基于结构稳定性的不锈钢点焊车体车顶焊点布置优化

Welding Spots Layout Optimization for Stainless Steel Spot Welding Carbody Roof based on Structural Stability

依据结构稳定性理论,研究不锈钢点焊车车顶焊点冗余问题.首先,研究某不锈钢点焊车体的车顶焊点数量对车顶纵向刚度的影响以及车顶各区域发生屈曲的顺序,确定车顶焊点冗余区域为弧顶;然后,对该冗余区域的三种焊点布置方案进行结构稳定性对比分析,确定弧顶区域可减少3 000多焊点的布置方案;最后,将弧顶区域焊点布置映射到整车车体模型中,在EN12663-2010标准的载荷作用下,对车顶焊点优化前后车体性能进行有限元分析.结果表明:超员状态的车体底架边梁下翼缘中心垂向位移变化小于0.2 mm;车顶边梁高度300 k N压缩下,最大应力发生部位不变,应力变化小于2 MPa;车体结构的一阶垂向弯曲、一阶扭转和车顶横向弯曲的振动频率变化均在0.1Hz以内.

Based on the theory of structural stability, the problem of redundant welding spots for stainless steel carbody roof is studied. First, arc area is determined as the redundant welding spots area after analyzing influence of the roof wehting spot number on the longitudinal stiffness and the sequence of buckling region. Then, comparing structural stability results of three kinds of welding spots layout scheme, the arrangement scheme of reducing more than .3000 is detennined. Finally, welding spot arrangement of the carbody is updated, and the finite element analysis is carried out between the pre-and post-optimization carbody supported by the load form EN12665 -2010 standard. According to the results after welding spots layout optimization, in the maximum vertical load case, the vertical displacement of underframe side beam bottom flange center changes less than 0.2 nun, and in the 300 kN longitudinal compression of the roof edge beam load case, the maximum stress is located at the same position, and the figure changes less than 2 MPa. Modal calculation is made on the carbody structure, and the first step vertical bend vibration, torsion and the lateral bending of the roof frequency change within 0.1 Hz.