Safety Envelope for Load Tolerance and Its Application to Fatigue Reliability Design

2006 ◽  
Author(s):  
Haoyu Wang ◽  
Nam Kim ◽  
Yoon Kim
Keyword(s):  
Fatigue Reliability ◽  
Reliability Design ◽  
Load Tolerance

Safety Envelope for Load Tolerance and its Application to Fatigue Reliability Design

2005 ◽  
Vol 128 (4) ◽  
pp. 919-927 ◽  
Author(s):  
Haoyu Wang ◽  
Nam H. Kim ◽  
Yoon-Jun Kim
Keyword(s):  
Load Capacity ◽  
Uncertainty Propagation ◽  
Random Variables ◽  
Function Evaluation ◽  
Fatigue Reliability ◽  
Reliability Design ◽  
Structural Part ◽  
Average Value ◽  
Current Design ◽  
Load Tolerance

In this paper, a safety envelope concept for load tolerance is introduced. This shows the capacity of the current design as a future reference for design upgrade, maintenance, and control. The safety envelope is applied to estimate the load tolerance of a structural part with respect to the fatigue reliability. First, the dynamic load history is decomposed into the average value and amplitude, which are modeled as random variables. Second, through fatigue analysis and uncertainty propagation, the reliability is calculated. Last, based on the implicit function evaluation for the reliability, the boundary of the safety envelope is calculated numerically. The effect of different distribution types of random variables is then investigated to identify the conservative envelope. In order to improve the efficiency of searching the boundary, probabilistic sensitivity information is utilized. When the relationship between the safety of the system and the load tolerance is linear or mildly nonlinear, the linear estimation of the safety envelope turns out to be accurate and efficient. During the application of the algorithm, a stochastic response surface of logarithmic fatigue life with respect to the load capacity coefficient is constructed, and the Monte Carlo simulation is utilized to calculate the reliability and its sensitivities.

The Iterative Method for Reliability Estimation of Fatigue Life

2012 ◽  
Vol 249-250 ◽  
pp. 628-631
Author(s):  
Xin Li Bai ◽  
Peng Xu ◽  
Jiang Yan Li
Keyword(s):  
Fatigue Life ◽  
Design Method ◽  
Estimation Method ◽  
Engineering Application ◽  
Reliability Estimation ◽  
Fatigue Reliability ◽  
Reliability Design ◽  
Fatigue Design ◽  
Machine Parts ◽  
Stress Cycles

The expression of reliability estimation method for fatigue life of machine parts was derived, and two kinds of stress cycles (reversed cycle and un-symmetric reversed cycle) were considered. An iteration method is presented and the corresponding computer program named STRENGTH-2 is developed for estimating reliable life of machine parts. The engineering application results show that the calculated results are close to experimental results. The proposed method can be convenient to carry out the fatigue reliability design for machine parts under the action of uni-axial and multi-axial loadings, and promote the popularization and application of existing anti-fatigue design method. It has the high value of engineering application.

Reliability Estimation of Fatigue Life for Machine Parts under Uniaxial Constant Amplitude Load

2012 ◽  
Vol 249-250 ◽  
pp. 632-635
Author(s):  
Yu He Li ◽  
Xin Li Bai ◽  
Ying Fang Zhang
Keyword(s):  
Fatigue Life ◽  
Design Method ◽  
Engineering Application ◽  
Reliability Estimation ◽  
Estimation Methods ◽  
Fatigue Reliability ◽  
Constant Amplitude ◽  
Reliability Design ◽  
Fatigue Design ◽  
Machine Parts

Two methods acquiring p-S-N curve for machine parts are given, namely directly searching out the p-S-N curve of the material from material database and using the idealized p-S-N curve. Reliability estimation methods of fatigue life of machine parts are derived under uniaxial constant amplitude load. Two kinds of circumstances (fixed stress and probabilistic stress) and two kinds of stress cycles (reversed cycle and unsymmetric reversed cycle) are considered. An iteration method is presented and the corresponding computer program is developed for estimating reliable life of machine parts. The engineering application results show that the calculated results are closer to experimental results. The suggested method can be convenient to fatigue reliability design of machine parts. It has good stimulative effect on popularization and application of existing anti-fatigue design method for machine parts, and high value of engineering application.

Single-point likelihood method to determine a generalized S-N surface

2006 ◽  
Vol 220 (10) ◽  
pp. 1519-1529 ◽  
Author(s):  
J J Xiong ◽  
R A Shenol
Keyword(s):  
Confidence Level ◽  
Single Point ◽  
Small Sample ◽  
Likelihood Method ◽  
Fatigue Reliability ◽  
Reliability Design ◽  
S Curve ◽  
A New Technique ◽  
Economic Use

This paper outlines a new technique to address the paucity of data in determining a generalized S-N surface on the basis of fatigue reliability design. A new single-point likelihood method (SPLM) is presented for estimating a P-S-N curve, dealing with small sample numbers of data. A confidence level formula for P-S-N curve estimated by SPLM is also given. The concepts are then applied for the determination of a generalized S-N surface. Finally, contrast tests for the P-S curve are conducted to examine the presented method, demonstrating the practical and economic use of the proposed technique. It is shown from the results that the P-S-N curve can be obtained realistically using small sample numbers and that the required number of test specimens in this case is less than those for the conventional method.

Fatigue reliability design of composite leaf springs based on ply scheme optimization

2017 ◽  
Vol 168 ◽  
pp. 40-46 ◽  
Author(s):  
Chen Qian ◽  
Wenku Shi ◽  
Zhiyong Chen ◽  
Shixiang Yang ◽  
Qianqian Song
Keyword(s):  
Fatigue Reliability ◽  
Reliability Design ◽  
Scheme Optimization ◽  
Leaf Springs

P27 Thermal fatigue reliability design of BGA package in electronic devices using CAE

2005 ◽  
Vol 2005 (0) ◽  
pp. 477-478
Author(s):  
Qiang YU ◽  
Tadahiro SHIBUTANI ◽  
Masaki SHIRATORI ◽  
Jae-Chul JIN ◽  
Satoshi KONDO
Keyword(s):  
Thermal Fatigue ◽  
Electronic Devices ◽  
Fatigue Reliability ◽  
Reliability Design ◽  
Bga Package
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