镁合金车体车顶边梁型材优化

Optimization of Roof Side Beam Profile of Magnesium Alloy Car Body

镁合金是有益的轻量化材料,由于弹性模量低于铝合金,导致车体刚度下降.车体边梁是影响车体的关键承载部位,提高其刚度可有效降低车体挠度.提取镁合金列车侧顶的边界条件,以侧顶挠度下降幅度最大部分为子模型,通过子模型与整车模型位移对比验证子模型准确性;采用多节点灵敏度分析方法筛选最佳设计变量,进行尺寸优化;随后采用hypermorph网格变形技术,实现边梁截面形状优化.结果表明:采用子模型进行尺寸-形状优化,可有效缩短计算时间,优化后侧顶最大垂向挠度减少10.68%,最大应力下降31.76%.

Due to the lower elastic modulus,the stiffness of magnesium alloy car body is below aluminum alloy one.The side beam of the car body is the key bearing part of the car body.Increasing its stiffness can effectively reduce the deflection of the car body.The boundary conditions of the magnesium alloy train side roof were extracted,and the maximum reduction of side roof deflection was taken as the sub-model.The accuracy of the submodel was verified by comparing the displacement of the sub-model with that of the vehicle model.Multi-node sensitivity analysis was used to screen the optimal design variables and optimize the size.Then hypermorph mesh deformation technology was used to optimize the section shape of the side beam.The results show that the sub-model used for the size-shape optimization can effectively shorten the calculation time,the maximum vertical deflection of the lateral roof is reduced by 10.68%,and the maximum stress is reduced by 31.76%after optimization.