基于有限单元法铰接式车身结构轻量化分析

Lightweight Analysis of Articulated Body Structure Based on Finite Element Method

针对某50t铰接式洒水车为研究对象,根据整车受力情况和铰接点受力特征,基于有限单元法建立罐体的动力学模型;以罐体轻量化设计为目标,各零件材料厚度作为设计变量,最大应力和变形量最为限定条件,开展优化设计,获取轻量化罐体结构;基于LS-DYNA对罐体进行瞬态动力学分析,分析制动行驶、水平转弯、右后轮过坑等三种典型工况下的运动状态,获取最大应力分布;基于优化后的实际车辆,采用应变片式应力测试系统,对有限元分析获取的应力较大部位进行实车测试,获取应力分布情况,并与仿真结果进行对比分析。结果可知:满足应力和变形要求的前提下,罐体的重量减轻了17.61%;三种工况下,仿真分析获取的应力最大部位为隔板和底板相连接处,应力最大值为235.7MPa;实车测试的应力最大值发生部位与仿真分析结果一致,之间的误差在6%以内;实测值均小于优化前数值,表明优化方案是可行的,降低了极值点的应力值,表明仿真分析是可靠的。

To a50 t articulated sprinkler as the research object, according to the force of the vehicle and the force characteristics of the hinge point,the dynamic model of the tank was established based on the finite element method. The lightweight design of the tank was the goal,and the material thickness of each part was taken as design variables,the maximum stress and deformation were the most restrictive conditions. The optimization design to obtain lightweight tank structure was carried out. The conduct transient dynamic analysis of the tank was taken based on LS-DYNA, and the motion state under three typical working conditions,such as braking driving,horizontal turning,and right rear wheel passing through a pit was analyzed,to obtain the maximum stress distribution. Based on the optimized actual vehicle,the strain gage stress test system was used to conduct the real vehicle test on the larger stress parts, which obtained by the finite element analysis,and the stress distribution was obtained to compare the results with the simulation results. The results show that: under the premise of meeting the stress and deformation requirements,the weight of the tank body is reduced by 17.61%. Under the three working conditions, the maximum stress obtained by the simulation analysis is the connection between the partition plate and the bottom plate, and the maximum stress is 235.7 MPa. The place where the maximum stress occurs in the actual vehicle test is consistent with the simulation analysis result,and the error between them is within 6%. The measured stress values are all smaller than the value before optimization,indicating that the optimization scheme is feasible,and the stress value at the extreme point is reduced.