基于梁与接头灵敏度分析的白车身刚度模态优化

Modal Optimization of Body-in-White Stiffness Based on Sensitivity Analysis of Beam and Joint

白车身结构显著影响整车性能,而车身框架是车身设计的基础.在某MPV车型概念设计阶段,通过参数化技术,快速将车身主要框架划分为梁和接头结构.分别局部刚化处理49处左右对称结构,分析各结构对扭转刚度、弯曲刚度、后部扭转模态影响的灵敏度.结果表明,D柱下段、顶盖后横梁、下地板后纵梁等结构的单位质量对扭转刚度贡献量超过5%;后地板横梁、前地板后纵梁、后地板纵梁等结构单位质量对弯曲刚度的贡献量超过4%.通过8处灵敏度较高的结构优化和厚度优化,同时对性能影响小的结构减薄、减件,结合工艺改进,实现白车身质量不增加,扭转刚度提高9.0%,弯曲刚度提高4.8%,后扭模态提高2.0%.

It is known that Body-in-White （BIW） structure significantly influences the vehicle performance, and vehicle body is the basis for its design. In a PMV conceptual design phase, the main frame structure was quickly divided into several joints and beam elements by means of parameterization technique. 49 kinds of bilaterally symmetrical joints and beams were locally treated as rigid. The sensitivity of torsional stiffness, bending stiffness, and rear torsional modal to each locked rigid structure was analyzed and ranked. The relative sensitivities of the structures, such as BEAM_D-PLR_LWR, BEAM_ROOF_RR, and RAIL_RR on the torsional stiffness were more than 5%, while the relative sensitivity of the structures, such as FLOOR_RR_CB_FRT, RAIL_CTR, and RAIL_RR on the bending stiffness was more than 4%. The torsional stiffness was increased by 9.0%, the bending stiffness was increased by 4.8%, and the rear torsional modal was increased by 2.0% by means of structure and thickness optimization, structural thinning and reduction, and processing improvement for sensitive structure. On the other hand, the mass of BIW was obviously not increased.