板宽对胶焊接头应力分布影响的数值分析

采用三维弹塑性有限元方法，研究了酚醛树脂和丙烯酸树脂两种胶粘剂的胶焊接头中，板宽对应力分布的影响。结果表明，酚醛树脂胶粘剂胶焊接头中，搭接区边缘应力值高于焊点边缘应力值，导致接头从搭接区边缘起裂，板宽增大时，焊点边缘处和搭接区边缘的峰应力都减小，对于提高胶焊接头的强度有利，但不会改变接头的断裂形式；丙烯酸树脂胶粘剂的胶焊接头，焊点边缘应力远高于搭接区边缘应力，因此接头从焊点边缘起裂，板宽增大时，焊点边缘应力基本不变。因此增加板宽对提高接头强度无明显作用，接头断裂形式也不发生改变。

NUMERICAL ANALYSIS ON EFFECT OF PLATE WIDTH ON STRESS DISTRIBUTION IN WELDBONDED JOINTS

Using three dimensional elastoplastic finite element method(FEM),the effect of plate width on stress distribution in weldbonded joints has been analysised numerically.Two kinds joints are made with different types of adhesives,one of which is phenolic resin of higher elastic modulus and the other is acrylic resin of lower elastic modulus.Results show that:for the phenolic resin joints,there exist greater stresses at the edge of the lap region than that at the edge of the spot weld.Cracks are initiated at the ege of the lap region.When the plate width increases,peak stresses at the edge of the lap region and the spot weld both decrease.The joint strength will be improved if the fracture mode of the joints does not vary.For the acrylic resin joints,much greater stresses are found at the spot weld edge than that at the lap region edge,so that fracture begins from the edge of the spot weld in stead of at the edge of the lap region.With increase of the plate width,stress variation around the spot weld is practically negligible.Thus increasing the plate width has no apparent effect on the joint strength and the joint fracture mode.