重型自卸汽车车架横梁异常断裂原因分析

Cause analysis of frame abnormal rupture of heavy dump truck

针对无副车架的重型自卸汽车在使用过程中出现的车架横梁异常断裂问题,建立了以板壳单元为基本单元的自卸汽车车架有限元分析模型,采用NASTRAN有限元分析软件对车架强度进行分析。有限元分析结果表明,车架横梁异常断裂现象是横梁连接部位应力值大于材料的屈服强度引起的,这与实车车架断裂结果吻合。根据实际工艺要求,改造车架结构,将连接第2根横梁和纵梁的L板厚度变大,并将平衡悬架推力杆支座由整体式支撑改为分体式支撑,从而使两处的最大应力值分别比原结构下降20.4%和51.7%。改进后车架断裂区的强度明显提高,这表明改造方法有效。

This article aims to present our analysis over the causes that are responsible for the rupture of the dump truck frame as well as the FEA model established by us, In order to find out the reasons of the frame without assistant-frame abnormal rupture, both the static analysis and the dynamic analysis were carried out by using the socalled NASTRAN FEAS software, The results of our analysis indicate that the rupture took place because the stress of the second cross-rail experienced Was bigger than the yield strength of the material under bending and torsion case, in addition to the stress experienced by the link plate and the saddle of equalizing type suspension rod with the fourth cross rail. If the above said situation remains true with the heavy vehicles at the overload transportation, it would be likely to cause the frame abnormal rupture. On the basis of calculation we have worked out the causes of the frame abnormal rupture, which is in perfect conformity with the actual rupture case. Thus, it can be verified that, the finite element model and analysis method are both credible and feasible to the transportation and traffic application. In answering to the demands of routine testing and measurement, we have also worked ottt the way for the reconstruction of the frame, which also proves effective by the reconstruction results. Compared with the original structure, the strengthened second cross rail and the layout of the saddle of equalizing type suspension turned to be much more reasonable. Under bending and torsion case, the maximal stress can be made to drop to 20.4% and 51.7%, respectively.