矿石冲击下自卸汽车车箱底板纵横梁开裂和断裂原因分析

摘要

Here, the cause of cracking and rupture of bodies floor's vertical and horizontal beams for a heavy dump truck under one impact was analyzed. The FE model of a dump truck was established with plate and shell elements as basic elements using so-called HyperMesh software, the FE model of ore was established according to the loading characteristics, the explicit dynamic finite element method was applied with ANSYS / LS-DYNA as solver and the impact responses with different masses of ore falling from different heights to the bodies floor of a dump truck was solved. The results indicated that the abnormal cracking and rupture of the bodies floor's vertical and horizontal beams are due to the impact stress value of floor joints on the vertical and horizontal beams being greater than the minimum tensile strength of the material, and this is consistent with the actual situation of cracking and rupture; when the thickness of bodies floor is 16mm and the mass of falling ore is more than 0. 3t, the maximum stress at the cracking and rupture is greater than the yield strength (345 Mpa) or the minimum tensile strength (470 Mpa) of the material; to avoid the phenomenon of the abnormal cracking and rupture of the bodies floor's vertical and horizontal beams, the mass and the falling height of ore have to be limited under the condition of the determined thickness of the bodies floor.%针对重型自卸汽车车箱在装载矿石过程中出现的车箱底板纵横梁异常开裂和断裂问题,应用HyperMesh有限元软件建立了以板壳单元为基本单元的车箱有限元分析模型,并针对装载矿石的特点建立了矿石有限元模型,采用显式动态有限元法,以ANSYS/LS-DYNA为求解器,求解了不同质量的矿石从不同高度下落对车箱底板的冲击响应.结果表明:车箱底板纵横梁异常开裂和断裂是底板纵横梁连接部位冲击应力值大于材料的最小抗拉强度产生的,这与实车车箱底板纵横梁开裂和断裂情况相吻合.当车箱底板厚度为16mm,下落矿石质量超过0.3t之后,开裂和断裂处最大应力已大于底板材料的屈服强度(345 MPa)或最小抗拉强度(470 MPa).为避免出现车箱底板大梁异常开裂和断裂现象,在确定的车箱底板厚度条件下,应限制装载矿石的质量和下落高度.