Reliability Sensitivity Estimation of Mechanical Components with Multiple Failure Modes

2012 ◽  
Vol 48 (02) ◽  
pp. 63 ◽  
Author(s):  
Hao LU
Keyword(s):  
Failure Modes ◽  
Multiple Failure Modes ◽  
Sensitivity Estimation ◽  
Reliability Sensitivity ◽  
Mechanical Components

Surrogate-model-based reliability method for structural systems with dependent truncated random variables

2017 ◽  
Vol 231 (3) ◽  
pp. 265-274 ◽  
Author(s):  
Ning-Cong Xiao ◽  
Libin Duan ◽  
Zhangchun Tang
Keyword(s):  
Surrogate Model ◽  
Failure Modes ◽  
Random Variables ◽  
Probability Of Failure ◽  
Structural Systems ◽  
Multiple Failure Modes ◽  
Model Based ◽  
Reliability Sensitivity ◽  
Reliability Method ◽  
Uncertainty Space

Calculating probability of failure and reliability sensitivity for a structural system with dependent truncated random variables and multiple failure modes efficiently is a challenge mainly due to the complicated features and intersections for the multiple failure modes, as well as the correlated performance functions. In this article, a new surrogate-model-based reliability method is proposed for structural systems with dependent truncated random variables and multiple failure modes. Copula functions are used to model the correlation for truncated random variables. A small size of uniformly distribution samples in the supported intervals is generated to cover the entire uncertainty space fully and properly. An accurate surrogate model is constructed based on the proposed training points and support vector machines to approximate the relationships between the inputs and system responses accurately for almost the entire uncertainty space. The approaches to calculate probability of failure and reliability sensitivity for structural systems with truncated random variables and multiple failure modes based on the constructed surrogate model are derived. The accuracy and efficiency of the proposed method are demonstrated using two numerical examples.

scholarly journals Reliability-Based Robust Design of Mechanical Components with Correlated Failure Modes Based on Moment Method

2014 ◽  
Vol 6 ◽  
pp. 568451 ◽  
Author(s):  
Hao Lu ◽  
Yonghui He ◽  
Yimin Zhang
Keyword(s):  
Robust Design ◽  
System Reliability ◽  
Moment Method ◽  
System Analysis ◽  
Failure Modes ◽  
Copula Function ◽  
Engineering Practice ◽  
Reliability Sensitivity ◽  
Mechanical Components ◽  
Reliability Based Optimization

There are usually several potential failure modes in mechanical components. The conventional model for the system analysis is built under the condition that all failure modes are independent of each other. However, in engineering practice, failure modes are mostly dependent due to the fact that the elements involved in each failure mode are closely interrelated. System reliability analysis and evaluation simply conducted under independent assumption often result in excessive errors or even wrong conclusion. A novel method to evaluate system reliability of mechanical components with multiple failure modes based on moment method are proposed here. Firstly, the moment-based reliability and reliability sensitivity analysis method is proposed with independent assumption. Secondly, the proposed method is deduced by taking the correlation between failure modes into account and the correlation model is established with the copula function, which is proved to be a useful tool to model nonlinear correlation with marginal distributions. The robust design is performed as a biobjection optimization process based on the reliability sensitivity. The numerical examples show that the applied procedure is able to efficiently consider various failure modes of mechanical components in probabilistic assessment and reliability-based optimization.

An Approach of Robust Reliability Design for Structure System with Multiple Failure Modes

2010 ◽  
Vol 118-120 ◽  
pp. 299-303
Author(s):  
Hao Lu ◽  
Yi Min Zhang ◽  
Xue Fei Tan
Keyword(s):  
Optimization Design ◽  
Optimization Problem ◽  
Failure Modes ◽  
Perturbation Technique ◽  
Multiple Failure Modes ◽  
Reliability Design ◽  
Structure System ◽  
Reliability Sensitivity ◽  
Reliability Based Optimization ◽  
Robust Reliability

Based on the reliability theory, the probability perturbation technique, the reliability sensitivity technique and robust design were employed to discuss the reliability-based robust optimization problem of structure system with multiple failure modes. By means of the probability network evaluation technique (PNET), the representative failure modes of structure system were defined. Then, the reliability and the reliability sensitivity of the system were obtained. By integrating the reliability sensitivity into the reliability-based optimization design model, the robust reliability design of structure system was discussed. According to the numerical results, the method proposed is validated to be practical and effective.

Materials Failure Logic Models—A Procedure for Systematic Identification of Material Failure Modes in Mechanical Components

1982 ◽  
Vol 104 (3) ◽  
pp. 626-634 ◽  
Author(s):  
D. L. Marriott ◽  
N. R. Miller
Keyword(s):  
Failure Modes ◽  
Planning Process ◽  
Service Failure ◽  
Failure Mechanisms ◽  
Material Failure ◽  
Cad System ◽  
Logic Models ◽  
Identification Technique ◽  
Mechanical Components ◽  
Systematic Identification

This paper addresses the problem of improvement of mechanical component reliability by the systematic identification of material failure mechanisms. Experience shows that, in many cases of service failure, failure was caused by a known mechanism which was overlooked, either by design, or elsewhere in the planning process. This paper describes one approach to designing mechanical components against failure by material deterioration, but may have application to other fields. It is based on a finding from the examination of case studies which shows that material failures follow logic structures which can be described by Boolean algebra expressions. These structures are defined as Material Failure Logic Models (MFLM’s), and can be used as a means of systematically identifying potential failure mechanisms in a complex process. The identification technique is based on the observation that MFLM’s are insensitive to the precise causes of the individual events. The paper deals primarily with problems of defining MFLM’s. Some examples of MFLM’s are given. A brief discussion is presented of a CAD system under development at the University of Illinois at Urbana-Champaign.

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