimizing the state of force on the arch. SQCC arches should be used for supporting in underground engineering, which is under stronger influence of the bending moment and non-uniform load on the supporting arches. The research results could provide a theoretical basis for the design of confined concrete support in underground engineering.

Comparative study on the mechanical mechanism of confined concrete supporting arches in underground engineering

PubMed Central

Qin, Qian; Jiang, Bei; Luan, Yingcheng; Yu, Hengchang

2018-01-01

In order to solve the supporting problem in underground engineering with high stress, square steel confined concrete (SQCC) supporting method is adopted to enhance the control on surrounding rocks, and the control effect is remarkable. The commonly used cross section shapes of confined concrete arch are square and circular. At present, designers have no consensus on which kind is more proper. To search for the answer, this paper makes an analysis on the mechanical properties of the two shapes of the cross-sections. A full-scale indoor comparative test was carried out on the commonly used straight-wall semi-circular SQCC arch and circular steel confined concrete arch (CCC arch). This test is based on self-developed full-scale test system for confined concrete arch. Our research, combining with the numerical analysis, shows: (1) SQCC arch is consistent with CCC arch in the deformation and failure mode. The largest damages parts are at the legs of both of them. (2) The SQCC arch’s bearing capability is 1286.9 kN, and the CCC arch’s ultimate bearing capability is 1072.4kN. Thus, the SQCC arch’s bearing capability is 1.2 times that of the CCC arch. (3) The arches are subjected to combined compression and bending, bending moment is the main reason for the arch failure. The section moment of inertia of SQCC arch is 1.26 times of that of CCC arch, and the former is better than the latter in bending performance. The ultimate bearing capacity is positively correlated with the size of the moment of inertia. Based on the above research, the engineering suggestions are as follows: (1) To improve the bearing capacity of the arch, the cross-sectional shape of the chamber should be optimized and the arch bearing mode changed accordingly. (2) The key damaged positions, such as the arch leg, should be reinforced, optimizing the state of force on the arch. SQCC arches should be used for supporting in underground engineering, which is under stronger influence of the bending moment and non-uniform load on the supporting arches. The research results could provide a theoretical basis for the design of confined concrete support in underground engineering. PMID:29447187

Pen-based Interfaces for Engineering and Education

NASA Astrophysics Data System (ADS)

Stahovich, Thomas F.

Sketches are an important problem-solving tool in many fields. This is particularly true of engineering design, where sketches facilitate creativity by providing an efficient medium for expressing ideas. However, despite the importance of sketches in engineering practice, current engineering software still relies on traditional mouse and keyboard interfaces, with little or no capabilities to handle free-form sketch input. With recent advances in machine-interpretation techniques, it is now becoming possible to create practical interpretation-based interfaces for such software. In this chapter, we report on our efforts to create interpretation techniques to enable pen-based engineering applications. We describe work on two fundamental sketch understanding problems. The first is sketch parsing, the task of clustering pen strokes or geometric primitives into individual symbols. The second is symbol recognition, the task of classifying symbols once they have been located by a parser. We have used the techniques that we have developed to construct several pen-based engineering analysis tools. These are used here as examples to illustrate our methods. We have also begun to use our techniques to create pen-based tutoring systems that scaffold students in solving problems in the same way they would ordinarily solve them with paper and pencil. The chapter concludes with a brief discussion of these systems.

Modal test of Shuttle engine nozzle

NASA Technical Reports Server (NTRS)

Johnston, G. D.; Coleman, A. D.

1983-01-01

A structural failure occurred on the main propulsion test stand at NSTL causing a hydrogen fire and damage to the engines to be used on the Orbiter Columbia. Scattered accelerometer measurements indicated very high response levels at 254 hertz and 311 hertz. The Engine Office at MSFC asked the Dynamics Test Branch to try and find out what caused the failure. All three nozzles were sent to Huntsville for testing. Modal test data revealed very quickly how the failure occurred in the steerhorn and also pointed out two other structural problems. A complete set of data is presented along with a narrative explanation of the steps taken to identify and verify the structural problem.

Bioengineered vascular scaffolds: the state of the art.

PubMed

Palumbo, Vincenzo D; Bruno, Antonio; Tomasello, Giovanni; Damiano, Giuseppe; Lo Monte, Attilio I

2014-07-31

To date, there is increasing clinical need for vascular substitutes due to accidents, malformations, and ischemic diseases. Over the years, many approaches have been developed to solve this problem, starting from autologous native vessels to artificial vascular grafts; unfortunately, none of these have provided the perfect vascular substitute. All have been burdened by various complications, including infection, thrombogenicity, calcification, foreign body reaction, lack of growth potential, late stenosis and occlusion from intimal hyperplasia, and pseudoaneurysm formation. In the last few years, vascular tissue engineering has emerged as one of the most promising approaches for producing mechanically competent vascular substitutes. Nanotechnologies have contributed their part, allowing extraordinarily biostable and biocompatible materials to be developed. Specifically, the use of electrospinning to manufacture conduits able to guarantee a stable flow of biological fluids and guide the formation of a new vessel has revolutionized the concept of the vascular substitute. The electrospinning technique allows extracellular matrix (ECM) to be mimicked with high fidelity, reproducing its porosity and complexity, and providing an environment suitable for cell growth. In the future, a better knowledge of ECM and the manufacture of new materials will allow us to "create" functional biological vessels - the base required to develop organ substitutes and eventually solve the problem of organ failure.

The Impact of Family Functioning on Caregiver Burden among Caregivers of Veterans with Congestive Heart Failure

ERIC Educational Resources Information Center

Moore, Crystal Dea

2010-01-01

A cross-sectional study of 76 family caregivers of older veterans with congestive heart failure utilized the McMaster model of family functioning to examine the impact of family functioning variables (problem solving, communication, roles, affective responsiveness, and affective involvement) on caregiver burden dimensions (relationship burden,…

Modelling and Inverse-Modelling: Experiences with O.D.E. Linear Systems in Engineering Courses

ERIC Educational Resources Information Center

Martinez-Luaces, Victor

2009-01-01

In engineering careers courses, differential equations are widely used to solve problems concerned with modelling. In particular, ordinary differential equations (O.D.E.) linear systems appear regularly in Chemical Engineering, Food Technology Engineering and Environmental Engineering courses, due to the usefulness in modelling chemical kinetics,…

Next gen perception and cognition: augmenting perception and enhancing cognition through mobile technologies

NASA Astrophysics Data System (ADS)

Goma, Sergio R.

2015-03-01

In current times, mobile technologies are ubiquitous and the complexity of problems is continuously increasing. In the context of advancement of engineering, we explore in this paper possible reasons that could cause a saturation in technology evolution - namely the ability of problem solving based on previous results and the ability of expressing solutions in a more efficient way, concluding that `thinking outside of brain' - as in solving engineering problems that are expressed in a virtual media due to their complexity - would benefit from mobile technology augmentation. This could be the necessary evolutionary step that would provide the efficiency required to solve new complex problems (addressing the `running out of time' issue) and remove the communication of results barrier (addressing the human `perception/expression imbalance' issue). Some consequences are discussed, as in this context the artificial intelligence becomes an automation tool aid instead of a necessary next evolutionary step. The paper concludes that research in modeling as problem solving aid and data visualization as perception aid augmented with mobile technologies could be the path to an evolutionary step in advancing engineering.

Problem Solving with General Semantics.

ERIC Educational Resources Information Center

Hewson, David

1996-01-01

Discusses how to use general semantics formulations to improve problem solving at home or at work--methods come from the areas of artificial intelligence/computer science, engineering, operations research, and psychology. (PA)

Comparison of defects in ProTaper hand-operated and engine-driven instruments after clinical use.

PubMed

Cheung, G S P; Bian, Z; Shen, Y; Peng, B; Darvell, B W

2007-03-01

To compare the type of defects and mode of material failure of engine-driven and hand-operated ProTaper instruments after clinical use. A total of 401 hand-operated and 325 engine-driven ProTaper instruments were discarded from an endodontic clinic over 17 months. Those that had fractured were examined for plastic deformation in lateral view and remounted for fractographical examination in scanning electron microscope. The mode of fracture was classified as 'fatigue' or 'shear' failure. The lengths of fractured segments in both instruments were recorded. Any distortion in hand instrument was noted. Data were analysed using chi-square, Fisher's exact or Student's t-test, where appropriate. Approximately 14% of all discarded hand-operated instruments and 14% of engine-driven instruments were fractured. About 62% of hand instruments failed because of shear fracture, compared with approximately 66% of engine-driven instruments as a result of fatigue (P < 0.05). Approximately 16% of hand instruments were affected by shear, and either remained intact or was fractured, compared with 5% of engine-driven instruments (P < 0.05). The length of the broken fragment was significantly shorter in hand versus engine-driven group (P < 0.05). Approximately 7% of hand instruments were discarded intact but distorted (rarely for engine-driven instruments); all were in the form of unscrewing of the flutes. The location of defects in hand Finishing instruments was significantly closer to the tip than that for Shaping instruments (P < 0.05). Under the conditions of this study (possibly high usage), the failure mode of ProTaper engine-driven and hand-operated instruments appeared to be different, with shear failure being more prevalent in the latter.

Rocket engine diagnostics using qualitative modeling techniques

NASA Technical Reports Server (NTRS)

Binder, Michael; Maul, William; Meyer, Claudia; Sovie, Amy

1992-01-01

Researchers at NASA Lewis Research Center are presently developing qualitative modeling techniques for automated rocket engine diagnostics. A qualitative model of a turbopump interpropellant seal system has been created. The qualitative model describes the effects of seal failures on the system steady-state behavior. This model is able to diagnose the failure of particular seals in the system based on anomalous temperature and pressure values. The anomalous values input to the qualitative model are generated using numerical simulations. Diagnostic test cases include both single and multiple seal failures.

Rocket engine diagnostics using qualitative modeling techniques

NASA Technical Reports Server (NTRS)

Binder, Michael; Maul, William; Meyer, Claudia; Sovie, Amy

1992-01-01

Researchers at NASA Lewis Research Center are presently developing qualitative modeling techniques for automated rocket engine diagnostics. A qualitative model of a turbopump interpropellant seal system was created. The qualitative model describes the effects of seal failures on the system steady state behavior. This model is able to diagnose the failure of particular seals in the system based on anomalous temperature and pressure values. The anomalous values input to the qualitative model are generated using numerical simulations. Diagnostic test cases include both single and multiple seal failures.

Failure analysis of a Stirling engine heat pipe

NASA Technical Reports Server (NTRS)

Moore, Thomas J.; Cairelli, James E.; Khalili, Kaveh

1989-01-01

Failure analysis was conducted on a heat pipe from a Stirling Engine test rig which was designed to operate at 1073 K. Premature failure had occurred due to localized overheating at the leading edge of the evaporator fin. It was found that a crack had allowed air to enter the fin and react with the sodium coolant. The origin of the crack was found to be located at the inner surface of the Inconel 600 fin where severe intergranular corrosion had taken place.

Advanced detection, isolation and accommodation of sensor failures: Real-time evaluation

NASA Technical Reports Server (NTRS)

Merrill, Walter C.; Delaat, John C.; Bruton, William M.

1987-01-01

The objective of the Advanced Detection, Isolation, and Accommodation (ADIA) Program is to improve the overall demonstrated reliability of digital electronic control systems for turbine engines by using analytical redundacy to detect sensor failures. The results of a real time hybrid computer evaluation of the ADIA algorithm are presented. Minimum detectable levels of sensor failures for an F100 engine control system are determined. Also included are details about the microprocessor implementation of the algorithm as well as a description of the algorithm itself.

Foil Bearing Starting Considerations and Requirements for Rotorcraft Engine Applications

NASA Technical Reports Server (NTRS)

Radil, Kevin C.; DellaCorte, Christopher

2009-01-01

Foil gas bearings under development for rotorcraft-sized, hot core engine applications have been susceptible to damage from the slow acceleration and rates typically encountered during the pre-ignition stage in conventional engines. Recent laboratory failures have been assumed to be directly linked to operating foil bearings below their lift-off speed while following conventional startup procedures for the engines. In each instance, the continuous sliding contact between the foils and shaft was believed to thermally overload the bearing and cause the engines to fail. These failures highlight the need to characterize required acceleration rates and minimum operating speeds for these applications. In this report, startup experiments were conducted with a large, rotorcraft engine sized foil bearing under moderate load and acceleration rates to identify the proper start procedures needed to avoid bearing failure. The results showed that a bearing under a 39.4 kPa static load can withstand a modest acceleration rate of 500 rpm/s and excessive loitering below the bearing lift-off speed provided an adequate solid lubricant is present.

14 CFR 23.367 - Unsymmetrical loads due to engine failure.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Unsymmetrical loads due to engine failure. 23.367 Section 23.367 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... may be based on the limit pilot forces specified in § 23.397 except that lower forces may be assumed...

14 CFR 25.367 - Unsymmetrical loads due to engine failure.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Unsymmetrical loads due to engine failure. 25.367 Section 25.367 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... may be based on the control forces specified in § 25.397(b) except that lower forces may be assumed...

14 CFR 25.367 - Unsymmetrical loads due to engine failure.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Unsymmetrical loads due to engine failure. 25.367 Section 25.367 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... may be based on the control forces specified in § 25.397(b) except that lower forces may be assumed...

14 CFR 23.367 - Unsymmetrical loads due to engine failure.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Unsymmetrical loads due to engine failure. 23.367 Section 23.367 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... may be based on the limit pilot forces specified in § 23.397 except that lower forces may be assumed...

14 CFR 23.367 - Unsymmetrical loads due to engine failure.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Unsymmetrical loads due to engine failure. 23.367 Section 23.367 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... may be based on the limit pilot forces specified in § 23.397 except that lower forces may be assumed...

46 CFR 112.25-5 - Failure of power from the normal source.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Failure of power from the normal source. 112.25-5 Section 112.25-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Systems Having an Automatic Starting Diesel Engine or Gas...

46 CFR 112.25-5 - Failure of power from the normal source.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Failure of power from the normal source. 112.25-5 Section 112.25-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Systems Having an Automatic Starting Diesel Engine or Gas...

46 CFR 112.25-5 - Failure of power from the normal source.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Failure of power from the normal source. 112.25-5 Section 112.25-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Systems Having an Automatic Starting Diesel Engine or Gas...

46 CFR 112.25-5 - Failure of power from the normal source.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Failure of power from the normal source. 112.25-5 Section 112.25-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Systems Having an Automatic Starting Diesel Engine or Gas...

46 CFR 112.25-5 - Failure of power from the normal source.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Failure of power from the normal source. 112.25-5 Section 112.25-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Systems Having an Automatic Starting Diesel Engine or Gas...

77 FR 26943 - Airworthiness Directives; Pratt & Whitney Canada Turboprop Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-08

...) first stage sun gears and planet gears installed in the reduction gearbox. This AD was prompted by failures of certain first stage sun gears manufactured by TAATI. We are issuing this AD to prevent failure of the sun gear and planet gears which will result in an engine in-flight shut down, possible...

Does Sequence Matter? Productive Failure and Designing Online Authentic Learning for Process Engineering

ERIC Educational Resources Information Center

Lai, Polly K.; Portolese, Alisha; Jacobson, Michael J.

2017-01-01

This paper presents a study that applied both "productive failure" (PF) and "authentic learning" instructional approaches in online learning activities for early-career process engineers' professional development. This study compares participants learning with either a PF (low-to-high [LH]) or a more traditional (high-to-low)…

Investigation of the fuel feed line failures on the Space Shuttle main engine

NASA Technical Reports Server (NTRS)

Larson, E. W.

1980-01-01

The Space Shuttle Main Engine (SSME) development program experienced two similar appearing fuel feed line failures during the shutdown portion of two engine tests. Failure investigations into each incident showed that a few cycles of high-amplitude transient strain occurring during the start and cutoff portions of each test could have either accumulated damage and led to a fatigue failure after 46 tests, or caused rupture in a low-strength weld joint. The cause of the high strain was traced to a period of unsteady flow separation during the start and cutoff of each test coincident with the oblique shock approaching the nozzle exit. Since elimination of the flow separation was impractical, the steps taken to allow engine development and flight preparations to continue were: (1) establish the safe operating life of the nozzle, (2) reinforce all low-strength welds, and (3) eliminate the use of thin-wall fuel feed lines. In parallel, the feed line was redesigned and fabrication was initiated on units to be incorporated into the development program.

Teambuilding, Innovation and the Engineering Communication Interface

ERIC Educational Resources Information Center

Prescott, David; El-Sakran, Tharwat; Albasha, Lutfi; Aloul, Fadi; Al-Assaf, Yousef

2012-01-01

Recent engineering industry-based research has identified a number of skill deficiencies in graduating engineers. Emphasis on communication and teamwork informed by attributes of self management, problem solving and mutual accountability have been recognized as important needs by The Engineering Accreditation Commission of ABET of the United…

Engineering Encounters: Catch Me if You Can!

ERIC Educational Resources Information Center

Lott, Kimberly; Wallin, Mark; Roghaar, Deborah; Price, Tyson

2013-01-01

A science, technology, engineering, and math (STEM) activity is any activity that integrates the use of science, technology, engineering, and mathematics to solve a problem. Traditionally, STEM activities are highly engaging and may involve competition among student teams. Young children are natural engineers and often times spontaneously build…

Autonomous power management and distribution

NASA Technical Reports Server (NTRS)

Dolce, Jim; Kish, Jim

1990-01-01

The goal of the Autonomous Power System program is to develop and apply intelligent problem solving and control to the Space Station Freedom's electric power testbed being developed at NASA's Lewis Research Center. Objectives are to establish artificial intelligence technology paths, craft knowledge-based tools and products for power systems, and integrate knowledge-based and conventional controllers. This program represents a joint effort between the Space Station and Office of Aeronautics and Space Technology to develop and demonstrate space electric power automation technology capable of: (1) detection and classification of system operating status, (2) diagnosis of failure causes, and (3) cooperative problem solving for power scheduling and failure recovery. Program details, status, and plans will be presented.

Engineering Antifragile Systems: A Change In Design Philosophy

NASA Technical Reports Server (NTRS)

Jones, Kennie H.

2014-01-01

While technology has made astounding advances in the last century, problems are confronting the engineering community that must be solved. Cost and schedule of producing large systems are increasing at an unsustainable rate and these systems often do not perform as intended. New systems are required that may not be achieved by current methods. To solve these problems, NASA is working to infuse concepts from Complexity Science into the engineering process. Some of these problems may be solved by a change in design philosophy. Instead of designing systems to meet known requirements that will always lead to fragile systems at some degree, systems should be designed wherever possible to be antifragile: designing cognitive cyberphysical systems that can learn from their experience, adapt to unforeseen events they face in their environment, and grow stronger in the face of adversity. Several examples are presented of on ongoing research efforts to employ this philosophy.

Failure modes and effects analysis automation

NASA Technical Reports Server (NTRS)

Kamhieh, Cynthia H.; Cutts, Dannie E.; Purves, R. Byron

1988-01-01

A failure modes and effects analysis (FMEA) assistant was implemented as a knowledge based system and will be used during design of the Space Station to aid engineers in performing the complex task of tracking failures throughout the entire design effort. The three major directions in which automation was pursued were the clerical components of the FMEA process, the knowledge acquisition aspects of FMEA, and the failure propagation/analysis portions of the FMEA task. The system is accessible to design, safety, and reliability engineers at single user workstations and, although not designed to replace conventional FMEA, it is expected to decrease by many man years the time required to perform the analysis.

Characteristic of student’s false concessive failure on fractions concept

NASA Astrophysics Data System (ADS)

Kurniawan, H.; Sutawidjaja, A.; As’ari, A. R.; Muksar, M.

2018-03-01

False concessive failure of students is students construction failure in achieving goals, where the process is false, the results obtained is true. This failure occurs because the schemes are not connected to each other, so it cannot form a new scheme. This research is a qualitative research that aim to describe the characteristics of students' false concessive failure on fractional concepts. This fractional concept is a fraction of the same part of the whole. To be able to solve the concept of this fraction, students must possess the concept of partition, the concept of addition and the concept of multiplication of the fraction.

Orthopaedic jack for scoliosis surgery purposes: Concept and design

NASA Astrophysics Data System (ADS)

Supriadi, Sugeng; Radhana, Rakha M.; Hidayanto, Taufik Eko; Whulanza, Yudan; Ali, Notario, Nanda; Rahyussalim

2017-02-01

Scoliosis surgery is one of the most difficult orthopedic surgery that have been committed today as the failure rate of orthopedic surgery for adult patients is 15%. Aside from the long duration of surgery, this surgical failure is caused by failure in biomedical instrumentation. Furthermore, this kind of failure is causing inefficiency of the surgery. With current known orthopedic surgery method, three surgeons are needed in a single orthopedic surgery. In fact, a single surgery can take up to 8 hours to be done, which increases the risk of surgical failure. Based on this problem, authors hope that our orthopedic jacks could solve the problem.

Advanced detection, isolation, and accommodation of sensor failures in turbofan engines: Real-time microcomputer implementation

NASA Technical Reports Server (NTRS)

Delaat, John C.; Merrill, Walter C.

1990-01-01

The objective of the Advanced Detection, Isolation, and Accommodation Program is to improve the overall demonstrated reliability of digital electronic control systems for turbine engines. For this purpose, an algorithm was developed which detects, isolates, and accommodates sensor failures by using analytical redundancy. The performance of this algorithm was evaluated on a real time engine simulation and was demonstrated on a full scale F100 turbofan engine. The real time implementation of the algorithm is described. The implementation used state-of-the-art microprocessor hardware and software, including parallel processing and high order language programming.

Integrating Literacy and Engineering Instruction for Young Learners

ERIC Educational Resources Information Center

Wilson-Lopez, Amy; Gregory, Stacie

2015-01-01

According to recently published national standards, elementary students should engage in engineering design activities. This article outlines ways that teachers can use literacy instruction to support young students' engineering design activity, such as by selecting texts in which characters face problems that can be solved through engineering,…

An Example of Concurrent Engineering

NASA Technical Reports Server (NTRS)

Rowe, Sidney; Whitten, David; Cloyd, Richard; Coppens, Chris; Rodriguez, Pedro

1998-01-01

The Collaborative Engineering Design and Analysis Room (CEDAR) facility allows on-the- spot design review capability for any project during all phases of development. The required disciplines assemble in this facility to work on any problems (analysis, manufacturing, inspection, etc.) associated with a particular design. A small highly focused team of specialists can meet in this room to better expedite the process of developing a solution to an engineering task within the framework of the constraints that are unique to each discipline. This facility provides the engineering tools and translators to develop a concept within the confines of the room or with remote team members that could access the team's data from other locations. The CEDAR area is envisioned as excellent for failure investigation meetings to be conducted where the computer capabilities can be utilized in conjunction with the Smart Board display to develop failure trees, brainstorm failure modes, and evaluate possible solutions.

The Evolution of a Flipped Classroom: Evidence-Based Recommendations

ERIC Educational Resources Information Center

Velegol, Stephanie Butler; Zappe, Sarah E.; Mahoney, Emily

2015-01-01

Engineering students benefit from an active and interactive classroom environment where they can be guided through the problem solving process. Typically faculty members spend class time presenting the technical content required to solve problems, leaving students to apply this knowledge and problem solve on their own at home. There has recently…

A concept for fault tolerant design and improved availability of active composite elastic structures

NASA Astrophysics Data System (ADS)

Soeffker, D.; Wolters, K.; Krajcin, I.

2005-05-01

New functionalities, higher comfort and increasing performance requirements are often be solved by adding new technologies to existing (passive) solutions. Monitoring and control approaches uses additional sensors and actuators, new materials, microprocessors and new devices realizing new and improved functionalities. Two effects are becoming more and more interesting: (1) the lifetime of new actuators/materials strongly depends on the usage-history, (2) the functionality of the new composed systems depends on the fully functionality of all elements. In the consequence, the availability of such new systems is decreased by the number of elements and depends strongly on the use. These effects are known and act against new developments improving performance behavior also in mechanical engineering, automotive systems etc. This will be also the case for multifunctional composite or compound systems such as piezomaterials, magnetostrictive alloys or smart memory alloys (SMA) and is actually within the focus of the Structural-Health-Monitoring (SHM)-community. This contribution explains a new and systematically structured methodological approach to avoid and eliminate failures in mechatronical systems in an integrated and intelligent way to achieve a desirable or required amount of utilization in compliance with a defined failure rate. The result is an enhancement of the dependability of such a system.

Selective Guide to Literature on Mining Engineering. Engineering Literature Guides, Number 6.

ERIC Educational Resources Information Center

Erdmann, Charlotte A., Comp.

The multidisciplinary field of mining engineering offers many challenges. Often, many sources must be used to solve a problem. This document is a survey of information sources in mining engineering and is intended to identify those core resources which can help engineers and librarians to find information about the discipline. Sections include:…

Passive Gamma-Ray Emission for Underwater Sediment-Disturbance Detection

DTIC Science & Technology

2017-07-18

Engineer Research and Development Center (ERDC) solves the nation’s toughest engineering and environmental challenges. ERDC develops innovative...solutions in civil and military engineering , geospatial sciences, water resources, and environmental sciences for the Army, the Department of Defense...Sediment-Disturbance Detection Jay L. Clausen U.S. Army Engineer Research and Development Center (ERDC) Cold Regions Research and Engineering

Multiphysics Object Oriented Simulation Environment

DOE Office of Scientific and Technical Information (OSTI.GOV)

The Multiphysics Object Oriented Simulation Environment (MOOSE) software library developed at Idaho National Laboratory is a tool. MOOSE, like other tools, doesn't actually complete a task. Instead, MOOSE seeks to reduce the effort required to create engineering simulation applications. MOOSE itself is a software library: a blank canvas upon which you write equations and then MOOSE can help you solve them. MOOSE is comparable to a spreadsheet application. A spreadsheet, by itself, doesn't do anything. Only once equations are entered into it will a spreadsheet application compute anything. Such is the same for MOOSE. An engineer or scientist can utilizemore » the equation solvers within MOOSE to solve equations related to their area of study. For instance, a geomechanical scientist can input equations related to water flow in underground reservoirs and MOOSE can solve those equations to give the scientist an idea of how water could move over time. An engineer might input equations related to the forces in steel beams in order to understand the load bearing capacity of a bridge. Because MOOSE is a blank canvas it can be useful in many scientific and engineering pursuits.« less

A real-time simulation evaluation of an advanced detection. Isolation and accommodation algorithm for sensor failures in turbine engines

NASA Technical Reports Server (NTRS)

Merrill, W. C.; Delaat, J. C.

1986-01-01

An advanced sensor failure detection, isolation, and accommodation (ADIA) algorithm has been developed for use with an aircraft turbofan engine control system. In a previous paper the authors described the ADIA algorithm and its real-time implementation. Subsequent improvements made to the algorithm and implementation are discussed, and the results of an evaluation presented. The evaluation used a real-time, hybrid computer simulation of an F100 turbofan engine.

National Dam Safety Program. Main Tailings Dam (MO 31082), Mississippi - St. Francis Basin, Madison County, Missouri. Phase I Inspection Report.

DTIC Science & Technology

1979-06-01

failure and other information. These reports were prepared by personnel from the Mis- souri Geology and Land Survey, Applied Engineering and Urban...34Report of the National Lead Stifling Basin Washout, Madison County, Missouri", Applied Engineering and Urban Geology, Geo- logy and Land Survey, 30...failure and other information are contained in reports by personnel from the Missouri Geology and Land Survey, Applied Engineering and Urban Geology

[Examination of safety improvement by failure record analysis that uses reliability engineering].

PubMed

Kato, Kyoichi; Sato, Hisaya; Abe, Yoshihisa; Ishimori, Yoshiyuki; Hirano, Hiroshi; Higashimura, Kyoji; Amauchi, Hiroshi; Yanakita, Takashi; Kikuchi, Kei; Nakazawa, Yasuo

2010-08-20

How the maintenance checks of the medical treatment system, including start of work check and the ending check, was effective for preventive maintenance and the safety improvement was verified. In this research, date on the failure of devices in multiple facilities was collected, and the data of the trouble repair record was analyzed by the technique of reliability engineering. An analysis of data on the system (8 general systems, 6 Angio systems, 11 CT systems, 8 MRI systems, 8 RI systems, and the radiation therapy system 9) used in eight hospitals was performed. The data collection period assumed nine months from April to December 2008. Seven items were analyzed. (1) Mean time between failures (MTBF) (2) Mean time to repair (MTTR) (3) Mean down time (MDT) (4) Number found by check in morning (5) Failure generation time according to modality. The classification of the breakdowns per device, the incidence, and the tendency could be understood by introducing reliability engineering. Analysis, evaluation, and feedback on the failure generation history are useful to keep downtime to a minimum and to ensure safety.

Rehabilitation engineering training for the future: influence of trends in academics, technology, and health reform.

PubMed

Winters, J M

1995-01-01

A perspective is offered on rehabilitation engineering educational strategies, with a focus on the bachelor's and master's levels. Ongoing changes in engineering education are summarized, especially as related to the integration of design and computers throughout the curriculum; most positively affect rehabilitation engineering training. The challenge of identifying long-term "niches" for rehabilitation engineers within a changing rehabilitation service delivery process is addressed. Five key training components are identified and developed: core science and engineering knowledge, synthesized open-ended problem-solving skill development, hands-on design experience, rehabilitation breadth exposure, and a clinical internship. Two unique abilities are identified that help demarcate the engineer from other providers: open-ended problem-solving skills that include quantitative analysis when appropriate, and objective quantitative evaluation of human performance. Educational strategies for developing these abilities are addressed. Finally, a case is made for training "hybrid" engineers/therapists, in particular bachelor-level engineers who go directly to graduate school to become certified orthotists/prosthetists or physical/occupational therapists, pass the RESNA-sponsored assistive technology service provision exam along the way, then later in life obtain a professional engineer's license and an engineering master's degree.

Imminent Engine Failure Probe Investigation.

DTIC Science & Technology

probe signature determination, development of data recording techniques, accumulation of data during durability testing of T56 or TF41 engines and...any other opportunistic gas turbine engine test. The electrostatic probe demonstrated some capability to detect engine distress in TF41 and T56 engines

Method for evaluating the reliability of compressor impeller of turbocharger for vehicle application in plateau area

NASA Astrophysics Data System (ADS)

Wang, Zheng; Wang, Zengquan; Wang, A.-na; Zhuang, Li; Wang, Jinwei

2016-10-01

As turbocharging diesel engines for vehicle application are applied in plateau area, the environmental adaptability of engines has drawn more attention. For the environmental adaptability problem of turbocharging diesel engines for vehicle application, the present studies almost focus on the optimization of performance match between turbocharger and engine, and the reliability problem of turbocharger is almost ignored. The reliability problem of compressor impeller of turbocharger for vehicle application when diesel engines operate in plateau area is studied. Firstly, the rule that the rotational speed of turbocharger changes with the altitude height is presented, and the potential failure modes of compressor impeller are analyzed. Then, the failure behavior models of compressor impeller are built, and the reliability models of compressor impeller operating in plateau area are developed. Finally, the rule that the reliability of compressor impeller changes with the altitude height is studied, the measurements for improving the reliability of the compressor impellers of turbocharger operating in plateau area are given. The results indicate that when the operating speed of diesel engine is certain, the rotational speed of turbocharger increases with the increase of altitude height, and the failure risk of compressor impeller with the failure modes of hub fatigue and blade resonance increases. The reliability of compressor impeller decreases with the increase of altitude height, and it also decreases as the increase of number of the mission profile cycle of engine. The method proposed can not only be used to evaluating the reliability of compressor impeller when diesel engines operate in plateau area but also be applied to direct the structural optimization of compressor impeller.

Graphical Displays Assist In Analysis Of Failures

NASA Technical Reports Server (NTRS)

Pack, Ginger; Wadsworth, David; Razavipour, Reza

1995-01-01

Failure Environment Analysis Tool (FEAT) computer program enables people to see and better understand effects of failures in system. Uses digraph models to determine what will happen to system if set of failure events occurs and to identify possible causes of selected set of failures. Digraphs or engineering schematics used. Also used in operations to help identify causes of failures after they occur. Written in C language.

76 FR 40219 - Airworthiness Directives; Various Aircraft Equipped With Rotax Aircraft Engines 912 A Series Engine

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-08

... Airworthiness Directives; Various Aircraft Equipped With Rotax Aircraft Engines 912 A Series Engine AGENCY... installed on a limited number of engines. No defective washers have been shipped as spare parts. This... consequent ignition failure, possibly resulting in damage to the engine, in- flight engine shutdown and...

40 CFR 1065.410 - Maintenance limits for stabilized test engines.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Engine Selection, Preparation, and Maintenance § 1065... scheduled maintenance on emission data engines must be representative of what is planned to be available to... no longer use it as an emission-data engine. Also, if your test engine has a major mechanical failure...

40 CFR 1065.410 - Maintenance limits for stabilized test engines.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Engine Selection, Preparation, and Maintenance § 1065... scheduled maintenance on emission data engines must be representative of what is planned to be available to... no longer use it as an emission-data engine. Also, if your test engine has a major mechanical failure...

Analyzing Log Files to Predict Students' Problem Solving Performance in a Computer-Based Physics Tutor

ERIC Educational Resources Information Center

Lee, Young-Jin

2015-01-01

This study investigates whether information saved in the log files of a computer-based tutor can be used to predict the problem solving performance of students. The log files of a computer-based physics tutoring environment called Andes Physics Tutor was analyzed to build a logistic regression model that predicted success and failure of students'…

A Weibull distribution accrual failure detector for cloud computing.

PubMed

Liu, Jiaxi; Wu, Zhibo; Wu, Jin; Dong, Jian; Zhao, Yao; Wen, Dongxin

2017-01-01

Failure detectors are used to build high availability distributed systems as the fundamental component. To meet the requirement of a complicated large-scale distributed system, accrual failure detectors that can adapt to multiple applications have been studied extensively. However, several implementations of accrual failure detectors do not adapt well to the cloud service environment. To solve this problem, a new accrual failure detector based on Weibull Distribution, called the Weibull Distribution Failure Detector, has been proposed specifically for cloud computing. It can adapt to the dynamic and unexpected network conditions in cloud computing. The performance of the Weibull Distribution Failure Detector is evaluated and compared based on public classical experiment data and cloud computing experiment data. The results show that the Weibull Distribution Failure Detector has better performance in terms of speed and accuracy in unstable scenarios, especially in cloud computing.

A General-Purpose Optimization Engine for Multi-Disciplinary Design Applications

NASA Technical Reports Server (NTRS)

Patnaik, Surya N.; Hopkins, Dale A.; Berke, Laszlo

1996-01-01

A general purpose optimization tool for multidisciplinary applications, which in the literature is known as COMETBOARDS, is being developed at NASA Lewis Research Center. The modular organization of COMETBOARDS includes several analyzers and state-of-the-art optimization algorithms along with their cascading strategy. The code structure allows quick integration of new analyzers and optimizers. The COMETBOARDS code reads input information from a number of data files, formulates a design as a set of multidisciplinary nonlinear programming problems, and then solves the resulting problems. COMETBOARDS can be used to solve a large problem which can be defined through multiple disciplines, each of which can be further broken down into several subproblems. Alternatively, a small portion of a large problem can be optimized in an effort to improve an existing system. Some of the other unique features of COMETBOARDS include design variable formulation, constraint formulation, subproblem coupling strategy, global scaling technique, analysis approximation, use of either sequential or parallel computational modes, and so forth. The special features and unique strengths of COMETBOARDS assist convergence and reduce the amount of CPU time used to solve the difficult optimization problems of aerospace industries. COMETBOARDS has been successfully used to solve a number of problems, including structural design of space station components, design of nozzle components of an air-breathing engine, configuration design of subsonic and supersonic aircraft, mixed flow turbofan engines, wave rotor topped engines, and so forth. This paper introduces the COMETBOARDS design tool and its versatility, which is illustrated by citing examples from structures, aircraft design, and air-breathing propulsion engine design.

What are the effects of hypertonic saline plus furosemide in acute heart failure?

PubMed

Zepeda, Patricio; Rain, Carmen; Sepúlveda, Paola

2015-08-27

In search of new therapies to solve diuretic resistance in acute heart failure, the addition of hypertonic saline has been proposed. Searching in Epistemonikos database, which is maintained by screening 30 databases, we identified two systematic reviews including nine pertinent randomized controlled trials. We combined the evidence and generated a summary of findings following the GRADE approach. We concluded hypertonic saline associated with furosemide probably decrease mortality, length of hospital stay and hospital readmission in patients with acute decompensated heart failure.

Structures and geriatrics from a failure analysis experience viewpoint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hopper, D.M.

In a failure analysis consulting engineering practice one sees a variety of structural failures from which observations may be made concerning geriatric structures. Representative experience with power plants, refineries, offshore structures, and forensic investigations is summarized and generic observations are made regarding the maintenance of fitness for purpose of structures. Although it is important to optimize the engineering design for a range of operational and environmental variables, it is essential that fabrication and inspection controls exist along with common sense based ongoing monitoring and operations procedures. 18 figs.

The integration of FMEA with other problem solving tools: A review of enhancement opportunities

NASA Astrophysics Data System (ADS)

Ng, W. C.; Teh, S. Y.; Low, H. C.; Teoh, P. C.

2017-09-01

Failure Mode Effect Analysis (FMEA) is one the most effective and accepted problem solving (PS) tools for most of the companies in the world. Since FMEA was first introduced in 1949, practitioners have implemented FMEA in various industries for their quality improvement initiatives. However, studies have shown that there are drawbacks that hinder the effectiveness of FMEA for continuous quality improvement from product design to manufacturing. Therefore, FMEA is integrated with other PS tools such as inventive problem solving methodology (TRIZ), Quality Function Deployment (QFD), Root Cause Analysis (RCA) and seven basic tools of quality to address the drawbacks. This study begins by identifying the drawbacks in FMEA. A comprehensive literature review on the integration of FMEA with other tools is carried out to categorise the integrations based on the drawbacks identified. The three categories are inefficiency of failure analysis, psychological inertia and neglect of customers’ perspective. This study concludes by discussing the gaps and opportunities in the integration for future research.

CABINS: Case-based interactive scheduler

NASA Technical Reports Server (NTRS)

Miyashita, Kazuo; Sycara, Katia

1992-01-01

In this paper we discuss the need for interactive factory schedule repair and improvement, and we identify case-based reasoning (CBR) as an appropriate methodology. Case-based reasoning is the problem solving paradigm that relies on a memory for past problem solving experiences (cases) to guide current problem solving. Cases similar to the current case are retrieved from the case memory, and similarities and differences of the current case to past cases are identified. Then a best case is selected, and its repair plan is adapted to fit the current problem description. If a repair solution fails, an explanation for the failure is stored along with the case in memory, so that the user can avoid repeating similar failures in the future. So far we have identified a number of repair strategies and tactics for factory scheduling and have implemented a part of our approach in a prototype system, called CABINS. As a future work, we are going to scale up CABINS to evaluate its usefulness in a real manufacturing environment.

The Technology of Forming of Innovative Content for Engineering Education

ERIC Educational Resources Information Center

Kayumova, Lilija A.; Savva, Lubov I.; Soldatchenko, Aleksandr L.; Sirazetdinov, Rustem M.; Akhmetov, Linar G.

2016-01-01

The relevance of the study is conditioned by the modernization of engineering education aimed at specialists' training to solve engineering and economic problems effectively. The goal of the paper is to develop the technology of the innovative content's formation for engineering education. The leading method to the study of this problem is a…

A Study of Competence in Mathematics and Mechanics in an Engineering Curriculum

ERIC Educational Resources Information Center

Munns, Andrew

2017-01-01

Professional bodies expect engineers to show competence in both mathematics and engineering topics such as mechanics, using their abilities in both of these to solve problems. Yet within engineering programmes there is a phenomenon known as "The Mathematics Problem", with students not demonstrating understanding of the subject. This…

How Cognitive Style and Problem Complexity Affect Preservice Agricultural Education Teachers' Abilities to Solve Problems in Agricultural Mechanics

ERIC Educational Resources Information Center

Blackburn, J. Joey; Robinson, J. Shane; Lamm, Alexa J.

2014-01-01

The purpose of this experimental study was to determine the effects of cognitive style and problem complexity on Oklahoma State University preservice agriculture teachers' (N = 56) ability to solve problems in small gasoline engines. Time to solution was operationalized as problem solving ability. Kirton's Adaption-Innovation Inventory was…

Role of Mental Representations in Problem Solving: Students' Approaches to Nondirected Tasks

ERIC Educational Resources Information Center

Ibrahim, Bashirah; Rebello, N. Sanjay

2013-01-01

In this paper, we report on a project concerned with the role of cognition during problem solving. We specifically explore the categories of mental representations that students work with during problem solving of different representational task formats. The sample, consisting of 19 engineering students taking a calculus-based physics course,…

Model-Eliciting Activities (MEAs) as a Bridge between Engineering Education Research and Mathematics Education Research

ERIC Educational Resources Information Center

Hamilton, Eric; Lesh, Richard; Lester, Frank; Brilleslyper, Michael

2008-01-01

This article introduces Model-Eliciting Activities (MEAs) as a form of case study team problem-solving. MEA design focuses on eliciting from students conceptual models that they iteratively revise in problem-solving. Though developed by mathematics education researchers to study the evolution of mathematical problem-solving expertise in middle…

A Problem-Solving Framework to Assist Students and Teachers in STEM Courses

ERIC Educational Resources Information Center

Phillips, Jeffrey A.; Clemmer, Katharine W.; McCallum, Jeremy E. B.; Zachariah, Thomas M.

2017-01-01

Well-developed, problem-solving skills are essential for any student enrolled in a science, technology, engineering, and mathematics (STEM) course as well as for graduates in the workforce. One of the most essential skills is the ability to monitor one's own progress and understanding while solving a problem. Successful monitoring during the…

Wind-tunnel Tests of a 2-engine Airplane Model as a Preliminary Study of Flight Conditions Arising on the Failure of the Engine

NASA Technical Reports Server (NTRS)

Hartman, Edwin P

1938-01-01

Wind tunnel tests of a 15-foot-span model of a two-engine low wing transport airplane were made as a preliminary study of the emergency arising from the failure of one engine in flight. Two methods of reducing the initial yawing moment resulting from the failure of one engine were investigated and the equilibrium conditions were explored for two basic modes on one engine, one with zero angle of sideslip and the other with several degrees of sideslip. The added drag resulting from the unsymmetrical attitudes required for flight on one engine was determined for the model airplane. The effects of the application of power upon the stability, controllability, lift, and drag of the model airplane were measured. A dynamic pressure survey of the propeller slipstream was made in the neighborhood of the tail surfaces at three angles of attack. The added parasite drag of the model airplane resulting from the unfavorable conditions of flight on one engine was estimated. From 35 to 50 percent of this added drag was due to the drag of the dead engine propeller and the other 50 to 65 percent was due to the unsymmetrical attitude of the airplane. The mode of flight on one engine in which the angle of sideslip was zero was found to require less power than the mode in which the angle of sideslip was several degrees.

A case study for retaining nuclear power experience

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beckjord, E.S.

1996-12-31

Nuclear engineering departments at U.S. universities are rethinking curricula to focus on essentials. Prospective engineers must know nuclear engineering disciplines, but knowing how their engineering forebears solved important problems will empower them even more by learning some history along with engineering. I suggest a way to retain experience, giving an example: the emergency core cooling system (ECCS) controversy and resolution.

Investigating the Extent That an Integrative Learning Module Broadens the Perception of First-Year Students about the Engineering Profession

ERIC Educational Resources Information Center

Singer, Kerri Patrick; Foutz, Tim; Navarro, Maria; Thompson, Sidney

2015-01-01

Engineers today need both engineering knowledge and social science knowledge to solve complex problems. However, most people have a traditional view of engineering as a field dominated by math and science foci, with little social consequence. This study examined and compared perceptions about engineering from Freshmen taking three different First…

Enabling Engineering Student Success: The Final Report for the Center for the Advancement of Engineering Education. CAEE-TR-10-02

ERIC Educational Resources Information Center

Atman, Cynthia J.; Sheppard, Sheri D.; Turns, Jennifer; Adams, Robin S.; Fleming, Lorraine N.; Stevens, Reed; Streveler, Ruth A.; Smith, Karl A.; Miller, Ronald L.; Leifer, Larry J.; Yasuhara, Ken; Lund, Dennis

2010-01-01

Today's engineering graduates will solve tomorrow's problems in a world that is advancing faster and facing more critical challenges than ever before. This situation creates significant demand for engineering education to evolve in order to effectively prepare a diverse community of engineers for these challenges. Such concerns have led to the…

Linear- and Repetitive-Feature Detection Within Remotely Sensed Imagery

DTIC Science & Technology

2017-04-01

public release; distribution is unlimited. The U.S. Army Engineer Research and Development Center (ERDC) solves the nation’s toughest...Imagery Brendan West U.S. Army Engineer Research and Development Center (ERDC) Cold Regions Research and Engineering Laboratory (CRREL) 72 Lyme Road...and Intelligence System (ARTEMIS) U.S. Army Engineer Research and Development Center (ERDC) Cold Regions Research and Engineering Laboratory (CRREL

Stirling Engine Heat Pump

NASA Astrophysics Data System (ADS)

Kagawa, Noboru

Recent advances in the feasibility studies related to the Stirling engines and Stirling engine heat pumps which have been considered attractive due to their promising role in helping to solve the global environmental and energy problems,are reviewed. This article begins to describe the brief history of the Stirling engines and theoretical thermodynamic analysis of the Stirling cycle in order to understand several advantages on the Stirling engine. Furthermore,they could throw light on our question why the dream engines had not been promoted to practical applications during two hundred years. The present review shows that the Stirling engines with several unique advantages including 30 to 40% thermal efficiency and preferable exhaust characteristics,had been designed and constructed by recent tackling for the development of the advanced automobile and other applications using them. Based on the current state of art,it is being provided to push the Stirling engines combined with heat pumps based on the reversed Rankine cycle to the market. At present,however, many problems, especially for the durability, cost, and delicate engine parts must be enforced to solve. In addition,there are some possibilities which can increase the attractiveness of the Stirling engines and heat pumps. The review closes with suggestions for further research.

Ways of thinking about and teaching ethical problem solving: microethics and macroethics in engineering.

PubMed

Herkert, Joseph R

2005-07-01

Engineering ethics entails three frames of reference: individual, professional, and social. "Microethics" considers individuals and internal relations of the engineering profession; "macroethics" applies to the collective social responsibility of the profession and to societal decisions about technology. Most research and teaching in engineering ethics, including online resources, has had a "micro" focus. Mechanisms for incorporating macroethical perspectives include: integrating engineering ethics and science, technology and society (STS); closer integration of engineering ethics and computer ethics; and consideration of the influence of professional engineering societies and corporate social responsibility programs on ethical engineering practice. Integrating macroethical issues and concerns in engineering ethics involves broadening the context of ethical problem solving. This in turn implies: developing courses emphasizing both micro and macro perspectives, providing faculty development that includes training in both STS and practical ethics; and revision of curriculum materials, including online resources. Multidisciplinary collaboration is recommended 1) to create online case studies emphasizing ethical decision making in individual, professional, and societal contexts; 2) to leverage existing online computer ethics resources with relevance to engineering education and practice; and 3) to create transparent linkages between public policy positions advocated by professional societies and codes of ethics.

Hierarchy curriculum for practical skills training in optics and photonics

NASA Astrophysics Data System (ADS)

Zheng, XiaoDong; Wang, XiaoPing; Liu, Xu; Liu, XiangDong; Lin, YuanFang

2017-08-01

The employers in optical engineering fields hope to recruit students who are capable of applying optical principles to solve engineering problems and have strong laboratory skills. In Zhejiang University, a hierarchy curriculum for practical skill training has been constructed to satisfy this demand. This curriculum includes "Introductive practicum" for freshmen, "Opto-mechanical systems design", "Engineering training", "Electronic system design", "Student research training program (SRTP)", "National University Students' Optical-Science-Technology Competition game", and "Offcampus externship". Without cutting optical theory credit hours, this hierarchy curriculum provides a step-by-step solution to enhance students' practical skills. By following such a hierarchy curriculum, students can smoothly advance from a novice to a qualified professional expert in optics. They will be able to utilize optical engineering tools to design, build, analyze, improve, and test systems, and will be able to work effectively in teams to solve problems in engineering and design.

Testing of a variable-stroke Stirling engine

NASA Technical Reports Server (NTRS)

Thieme, Lanny G.; Allen, David J.

1986-01-01

Testing of a variable-stroke Stirling engine at NASA Lewis has been completed. In support of the DOE Stirling Engine Highway Vehicle Systems Program, the engine was tested for about 70 hours total with both He and H2 as working fluids over a range of pressures and strokes. A direct comparison was made of part-load efficiencies obtained with variable-stroke (VS) and variable-pressure operation. Two failures with the variable-angle swash-plate drive system limited testing to low power levels. These failures are not thought to be caused by problems inherent with the VS concept but do emphasize the need for careful design in the area of the crossheads.

Testing of a variable-stroke Stirling engine

NASA Technical Reports Server (NTRS)

Thieme, L. G.; Allen, D. J.

1986-01-01

Testing of a variable-stroke Stirling engine at NASA Lewis has been completed. In support of the DOE Stirling Engine Highway Vehicle Systems Program, the engine was tested for about 70 hours total with both He and H2 working fluids over a range of pressures and strokes. A direct comparison was made of part-load efficiencies obtained with variable-stroke (VS) and variable-pressure operation. Two failures with the variable-angle swash-plate drive system limited testing to low power levels. These failures are not thought to be caused by problems inherent with the VS concept but do emphasize the need for careful design in the area of the crossheads.

Advanced orbit transfer vehicle propulsion system study

NASA Technical Reports Server (NTRS)

Cathcart, J. A.; Cooper, T. W.; Corringrato, R. M.; Cronau, S. T.; Forgie, S. C.; Harder, M. J.; Mcallister, J. G.; Rudman, T. J.; Stoneback, V. W.

1985-01-01

A reuseable orbit transfer vehicle concept was defined and subsequent recommendations for the design criteria of an advanced LO2/LH2 engine were presented. The major characteristics of the vehicle preliminary design include a low lift to drag aerocapture capability, main propulsion system failure criteria of fail operational/fail safe, and either two main engines with an attitude control system for backup or three main engines to meet the failure criteria. A maintenance and servicing approach was also established for the advanced vehicle and engine concepts. Design tradeoff study conclusions were based on the consideration of reliability, performance, life cycle costs, and mission flexibility.

Reusable rocket engine intelligent control system framework design, phase 2

NASA Technical Reports Server (NTRS)

Nemeth, ED; Anderson, Ron; Ols, Joe; Olsasky, Mark

1991-01-01

Elements of an advanced functional framework for reusable rocket engine propulsion system control are presented for the Space Shuttle Main Engine (SSME) demonstration case. Functional elements of the baseline functional framework are defined in detail. The SSME failure modes are evaluated and specific failure modes identified for inclusion in the advanced functional framework diagnostic system. Active control of the SSME start transient is investigated, leading to the identification of a promising approach to mitigating start transient excursions. Key elements of the functional framework are simulated and demonstration cases are provided. Finally, the advanced function framework for control of reusable rocket engines is presented.

Real-time sensor data validation

NASA Technical Reports Server (NTRS)

Bickmore, Timothy W.

1994-01-01

This report describes the status of an on-going effort to develop software capable of detecting sensor failures on rocket engines in real time. This software could be used in a rocket engine controller to prevent the erroneous shutdown of an engine due to sensor failures which would otherwise be interpreted as engine failures by the control software. The approach taken combines analytical redundancy with Bayesian belief networks to provide a solution which has well defined real-time characteristics and well-defined error rates. Analytical redundancy is a technique in which a sensor's value is predicted by using values from other sensors and known or empirically derived mathematical relations. A set of sensors and a set of relations among them form a network of cross-checks which can be used to periodically validate all of the sensors in the network. Bayesian belief networks provide a method of determining if each of the sensors in the network is valid, given the results of the cross-checks. This approach has been successfully demonstrated on the Technology Test Bed Engine at the NASA Marshall Space Flight Center. Current efforts are focused on extending the system to provide a validation capability for 100 sensors on the Space Shuttle Main Engine.

Differential reliability : probabilistic engineering applied to wood members in bending-tension

Treesearch

Stanley K. Suddarth; Frank E. Woeste; William L. Galligan

1978-01-01

Reliability analysis is a mathematical technique for appraising the design and materials of engineered structures to provide a quantitative estimate of probability of failure. Two or more cases which are similar in all respects but one may be analyzed by this method; the contrast between the probabilities of failure for these cases allows strong analytical focus on the...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raudsepp, E.

A test is given to determine if an engineer suffers from one of the three barriers to technical success: fear of success, fear of failure, or perfectionism. As in most such tests, the middle way is best. Successful engineers know that perfection cannot be attained, that they don't have time to worry about failure or success, and that by aiming and perservering in doing things well, success can be achieved.

Application of Function-Failure Similarity Method to Rotorcraft Component Design

NASA Technical Reports Server (NTRS)

Roberts, Rory A.; Stone, Robert E.; Tumer, Irem Y.; Clancy, Daniel (Technical Monitor)

2002-01-01

Performance and safety are the top concerns of high-risk aerospace applications at NASA. Eliminating or reducing performance and safety problems can be achieved with a thorough understanding of potential failure modes in the designs that lead to these problems. The majority of techniques use prior knowledge and experience as well as Failure Modes and Effects as methods to determine potential failure modes of aircraft. During the design of aircraft, a general technique is needed to ensure that every potential failure mode is considered, while avoiding spending time on improbable failure modes. In this work, this is accomplished by mapping failure modes to specific components, which are described by their functionality. The failure modes are then linked to the basic functions that are carried within the components of the aircraft. Using this technique, designers can examine the basic functions, and select appropriate analyses to eliminate or design out the potential failure modes. The fundamentals of this method were previously introduced for a simple rotating machine test rig with basic functions that are common to a rotorcraft. In this paper, this technique is applied to the engine and power train of a rotorcraft, using failures and functions obtained from accident reports and engineering drawings.

Causes and risk factors for fatal accidents in non-commercial twin engine piston general aviation aircraft.

PubMed

Boyd, Douglas D

2015-04-01

Accidents in twin-engine aircraft carry a higher risk of fatality compared with single engine aircraft and constitute 9% of all general aviation accidents. The different flight profile (higher airspeed, service ceiling, increased fuel load, and aircraft yaw in engine failure) may make comparable studies on single-engine aircraft accident causes less relevant. The objective of this study was to identify the accident causes for non-commercial operations in twin engine aircraft. A NTSB accident database query for accidents in twin piston engine airplanes of 4-8 seat capacity with a maximum certified weight of 3000-8000lbs. operating under 14CFR Part 91 for the period spanning 2002 and 2012 returned 376 accidents. Accident causes and contributing factors were as per the NTSB final report categories. Total annual flight hour data for the twin engine piston aircraft fleet were obtained from the FAA. Statistical analyses employed Chi Square, Fisher's Exact and logistic regression analysis. Neither the combined fatal/non-fatal accident nor the fatal accident rate declined over the period spanning 2002-2012. Under visual weather conditions, the largest number, n=27, (27%) of fatal accidents was attributed to malfunction with a failure to follow single engine procedures representing the most common contributing factor. In degraded visibility, poor instrument approach procedures resulted in the greatest proportion of fatal crashes. Encountering thunderstorms was the most lethal of all accident causes with all occupants sustaining fatal injuries. At night, a failure to maintain obstacle/terrain clearance was the most common accident cause leading to 36% of fatal crashes. The results of logistic regression showed that operations at night (OR 3.7), off airport landings (OR 14.8) and post-impact fire (OR 7.2) all carried an excess risk of a fatal flight. This study indicates training areas that should receive increased emphasis for twin-engine training/recency. First, increased training should be provided on single engine procedures in the event of an engine failure. Second, more focus should be placed on instrument approaches and recovery from unusual aircraft attitude where visibility is degraded. Third, pilots should be made aware of appropriate speed selection for inadvertent flights in convective weather. Finally, emphasizing the importance of conducting night operations under instrument flight rules with its altitude restrictions should lead to a diminished proportion of accidents attributed to failure to maintain obstacle/terrain clearance. Copyright © 2015 Elsevier Ltd. All rights reserved.

Preliminary Study on Acoustic Detection of Faults Experienced by a High-Bypass Turbofan Engine

NASA Technical Reports Server (NTRS)

Boyle, Devin K.

2014-01-01

The vehicle integrated propulsion research (VIPR) effort conducted by NASA and several partners provided an unparalleled opportunity to test a relatively low TRL concept regarding the use of far field acoustics to identify faults occurring in a high bypass turbofan engine. Though VIPR Phase II ground based aircraft installed engine testing wherein a multitude of research sensors and methods were evaluated, an array of acoustic microphones was used to determine the viability of such an array to detect failures occurring in a commercially representative high bypass turbofan engine. The failures introduced during VIPR testing included commanding the engine's low pressure compressor (LPC) exit and high pressure compressor (HPC) 14th stage bleed values abruptly to their failsafe positions during steady state

Studies and analyses of the space shuttle main engine

NASA Technical Reports Server (NTRS)

Tischer, Alan E.; Glover, R. C.

1987-01-01

The primary objectives were to: evaluate ways to maximize the information yield from the current Space Shuttle Main Engine (SSME) condition monitoring sensors, identify additional sensors or monitoring capabilities which would significantly improve SSME data, and provide continuing support of the Main Engine Cost/Operations (MECO) model. In the area of SSME condition monitoring, the principal tasks were a review of selected SSME failure data, a general survey of condition monitoring, and an evaluation of the current engine monitoring system. A computerized data base was developed to assist in modeling engine failure information propagations. Each of the above items is discussed in detail. Also included is a brief discussion of the activities conducted in support of the MECO model.

Advanced Engine Health Management Applications of the SSME Real-Time Vibration Monitoring System

NASA Technical Reports Server (NTRS)

Fiorucci, Tony R.; Lakin, David R., II; Reynolds, Tracy D.; Turner, James E. (Technical Monitor)

2000-01-01

The Real Time Vibration Monitoring System (RTVMS) is a 32-channel high speed vibration data acquisition and processing system developed at Marshall Space Flight Center (MSFC). It Delivers sample rates as high as 51,200 samples/second per channel and performs Fast Fourier Transform (FFT) processing via on-board digital signal processing (DSP) chips in a real-time format. Advanced engine health assessment is achieved by utilizing the vibration spectra to provide accurate sensor validation and enhanced engine vibration redlines. Discrete spectral signatures (such as synchronous) that are indicators of imminent failure can be assessed and utilized to mitigate catastrophic engine failures- a first in rocket engine health assessment. This paper is presented in viewgraph form.

Motion-base simulator study of control of an externally blown flap STOL transport aircraft after failure of an outboard engine during landing approach

NASA Technical Reports Server (NTRS)

Middleton, D. B.; Hurt, G. J., Jr.; Bergeron, H. P.; Patton, J. M., Jr.; Deal, P. L.; Champine, R. A.

1975-01-01

A moving-base simulator investigation of the problems of recovery and landing of a STOL aircraft after failure of an outboard engine during final approach was made. The approaches were made at 75 knots along a 6 deg glide slope. The engine was failed at low altitude and the option to go around was not allowed. The aircraft was simulated with each of three control systems, and it had four high-bypass-ratio fan-jet engines exhausting against large triple-slotted wing flaps to produce additional lift. A virtual-image out-the-window television display of a simulated STOL airport was operating during part of the investigation. Also, a simple heads-up flight director display superimposed on the airport landing scene was used by the pilots to make some of the recoveries following an engine failure. The results of the study indicated that the variation in visual cues and/or motion cues had little effect on the outcome of a recovery, but they did have some effect on the pilot's response and control patterns.

Independent Orbiter Assessment (IOA): Analysis of the ascent thrust vector control actuator subsystem

NASA Technical Reports Server (NTRS)

Wilson, R. E.; Riccio, J. R.

1986-01-01

The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. The independent analysis results for the Ascent Thrust Vector Control (ATVC) Actuator hardware are documented. The function of the Ascent Thrust Vector Control Actuators (ATVC) is to gimbal the main engines to provide for attitude and flight path control during ascent. During first stage flight, the SRB nozzles provide nearly all the steering. After SRB separation, the Orbiter is steered by gimbaling of its main engines. There are six electrohydraulic servoactuators, one pitch and one yaw for each of the three main engines. Each servoactuator is composed of four electrohydraulic servovalve assemblies, one second stage power spool valve assembly, one primary piston assembly and a switching valve. Each level of hardware was evaluated and analyzed for possible failure modes and effects. Criticality was assigned based upon the severity of the effect for each failure mode. Critical failures resulting in loss of ATVC were mainly due to loss of hydraulic fluid, fluid contamination and mechanical failures.

76 FR 56637 - Airworthiness Directives; Lycoming Engines Model IO-720-A1B Reciprocating Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-14

... Airworthiness Directives; Lycoming Engines Model IO-720-A1B Reciprocating Engines AGENCY: Federal Aviation... directive (AD) for certain model IO-720-A1B Lycoming Engines reciprocating engines. This AD requires a... crankshaft due to incorrect parts installed. We are issuing this AD to prevent engine crankshaft failure and...

Genetic-evolution-based optimization methods for engineering design

NASA Technical Reports Server (NTRS)

Rao, S. S.; Pan, T. S.; Dhingra, A. K.; Venkayya, V. B.; Kumar, V.

1990-01-01

This paper presents the applicability of a biological model, based on genetic evolution, for engineering design optimization. Algorithms embodying the ideas of reproduction, crossover, and mutation are developed and applied to solve different types of structural optimization problems. Both continuous and discrete variable optimization problems are solved. A two-bay truss for maximum fundamental frequency is considered to demonstrate the continuous variable case. The selection of locations of actuators in an actively controlled structure, for minimum energy dissipation, is considered to illustrate the discrete variable case.

Inverse problems in the design, modeling and testing of engineering systems

NASA Technical Reports Server (NTRS)

Alifanov, Oleg M.

1991-01-01

Formulations, classification, areas of application, and approaches to solving different inverse problems are considered for the design of structures, modeling, and experimental data processing. Problems in the practical implementation of theoretical-experimental methods based on solving inverse problems are analyzed in order to identify mathematical models of physical processes, aid in input data preparation for design parameter optimization, help in design parameter optimization itself, and to model experiments, large-scale tests, and real tests of engineering systems.

The GRASP 3: Graphical Reliability Analysis Simulation Program. Version 3: A users' manual and modelling guide

NASA Technical Reports Server (NTRS)

Phillips, D. T.; Manseur, B.; Foster, J. W.

1982-01-01

Alternate definitions of system failure create complex analysis for which analytic solutions are available only for simple, special cases. The GRASP methodology is a computer simulation approach for solving all classes of problems in which both failure and repair events are modeled according to the probability laws of the individual components of the system.

A real time microcomputer implementation of sensor failure detection for turbofan engines

NASA Technical Reports Server (NTRS)

Delaat, John C.; Merrill, Walter C.

1989-01-01

An algorithm was developed which detects, isolates, and accommodates sensor failures using analytical redundancy. The performance of this algorithm was demonstrated on a full-scale F100 turbofan engine. The algorithm was implemented in real-time on a microprocessor-based controls computer which includes parallel processing and high order language programming. Parallel processing was used to achieve the required computational power for the real-time implementation. High order language programming was used in order to reduce the programming and maintenance costs of the algorithm implementation software. The sensor failure algorithm was combined with an existing multivariable control algorithm to give a complete control implementation with sensor analytical redundancy. The real-time microprocessor implementation of the algorithm which resulted in the successful completion of the algorithm engine demonstration, is described.

Design study of magnetic eddy-current vibration suppression dampers for application to cryogenic turbomachinery

NASA Technical Reports Server (NTRS)

Gunter, E. J.; Humphris, R. R.; Severson, S. J.

1983-01-01

Cryogenic turbomachinery used to pump high pressure fuel (liquid H2) and oxidizer (liquid O2) to the main engines of the Space Shuttle have experienced rotor instabilities. Subsynchronous whirl, an extremely destructive instability, has caused bearing failures and severe rubs in the seals. These failures have resulted in premature engine shutdowns or, in many instances, have limited the power level to which the turbopumps could be operated. The feasibility of using an eddy current type of damping mechanism for the Space Shuttle Main Engine is outlined.

Investigation of HP Turbine Blade Failure in a Military Turbofan Engine

NASA Astrophysics Data System (ADS)

Mishra, R. K.; Thomas, Johny; Srinivasan, K.; Nandi, Vaishakhi; Bhatt, R. Raghavendra

2017-04-01

Failure of a high pressure (HP) turbine blade in a military turbofan engine is investigated to determine the root cause of failure. Forensic and metallurgical investigations are carried out on the affected blades. The loss of coating and the presence of heavily oxidized intergranular fracture features including substrate material aging and airfoil curling in the trailing edge of a representative blade indicate that the coating is not providing adequate oxidation protection and the blade material substrate is not suitable for the application at hand. Coating spallation followed by substrate oxidation and aging leading to intergranular cracking and localized trailing edge curling is the root cause of the blade failure. The remaining portion of the blade fracture surface showed ductile overload features in the final failure. The damage observed in downstream components is due to secondary effects.

The Use of Executive Control Processes in Engineering Design by Engineering Students and Professional Engineers

ERIC Educational Resources Information Center

Dixon, Raymond A.; Johnson, Scott D.

2012-01-01

A cognitive construct that is important when solving engineering design problems is executive control process, or metacognition. It is a central feature of human consciousness that enables one "to be aware of, monitor, and control mental processes." The framework for this study was conceptualized by integrating the model for creative design, which…

PLTW and Epics-High: Curriculum Comparisons to Support Problem Solving in the Context of Engineering Design. Research in Engineering and Technology Education

ERIC Educational Resources Information Center

Kelley, Todd; Brenner, Daniel C.; Pieper, Jon T.

2010-01-01

A comparative study was conducted to compare two approaches to engineering design curriculum between different schools (inter-school) and between two curricular approaches, "Project Lead the Way" (PLTW) and "Engineering Projects in Community Service" (EPIC High) (inter-curricular). The researchers collected curriculum…

Engineering Design for Engineering Design: Benefits, Models, and Examples from Practice

ERIC Educational Resources Information Center

Turner, Ken L., Jr.; Kirby, Melissa; Bober, Sue

2016-01-01

Engineering design, a framework for studying and solving societal problems, is a key component of STEM education. It is also the area of greatest challenge within the Next Generation Science Standards, NGSS. Many teachers feel underprepared to teach or create activities that feature engineering design, and integrating a lesson plan of core content…

Investigating students’ failure in fractional concept construction

NASA Astrophysics Data System (ADS)

Kurniawan, Henry; Sutawidjaja, Akbar; Rahman As’ari, Abdur; Muksar, Makbul; Setiawan, Iwan

2018-04-01

Failure is a failure to achieve goals. This failure occurs because a larger scheme integrates the schemes in mind that are related to the problem at hand. These schemes are integrated so that they are interconnected to form new structures. This new scheme structure is used to interpret the problems at hand. This research is a qualitative research done to trace student’s failure which happened in fractional concept construction. Subjects in this study as many as 2 students selected from 15 students with the consideration of these students meet the criteria that have been set into two groups that fail in solving the problem. Both groups, namely group 1 is a search group for the failure of students of S1 subject and group 2 is a search group for the failure of students of S2 subject.

A Weibull distribution accrual failure detector for cloud computing

PubMed Central

Wu, Zhibo; Wu, Jin; Zhao, Yao; Wen, Dongxin

2017-01-01

Failure detectors are used to build high availability distributed systems as the fundamental component. To meet the requirement of a complicated large-scale distributed system, accrual failure detectors that can adapt to multiple applications have been studied extensively. However, several implementations of accrual failure detectors do not adapt well to the cloud service environment. To solve this problem, a new accrual failure detector based on Weibull Distribution, called the Weibull Distribution Failure Detector, has been proposed specifically for cloud computing. It can adapt to the dynamic and unexpected network conditions in cloud computing. The performance of the Weibull Distribution Failure Detector is evaluated and compared based on public classical experiment data and cloud computing experiment data. The results show that the Weibull Distribution Failure Detector has better performance in terms of speed and accuracy in unstable scenarios, especially in cloud computing. PMID:28278229

Engine throat/nozzle optics for plume spectroscopy

NASA Technical Reports Server (NTRS)

Bickford, R. L.; Duncan, D. B.

1991-01-01

The Task 2.0 Engine Throat/Nozzle Optics for Plume Spectroscopy, effort was performed under the NASA LeRC Development of Life Prediction Capabilities for Liquid Propellant Rocket Engines program. This Task produced the engineering design of an optical probe to enable spectroscopic measurements within the SSME main chamber. The probe mounts on the SSME nozzle aft manifold and collects light emitted from the throat plane and chamber. Light collected by the probe is transferred to a spectrometer through a fiber optic cable. The design analyses indicate that the probe will function throughout the engine operating cycle and is suitable for both test stand and flight operations. By detecting metallic emissions that are indicative of component degradation or incipient failure, engine shutdown can be initiated before catastrophic failure. This capability will protect valuable test stand hardware and provide enhanced mission safety.

Mathematics as a Course of Study in Problem Solving: Then and Now.

ERIC Educational Resources Information Center

Ellis, Wade, Jr.

The mathematics curriculum in the first 2 years of college is a tool created to assist in solving problems. The current mathematics curriculum has changed little; the same topics, tied to the engineering and science curriculum, are taught as they were being taught in 1945. The problems that students need to solve have changed however. Both the…

Deriving Function-failure Similarity Information for Failure-free Rotorcraft Component Design

NASA Technical Reports Server (NTRS)

Roberts, Rory A.; Stone, Robert B.; Tumer, Irem Y.; Clancy, Daniel (Technical Monitor)

2002-01-01

Performance and safety are the top concerns of high-risk aerospace applications at NASA. Eliminating or reducing performance and safety problems can be achieved with a thorough understanding of potential failure modes in the design that lead to these problems. The majority of techniques use prior knowledge and experience as well as Failure Modes and Effects as methods to determine potential failure modes of aircraft. The aircraft design needs to be passed through a general technique to ensure that every potential failure mode is considered, while avoiding spending time on improbable failure modes. In this work, this is accomplished by mapping failure modes to certain components, which are described by their functionality. In turn, the failure modes are then linked to the basic functions that are carried within the components of the aircraft. Using the technique proposed in this paper, designers can examine the basic functions, and select appropriate analyses to eliminate or design out the potential failure modes. This method was previously applied to a simple rotating machine test rig with basic functions that are common to a rotorcraft. In this paper, this technique is applied to the engine and power train of a rotorcraft, using failures and functions obtained from accident reports and engineering drawings.

Importance Sampling in the Evaluation and Optimization of Buffered Failure Probability

DTIC Science & Technology

2015-07-01

12th International Conference on Applications of Statistics and Probability in Civil Engineering, ICASP12 Vancouver, Canada, July 12-15, 2015...Importance Sampling in the Evaluation and Optimization of Buffered Failure Probability Marwan M. Harajli Graduate Student, Dept. of Civil and Environ...criterion is usually the failure probability . In this paper, we examine the buffered failure probability as an attractive alternative to the failure

The Strength of the Strongest Ties in Collaborative Problem Solving

NASA Astrophysics Data System (ADS)

de Montjoye, Yves-Alexandre; Stopczynski, Arkadiusz; Shmueli, Erez; Pentland, Alex; Lehmann, Sune

2014-06-01

Complex problem solving in science, engineering, and business has become a highly collaborative endeavor. Teams of scientists or engineers collaborate on projects using their social networks to gather new ideas and feedback. Here we bridge the literature on team performance and information networks by studying teams' problem solving abilities as a function of both their within-team networks and their members' extended networks. We show that, while an assigned team's performance is strongly correlated with its networks of expressive and instrumental ties, only the strongest ties in both networks have an effect on performance. Both networks of strong ties explain more of the variance than other factors, such as measured or self-evaluated technical competencies, or the personalities of the team members. In fact, the inclusion of the network of strong ties renders these factors non-significant in the statistical analysis. Our results have consequences for the organization of teams of scientists, engineers, and other knowledge workers tackling today's most complex problems.

The strength of the strongest ties in collaborative problem solving.

PubMed

de Montjoye, Yves-Alexandre; Stopczynski, Arkadiusz; Shmueli, Erez; Pentland, Alex; Lehmann, Sune

2014-06-20

Complex problem solving in science, engineering, and business has become a highly collaborative endeavor. Teams of scientists or engineers collaborate on projects using their social networks to gather new ideas and feedback. Here we bridge the literature on team performance and information networks by studying teams' problem solving abilities as a function of both their within-team networks and their members' extended networks. We show that, while an assigned team's performance is strongly correlated with its networks of expressive and instrumental ties, only the strongest ties in both networks have an effect on performance. Both networks of strong ties explain more of the variance than other factors, such as measured or self-evaluated technical competencies, or the personalities of the team members. In fact, the inclusion of the network of strong ties renders these factors non-significant in the statistical analysis. Our results have consequences for the organization of teams of scientists, engineers, and other knowledge workers tackling today's most complex problems.

Analyzing Team Based Engineering Design Process in Computer Supported Collaborative Learning

ERIC Educational Resources Information Center

Lee, Dong-Kuk; Lee, Eun-Sang

2016-01-01

The engineering design process has been largely implemented in a collaborative project format. Recently, technological advancement has helped collaborative problem solving processes such as engineering design to have efficient implementation using computers or online technology. In this study, we investigated college students' interaction and…

Limestone or Wax?

ERIC Educational Resources Information Center

Sargianis, Kristin; Lachapelle, Cathy P.; Cunningham, Christine M.; Facchiano, Jean; Sanderson, Cheryl; Slater, Patricia

2012-01-01

In this article, the authors focus on an Engineering is Elementary unit that emphasizes students' understanding and application of properties of materials in the context of an engineering design challenge. Students build understanding through a series of hands-on activities, then apply their knowledge to solve a materials engineering problem:…

Engineering extracellular matrix through nanotechnology.

PubMed

Kelleher, Cassandra M; Vacanti, Joseph P

2010-12-06

The goal of tissue engineering is the creation of a living device that can restore, maintain or improve tissue function. Behind this goal is a new idea that has emerged from twentieth century medicine, science and engineering. It is preceded by centuries of human repair and replacement with non-living materials adapted to restore function and cosmetic appearance to patients whose tissues have been destroyed by disease, trauma or congenital abnormality. The nineteenth century advanced replacement and repair strategies based on moving living structures from a site of normal tissue into a site of defects created by the same processes. Donor skin into burn wounds, tendon transfers, intestinal replacements into the urinary tract, toes to replace fingers are all examples. The most radical application is that of vital organ transplantation in which a vital part such as heart, lung or liver is removed from one donor, preserved for transfer and implanted into a patient dying of end-stage organ failure. Tissue engineering and regenerative medicine have advanced a general strategy combining the cellular elements of living tissue with sophisticated biomaterials to produce living structures of sufficient size and function to improve patients' lives. Multiple strategies have evolved and the application of nanotechnology can only improve the field. In our era, by necessity, any medical advance must be successfully commercialized to allow widespread application to help the greatest number of patients. It follows that business models and regulatory agencies must adapt and change to enable these new technologies to emerge. This brief review will discuss the science of nanotechnology and how it has been applied to this evolving field. We will then briefly summarize the history of commercialization of tissue engineering and suggest that nanotechnology may be of use in breeching the barriers to commercialization although its primary mission is to improve the technology by solving some remaining and vexing problems in its science and engineering aspects.

14 CFR 33.70 - Engine life-limited parts.

Code of Federal Regulations, 2014 CFR

2014-01-01

... parts are rotor and major static structural parts whose primary failure is likely to result in a....70 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.70 Engine life...

Methodology for Physics and Engineering of Reliable Products

NASA Technical Reports Server (NTRS)

Cornford, Steven L.; Gibbel, Mark

1996-01-01

Physics of failure approaches have gained wide spread acceptance within the electronic reliability community. These methodologies involve identifying root cause failure mechanisms, developing associated models, and utilizing these models to inprove time to market, lower development and build costs and higher reliability. The methodology outlined herein sets forth a process, based on integration of both physics and engineering principles, for achieving the same goals.

77 FR 40479 - Airworthiness Directives; Rolls-Royce Corporation Turboshaft Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-10

... inspection (FPI) on certain 3rd and 4th stage turbine wheels for cracks in the turbine blades. We are issuing this AD to prevent failure of 3rd or 4th stage turbine wheel blades which could cause engine failure... certain 3rd and 4th stage turbine wheels for cracks in the turbine blades. Comments We gave the public the...

Design and Application of Interactive Simulations in Problem-Solving in University-Level Physics Education

NASA Astrophysics Data System (ADS)

Ceberio, Mikel; Almudí, José Manuel; Franco, Ángel

2016-08-01

In recent years, interactive computer simulations have been progressively integrated in the teaching of the sciences and have contributed significant improvements in the teaching-learning process. Practicing problem-solving is a key factor in science and engineering education. The aim of this study was to design simulation-based problem-solving teaching materials and assess their effectiveness in improving students' ability to solve problems in university-level physics. Firstly, we analyze the effect of using simulation-based materials in the development of students' skills in employing procedures that are typically used in the scientific method of problem-solving. We found that a significant percentage of the experimental students used expert-type scientific procedures such as qualitative analysis of the problem, making hypotheses, and analysis of results. At the end of the course, only a minority of the students persisted with habits based solely on mathematical equations. Secondly, we compare the effectiveness in terms of problem-solving of the experimental group students with the students who are taught conventionally. We found that the implementation of the problem-solving strategy improved experimental students' results regarding obtaining a correct solution from the academic point of view, in standard textbook problems. Thirdly, we explore students' satisfaction with simulation-based problem-solving teaching materials and we found that the majority appear to be satisfied with the methodology proposed and took on a favorable attitude to learning problem-solving. The research was carried out among first-year Engineering Degree students.

Main propulsion system design recommendations for an advanced Orbit Transfer Vehicle

NASA Technical Reports Server (NTRS)

Redd, L.

1985-01-01

Various main propulsion system configurations of an advanced OTV are evaluated with respect to the probability of nonindependent failures, i.e., engine failures that disable the entire main propulsion system. Analysis of the life-cycle cost (LCC) indicates that LCC is sensitive to the main propulsion system reliability, vehicle dry weight, and propellant cost; it is relatively insensitive to the number of missions/overhaul, failures per mission, and EVA and IVA cost. In conclusion, two or three engines are recommended in view of their highest reliability, minimum life-cycle cost, and fail operational/fail safe capability.

40 CFR 1048.325 - What happens if an engine family fails the production-line testing requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... steps you must take to remedy the cause of the engine family's production-line failure. All the engines... 40 Protection of Environment 32 2010-07-01 2010-07-01 false What happens if an engine family fails... SPARK-IGNITION ENGINES Testing Production-line Engines § 1048.325 What happens if an engine family fails...

40 CFR 1045.325 - What happens if an engine family fails the production-line testing requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... steps you must take to remedy the cause of the engine family's production-line failure. All the engines... 40 Protection of Environment 32 2010-07-01 2010-07-01 false What happens if an engine family fails... PROPULSION MARINE ENGINES AND VESSELS Testing Production-line Engines § 1045.325 What happens if an engine...

Experience reveals ways to minimize failures in rod-pumped wells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patterson, J.C.; Bucaram, S.M.; Curfew, J.V.

From the experience gained over the past 25 years, ARCO Oil and Gas Co. has developed recommendations to reduce equipment failure in sucker-rod pumping installations. These recommendations include equipment selection and design, operating procedures, and chemical treatment. Equipment failure and its attendant costs are extremely important in today's petroleum industry. Because rod pumping is the predominant means of artificial lift, minimizing equipment failure in rod pumped wells can have a significant impact on profitability. This compilation of recommendations comes from field locations throughout the US and other countries. The goal is to address and solve problems on a well-by-well basis.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phillips, Monica

Monica Phillips discuss her role as an engineer at Savannah River National Laboratory. Her mission is to provide support to various customers on-site through engineered equipment and solutions, along with solving complex problems to help them meet their needs.

Bio-engineering for land stabilization : final report.

DOT National Transportation Integrated Search

2010-06-01

As part of the Ohio Department of Transportations (ODOTs) ongoing effort to solve engineering problems for the Ohio : transportation system through research, The Ohio State University has undertaken a study entitled Bioengineering for : Land...

Model Based Autonomy for Robust Mars Operations

NASA Technical Reports Server (NTRS)

Kurien, James A.; Nayak, P. Pandurang; Williams, Brian C.; Lau, Sonie (Technical Monitor)

1998-01-01

Space missions have historically relied upon a large ground staff, numbering in the hundreds for complex missions, to maintain routine operations. When an anomaly occurs, this small army of engineers attempts to identify and work around the problem. A piloted Mars mission, with its multiyear duration, cost pressures, half-hour communication delays and two-week blackouts cannot be closely controlled by a battalion of engineers on Earth. Flight crew involvement in routine system operations must also be minimized to maximize science return. It also may be unrealistic to require the crew have the expertise in each mission subsystem needed to diagnose a system failure and effect a timely repair, as engineers did for Apollo 13. Enter model-based autonomy, which allows complex systems to autonomously maintain operation despite failures or anomalous conditions, contributing to safe, robust, and minimally supervised operation of spacecraft, life support, In Situ Resource Utilization (ISRU) and power systems. Autonomous reasoning is central to the approach. A reasoning algorithm uses a logical or mathematical model of a system to infer how to operate the system, diagnose failures and generate appropriate behavior to repair or reconfigure the system in response. The 'plug and play' nature of the models enables low cost development of autonomy for multiple platforms. Declarative, reusable models capture relevant aspects of the behavior of simple devices (e.g. valves or thrusters). Reasoning algorithms combine device models to create a model of the system-wide interactions and behavior of a complex, unique artifact such as a spacecraft. Rather than requiring engineers to all possible interactions and failures at design time or perform analysis during the mission, the reasoning engine generates the appropriate response to the current situation, taking into account its system-wide knowledge, the current state, and even sensor failures or unexpected behavior.

Thermal barrier coatings for gas-turbine engine applications.

PubMed

Padture, Nitin P; Gell, Maurice; Jordan, Eric H

2002-04-12

Hundreds of different types of coatings are used to protect a variety of structural engineering materials from corrosion, wear, and erosion, and to provide lubrication and thermal insulation. Of all these, thermal barrier coatings (TBCs) have the most complex structure and must operate in the most demanding high-temperature environment of aircraft and industrial gas-turbine engines. TBCs, which comprise metal and ceramic multilayers, insulate turbine and combustor engine components from the hot gas stream, and improve the durability and energy efficiency of these engines. Improvements in TBCs will require a better understanding of the complex changes in their structure and properties that occur under operating conditions that lead to their failure. The structure, properties, and failure mechanisms of TBCs are herein reviewed, together with a discussion of current limitations and future opportunities.

Integrating Innovation Skills in an Introductory Engineering Design-Build Course

ERIC Educational Resources Information Center

Liebenberg, Leon; Mathews, Edward Henry

2012-01-01

Modern engineering curricula have started to emphasize design, mostly in the form of design-build experiences. Apart from instilling important problem-solving skills, such pedagogical frameworks address the critical social skill aspects of engineering education due to their team-based, project-based nature. However, it is required of the…

Ingenuity in Action: Connecting Tinkering to Engineering Design Processes

ERIC Educational Resources Information Center

Wang, Jennifer; Werner-Avidon, Maia; Newton, Lisa; Randol, Scott; Smith, Brooke; Walker, Gretchen

2013-01-01

The Lawrence Hall of Science, a science center, seeks to replicate real-world engineering at the "Ingenuity in Action" exhibit, which consists of three open-ended challenges. These problems encourage children to engage in engineering design processes and problem-solving techniques through tinkering. We observed and interviewed 112…

Creativity among Geomatical Engineering Students

ERIC Educational Resources Information Center

Keh, Lim Keng; Ismail, Zaleha; Yusof, Yudariah Mohammad

2017-01-01

This research aims to find out the creativity among the geomatical engineering students. 96 geomatical engineering students participated in the research. They were divided into 24 groups of 4 students. Each group were asked to solve a real world problem collaboratively with their creative thinking. Their works were collected and then analysed as…

40 CFR 1042.340 - When may EPA revoke my certificate under this subpart and how may I sell these engines again?

Code of Federal Regulations, 2010 CFR

2010-07-01

... your proposed remedy to address a suspended certificate under § 1042.325 is inadequate to solve the problem or requires you to change the engine's design or emission control system. (b) To sell engines from...

Process Systems Engineering Education: Learning by Research

ERIC Educational Resources Information Center

Abbas, A.; Alhammadi, H. Y.; Romagnoli, J. A.

2009-01-01

In this paper, we discuss our approach in teaching the final-year course Process Systems Engineering. Students are given ownership of the course by transferring to them the responsibility of learning. A project-based group environment stimulates learning while solving a real engineering problem. We discuss postgraduate student involvement and how…

Technological Literacy Learning with Cumulative and Stepwise Integration of Equations into Electrical Circuit Diagrams

ERIC Educational Resources Information Center

Ozogul, G.; Johnson, A. M.; Moreno, R.; Reisslein, M.

2012-01-01

Technological literacy education involves the teaching of basic engineering principles and problem solving, including elementary electrical circuit analysis, to non-engineering students. Learning materials on circuit analysis typically rely on equations and schematic diagrams, which are often unfamiliar to non-engineering students. The goal of…

Engine Icing Modeling and Simulation (Part 2): Performance Simulation of Engine Rollback Phenomena

NASA Technical Reports Server (NTRS)

May, Ryan D.; Guo, Ten-Huei; Veres, Joseph P.; Jorgenson, Philip C. E.

2011-01-01

Ice buildup in the compressor section of a commercial aircraft gas turbine engine can cause a number of engine failures. One of these failure modes is known as engine rollback: an uncommanded decrease in thrust accompanied by a decrease in fan speed and an increase in turbine temperature. This paper describes the development of a model which simulates the system level impact of engine icing using the Commercial Modular Aero-Propulsion System Simulation 40k (C-MAPSS40k). When an ice blockage is added to C-MAPSS40k, the control system responds in a manner similar to that of an actual engine, and, in cases with severe blockage, an engine rollback is observed. Using this capability to simulate engine rollback, a proof-of-concept detection scheme is developed and tested using only typical engine sensors. This paper concludes that the engine control system s limit protection is the proximate cause of iced engine rollback and that the controller can detect the buildup of ice particles in the compressor section. This work serves as a feasibility study for continued research into the detection and mitigation of engine rollback using the propulsion control system.

SWCC Prediction: Seep/W Add-In Functions

DTIC Science & Technology

2017-06-01

The U.S. Army Engineer Research and Development Center (ERDC) solves the nation’s toughest engineering and environmental challenges. ERDC develops...innovative solutions in civil and military engineering, geospatial sciences, water resources, and environmental sciences for the Army, the Department...Engineer Research and Development Center 3909 Halls Ferry Road Vicksburg, MS 39180-6199 Final report Approved for public release; distribution is

The Chemical Engineering behind How Carbonated Beverages Go Flat: A Hands-On Experiment for Freshmen Students

ERIC Educational Resources Information Center

Hohn, Keith L.

2007-01-01

A hands-on project was developed to educate new chemical engineering students about the types of problems chemical engineers solve and to improve student enthusiasm for studying chemical engineering. In this project, students studied the phenomenon of carbonated beverages going flat. The project was implemented in 2003 and 2004 at Kansas State…

Performance of HESCO Bastion Units Under Combined Normal and Cyclic Lateral Loading

DTIC Science & Technology

2017-02-01

technology was not designed for residential applications, engineering standards would be needed to guide the designers of soldier contingency housing. In...public release; distribution is unlimited. The U.S. Army Engineer Research and Development Center (ERDC) solves the nation’s toughest... engineering and environmental challenges. ERDC develops innovative solutions in civil and military engineering , geospatial sciences, water resources, and

What kind of students should be developed through aeronautical engineering education?

NASA Technical Reports Server (NTRS)

Holloway, R. B.

1975-01-01

The educational requirements for future aeronautical engineering students are postulated. The change in aeronautical engineering from increasing aircraft performance without regard to cost is compared with the cost effective aspects of future research. The capabilities of future engineers are discussed with respect to the following areas: (1) problem solving, (2) planning and organizing, (3) communication, and (4) professionalism.

Comparison of cyclic correlation algorithm implemented in matlab and python

NASA Astrophysics Data System (ADS)

Carr, Richard; Whitney, James

Simulation is a necessary step for all engineering projects. Simulation gives the engineers an approximation of how their devices will perform under different circumstances, without hav-ing to build, or before building a physical prototype. This is especially true for space bound devices, i.e., space communication systems, where the impact of system malfunction or failure is several orders of magnitude over that of terrestrial applications. Therefore having a reliable simulation tool is key in developing these devices and systems. Math Works Matrix Laboratory (MATLAB) is a matrix based software used by scientists and engineers to solve problems and perform complex simulations. MATLAB has a number of applications in a wide variety of fields which include communications, signal processing, image processing, mathematics, eco-nomics and physics. Because of its many uses MATLAB has become the preferred software for many engineers; it is also very expensive, especially for students and startups. One alternative to MATLAB is Python. The Python is a powerful, easy to use, open source programming environment that can be used to perform many of the same functions as MATLAB. Python programming environment has been steadily gaining popularity in niche programming circles. While there are not as many function included in the software as MATLAB, there are many open source functions that have been developed that are available to be downloaded for free. This paper illustrates how Python can implement the cyclic correlation algorithm and com-pares the results to the cyclic correlation algorithm implemented in the MATLAB environment. Some of the characteristics to be compared are the accuracy and precision of the results, and the length of the programs. The paper will demonstrate that Python is capable of performing simulations of complex algorithms such cyclic correlation.

Distributed Optimization of Multi-Agent Systems: Framework, Local Optimizer, and Applications

NASA Astrophysics Data System (ADS)

Zu, Yue

Convex optimization problem can be solved in a centralized or distributed manner. Compared with centralized methods based on single-agent system, distributed algorithms rely on multi-agent systems with information exchanging among connected neighbors, which leads to great improvement on the system fault tolerance. Thus, a task within multi-agent system can be completed with presence of partial agent failures. By problem decomposition, a large-scale problem can be divided into a set of small-scale sub-problems that can be solved in sequence/parallel. Hence, the computational complexity is greatly reduced by distributed algorithm in multi-agent system. Moreover, distributed algorithm allows data collected and stored in a distributed fashion, which successfully overcomes the drawbacks of using multicast due to the bandwidth limitation. Distributed algorithm has been applied in solving a variety of real-world problems. Our research focuses on the framework and local optimizer design in practical engineering applications. In the first one, we propose a multi-sensor and multi-agent scheme for spatial motion estimation of a rigid body. Estimation performance is improved in terms of accuracy and convergence speed. Second, we develop a cyber-physical system and implement distributed computation devices to optimize the in-building evacuation path when hazard occurs. The proposed Bellman-Ford Dual-Subgradient path planning method relieves the congestion in corridor and the exit areas. At last, highway traffic flow is managed by adjusting speed limits to minimize the fuel consumption and travel time in the third project. Optimal control strategy is designed through both centralized and distributed algorithm based on convex problem formulation. Moreover, a hybrid control scheme is presented for highway network travel time minimization. Compared with no controlled case or conventional highway traffic control strategy, the proposed hybrid control strategy greatly reduces total travel time on test highway network.

A Take Stock of Turbine Blades Failure Phenomenon

NASA Astrophysics Data System (ADS)

Roy, Abhijit

2018-02-01

Turbine Blade design and engineering is one of the most complicated and important aspects of turbine technology. Experiments with blades can be simple or very complicated, depending upon parameters of analysis. Turbine blades are subjected to vigorous environments, such as high temperatures, high stresses, and a potentially high vibration environment. All these factors can lead to blade failures, which can destroy the turbine, and engine, so careful design is the prime consideration to resist those conditions. A high cycle of fatigue of compressor and turbine blades due to high dynamic stress caused by blade vibration and resonance within the operating range of machinery is common failure mode for turbine machine. Continuous study and investigation on failure of turbine blades are going on since last five decades. Some review papers published during these days aiming to present a review on recent studies and investigations done on failures of turbine blades. All the detailed literature related with the turbine blades has not been described but emphasized to provide all the methodologies of failures adopted by various researches to investigate turbine blade. This paper illustrate on various factors of failure.

The Student-Centered Active Learning Environment for Undergraduate Programs (SCALE-UP) Project

NASA Astrophysics Data System (ADS)

Beichner, Robert J.

2011-04-01

How do you keep a classroom of 100 undergraduates actively learning? Can students practice communication and teamwork skills in a large class? How do you boost the performance of underrepresented groups? The Student-Centered Active Learning Environment for Undergraduate Programs (SCALE-UP) Project has addressed these concerns. Because of their inclusion in a leading introductory physics textbook, project materials are used by more than 1/3 of all science, math, and engineering majors nationwide. The room design and pedagogy have been adopted at more than 100 leading institutions across the country. Physics, chemistry, math, astronomy, biology, engineering, earth sciences, and even literature classes are currently being taught this way. Educational research indicates that students should collaborate on interesting tasks and be deeply involved with the material they are studying. We promote active learning in a redesigned classroom for 100 students or more. (Of course, smaller classes can also benefit.) Class time is spent primarily on "tangibles" and "ponderables"--hands-on activities, simulations, and interesting questions. Nine students sit in three teams at round tables. Instructors circulate and engage in Socratic dialogues. The setting looks like a banquet hall, with lively interactions nearly all the time. Hundreds of hours of classroom video and audio recordings, transcripts of numerous interviews and focus groups, data from conceptual learning assessments (using widely-recognized instruments in a pretest/posttest protocol), and collected portfolios of student work are part of our rigorous assessment effort. Our findings (based on data from over 16,000 students collected over five years as well as replications at adopting sites) can be summarized as the following: 1) Female failure rate is 1/5 of previous levels, even though more is demanded of students. 2) Minority failure rate is 1/4 that seen in traditionally taught courses. 3) At-risk students are more successful in later engineering courses. 4) Top students gain the most, although students at all levels benefit. 5) Conceptual learning and problem solving are significantly improved, with same content coverage. In this talk I will discuss the need for reform, the SCALE-UP classroom environment, and examine the findings of studies of learning.

Computational structural mechanics engine structures computational simulator

NASA Technical Reports Server (NTRS)

Chamis, C. C.

1989-01-01

The Computational Structural Mechanics (CSM) program at Lewis encompasses: (1) fundamental aspects for formulating and solving structural mechanics problems, and (2) development of integrated software systems to computationally simulate the performance/durability/life of engine structures.

Emission control apparatus for internal combustion engines with a controllably disabled clamping circuit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Asano, M.

1979-08-28

The invention discloses an emission control apparatus for internal combustion engine includes an exhaust composition sensor to sense the mixture ratio, a circuit for clamping the mixture ratio to a predetermined constant value to prevent the mixture from becoming too rich or too lean when a failure should occur in the control loop, for example, in the exhaust composition sensor failure and a circuit for interrupting the clamping circuit when the engine operating condition is such that the sensor is caused to produce low voltage signals although the sensor is functioning properly.

Computational structural mechanics for engine structures

NASA Technical Reports Server (NTRS)

Chamis, Christos C.

1988-01-01

The computational structural mechanics (CSM) program at Lewis encompasses the formulation and solution of structural mechanics problems and the development of integrated software systems to computationally simulate the performance, durability, and life of engine structures. It is structured to supplement, complement, and, whenever possible, replace costly experimental efforts. Specific objectives are to investigate unique advantages of parallel and multiprocessing for reformulating and solving structural mechanics and formulating and solving multidisciplinary mechanics and to develop integrated structural system computational simulators for predicting structural performance, evaluating newly developed methods, and identifying and prioritizing improved or missing methods.

Computational structural mechanics for engine structures

NASA Technical Reports Server (NTRS)

Chamis, Christos C.

1989-01-01

The computational structural mechanics (CSM) program at Lewis encompasses the formulation and solution of structural mechanics problems and the development of integrated software systems to computationally simulate the performance, durability, and life of engine structures. It is structured to supplement, complement, and, whenever possible, replace costly experimental efforts. Specific objectives are to investigate unique advantages of parallel and multiprocessing for reformulating and solving structural mechanics and formulating and solving multidisciplinary mechanics and to develop integrated structural system computational simulators for predicting structural performance, evaluating newly developed methods, and identifying and prioritizing improved or missing methods.

Characterization of tribological sealing system componenets using Scanning Electron Microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shuster, M.; Deis, M.

1996-12-31

A system approach to solving the tribological problems associated with sealing joints implies comprehensive investigation of all the components. Any measurable parameters, including geometry, density (porosity), hardness distributions, microstructure and grain size changes observed during routine metallurgical analysis could provide evidence of the root cause of failure. In the head-gasket-block sealing system of the internal combustion engine, the EDS evaluation of the chlorine and sulfur distribution through the head gasket flange fracture in conjunction with analysis of the sludge between the head, block and gasket surfaces pointed to the corrosive nature of the gasket flange cracking. This approach is evenmore » more useful for the closed tribological system of telescopic hydraulic cylinders or rotary axle shaft oil seals. In these cases in addition to the routine metallurgical analysis of the metal shaft surface, we have to analyze the rubber or plastic sealing elements. The influence of oil contamination as a destructive mechanism must also be evaluated.« less

Technology development and innovation for the bottom of the economic pyramid

NASA Astrophysics Data System (ADS)

Gadgil, Ashok

2015-04-01

Directed development of new technologies to solve specific problems of the poor in the developing world is a daunting task. Developing countries can be a wasteland littered with failed technologies sent there with much goodwill and effort from the industrial countries. Drawing on my team's experience I summarize our answers to some key questions for the technology designer or developer: How might one go about it? What works and what doesn't? What lessons can one draw from an examination of select successes and failures? The key lessons from our experience are: (1) successful technology design and implementation can not be separated from each other - they are tightly intertwined, (2) social factors are as critical for a technology's success as factors based on engineering science, and (3) ignorance of political economy, behavioral economics, organizational behavior, institutional imperatives, cultural norms and social drivers can prove fatal flaws when a new technology leaves the laboratory and meets the real world.

40 CFR 1054.325 - What happens if an engine family fails the production-line testing requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... steps you must take to remedy the cause of the engine family's production-line failure. All the engines... 40 Protection of Environment 32 2010-07-01 2010-07-01 false What happens if an engine family fails... SPARK-IGNITION ENGINES AND EQUIPMENT Production-line Testing § 1054.325 What happens if an engine family...

14 CFR 63.41 - Retesting after failure.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Retesting after failure. 63.41 Section 63.41 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED... failure. An applicant for a flight engineer certificate who fails a written test or practical test for...

14 CFR 63.41 - Retesting after failure.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Retesting after failure. 63.41 Section 63.41 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED... failure. An applicant for a flight engineer certificate who fails a written test or practical test for...

14 CFR 63.41 - Retesting after failure.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Retesting after failure. 63.41 Section 63.41 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED... failure. An applicant for a flight engineer certificate who fails a written test or practical test for...

14 CFR 63.41 - Retesting after failure.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Retesting after failure. 63.41 Section 63.41 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED... failure. An applicant for a flight engineer certificate who fails a written test or practical test for...

Detecting Solenoid Valve Deterioration in In-Use Electronic Diesel Fuel Injection Control Systems

PubMed Central

Tsai, Hsun-Heng; Tseng, Chyuan-Yow

2010-01-01

The diesel engine is the main power source for most agricultural vehicles. The control of diesel engine emissions is an important global issue. Fuel injection control systems directly affect fuel efficiency and emissions of diesel engines. Deterioration faults, such as rack deformation, solenoid valve failure, and rack-travel sensor malfunction, are possibly in the fuel injection module of electronic diesel control (EDC) systems. Among these faults, solenoid valve failure is most likely to occur for in-use diesel engines. According to the previous studies, this failure is a result of the wear of the plunger and sleeve, based on a long period of usage, lubricant degradation, or engine overheating. Due to the difficulty in identifying solenoid valve deterioration, this study focuses on developing a sensor identification algorithm that can clearly classify the usability of the solenoid valve, without disassembling the fuel pump of an EDC system for in-use agricultural vehicles. A diagnostic algorithm is proposed, including a feedback controller, a parameter identifier, a linear variable differential transformer (LVDT) sensor, and a neural network classifier. Experimental results show that the proposed algorithm can accurately identify the usability of solenoid valves. PMID:22163597

Detecting solenoid valve deterioration in in-use electronic diesel fuel injection control systems.

PubMed

Tsai, Hsun-Heng; Tseng, Chyuan-Yow

2010-01-01

The diesel engine is the main power source for most agricultural vehicles. The control of diesel engine emissions is an important global issue. Fuel injection control systems directly affect fuel efficiency and emissions of diesel engines. Deterioration faults, such as rack deformation, solenoid valve failure, and rack-travel sensor malfunction, are possibly in the fuel injection module of electronic diesel control (EDC) systems. Among these faults, solenoid valve failure is most likely to occur for in-use diesel engines. According to the previous studies, this failure is a result of the wear of the plunger and sleeve, based on a long period of usage, lubricant degradation, or engine overheating. Due to the difficulty in identifying solenoid valve deterioration, this study focuses on developing a sensor identification algorithm that can clearly classify the usability of the solenoid valve, without disassembling the fuel pump of an EDC system for in-use agricultural vehicles. A diagnostic algorithm is proposed, including a feedback controller, a parameter identifier, a linear variable differential transformer (LVDT) sensor, and a neural network classifier. Experimental results show that the proposed algorithm can accurately identify the usability of solenoid valves.

Cost effective simulation-based multiobjective optimization in the performance of an internal combustion engine

NASA Astrophysics Data System (ADS)

Aittokoski, Timo; Miettinen, Kaisa

2008-07-01

Solving real-life engineering problems can be difficult because they often have multiple conflicting objectives, the objective functions involved are highly nonlinear and they contain multiple local minima. Furthermore, function values are often produced via a time-consuming simulation process. These facts suggest the need for an automated optimization tool that is efficient (in terms of number of objective function evaluations) and capable of solving global and multiobjective optimization problems. In this article, the requirements on a general simulation-based optimization system are discussed and such a system is applied to optimize the performance of a two-stroke combustion engine. In the example of a simulation-based optimization problem, the dimensions and shape of the exhaust pipe of a two-stroke engine are altered, and values of three conflicting objective functions are optimized. These values are derived from power output characteristics of the engine. The optimization approach involves interactive multiobjective optimization and provides a convenient tool to balance between conflicting objectives and to find good solutions.

An energy-efficient failure detector for vehicular cloud computing.

PubMed

Liu, Jiaxi; Wu, Zhibo; Dong, Jian; Wu, Jin; Wen, Dongxin

2018-01-01

Failure detectors are one of the fundamental components for maintaining the high availability of vehicular cloud computing. In vehicular cloud computing, lots of RSUs are deployed along the road to improve the connectivity. Many of them are equipped with solar battery due to the unavailability or excess expense of wired electrical power. So it is important to reduce the battery consumption of RSU. However, the existing failure detection algorithms are not designed to save battery consumption RSU. To solve this problem, a new energy-efficient failure detector 2E-FD has been proposed specifically for vehicular cloud computing. 2E-FD does not only provide acceptable failure detection service, but also saves the battery consumption of RSU. Through the comparative experiments, the results show that our failure detector has better performance in terms of speed, accuracy and battery consumption.

An energy-efficient failure detector for vehicular cloud computing

PubMed Central

Liu, Jiaxi; Wu, Zhibo; Wu, Jin; Wen, Dongxin

2018-01-01

Failure detectors are one of the fundamental components for maintaining the high availability of vehicular cloud computing. In vehicular cloud computing, lots of RSUs are deployed along the road to improve the connectivity. Many of them are equipped with solar battery due to the unavailability or excess expense of wired electrical power. So it is important to reduce the battery consumption of RSU. However, the existing failure detection algorithms are not designed to save battery consumption RSU. To solve this problem, a new energy-efficient failure detector 2E-FD has been proposed specifically for vehicular cloud computing. 2E-FD does not only provide acceptable failure detection service, but also saves the battery consumption of RSU. Through the comparative experiments, the results show that our failure detector has better performance in terms of speed, accuracy and battery consumption. PMID:29352282

INVENTION IS NOT AN OPTION

PubMed Central

Comedy, Yolanda L.; Gilbert, Juan E.; Pun, Suzie H.

2017-01-01

Inventors help solve all kinds of problems. The AAAS-Lemelson Invention Ambassador program celebrates inventors who have an impact on global challenges, making our communities and the globe better, one invention at a time. In this paper, we introduce two of these invention ambassadors: Dr. Suzie Pun and Dr. Juan Gilbert. Dr. Suzie Pun is the Robert F. Rushmer Professor of Bioengineering, an adjunct professor of chemical engineering, and a member of the Molecular Engineering and Sciences Institute at the University of Washington. Dr. Juan Gilbert is the Andrew Banks Family Preeminence Endowed Professor and chair of the Computer & Information Science & Engineering Department at the University of Florida. Both have a passion for solving problems and are dedicated to teaching their students to change the world. PMID:29527271

14 CFR 23.149 - Minimum control speed.

Code of Federal Regulations, 2012 CFR

2012-01-01

... extended; and (5) All propeller controls in the position recommended for approach with all engines... engine is suddenly made inoperative, it is possible to maintain control of the airplane with that engine... not more than 5 degrees. The method used to simulate critical engine failure must represent the most...

14 CFR 23.149 - Minimum control speed.

Code of Federal Regulations, 2014 CFR

2014-01-01

... extended; and (5) All propeller controls in the position recommended for approach with all engines... engine is suddenly made inoperative, it is possible to maintain control of the airplane with that engine... not more than 5 degrees. The method used to simulate critical engine failure must represent the most...

Reconfigurable Polymer Networks for Improved Treatment of Intracranial Aneurysms

NASA Astrophysics Data System (ADS)

Ninh, Chi Suze Q.

Endovascular embolization of intracranial aneurysms is a minimally invasive treatment in which an implanted material forms a clot to isolate the weakened vessel. Current strategy suffers from long-term potential failure modes. These potential failure modes include (1) enzymatic degradation of the fibrin clot that leads to compaction of the embolic agent, (2) incomplete filling of the aneurysm sac by embolic agent, and (3) challenging geometry of wide neck aneurysms. In the case of wide neck aneurysms, usually an assisting metal stent is used to help open the artery. However, metal stents with much higher modulus in comparison to the soft blood vessel can cause biocompatibilities issues in the long term such as infection and scarring. Motivated to solve these challenges associated with endovascular embolization, strategies to synthesize and engineer reconfigurable and biodegradable polymers as alternative therapies are evaluated in this thesis. (1) Reconfiguration of fibrin gel's modulus was achieved through crosslinking with genipin released from a biodegradable polymer matrix. (2) Reconfigurability can also be achieved by transforming triblock co-polymer hydrogel into photoresponsive material through incorporation of melanin nanoparticles as efficient photosensitizers. (3) Finally, reconfigurability can be conferred on biodegradable polyester networks via Diels-Alder coupling of furan pendant groups and dimaleimide crosslinking agent. Taken all together, this thesis describes strategies to transform a broad class of polymer networks into reconfigurable materials for improved treatment of intracranial aneurysms as well as for other biomedical applications.

Aeronautical Engineering. A Continuing Bibliography with Indexes

DTIC Science & Technology

1987-09-01

engines 482 01 AERONAUTICS (GENERAL) i-10 aircraft equipped with turbine engine ...rate adaptive control with applications to lateral Statistics on aircraft gas turbine engine rotor failures Unified model for the calculation of blade ...PUMPS p 527 A87-35669 to test data for a composite prop-tan model Gas turbine combustor and engine augmentor tube GENERAL AVIATION AIRCRAFT

Framework for Implementing Engineering Senior Design Capstone Courses and Design Clinics

ERIC Educational Resources Information Center

Franchetti, Matthew; Hefzy, Mohamed Samir; Pourazady, Mehdi; Smallman, Christine

2012-01-01

Senior design capstone projects for engineering students are essential components of an undergraduate program that enhances communication, teamwork, and problem solving skills. Capstone projects with industry are well established in management, but not as heavily utilized in engineering. This paper outlines a general framework that can be used by…

Introducing the "Decider" Design Process

ERIC Educational Resources Information Center

Prasa, Anthony R., Jr.; Del Guercio, Ryan

2016-01-01

Engineers are faced with solving important problems every day and must follow a step-by-step design process to arrive at solutions. Students who are taught an effective design process to apply to engineering projects begin to see problems as an engineer would, consider all ideas, and arrive at the best solution. Using an effective design process…

Design, Test, Redesign: Simulation in Technology, Engineering, and Design Education Classrooms

ERIC Educational Resources Information Center

Swinson, Ronnie; Clark, Aaron C.; Ernst, Jeremy V.; Sutton, Kevin

2016-01-01

Today's engineers, designers, and technologists are often thrust into the role of problem solver, from the initial design phase of a product or process all the way to final development. Many engineers in manufacturing environments are tasked with solving problems and continuously improving processes to enhance company profitability, efficiency,…

Design Approaches and Comparison of TAPS Packages for Engineering

ERIC Educational Resources Information Center

Sidhu, S. Manjit

2007-01-01

Purpose: The paper's purpose is to promote the use of modern technologies such as multimedia packages to engineering students. The aim is to help them to learning in their learning, visualization, problem solving and understanding engineering concepts such as in mechanics dynamics. Design/methodology/approach: TAPS packages are developed to help…

Integration, Authenticity, and Relevancy in College Science through Engineering Design

ERIC Educational Resources Information Center

Turner, Ken L., Jr.; Hoffman, Adam R.

2018-01-01

Engineering design is an ideal perspective for engaging students in college science classes. An engineering design problem-solving framework was used to create a general chemistry lab activity focused on an important environmental issue--dead zones. Dead zones impact over 400 locations around the world and are a result of nutrient pollution, one…

Performance Parameters Analysis of an XD3P Peugeot Engine Using Artificial Neural Networks (ANN) Concept in MATLAB

NASA Astrophysics Data System (ADS)

Rangaswamy, T.; Vidhyashankar, S.; Madhusudan, M.; Bharath Shekar, H. R.

2015-04-01

The current trends of engineering follow the basic rule of innovation in mechanical engineering aspects. For the engineers to be efficient, problem solving aspects need to be viewed in a multidimensional perspective. One such methodology implemented is the fusion of technologies from other disciplines in order to solve the problems. This paper mainly deals with the application of Neural Networks in order to analyze the performance parameters of an XD3P Peugeot engine (used in Ministry of Defence). The basic propaganda of the work is divided into two main working stages. In the former stage, experimentation of an IC engine is carried out in order to obtain the primary data. In the latter stage the primary database formed is used to design and implement a predictive neural network in order to analyze the output parameters variation with respect to each other. A mathematical governing equation for the neural network is obtained. The obtained polynomial equation describes the characteristic behavior of the built neural network system. Finally, a comparative study of the results is carried out.

Interim Report on the Investigation of the Fresh Properties of Synthetic Fiber-Reinforced Concrete for the Richardson Landing Casting Field

DTIC Science & Technology

2017-04-01

nation’s toughest engineering and environmental challenges. ERDC develops innovative solutions in civil and military engineering , geospatial sciences... civil engineer , Concrete and Materials Branch CEERD-GM-C Kirk Walker 601.634.3237 Kirk.E.Walker@usace.army.mil Engineering technician, Concrete...2017 Approved for public release; distribution is unlimited. The U.S. Army Engineer Research and Development Center (ERDC) solves the

A Design for Computationally Enabled Analyses Supporting the Pre-Intervention Analytical Framework (PIAF)

DTIC Science & Technology

2015-06-01

public release; distribution is unlimited. The US Army Engineer Research and Development Center (ERDC) solves the nation’s toughest engineering and...Framework (PIAF) Timothy K. Perkins and Chris C. Rewerts Construction Engineering Research Laboratory U.S. Army Engineer Research and Development Center...Prepared for U.S. Army Corps of Engineers Washington, DC 20314-1000 Under Project P2 335530, “Cultural Reasoning and Ethnographic Analysis for the

Analysis of strain gage reliability in F-100 jet engine testing at NASA Lewis Research Center

NASA Technical Reports Server (NTRS)

Holanda, R.

1983-01-01

A reliability analysis was performed on 64 strain gage systems mounted on the 3 rotor stages of the fan of a YF-100 engine. The strain gages were used in a 65 hour fan flutter research program which included about 5 hours of blade flutter. The analysis was part of a reliability improvement program. Eighty-four percent of the strain gages survived the test and performed satisfactorily. A post test analysis determined most failure causes. Five failures were caused by open circuits, three failed gages showed elevated circuit resistance, and one gage circuit was grounded. One failure was undetermined.

Studies and analyses of the Space Shuttle Main Engine: SSME failure data review, diagnostic survey and SSME diagnostic evaluation

NASA Technical Reports Server (NTRS)

Glover, R. C.; Kelley, B. A.; Tischer, A. E.

1986-01-01

The results of a review of the Space Shuttle Main Engine (SSME) failure data for the period 1980 through 1983 are presented. The data was collected, evaluated, and ranked according to procedures established during this study. A number of conclusions and recommendations are made based upon this failure data review. The results of a state-of-the-art diagnostic survey are also presented. This survey covered a broad range of diagnostic sensors and techniques and the findings were evaluated for application to the SSME. Finally, a discussion of the initial activities for the on-going SSME diagnostic evaluation is included.

Linear quadratic servo control of a reusable rocket engine

NASA Technical Reports Server (NTRS)

Musgrave, Jeffrey L.

1991-01-01

A design method for a servo compensator is developed in the frequency domain using singular values. The method is applied to a reusable rocket engine. An intelligent control system for reusable rocket engines was proposed which includes a diagnostic system, a control system, and an intelligent coordinator which determines engine control strategies based on the identified failure modes. The method provides a means of generating various linear multivariable controllers capable of meeting performance and robustness specifications and accommodating failure modes identified by the diagnostic system. Command following with set point control is necessary for engine operation. A Kalman filter reconstructs the state while loop transfer recovery recovers the required degree of robustness while maintaining satisfactory rejection of sensor noise from the command error. The approach is applied to the design of a controller for a rocket engine satisfying performance constraints in the frequency domain. Simulation results demonstrate the performance of the linear design on a nonlinear engine model over all power levels during mainstage operation.

Paving the way : recruiting students into the transportation professions.

DOT National Transportation Integrated Search

2009-06-01

The transportation industry faces a growing shortage of professional engineers and planners. One key strategy in : solving this problem will be to encourage more civil engineering and urban planning students to specialize in : transportation while co...

Eco-innovative design approach: Integrating quality and environmental aspects in prioritizing and solving engineering problems

NASA Astrophysics Data System (ADS)

Chakroun, Mahmoud; Gogu, Grigore; Pacaud, Thomas; Thirion, François

2014-09-01

This study proposes an eco-innovative design process taking into consideration quality and environmental aspects in prioritizing and solving technical engineering problems. This approach provides a synergy between the Life Cycle Assessment (LCA), the nonquality matrix, the Theory of Inventive Problem Solving (TRIZ), morphological analysis and the Analytical Hierarchy Process (AHP). In the sequence of these tools, LCA assesses the environmental impacts generated by the system. Then, for a better consideration of environmental aspects, a new tool is developed, the non-quality matrix, which defines the problem to be solved first from an environmental point of view. The TRIZ method allows the generation of new concepts and contradiction resolution. Then, the morphological analysis offers the possibility of extending the search space of solutions in a design problem in a systematic way. Finally, the AHP identifies the promising solution(s) by providing a clear logic for the choice made. Their usefulness has been demonstrated through their application to a case study involving a centrifugal spreader with spinning discs.

Reliability Estimation of Aero-engine Based on Mixed Weibull Distribution Model

NASA Astrophysics Data System (ADS)

Yuan, Zhongda; Deng, Junxiang; Wang, Dawei

2018-02-01

Aero-engine is a complex mechanical electronic system, based on analysis of reliability of mechanical electronic system, Weibull distribution model has an irreplaceable role. Till now, only two-parameter Weibull distribution model and three-parameter Weibull distribution are widely used. Due to diversity of engine failure modes, there is a big error with single Weibull distribution model. By contrast, a variety of engine failure modes can be taken into account with mixed Weibull distribution model, so it is a good statistical analysis model. Except the concept of dynamic weight coefficient, in order to make reliability estimation result more accurately, three-parameter correlation coefficient optimization method is applied to enhance Weibull distribution model, thus precision of mixed distribution reliability model is improved greatly. All of these are advantageous to popularize Weibull distribution model in engineering applications.

40 CFR 86.430-78 - Vehicle failure.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Vehicle failure. 86.430-78 Section 86...) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1978 and Later New Motorcycles, General Provisions § 86.430-78 Vehicle failure. Any test vehicle which incurs...

40 CFR 86.430-78 - Vehicle failure.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Vehicle failure. 86.430-78 Section 86...) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1978 and Later New Motorcycles, General Provisions § 86.430-78 Vehicle failure. Any test vehicle which incurs...

40 CFR 86.430-78 - Vehicle failure.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Vehicle failure. 86.430-78 Section 86...) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1978 and Later New Motorcycles, General Provisions § 86.430-78 Vehicle failure. Any test vehicle which incurs...

40 CFR 86.430-78 - Vehicle failure.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 19 2013-07-01 2013-07-01 false Vehicle failure. 86.430-78 Section 86...) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1978 and Later New Motorcycles, General Provisions § 86.430-78 Vehicle failure. Any test vehicle which incurs...

40 CFR 86.430-78 - Vehicle failure.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 19 2014-07-01 2014-07-01 false Vehicle failure. 86.430-78 Section 86...) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1978 and Later New Motorcycles, General Provisions § 86.430-78 Vehicle failure. Any test vehicle which incurs...

40 CFR 63.9375 - What definitions apply to this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

... malfunction, regardless or whether or not such failure is permitted by this subpart. Engine means any internal.... Malfunction means any sudden, infrequent, and not reasonably preventable failure of air pollution control... potential to cause, the emission limitations in an applicable standard to be exceeded. Failures that are...

40 CFR 63.9375 - What definitions apply to this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

... malfunction, regardless or whether or not such failure is permitted by this subpart. Engine means any internal.... Malfunction means any sudden, infrequent, and not reasonably preventable failure of air pollution control... potential to cause, the emission limitations in an applicable standard to be exceeded. Failures that are...

40 CFR 63.9375 - What definitions apply to this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

... malfunction, regardless or whether or not such failure is permitted by this subpart. Engine means any internal.... Malfunction means any sudden, infrequent, and not reasonably preventable failure of air pollution control... potential to cause, the emission limitations in an applicable standard to be exceeded. Failures that are...

40 CFR 63.9375 - What definitions apply to this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

... malfunction, regardless or whether or not such failure is permitted by this subpart. Engine means any internal.... Malfunction means any sudden, infrequent, and not reasonably preventable failure of air pollution control... potential to cause, the emission limitations in an applicable standard to be exceeded. Failures that are...

Who Is Doing the Engineering, the Student or the Teacher? The Development and Use of a Rubric to Categorize Level of Design for the Elementary Classroom

ERIC Educational Resources Information Center

Nadelson, Louis S.; Pfiester, Joshua; Callahan, Janet; Pyke, Patricia

2015-01-01

Science, technology, engineering, and mathematics (STEM) professional development for K-5 teachers often includes engineering design as a focus. Because engineering applications provide perspective to both teachers and their students in terms of how mathematic and scientific principles are employed to solve real-world problems (Baine, 2004; Roden,…

How to apply clinical cases and medical literature in the framework of a modified "failure mode and effects analysis" as a clinical reasoning tool--an illustration using the human biliary system.

PubMed

Wong, Kam Cheong

2016-04-06

Clinicians use various clinical reasoning tools such as Ishikawa diagram to enhance their clinical experience and reasoning skills. Failure mode and effects analysis, which is an engineering methodology in origin, can be modified and applied to provide inputs into an Ishikawa diagram. The human biliary system is used to illustrate a modified failure mode and effects analysis. The anatomical and physiological processes of the biliary system are reviewed. Failure is defined as an abnormality caused by infective, inflammatory, obstructive, malignancy, autoimmune and other pathological processes. The potential failures, their effect(s), main clinical features, and investigation that can help a clinician to diagnose at each anatomical part and physiological process are reviewed and documented in a modified failure mode and effects analysis table. Relevant medical and surgical cases are retrieved from the medical literature and weaved into the table. A total of 80 clinical cases which are relevant to the modified failure mode and effects analysis for the human biliary system have been reviewed and weaved into a designated table. The table is the backbone and framework for further expansion. Reviewing and updating the table is an iterative and continual process. The relevant clinical features in the modified failure mode and effects analysis are then extracted and included in the relevant Ishikawa diagram. This article illustrates an application of engineering methodology in medicine, and it sows the seeds of potential cross-pollination between engineering and medicine. Establishing a modified failure mode and effects analysis can be a teamwork project or self-directed learning process, or a mix of both. Modified failure mode and effects analysis can be deployed to obtain inputs for an Ishikawa diagram which in turn can be used to enhance clinical experiences and clinical reasoning skills for clinicians, medical educators, and students.

Impact of Context-Rich, Multifaceted Problems on Students' Attitudes Towards Problem-Solving

NASA Astrophysics Data System (ADS)

Ogilvie, Craig

2008-04-01

Young scientists and engineers need strong problem-solving skills to enable them to address the broad challenges they will face in their careers. These challenges will likely be ill-defined and open-ended with either unclear goals, insufficient constraints, multiple possible solutions, and different criteria for evaluating solutions so that our young scientists and engineers must be able to make judgments and defend their proposed solutions. In contrast, many students believe that problem-solving is being able to apply set procedures or algorithms to tasks and that their job as students is to master an ever-increasing list of procedures. This gap between students' beliefs and the broader, deeper approaches of experts is a strong barrier to the educational challenge of preparing students to succeed in their future careers. To start to address this gap, we have used multi-faceted, context-rich problems in a sophomore calculus-based physics course. To assess whether there was any change in students' attitudes or beliefs towards problem-solving, students were asked to reflect on their problem-solving at the beginning and at the end of the semester. These reflections were coded as containing one or more problem-solving ideas. The change in students' beliefs will be shown in this talk.

Engineering neural systems for high-level problem solving.

PubMed

Sylvester, Jared; Reggia, James

2016-07-01

There is a long-standing, sometimes contentious debate in AI concerning the relative merits of a symbolic, top-down approach vs. a neural, bottom-up approach to engineering intelligent machine behaviors. While neurocomputational methods excel at lower-level cognitive tasks (incremental learning for pattern classification, low-level sensorimotor control, fault tolerance and processing of noisy data, etc.), they are largely non-competitive with top-down symbolic methods for tasks involving high-level cognitive problem solving (goal-directed reasoning, metacognition, planning, etc.). Here we take a step towards addressing this limitation by developing a purely neural framework named galis. Our goal in this work is to integrate top-down (non-symbolic) control of a neural network system with more traditional bottom-up neural computations. galis is based on attractor networks that can be "programmed" with temporal sequences of hand-crafted instructions that control problem solving by gating the activity retention of, communication between, and learning done by other neural networks. We demonstrate the effectiveness of this approach by showing that it can be applied successfully to solve sequential card matching problems, using both human performance and a top-down symbolic algorithm as experimental controls. Solving this kind of problem makes use of top-down attention control and the binding together of visual features in ways that are easy for symbolic AI systems but not for neural networks to achieve. Our model can not only be instructed on how to solve card matching problems successfully, but its performance also qualitatively (and sometimes quantitatively) matches the performance of both human subjects that we had perform the same task and the top-down symbolic algorithm that we used as an experimental control. We conclude that the core principles underlying the galis framework provide a promising approach to engineering purely neurocomputational systems for problem-solving tasks that in people require higher-level cognitive functions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Applications of hybrid and digital computation methods in aerospace-related sciences and engineering. [problem solving methods at the University of Houston

NASA Technical Reports Server (NTRS)

Huang, C. J.; Motard, R. L.

1978-01-01

The computing equipment in the engineering systems simulation laboratory of the Houston University Cullen College of Engineering is described and its advantages are summarized. The application of computer techniques in aerospace-related research psychology and in chemical, civil, electrical, industrial, and mechanical engineering is described in abstracts of 84 individual projects and in reprints of published reports. Research supports programs in acoustics, energy technology, systems engineering, and environment management as well as aerospace engineering.

Thermophysical and Thermomechanical Properties of Thermal Barrier Coating Systems

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Miller, Robert A.

2000-01-01

Thermal barrier coatings have been developed for advanced gas turbine and diesel engine applications to improve engine reliability and fuel efficiency. However, the issue of coating durability under high temperature cyclic conditions is still of major concern. The coating failure is closely related to thermal stresses and oxidation in the coating systems. Coating shrinkage cracking resulting from ceramic sintering and creep at high temperatures can further accelerate the coating failure process. The purpose of this paper is to address critical issues such as ceramic sintering and creep, thermal fatigue and their relevance to coating life prediction. Novel test approaches have been established to obtain critical thermophysical and thermomechanical properties of the coating systems under near-realistic temperature and stress gradients encountered in advanced engine systems. Emphasis is placed on the dynamic changes of the coating thermal conductivity and elastic modulus, fatigue and creep interactions, and resulting failure mechanisms during the simulated engine tests. Detailed experimental and modeling results describing processes occurring in the thermal barrier coating systems provide a framework for developing strategies to manage ceramic coating architecture, microstructure and properties.

Sculpting in cyberspace: Parallel processing the development of new software

NASA Technical Reports Server (NTRS)

Fisher, Rob

1993-01-01

Stimulating creativity in problem solving, particularly where software development is involved, is applicable to many disciplines. Metaphorical thinking keeps the problem in focus but in a different light, jarring people out of their mental ruts and sparking fresh insights. It forces the mind to stretch to find patterns between dissimilar concepts, in the hope of discovering unusual ideas in odd associations (Technology Review January 1993, p. 37). With a background in Engineering and Visual Design from MIT, I have for the past 30 years pursued a career as a sculptor of interdisciplinary monumental artworks that bridge the fields of science, engineering and art. Since 1979, I have pioneered the application of computer simulation to solve the complex problems associated with these projects. A recent project for the roof of the Carnegie Science Center in Pittsburgh made particular use of the metaphoric creativity technique described above. The problem-solving process led to the creation of hybrid software combining scientific, architectural and engineering visualization techniques. David Steich, a Doctoral Candidate in Electrical Engineering at Penn State, was commissioned to develop special software that enabled me to create innovative free-form sculpture. This paper explores the process of inventing the software through a detailed analysis of the interaction between an artist and a computer programmer.

Key Reliability Drivers of Liquid Propulsion Engines and A Reliability Model for Sensitivity Analysis

NASA Technical Reports Server (NTRS)

Huang, Zhao-Feng; Fint, Jeffry A.; Kuck, Frederick M.

2005-01-01

This paper is to address the in-flight reliability of a liquid propulsion engine system for a launch vehicle. We first establish a comprehensive list of system and sub-system reliability drivers for any liquid propulsion engine system. We then build a reliability model to parametrically analyze the impact of some reliability parameters. We present sensitivity analysis results for a selected subset of the key reliability drivers using the model. Reliability drivers identified include: number of engines for the liquid propulsion stage, single engine total reliability, engine operation duration, engine thrust size, reusability, engine de-rating or up-rating, engine-out design (including engine-out switching reliability, catastrophic fraction, preventable failure fraction, unnecessary shutdown fraction), propellant specific hazards, engine start and cutoff transient hazards, engine combustion cycles, vehicle and engine interface and interaction hazards, engine health management system, engine modification, engine ground start hold down with launch commit criteria, engine altitude start (1 in. start), Multiple altitude restart (less than 1 restart), component, subsystem and system design, manufacturing/ground operation support/pre and post flight check outs and inspection, extensiveness of the development program. We present some sensitivity analysis results for the following subset of the drivers: number of engines for the propulsion stage, single engine total reliability, engine operation duration, engine de-rating or up-rating requirements, engine-out design, catastrophic fraction, preventable failure fraction, unnecessary shutdown fraction, and engine health management system implementation (basic redlines and more advanced health management systems).

New computer program solves wide variety of heat flow problems

NASA Technical Reports Server (NTRS)

Almond, J. C.

1966-01-01

Boeing Engineering Thermal Analyzer /BETA/ computer program uses numerical methods to provide accurate heat transfer solutions to a wide variety of heat flow problems. The program solves steady-state and transient problems in almost any situation that can be represented by a resistance-capacitance network.

Advances in Thrust-Based Emergency Control of an Airplane

NASA Technical Reports Server (NTRS)

Creech, Gray; Burken, John J.; Burcham, Bill

2003-01-01

Engineers at NASA's Dryden Flight Research Center have received a patent on an emergency flight-control method implemented by a propulsion-controlled aircraft (PCA) system. Utilizing the preexisting auto-throttle and engine-pressure-ratio trim controls of the airplane, the PCA system provides pitch and roll control for landing an airplane safely without using aerodynamic control surfaces that have ceased to function because of a primary-flight-control-system failure. The installation of the PCA does not entail any changes in pre-existing engine hardware or software. [Aspects of the method and system at previous stages of development were reported in Thrust-Control System for Emergency Control of an Airplane (DRC-96-07), NASA Tech Briefs, Vol. 25, No. 3 (March 2001), page 68 and Emergency Landing Using Thrust Control and Shift of Weight (DRC-96-55), NASA Tech Briefs, Vol. 26, No. 5 (May 2002), page 58.]. Aircraft flight-control systems are designed with extensive redundancy to ensure low probabilities of failure. During recent years, however, several airplanes have exhibited major flight-control-system failures, leaving engine thrust as the last mode of flight control. In some of these emergency situations, engine thrusts were successfully modulated by the pilots to maintain flight paths or pitch angles, but in other situations, lateral control was also needed. In the majority of such control-system failures, crashes resulted and over 1,200 people died. The challenge lay in creating a means of sufficient degree of thrust-modulation control to safely fly and land a stricken airplane. A thrust-modulation control system designed for this purpose was flight-tested in a PCA an MD-11 airplane. The results of the flight test showed that without any operational control surfaces, a pilot can land a crippled airplane (U.S. Patent 5,330,131). The installation of the original PCA system entailed modifications not only of the flight-control computer (FCC) of the airplane but also of each engine-control computer. Inasmuch as engine-manufacturer warranties do not apply to modified engines, the challenge became one of creating a PCA system that does not entail modifications of the engine computers.

On the Development of an Efficient Parallel Hybrid Solver with Application to Acoustically Treated Aero-Engine Nacelles

NASA Technical Reports Server (NTRS)

Watson, Willie R.; Nark, Douglas M.; Nguyen, Duc T.; Tungkahotara, Siroj

2006-01-01

A finite element solution to the convected Helmholtz equation in a nonuniform flow is used to model the noise field within 3-D acoustically treated aero-engine nacelles. Options to select linear or cubic Hermite polynomial basis functions and isoparametric elements are included. However, the key feature of the method is a domain decomposition procedure that is based upon the inter-mixing of an iterative and a direct solve strategy for solving the discrete finite element equations. This procedure is optimized to take full advantage of sparsity and exploit the increased memory and parallel processing capability of modern computer architectures. Example computations are presented for the Langley Flow Impedance Test facility and a rectangular mapping of a full scale, generic aero-engine nacelle. The accuracy and parallel performance of this new solver are tested on both model problems using a supercomputer that contains hundreds of central processing units. Results show that the method gives extremely accurate attenuation predictions, achieves super-linear speedup over hundreds of CPUs, and solves upward of 25 million complex equations in a quarter of an hour.

Numerical simulation of flow through the Langley parametric scramjet engine

NASA Technical Reports Server (NTRS)

Srinivasan, Shivakumar; Kamath, Pradeep S.; Mcclinton, Charles R.

1989-01-01

The numerical simulation of a three-dimensional turbulent, reacting flow through the entire Langley parametric scramjet engine has been obtained using a piecewise elliptic approach. The last section in the combustor has been analyzed using a parabolized Navier-Stokes code. The facility nozzle flow was analyzed as a first step. The outflow conditions from the nozzle were chosen as the inflow conditions of the scramjet inlet. The nozzle and the inlet simulation were accomplished by solving the three-dimensional Navier-Stokes equations with a perfect gas assumption. The inlet solution downstream of the scramjet throat was used to provide inflow conditions for the combustor region. The first two regions of the combustor were analyzed using the MacCormack's explicit scheme. However, the source terms in the species equations were solved implicitly. The finite rate chemistry was modeled using the two-step reaction model of Rogers and Chinitz. A complete reaction model was used in the PNS code to solve the last combustor region. The numerical solutions provide an insight of the flow details in a complete hydrogen-fueled scramjet engine module.

Levels of Simplification. The Use of Assumptions, Restrictions, and Constraints in Engineering Analysis.

ERIC Educational Resources Information Center

Whitaker, Stephen

1988-01-01

Describes the use of assumptions, restrictions, and constraints in solving difficult analytical problems in engineering. Uses the Navier-Stokes equations as examples to demonstrate use, derivations, advantages, and disadvantages of the technique. (RT)

Modelling of Safety Instrumented Systems by using Bernoulli trials: towards the notion of odds on for SIS failures analysis

NASA Astrophysics Data System (ADS)

Cauffriez, Laurent

2017-01-01

This paper deals with the modeling of a random failures process of a Safety Instrumented System (SIS). It aims to identify the expected number of failures for a SIS during its lifecycle. Indeed, the fact that the SIS is a system being tested periodically gives the idea to apply Bernoulli trials to characterize the random failure process of a SIS and thus to verify if the PFD (Probability of Failing Dangerously) experimentally obtained agrees with the theoretical one. Moreover, the notion of "odds on" found in Bernoulli theory allows engineers and scientists determining easily the ratio between “outcomes with success: failure of SIS” and “outcomes with unsuccess: no failure of SIS” and to confirm that SIS failures occur sporadically. A Stochastic P-temporised Petri net is proposed and serves as a reference model for describing the failure process of a 1oo1 SIS architecture. Simulations of this stochastic Petri net demonstrate that, during its lifecycle, the SIS is rarely in a state in which it cannot perform its mission. Experimental results are compared to Bernoulli trials in order to validate the powerfulness of Bernoulli trials for the modeling of the failures process of a SIS. The determination of the expected number of failures for a SIS during its lifecycle opens interesting research perspectives for engineers and scientists by completing the notion of PFD.

Solving Component Structural Dynamic Failures Due to Extremely High Frequency Structural Response on the Space Shuttle Program

NASA Technical Reports Server (NTRS)

Frady, Greg; Nesman, Thomas; Zoladz, Thomas; Szabo, Roland

2010-01-01

For many years, the capabilities to determine the root-cause failure of component failures have been limited to the analytical tools and the state of the art data acquisition systems. With this limited capability, many anomalies have been resolved by adding material to the design to increase robustness without the ability to determine if the design solution was satisfactory until after a series of expensive test programs were complete. The risk of failure and multiple design, test, and redesign cycles were high. During the Space Shuttle Program, many crack investigations in high energy density turbomachines, like the SSME turbopumps and high energy flows in the main propulsion system, have led to the discovery of numerous root-cause failures and anomalies due to the coexistences of acoustic forcing functions, structural natural modes, and a high energy excitation, such as an edge tone or shedding flow, leading the technical community to understand many of the primary contributors to extremely high frequency high cycle fatique fluid-structure interaction anomalies. These contributors have been identified using advanced analysis tools and verified using component and system tests during component ground tests, systems tests, and flight. The structural dynamics and fluid dynamics communities have developed a special sensitivity to the fluid-structure interaction problems and have been able to adjust and solve these problems in a time effective manner to meet budget and schedule deadlines of operational vehicle programs, such as the Space Shuttle Program over the years.

The Problem of Ensuring Reliability of Gas Turbine Engines

NASA Astrophysics Data System (ADS)

Nozhnitsky, Yu A.

2018-01-01

Requirements to advanced engines for civil aviation are discussing. Some significant problems of ensuring reliability of advanced gas turbine engines are mentioned. Special attention is paid to successful utilization of new materials and critical technologies. Also the problem of excluding failure of engine part due to low cycle or high cycle fatigue is discussing.

Elementary Students' Engagement in Failure-Prone Engineering Design Tasks

ERIC Educational Resources Information Center

Andrews, Chelsea Joy

2017-01-01

Although engineering education has been practiced at the undergraduate level for over a century, only fairly recently has the field broadened to include the elementary level; the pre-college division of the American Society of Engineering Education was established in 2003. As a result, while recent education standards require engineering in…

78 FR 31851 - Harmonization of Airworthiness Standards-Gust and Maneuver Load Requirements

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-28

... airplanes equipped with wing-mounted engines; revise the engine torque loads criteria; add an engine failure... equipped with wing-mounted engines. Following an accident in which an airplane shed a large wing- mounted...-93-137, November 15, 1993). This recommendation was specifically aimed at gust loads on wing-mounted...

Katrina: macro-ethical issues for engineers.

PubMed

Newberry, Byron

2010-09-01

Hurricane Katrina was one of the worst disasters in United States history. Failures within New Orleans' engineered hurricane protection system (levees and floodwalls) contributed to the severity of the event and have drawn considerable public attention. In the time since Katrina, forensic investigations have uncovered a range of issues and problems related to the engineering work. In this article, my goal is to distill from these investigations, and the related literature that has accumulated, some overarching macro-ethical issues that are relevant for all engineers. I attempt to frame these issues, using illustrative examples taken from Katrina, in a way that might be of pedagogical use and benefit for engineering educators interested in engaging their students in discussions of engineering ethics, societal impact of engineered systems, engineering design, or related topics. Some of the issues discussed are problems of unanticipated failure modes, faulty assumptions, lack or misuse of information, the importance of resiliency, the effects of time, balancing competing interests, attending to the details of interfaces, the fickleness of risk perception, and how the past constrains the present.

40 CFR 1042.325 - What happens if an engine family fails the production-line testing requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... specifies steps you must take to remedy the cause of the engine family's production-line failure. All the... 40 Protection of Environment 32 2010-07-01 2010-07-01 false What happens if an engine family fails... MARINE COMPRESSION-IGNITION ENGINES AND VESSELS Testing Production-line Engines § 1042.325 What happens...

Sliding Mode Control of the X-33 with an Engine Failure

NASA Technical Reports Server (NTRS)

Shtessel, Yuri B.; Hall, Charles E.

2000-01-01

Ascent flight control of the X-3 is performed using two XRS-2200 linear aerospike engines. in addition to aerosurfaces. The baseline control algorithms are PID with gain scheduling. Flight control using an innovative method. Sliding Mode Control. is presented for nominal and engine failed modes of flight. An easy to implement, robust controller. requiring no reconfiguration or gain scheduling is demonstrated through high fidelity flight simulations. The proposed sliding mode controller utilizes a two-loop structure and provides robust. de-coupled tracking of both orientation angle command profiles and angular rate command profiles in the presence of engine failure, bounded external disturbances (wind gusts) and uncertain matrix of inertia. Sliding mode control causes the angular rate and orientation angle tracking error dynamics to be constrained to linear, de-coupled, homogeneous, and vector valued differential equations with desired eigenvalues. Conditions that restrict engine failures to robustness domain of the sliding mode controller are derived. Overall stability of a two-loop flight control system is assessed. Simulation results show that the designed controller provides robust, accurate, de-coupled tracking of the orientation angle command profiles in the presence of external disturbances and vehicle inertia uncertainties, as well as the single engine failed case. The designed robust controller will significantly reduce the time and cost associated with flying new trajectory profiles or orbits, with new payloads, and with modified vehicles

49 CFR 830.2 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., search and rescue, law enforcement, aeronautical research, or biological or geological resource..., and which would normally require major repair or replacement of the affected component. Engine failure or damage limited to an engine if only one engine fails or is damaged, bent fairings or cowling...

49 CFR 830.2 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., search and rescue, law enforcement, aeronautical research, or biological or geological resource..., and which would normally require major repair or replacement of the affected component. Engine failure or damage limited to an engine if only one engine fails or is damaged, bent fairings or cowling...

49 CFR 830.2 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., search and rescue, law enforcement, aeronautical research, or biological or geological resource..., and which would normally require major repair or replacement of the affected component. Engine failure or damage limited to an engine if only one engine fails or is damaged, bent fairings or cowling...

49 CFR 830.2 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., search and rescue, law enforcement, aeronautical research, or biological or geological resource..., and which would normally require major repair or replacement of the affected component. Engine failure or damage limited to an engine if only one engine fails or is damaged, bent fairings or cowling...

Comparison of flight results with digital simulation for a digital electronic engine control in an F-15 airplane

NASA Technical Reports Server (NTRS)

Myers, L. P.; Burcham, F. W., Jr.

1983-01-01

Substantial benefits of a full authority digital electronic engine control on an air breathing engine were demonstrated repeatedly in simulation studies, ground engine tests, and engine altitude test facilities. A digital engine electronic control system showed improvements in efficiency, performance, and operation. An additional benefit of full authority digital controls is the capability of detecting and correcting failures and providing engine health diagnostics.

Regeneration of Tissues and Organs Using Autologous Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anthony Atala, M D

2012-10-11

The proposed work aims to address three major challenges to the field of regenerative medicine: 1) the growth and expansion of regenerative cells outside the body in controlled in vitro environments, 2) supportive vascular supply for large tissue engineered constructs, and 3) interactive biomaterials that can orchestrate tissue development in vivo. Toward this goal, we have engaged a team of scientists with expertise in cell and molecular biology, physiology, biomaterials, controlled release, nanomaterials, tissue engineering, bioengineering, and clinical medicine to address all three challenges. This combination of resources, combined with the vast infrastructure of the WFIRM, have brought to bearmore » on projects to discover and test new sources of autologous cells that can be used therapeutically, novel methods to improve vascular support for engineered tissues in vivo, and to develop intelligent biomaterials and bioreactor systems that interact favorably with stem and progenitor cells to drive tissue maturation. The Institute's ongoing programs are aimed at developing regenerative medicine technologies that employ a patient's own cells to help restore or replace tissue and organ function. This DOE program has provided a means to solve some of the vexing problems that are germane to many tissue engineering applications, regardless of tissue type or target disease. By providing new methods that are the underpinning of tissue engineering, this program facilitated advances that can be applied to conditions including heart disease, diabetes, renal failure, nerve damage, vascular disease, and cancer, to name a few. These types of conditions affect millions of Americans at a cost of more than $400 billion annually. Regenerative medicine holds the promise of harnessing the body's own power to heal itself. By addressing the fundamental challenges of this field in a comprehensive and focused fashion, this DOE program has opened new opportunities to treat conditions where other approaches have failed.« less

The New Global Responsibilities of Engineers Create Challenges for Engineering Education

ERIC Educational Resources Information Center

Fuchs, Willi

2012-01-01

Modern societies aim to solve the global challenges of the 21st century with sustainable solutions such as resource efficiency, use of renewable energy sources and recycling. Engineers are called upon to create the cutting edge technological solutions that can help to address these challenges. In developed as well as in developing countries,…

Constructing an Engineering Model for Raising an Egyptian Obelisk

ERIC Educational Resources Information Center

Beck, Charles R.

2009-01-01

One of the greatest mysteries of ancient times is how the Egyptians managed to raise huge obelisks using very simple technology. This remarkable task has puzzled engineers for thousand of years. After failing to raise an obelisk with simple machines, such as levers and pulleys, a team of modern engineers solved the mystery using a sandpit and the…

Competences of Engineers in the Iron and Steel Industry

NASA Astrophysics Data System (ADS)

Kozhevnikov, A. V.

2017-12-01

The article presents the results of assessment of the professional performance of engineers working in the iron and steel industry. A competence-based profile of highly-qualified professionals has been built. The study of the competences of the iron and steel industry engineers has shown that their knowledge and skills may be mobilized to solve professional tasks.

Providing Formative Assessment to Students Solving Multipath Engineering Problems with Complex Arrangements of Interacting Parts: An Intelligent Tutor Approach

ERIC Educational Resources Information Center

Steif, Paul S.; Fu, Luoting; Kara, Levent Burak

2016-01-01

Problems faced by engineering students involve multiple pathways to solution. Students rarely receive effective formative feedback on handwritten homework. This paper examines the potential for computer-based formative assessment of student solutions to multipath engineering problems. In particular, an intelligent tutor approach is adopted and…

Evaluation of Creative Problem-Solving Abilities in Undergraduate Structural Engineers through Interdisciplinary Problem-Based Learning

ERIC Educational Resources Information Center

McCrum, Daniel Patrick

2017-01-01

For a structural engineer, effective communication and interaction with architects cannot be underestimated as a key skill to success throughout their professional career. Structural engineers and architects have to share a common language and understanding of each other in order to achieve the most desirable architectural and structural designs.…

Engineering for Sustainable Energy Education within Suburban, Urban and Developing Secondary Schools

ERIC Educational Resources Information Center

Kaikai, Moijue; Baker, Erin

2016-01-01

It is crucial that the younger generation be included in the conversation of sustainable development, given the urgent need of a global transition to cleaner energy solutions. Sustainable energy engineering (SEE) taught as early as secondary school can not only increase the number of students that will potentially study engineering to solve global…

A Guideline of Using Case Method in Software Engineering Courses

ERIC Educational Resources Information Center

Zainal, Dzulaiha Aryanee Putri; Razali, Rozilawati; Shukur, Zarina

2014-01-01

Software Engineering (SE) education has been reported to fall short in producing high quality software engineers. In seeking alternative solutions, Case Method (CM) is regarded as having potential to solve the issue. CM is a teaching and learning (T&L) method that has been found to be effective in Social Science education. In principle,…

Consequences of Team Charter Quality: Teamwork Mental Model Similarity and Team Viability in Engineering Design Student Teams

ERIC Educational Resources Information Center

Conway Hughston, Veronica

2014-01-01

Since 1996 ABET has mandated that undergraduate engineering degree granting institutions focus on learning outcomes such as professional skills (i.e. solving unstructured problems and working in teams). As a result, engineering curricula were restructured to include team based learning--including team charters. Team charters were diffused into…

Stimulating Creativity and Innovation through Intelligent Fast Failure

ERIC Educational Resources Information Center

Tahirsylaj, Armend S.

2012-01-01

Literature on creativity and innovation has discussed the issue of failure in the light of its benefits and limitations for enhancing human potential in all domains of life, but in business, science, engineering, and industry more specifically. In this paper, the Intelligent Fast Failure (IFF) as a useful tool of creativity and innovation for…

Clarity of objectives and working principles enhances the success of biomimetic programs.

PubMed

Wolff, Jonas O; Wells, David; Reid, Chris R; Blamires, Sean J

2017-09-26

Biomimetics, the transfer of functional principles from living systems into product designs, is increasingly being utilized by engineers. Nevertheless, recurring problems must be overcome if it is to avoid becoming a short-lived fad. Here we assess the efficiency and suitability of methods typically employed by examining three flagship examples of biomimetic design approaches from different disciplines: (1) the creation of gecko-inspired adhesives; (2) the synthesis of spider silk, and (3) the derivation of computer algorithms from natural self-organizing systems. We find that identification of the elemental working principles is the most crucial step in the biomimetic design process. It bears the highest risk of failure (e.g. losing the target function) due to false assumptions about the working principle. Common problems that hamper successful implementation are: (i) a discrepancy between biological functions and the desired properties of the product, (ii) uncertainty about objectives and applications, (iii) inherent limits in methodologies, and (iv) false assumptions about the biology of the models. Projects that aim for multi-functional products are particularly challenging to accomplish. We suggest a simplification, modularisation and specification of objectives, and a critical assessment of the suitability of the model. Comparative analyses, experimental manipulation, and numerical simulations followed by tests of artificial models have led to the successful extraction of working principles. A searchable database of biological systems would optimize the choice of a model system in top-down approaches that start at an engineering problem. Only when biomimetic projects become more predictable will there be wider acceptance of biomimetics as an innovative problem-solving tool among engineers and industry.

Integrating electron microscopy into nanoscience and materials engineering programs

NASA Astrophysics Data System (ADS)

Cormia, Robert D.; Oye, Michael M.; Nguyen, Anh; Skiver, David; Shi, Meng; Torres, Yessica

2014-10-01

Preparing an effective workforce in high technology is the goal of both academic and industry training, and has been the engine that drives innovation and product development in the United States for over a century. During the last 50 years, technician training has comprised a combination of two-year academic programs, internships and apprentice training, and extensive On-the-Job Training (OJT). Recently, and especially in Silicon Valley, technicians have four-year college degrees, as well as relevant hands-on training. Characterization in general, and microscopy in particular, is an essential tool in process development, manufacturing and QA/QC, and failure analysis. Training for a broad range of skills and practice is challenging, especially for community colleges. Workforce studies (SRI/Boeing) suggest that even four year colleges often do not provide the relevant training and experience in laboratory skills, especially design of experiments and analysis of data. Companies in high-tech further report difficulty in finding skilled labor, especially with industry specific experience. Foothill College, in partnership with UCSC, SJSU, and NASA-Ames, has developed a microscopy training program embedded in a research laboratory, itself a partnership between university and government, providing hands-on experience in advanced instrumentation, experimental design and problem solving, with real-world context from small business innovators, in an environment called `the collaboratory'. The program builds on AFM-SEM training at Foothill, and provides affordable training in FE-SEM and TEM through a cost recovery model. In addition to instrument and engineering training, the collaboratory also supports academic and personal growth through a multiplayer social network of students, faculty, researchers, and innovators.

Analysis of Failures of High Speed Shaft Bearing System in a Wind Turbine

NASA Astrophysics Data System (ADS)

Wasilczuk, Michał; Gawarkiewicz, Rafał; Bastian, Bartosz

2018-01-01

During the operation of wind turbines with gearbox of traditional configuration, consisting of one planetary stage and two helical stages high failure rate of high speed shaft bearings is observed. Such a high failures frequency is not reflected in the results of standard calculations of bearing durability. Most probably it can be attributed to atypical failure mechanism. The authors studied problems in 1.5 MW wind turbines of one of Polish wind farms. The analysis showed that the problems of high failure rate are commonly met all over the world and that the statistics for the analysed turbines were very similar. After the study of potential failure mechanism and its potential reasons, modification of the existing bearing system was proposed. Various options, with different bearing types were investigated. Different versions were examined for: expected durability increase, extent of necessary gearbox modifications and possibility to solve existing problems in operation.

Application of artificial intelligence to pharmacy and medicine.

PubMed

Dasta, J F

1992-04-01

Artificial intelligence (AI) is a branch of computer science dealing with solving problems using symbolic programming. It has evolved into a problem solving science with applications in business, engineering, and health care. One application of AI is expert system development. An expert system consists of a knowledge base and inference engine, coupled with a user interface. A crucial aspect of expert system development is knowledge acquisition and implementing computable ways to solve problems. There have been several expert systems developed in medicine to assist physicians with medical diagnosis. Recently, several programs focusing on drug therapy have been described. They provide guidance on drug interactions, drug therapy monitoring, and drug formulary selection. There are many aspects of pharmacy that AI can have an impact on and the reader is challenged to consider these possibilities because they may some day become a reality in pharmacy.

Effect of Crystal Orientation on Fatigue Failure of Single Crystal Nickel Base Turbine Blade Superalloys

NASA Technical Reports Server (NTRS)

Arakere, Nagaraj K.; Swanson, Gregory R.

2000-01-01

High Cycle Fatigue (HCF) induced failures in aircraft gas-turbine engines is a pervasive problem affecting a wide range of components and materials. HCF is currently the primary cause of component failures in gas turbine aircraft engines. Turbine blades in high performance aircraft and rocket engines are increasingly being made of single crystal nickel superalloys. Single-crystal Nickel-base superalloys were developed to provide superior creep, stress rupture, melt resistance and thermomechanical fatigue capabilities over polycrystalline alloys previously used in the production of turbine blades and vanes. Currently the most widely used single crystal turbine blade superalloys are PWA 1480/1493 and PWA 1484. These alloys play an important role in commercial, military and space propulsion systems. PWA1493, identical to PWA1480, but with tighter chemical constituent control, is used in the NASA SSME (Space Shuttle Main Engine) alternate turbopump, a liquid hydrogen fueled rocket engine. Objectives for this paper are motivated by the need for developing failure criteria and fatigue life evaluation procedures for high temperature single crystal components, using available fatigue data and finite element modeling of turbine blades. Using the FE (finite element) stress analysis results and the fatigue life relations developed, the effect of variation of primary and secondary crystal orientations on life is determined, at critical blade locations. The most advantageous crystal orientation for a given blade design is determined. Results presented demonstrates that control of secondary and primary crystallographic orientation has the potential to optimize blade design by increasing its resistance to fatigue crack growth without adding additional weight or cost.

Mesh and Time-Step Independent Computational Fluid Dynamics (CFD) Solutions

ERIC Educational Resources Information Center

Nijdam, Justin J.

2013-01-01

A homework assignment is outlined in which students learn Computational Fluid Dynamics (CFD) concepts of discretization, numerical stability and accuracy, and verification in a hands-on manner by solving physically realistic problems of practical interest to engineers. The students solve a transient-diffusion problem numerically using the common…

Class and Home Problems: Optimization Problems

ERIC Educational Resources Information Center

Anderson, Brian J.; Hissam, Robin S.; Shaeiwitz, Joseph A.; Turton, Richard

2011-01-01

Optimization problems suitable for all levels of chemical engineering students are available. These problems do not require advanced mathematical techniques, since they can be solved using typical software used by students and practitioners. The method used to solve these problems forces students to understand the trends for the different terms…

Group Discussions in the Chemistry Classroom and the Problem-Solving Skills of Students.

ERIC Educational Resources Information Center

Fasching, James L.; Erickson, Bette LaSere

1985-01-01

Five years ago, an introductory chemistry course for chemists and chemical engineers was redesigned to stress the scientific method, problem-solving, and reasoning skills. Describes: (1) changes made in the course; (2) impacts on student achievement; and (3) student ratings of the course. (JN)

Representational Task Formats and Problem Solving Strategies in Kinematics and Work

ERIC Educational Resources Information Center

Ibrahim, Bashirah; Rebello, N. Sanjay

2012-01-01

Previous studies have reported that students employed different problem solving approaches when presented with the same task structured with different representations. In this study, we explored and compared students' strategies as they attempted tasks from two topical areas, kinematics and work. Our participants were 19 engineering students…

Problem Solving by Design

ERIC Educational Resources Information Center

Capobianco, Brenda M.; Tyrie, Nancy

2009-01-01

In a unique school-university partnership, methods students collaborated with fifth graders to use the engineering design process to build their problem-solving skills. By placing the problem in the context of a client having particular needs, the problem took on a real-world appeal that students found intriguing and inviting. In this article, the…

Solving Adolescent Verbal Aggressions through Transactional Analysis Counseling Approach

ERIC Educational Resources Information Center

Netrawati; Furqon; Yusuf, Syamsu; Rusmana, Nandang

2016-01-01

This study aimed at helping school counselors in solving issues related to adolescent verbal aggressions through implementing Transactional Analysis (TA) counseling, which was particularly given to the students in public vocational schools (SMKs) in Padang city who were majoring in engineering. Recent phenomena in Padang had revealed that among…

Validation of Symbolic Expressions in Circuit Analysis E-Learning

ERIC Educational Resources Information Center

Weyten, L.; Rombouts, P.; Catteau, B.; De Bock, M.

2011-01-01

Symbolic circuit analysis is a cornerstone of electrical engineering education. Solving a suitable set of selected problems is essential to developing professional skills in the field. A new method is presented for automatic validation of circuit equations representing a student's intermediate steps in the solving process. Providing this immediate…

Hearings Before the Subcommittee on Space Science and Applications of the Committee on Science and Astronautics. U.S. House of Representatives, Ninety-Third Congress, Second Session

DTIC Science & Technology

1974-07-18

so on. We say OK, we will work with Honda . We made an agreement and got the engine. They don’t have the problem solved at allfor us, but they have me...with our prechamber Honda CVCC program. hhile there are more design problems to be solved with the PROCO engine, and more time may be necessary to...But Mr. Sugiura was quoted by the agency ofcials as explaining Honda still has problems with fuel economy and driving performances and that it Is Impos

Predicted performance of an integrated modular engine system

NASA Technical Reports Server (NTRS)

Binder, Michael; Felder, James L.

1993-01-01

Space vehicle propulsion systems are traditionally comprised of a cluster of discrete engines, each with its own set of turbopumps, valves, and a thrust chamber. The Integrated Modular Engine (IME) concept proposes a vehicle propulsion system comprised of multiple turbopumps, valves, and thrust chambers which are all interconnected. The IME concept has potential advantages in fault-tolerance, weight, and operational efficiency compared with the traditional clustered engine configuration. The purpose of this study is to examine the steady-state performance of an IME system with various components removed to simulate fault conditions. An IME configuration for a hydrogen/oxygen expander cycle propulsion system with four sets of turbopumps and eight thrust chambers has been modeled using the Rocket Engine Transient Simulator (ROCETS) program. The nominal steady-state performance is simulated, as well as turbopump thrust chamber and duct failures. The impact of component failures on system performance is discussed in the context of the system's fault tolerant capabilities.

Development of High Precision Tsunami Runup Calculation Method Coupled with Structure Analysis

NASA Astrophysics Data System (ADS)

Arikawa, Taro; Seki, Katsumi; Chida, Yu; Takagawa, Tomohiro; Shimosako, Kenichiro

2017-04-01

The 2011 Great East Japan Earthquake (GEJE) has shown that tsunami disasters are not limited to inundation damage in a specified region, but may destroy a wide area, causing a major disaster. Evaluating standing land structures and damage to them requires highly precise evaluation of three-dimensional fluid motion - an expensive process. Our research goals were thus to develop a coupling STOC-CADMAS (Arikawa and Tomita, 2016) coupling with the structure analysis (Arikawa et. al., 2009) to efficiently calculate all stages from tsunami source to runup including the deformation of structures and to verify their applicability. We also investigated the stability of breakwaters at Kamaishi Bay. Fig. 1 shows the whole of this calculation system. The STOC-ML simulator approximates pressure by hydrostatic pressure and calculates the wave profiles based on an equation of continuity, thereby lowering calculation cost, primarily calculating from a e epi center to the shallow region. As a simulator, STOC-IC solves pressure based on a Poisson equation to account for a shallower, more complex topography, but reduces computation cost slightly to calculate the area near a port by setting the water surface based on an equation of continuity. CS3D also solves a Navier-Stokes equation and sets the water surface by VOF to deal with the runup area, with its complex surfaces of overflows and bores. STR solves the structure analysis including the geo analysis based on the Biot's formula. By coupling these, it efficiently calculates the tsunami profile from the propagation to the inundation. The numerical results compared with the physical experiments done by Arikawa et. al.,2012. It was good agreement with the experimental ones. Finally, the system applied to the local situation at Kamaishi bay. The almost breakwaters were washed away, whose situation was similar to the damage at Kamaishi bay. REFERENCES T. Arikawa and T. Tomita (2016): "Development of High Precision Tsunami Runup Calculation Method Based on a Hierarchical Simulation", Journal of Disaster ResearchVol.11 No.4 T. Arikawa, K. Hamaguchi, K. Kitagawa, T. Suzuki (2009): "Development of Numerical Wave Tank Coupled with Structure Analysis Based on FEM", Journal of J.S.C.E., Ser. B2 (Coastal Engineering) Vol. 65, No. 1 T. Arikawa et. al.(2012) "Failure Mechanism of Kamaishi Breakwaters due to the Great East Japan Earthquake Tsunami", 33rd International Conference on Coastal Engineering, No.1191

Rate-based structural health monitoring using permanently installed sensors

PubMed Central

2017-01-01

Permanently installed sensors are becoming increasingly ubiquitous, facilitating very frequent in situ measurements and consequently improved monitoring of ‘trends’ in the observed system behaviour. It is proposed that this newly available data may be used to provide prior warning and forecasting of critical events, particularly system failure. Numerous damage mechanisms are examples of positive feedback; they are ‘self-accelerating’ with an increasing rate of damage towards failure. The positive feedback leads to a common time-response behaviour which may be described by an empirical relation allowing prediction of the time to criticality. This study focuses on Structural Health Monitoring of engineering components; failure times are projected well in advance of failure for fatigue, creep crack growth and volumetric creep damage experiments. The proposed methodology provides a widely applicable framework for using newly available near-continuous data from permanently installed sensors to predict time until failure in a range of application areas including engineering, geophysics and medicine. PMID:28989308

Failure environment analysis tool applications

NASA Astrophysics Data System (ADS)

Pack, Ginger L.; Wadsworth, David B.

1993-02-01

Understanding risks and avoiding failure are daily concerns for the women and men of NASA. Although NASA's mission propels us to push the limits of technology, and though the risks are considerable, the NASA community has instilled within, the determination to preserve the integrity of the systems upon which our mission and, our employees lives and well-being depend. One of the ways this is being done is by expanding and improving the tools used to perform risk assessment. The Failure Environment Analysis Tool (FEAT) was developed to help engineers and analysts more thoroughly and reliably conduct risk assessment and failure analysis. FEAT accomplishes this by providing answers to questions regarding what might have caused a particular failure; or, conversely, what effect the occurrence of a failure might have on an entire system. Additionally, FEAT can determine what common causes could have resulted in other combinations of failures. FEAT will even help determine the vulnerability of a system to failures, in light of reduced capability. FEAT also is useful in training personnel who must develop an understanding of particular systems. FEAT facilitates training on system behavior, by providing an automated environment in which to conduct 'what-if' evaluation. These types of analyses make FEAT a valuable tool for engineers and operations personnel in the design, analysis, and operation of NASA space systems.

Failure environment analysis tool applications

NASA Technical Reports Server (NTRS)

Pack, Ginger L.; Wadsworth, David B.

1993-01-01

Understanding risks and avoiding failure are daily concerns for the women and men of NASA. Although NASA's mission propels us to push the limits of technology, and though the risks are considerable, the NASA community has instilled within, the determination to preserve the integrity of the systems upon which our mission and, our employees lives and well-being depend. One of the ways this is being done is by expanding and improving the tools used to perform risk assessment. The Failure Environment Analysis Tool (FEAT) was developed to help engineers and analysts more thoroughly and reliably conduct risk assessment and failure analysis. FEAT accomplishes this by providing answers to questions regarding what might have caused a particular failure; or, conversely, what effect the occurrence of a failure might have on an entire system. Additionally, FEAT can determine what common causes could have resulted in other combinations of failures. FEAT will even help determine the vulnerability of a system to failures, in light of reduced capability. FEAT also is useful in training personnel who must develop an understanding of particular systems. FEAT facilitates training on system behavior, by providing an automated environment in which to conduct 'what-if' evaluation. These types of analyses make FEAT a valuable tool for engineers and operations personnel in the design, analysis, and operation of NASA space systems.

Failure environment analysis tool applications

NASA Technical Reports Server (NTRS)

Pack, Ginger L.; Wadsworth, David B.

1994-01-01

Understanding risks and avoiding failure are daily concerns for the women and men of NASA. Although NASA's mission propels us to push the limits of technology, and though the risks are considerable, the NASA community has instilled within it, the determination to preserve the integrity of the systems upon which our mission and, our employees lives and well-being depend. One of the ways this is being done is by expanding and improving the tools used to perform risk assessment. The Failure Environment Analysis Tool (FEAT) was developed to help engineers and analysts more thoroughly and reliably conduct risk assessment and failure analysis. FEAT accomplishes this by providing answers to questions regarding what might have caused a particular failure; or, conversely, what effect the occurrence of a failure might have on an entire system. Additionally, FEAT can determine what common causes could have resulted in other combinations of failures. FEAT will even help determine the vulnerability of a system to failures, in light of reduced capability. FEAT also is useful in training personnel who must develop an understanding of particular systems. FEAT facilitates training on system behavior, by providing an automated environment in which to conduct 'what-if' evaluation. These types of analyses make FEAT a valuable tool for engineers and operations personnel in the design, analysis, and operation of NASA space systems.