基于微观组织三维特征分析的钢铝车身结构轻量化设计基础研究

项目名称： 基于微观组织三维特征分析的钢铝车身结构轻量化设计基础研究

项目编号： No.51475336

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 机械、仪表工业

项目作者： 龙江启

作者单位： 温州大学

项目金额： 80万元

中文摘要： 车身轻量化对整车轻量化起着举足轻重的作用，钢铝混合车身结构的理念较好地兼顾各方面要求，代表了车身结构发展的最新趋势。然而，异种金属的连接技术已成钢铝混合车身结构设计过程中的瓶颈。激光熔钎焊具有效率高、工艺灵活且易控制的突出特点，有可能成为解决钢铝异种金属连接问题的理想技术手段。本项目以钢铝混合材料车身结构为研究对象，以钢铝异种材料激光熔钎焊接研究为主线，以综合提高激光焊接结构的力学特性与疲劳性能、优化接头设计及车身材料匹配为目标。以钢铝激光焊缝三维显微组织特征分析为切入点，以3D X-ray原位观察和微观孔洞几何模型有限元分析为技术手段，系统研究工艺参数对微观孔洞特征的作用规律与显微组织结构对钢铝焊接结构疲劳性能的影响规律，探明微观孔洞对接头疲劳裂纹形成与扩展作用的机理。建立材料类型与板件厚度多目标优化模型，提出一套钢铝车身材料匹配方案，为我国自主开发钢铝轻量化车身结构提供理论和技术支撑。

中文关键词： 钢铝车身；轻量化；激光焊接；三维X；射线断层扫描；微观孔洞

英文摘要： The lightweight of car body play an important role in the development of lightweight vehicles. The new concept of steel-aluminum hybrid car body structures can better take into account all aspects of lightweight requirements and it represents the latest trends for the future development of car body structures. However, the problem of the connection of dissimilar metals in the steel-aluminum hybrid car body is a bottleneck. For the high efficiency, flexible and easy to control the process parameters, laser welding-brazing technique might be an ideal technical means to solve the problem of the connection between steel and aluminum. The connection between steel and aluminum by laser welding-brazing will be investigated in the steel-aluminum hybrid car-body and the purposes are to improve the mechanical properties and fatigue performance of the laser welding joint, optimize the design of the joint and the material matching of the steel-aluminum hybrid car body structures. The 3D microstructure characteristics of laser welding joint will be observed by 3D X-ray in situ observation and further the FEM modeling to analyze microporosity is established. The effect law of process parameters on the characteristics of microporosity and microstructure characteristics on the fatigue property of the laser welding joint will be systematically investigated. The mechanism of effect of microporosity on fatigue crack generation and propagation of the joints of steel and aluminum will be discovered. Finally, the multi-object optimization modeling will be built up and solved. The strategy of the material matching, selection and structural size in the steel-aluminum hybrid car body structures will be obtained. The basic research achievements will be the theoretical and technical support for independently developing the car body using steel-aluminum hybrid structures.

英文关键词： Steel-aluminum car body;Lightweight;Laser welding;3D X-ray Tomography;Microporosity