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Missouri University of Science and Technology

Mechanical Engineering

Theses/Dissertations

Optimization

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Full-Text Articles in Engineering

Time-Dependent Reliability Methodologies With Saddlepoint Approximation, Zhangli Hu Jan 2019

Time-Dependent Reliability Methodologies With Saddlepoint Approximation, Zhangli Hu

Doctoral Dissertations

"Engineers always encounter time-dependent uncertainties that ubiquitously exist, such as the random deterioration of material properties and time-variant loads. Therefore the reliability of engineering systems becomes time-dependent. It is crucial to predict the time-dependent reliability in the design stage, given possible catastrophic consequences of a failure. Although extensive research has been conducted on reliability analysis, estimating the reliability accurately and efficiently is still challenging. The objective of this work is to develop accurate and efficient reliability methodologies for engineering design. The basic idea is the integration of traditional reliability methods with saddlepoint approximation (SPA), which can accurately approximate the tail …


The Evaluation Of Sequential Optimization And Reliability Analysis, Guannan Liu Jan 2016

The Evaluation Of Sequential Optimization And Reliability Analysis, Guannan Liu

Masters Theses

"Sequential Optimization and Reliability Assessment (SORA) has been used for more than one decade for reliability-based design (RBD), but comprehensive theoretical studies on its performance have not been conducted. Further investigations on its performance are still needed. The objective of this thesis is to evaluate the performance of SORA for various testing problems. The performance of SORA evaluated in this thesis includes (1) accuracy, (2) efficiency, and (3) convergence behavior or robustness with numerical testing problems. SORA is evaluated with comparison with other major RBD methodologies. The testing problems are in different scales (numbers of design variables, random variables, and …


Probabilistic Engineering Analysis And Design Under Time-Dependent Uncertainty, Zhen Hu Jan 2014

Probabilistic Engineering Analysis And Design Under Time-Dependent Uncertainty, Zhen Hu

Doctoral Dissertations

"Time-dependent uncertainties, such as time-variant stochastic loadings and random deterioration of material properties, are inherent in engineering applications. Not considering these uncertainties in the design process may result in catastrophic failures after the designed products are put into operation. Although significant progress has been made in probabilistic engineering design, quantifying and mitigating the effects of time-dependent uncertainty is still challenging. This dissertation aims to help build high reliability into products under time-dependent uncertainty by addressing two research issues. The first one is to efficiently and accurately predict the time-dependent reliability while the second one is to effectively design the time-dependent …