大型机械结构复合型裂纹随机-非概率诊断方法研究

项目名称： 大型机械结构复合型裂纹随机-非概率诊断方法研究

项目编号： No.51205292

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 机械工程学科

项目作者： 孙远韬

作者单位： 同济大学

项目金额： 25万元

中文摘要： 结构本身的非完善性及其性能逐步劣化是安全事故的主要原因，但目前针对诸如裂纹这类缺陷的诊断方法受不确定影响因素较大，而这些因素的信息又往往不易获得，使得基于大样本数理统计理论的随机可靠性分析失去数据支持导致诊断结果可靠程度不高。为了提高结构失效评估的可靠程度，本项目首先研究不确定变量在仿射空间下表达方式与运算法则,建立随机-非概率混合可靠性的数学表达式，然后以复合型裂纹为对象，通过界定裂纹速率中变量本身及相互间的影响，给出多维仿射空间转化下的裂纹寿命可靠性分析模型并通过复合型裂纹扩展试验修正;结合裂纹扩展的动态网格划分策略和状态函数不断发生变化情况下的蒙特卡洛模拟方法求解该模型，最终得到复合型裂纹扩展规律及其混合可靠性评价结果，形成大型机械结构复合型裂纹随机-非概率诊断方法；项目将理论成果应用于大型海上浮吊的裂纹分析，并通过实验验证来指导裂纹巡检。

中文关键词： 裂纹；非概率；可靠性；仿射；

英文摘要： The imperfectness and the weakeningness of structure itself were the main reasons which caused the accidents. The diagnosis methods for the crack which is one of those reasons are influenced by many uncertainties. The detail information of such uncertainties is always hard to obtain, lead to the incredibleness of the diagnosis results where the uncertainties were analyzed by the stochastic reliability analysis based on mass samples statistics. In order to improve the receivable degree of the failure estimation for structures, firstly study the means of expression for uncertain variables in the affine space and the operation rules of affine arithmetic; construct the hybrid stochastic and non-probabilistic model for reliability analysis; present the crack lifetime reliability analysis model which was modified by composited crack expanding experiment in the multi-affine space by defining the influences of the variables in the crack expanding velocity. Then resolve the model by integrating the dynamic grid partition method and the Monte-Carlo method under the circumstance that the state function changes all the time. Eventually obtain the rules of the composited crack expanding and calculate the estimation of the hybrid reliability model; form the stochastic and non-probabilistic diagnosis method of the composited c

英文关键词： crack；non-probabilistic；reliablity；affine；