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Reliability Analysis of Structures with Multiple Site Fatigue Cracks

多部位疲劳裂纹结构的可靠性分析

基本信息

批准号：
04302034
负责人：
ITAGAKI Hiroshi
金额：
$ 7.68万
依托单位：
YOKOHAMA NATIONAL UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Co-operative Research (A)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

1. Reliability Analysis based on Non-Destructive Inspection of Structures with Multiple Site Fatigue cracks.The influence of inevitable uncertain parameters on inspection planning was discussed. The uncertainties related to inspection planning can be classified into two categories : engineering uncertainty and economical/social uncertainty. Initial uncertainty can be gradually reduced by being updated through inspection results and/or service experience. The Baysian analysis is applied in conjunction with the sequential cost minimization method for a member set which has an uncertainty in the fatigue property of members.2. Estimation of Distribution of Material Properties and its Effect on Fatigue Propagation Life.A stochastic model for predicting fatigue crack growth was discussed by experimental approach. The model is based on the results of fatigue test using relatively large compact-tension-specimen under constant stress intensity factor range, (〕SY.upper filled triangle.〔) K, condition. The main results are : 1) There are large scale variation and small scale variation of material properties of fatigue crack growth. 2) It is very important to model the statistical correlation of material properties along crack path, particularly when the correlation length is large.3. Selection of the First Inspection Time based Maximization of Amount of Information.The first inspection time heavily infuences the overall structural reliability, and therfore several cost components as was noticed from pervious works. By optimizing an utility function, here simply regarded as mean Shannon information, a suitable criteria for selecting the first inspection time was discussed.

1. 基于多点疲劳裂纹结构无损检测的可靠性分析。讨论了不可避免的不确定性参数对检测计划的影响。与检验规划相关的不确定性可分为两类：工程不确定性和经济/社会不确定性。最初的不确定性可以通过检查结果和/或服务经验的更新来逐渐减少。针对构件疲劳性能具有不确定性的构件集，将贝叶斯分析与顺序代价最小化方法相结合。材料性能分布估计及其对疲劳扩展寿命的影响。用实验方法探讨了疲劳裂纹扩展的随机预测模型。该模型基于恒应力强度因子范围下较大压紧试样的疲劳试验结果，[]SY。上部填充三角形。[) K, condition。结果表明：1)疲劳裂纹扩展的材料性能存在大尺度变化和小尺度变化。2)建立材料性能沿裂纹路径的统计相关性模型是非常重要的，特别是当相关长度较大时。基于信息量最大化的首次检测时间选择。第一次检查时间严重影响整体结构的可靠性，因此从以前的工作中可以看出，几个成本组成部分。通过优化效用函数，简单地将其视为Shannon信息的均值，讨论了选择首次检查时间的合适准则。