基于故障物理技术的结构疲劳可靠性设计理论及其应用研究

To overcome the shortcomings existing in tradational structural reliability analysis theory (like the inaccuracy, costly and long time for running reliability test), Physics of Failure (PoF) based fatigue crack initiation analysis, probabilistic life prediction, fatigue reliability and accelerated life test (ALT) design of welded bogie frame for high-speed train will be studied systematically in both theoretical and engineering applications in this project. In order to improve the design, fatigue strength and reliability of bogie frame, the main work is as follows: From the viewpoint of integration of design and manufacture, development of Physics-of-Failure based fatigue crack initiation theory and CAE integrative simulation platform considering weld imperfection under random loading, development of a probabilistic PoF-based life prediction model, ALT design and time-variant reliability model under complex environmental, applied engineering and multi-loading cases. Fatigue reliability theory and methodology of welded bogie frame for high-speed train in the life-cycle will be carefully studied which has important scientific and practical significance for fatigue crack initiation life prediction, maintenance decision-making and reliability evaluation of railway structures.

针对传统的结构可靠性分析方法不准确、可靠性试验时间过长和费用太大等问题，本项目以高速列车转向架焊接构架为研究对象，运用故障物理技术，系统地研究其在多工况、复杂环境-随机性交互作用下基于故障物理的裂纹萌生机理、概率寿命预测和疲劳时变可靠性分析以及加速寿命试验验证问题，具体研究内容包括：复杂随机载荷作用下考虑制造过程中焊接缺欠的、基于故障物理的裂纹萌生行为描述与CAE综合仿真平台的搭建，在多工况、复杂环境-随机交互作用下考虑其复杂运用工程特点的概率寿命预测故障物理模型与试验研究，以及疲劳时变可靠性分析和评估方法研究，以期改进结构设计，提高复杂结构的疲劳强度可靠性。本项目拟从全寿命周期角度对高速列车转向架焊接构架的疲劳强度与时变可靠性理论和方法开展深入研究，研究成果对推动高速列车结构疲劳裂纹萌生寿命预测、维修决策的制定和可靠性评估技术的工程应用具有重要的科学意义和实用价值。