摘要
为探究新型轻质铝合金车身的设计方法,本文中以铝合金下车体为例,重点探讨铝合金车体的有限元分析方法和结构的整体评估方法。首先采用shell单元模拟铝合金焊缝,建立车体的有限元模型,并对其基础性能进行仿真,其结果与弯扭刚度和模态实验的对比,弯曲刚度、扭转刚度、1阶弯曲模态和1阶扭转模态的误差分别为-2.45%,-3.59%,-3.43%和-2.73%,验证了铝合金车体有限元模型的正确性。然后为评估车体的传力性能,引入广义结构刚度的概念,通过对车体传力路径的识别,确定车体结构中的薄弱区域,并进行结构改进。改进后,在质量稍有增加(0.19 kg)的情况下,车体的弯曲刚度、扭转刚度、1阶弯曲模态和1阶扭转模态分别提升了5.59%,1.99%,2.42%和0.65%,表明了基于广义结构刚度的车体整体结构评估方法的有效性。
In order to explore the design method of lightweight aluminum-alloy vehicle body, the finite element analysis method and the overall evaluation method of aluminum-alloy body structure are emphatically discussed with an aluminum underbody as an example in this paper. Firstly, the shell element is used to simulate the welds of aluminum-alloy, a finite element model for vehicle body is built, and a simulation on its basic performance is conducted with a result showing that compared with the results of bending/torsional stiffness tests and modal test, the relative error of bending stiffness, torsional stiffness, 1 st-order bending mode and 1 st-order torsional mode are -2.45%,-3.59%,-3.43% and -2.73% respectively, verifying the correctness of the FE model for aluminum-alloy vehicle body. Then a concept of generalized structure stiffness is introduced for evaluating the force transfer performance of vehicle body, and by identifying the force transfer path of vehicle body the weak regions of vehicle body structure are located and a structural modification is performed. After optimization, the bending stiffness, torsional stiffness, 1 st-order bending mode and 1 st-order torsional mode of vehicle body increase by 5.59%, 1.99%, 2.42% and 0.65% respectively, while the body mass has a slight rise(0.19 kg), demonstrating the effectiveness of the overall structure assessment method of vehicle body based on generalized structure stiffness.
引文
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