高强度硼钢热冲压板料初始轮廓线优化分析

发布时间：2018-08-18 10:29

【摘要】：新世纪以来，汽车作为一种方便、快捷、时尚的代名词逐渐走进千家万户，丰富着人们的生活。汽车工业的迅速发展也带来一定的社会问题，如汽车燃油加速能源消耗、汽车尾气排放超标造成大气污染等，严重影响人们的健康生活并带来一系列安全隐患。面对这样的时代现状，汽车轻量化概念被提出并渐渐被接受，热冲压成形及其数值模拟技术应运而生。热冲压成形将高强度钢板加热到奥氏体状态下进行冲压成形和冷却，最终获得室温下组织均匀、回弹量小、强度级别高的马氏体制件，目前，已被广泛应用于轿车门内侧梁、车身横梁和纵梁、防撞梁、A柱、B柱和C柱加强件的生产等，是当前汽车制造及相关行业的热门技术。初始板料的形状关系到制件的整体成形质量，恰当、合理的板料初始轮廓线的设计有利于减少板料成形缺陷、提高制件的质量和性能。长期以来，为了确定板料初始轮廓线，相关工作者进行了大量的研究，，并提出诸如滑移线法、几何映射法等估算方法。然而，对于工程应用来说，由于假设条件和环境变量不同，这些方法都仅适用于某一范围。目前，对于热冲压成形板料，主要根据一步逆算法得到板料轮廓，扩大10%左右进行板料冲裁，成形后利用激光切割将制件的多余部分切除，不仅浪费原材料，而且后续切边消耗大量资源和能源，生产效率低下。本文基于多次迭代反算法，利用板料成形模拟分析软件模拟板料热冲压成形过程，建立高强度硼钢板料初始轮廓线优化模型，获得优化的板料初始轮廓线，实现热冲压一次成形，省去或减少切边工序，节约材料和生产周期，从而有效指导高精度、高质量、高效率的热冲压制件的生产。本文主要研究工作如下：（1）设计简单U形件，根据一步逆算法计算获得板料初始轮廓线；基于热冲压成形原理，建立板料热冲压成形模型及相应的板料初始轮廓线优化模型；研究板料厚度对板料初始轮廓线优化的影响；按照优化后的板料初始轮廓尺寸进行U形件热冲压成形实验，对比成形制件与理想零件相关尺寸数据。（2）建立某车型防撞梁热冲压成形模型及板料初始轮廓线优化模型，对比分析优化前后板料热冲压成形尺寸精度；分析优化后的板料所得成形制件的减薄分布、应力应变分布等。（3）建立某车型B柱板料初始轮廓线整体优化模型和局部优化模型，分析优化结果；研究压边力对成形质量和板料初始轮廓线优化的影响，分析优化不足原因并做出合理解释。
[Abstract]:Since the new century, automobile as a convenient, fast, fashion synonyms gradually into thousands of households, enriching people's lives. The rapid development of automobile industry has also brought some social problems, such as accelerated energy consumption of automobile fuel, air pollution caused by excessive exhaust emissions and so on, which seriously affected people's healthy life and brought a series of hidden dangers to safety. Faced with the present situation of the times, the concept of automobile lightweight has been put forward and gradually accepted, and the hot stamping forming and its numerical simulation technology have emerged as the times require. High strength steel sheet is heated to austenitic state for stamping and cooling by hot stamping forming. Finally, the martensite parts with uniform microstructure, small springback and high strength grade are obtained at room temperature. At present, they have been widely used in the inside beam of passenger car door. The production of body cross beam, longitudinal beam, collision proof beam, A column, B column and C column reinforced parts is a popular technology in automobile manufacturing and related industries at present. The shape of the initial sheet metal is related to the whole forming quality of the workpiece. The proper and reasonable design of the initial profile of the sheet metal is helpful to reduce the forming defects and improve the quality and performance of the parts. For a long time, in order to determine the initial profile of sheet metal, many researchers have done a lot of research, and put forward some estimation methods such as slip line method, geometric mapping method and so on. However, for engineering applications, these methods are only applicable to a certain range due to the differences of assumptions and environmental variables. At present, for hot stamping sheet metal, the profile of sheet metal is obtained mainly by one step inverse algorithm, and the sheet metal blanking is expanded by about 10%. After forming, the spare parts of the parts are cut off by laser cutting, which not only wastes raw materials, And subsequent edge cutting consumes a large number of resources and energy, production efficiency is low. In this paper, based on the iterative inverse algorithm, the sheet metal forming simulation analysis software is used to simulate the hot stamping process of the sheet metal, and the optimization model of the initial contour line of the high strength boron steel sheet is established, and the optimized initial profile line of the sheet metal is obtained. The hot stamping process can be realized once, the cutting process can be eliminated or reduced, and the material and production cycle can be saved, which can effectively guide the production of hot stamping parts with high precision, high quality and high efficiency. The main research work of this paper is as follows: (1) Design simple U-shaped parts and calculate the initial profile of sheet metal according to one-step inverse algorithm, based on the principle of hot stamping, Establish the hot stamping forming model of sheet metal and corresponding initial profile optimization model of sheet metal, study the influence of sheet thickness on the optimization of initial profile line of sheet metal, carry out the hot stamping forming experiment of U-shaped part according to the initial profile size of the optimized sheet metal. Compare the dimension data between the forming parts and the ideal parts. (2) establish the Liang Re stamping forming model and the initial profile optimization model of a vehicle, and compare and analyze the size accuracy of hot stamping before and after the optimization; The thinning distribution, stress-strain distribution and so on are analyzed. (3) the integral optimization model and local optimization model of the initial profile of a certain type B column sheet are established, and the optimization results are analyzed. The influence of blank holder force on forming quality and initial profile optimization of sheet metal was studied, and the reasons for optimization were analyzed and reasonable explanation was made.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG306

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