基于代理模型的高速列车焊接结构轻量化设计

Reliability of high-speed train is mainly measured by anti-fatigue capability which is controled by anti-fatigue capability of welds, so it will have more actual significance to perform structure optimizaiton considering weld fatigue constraints.This proposal takes car body of high-speed train as a study object, and the work is developed by two aspects: providing light-weighted optimizaiton model and proposing effective solve method. firstly, the effect relationship matrix between the quality indexes including strength, stiffness, fatigue life and noise and the thickness variables of car body will be constructed,and it will be analyzed and rearranged.Based on the rearranged matrix,a system optimizaiton model with weld fatigue cosntraints will be provided.For this system optimizaiton model, a half-interpolated and half-fitted kriging surrogate model will be proposed by introduce an assumption that the mean of predicted error is nonzero, which is achieved on the basis of the profound understanding of the kriging surrogate theory. For sampling criterion, a parameter describing nonlinear action of the target problem will be introduced to construct a kind of new target-adaptive optimization method which can be performed using small sample size..Based on the proposed optmization model and new optimization method, a light-weighted optimization frame considering weld fatigue is costructed, on which the structure optimization of car body of high-speed train is performed effectively.

高速列车的可靠性主要由抗疲劳能力度量，而列车的抗疲劳能力实际上是由焊缝的抗疲劳能力控制的,因此考虑焊缝疲劳的结构优化设计将更具实际意义。该课题以高速列车车体的焊接结构为研究对象，围绕轻量化模型及其有效的求解方法两方面的内容而展开。首先构建列车车体各载荷工况下，强度、刚度、疲劳寿命以及噪声等多种响应指标与车体铝合金板材厚度变量之间的影响关系阵，并对该阵进行分析整理，从而构建出含焊缝疲劳寿命约束的系统优化模型。针对该优化模型，在深刻理解kriging代理模型构建机制的基础上，引入预测误差的均值不为零的假定，推导半插值半拟合kriging代理模型。同时从加点策略方面入手，引入描述目标问题非线性的参数，构建基于小样本取样、对目标问题具有自适应功能的优化新方法。基于提出的系统优化模型和发展的优化新方法，搭建起考虑焊缝疲劳的轻量化设计平台并对列车车体进行有效的优化设计。

高速列车的可靠性主要由抗疲劳能力度量，而列车的抗疲劳能力实际上是由焊缝的抗疲劳能力控制的,因此考虑焊缝疲劳的结构优化设计将更具实际意义。该课题工作以高速列车的焊接结构为研究对象，围绕轻量化模型及其有效的求解方法两方面的内容展开了研究工作。针对关键焊接结构，施加载荷工况，依据实际问题提出合理的考虑焊缝疲劳寿命的优化模型。针对考虑焊缝疲劳寿命约束的优化模型，在深刻理解kriging 代理模型构建机制的基础上，从加点策略方面入手，发展了基于小样本取样、对目标问题具有自适应功能的优化新方法。基于提出的优化模型和发展的优化新方法，搭建起考虑焊缝疲劳的轻量化设计平台并对列车的关键焊接结构进行了有效的优化设计。