铝/钢爆炸焊复合板界面裂纹的扩展路径

Propagation path of interface crack on aluminum/steel explosively welded composite plate

以双向受均匀拉伸的铝/钢爆炸焊复合板为研究对象,采用应变能密度因子理论,分析表面对称中心的Ⅰ型裂纹扩展到复合板结合处时的扩展方向,讨论泊松比μ和裂纹尺寸对裂纹扩展路径的影响.结果表明:双向受均匀拉伸的铝/钢爆炸焊复合板中垂直于表面对称中心的Ⅰ型裂纹扩展到复合板结合处时,其扩展方向存在两种可能,一是裂纹继续沿着垂直于复合板结合处的方向扩展,二是裂纹扩展方向发生改变,沿着平行于复合板结合处的方向扩展,对此起决定性作用的是铝/钢爆炸焊复合板结合处熔化层材料的泊松比μ,并且当|μ-0.25|越大,复合板的板宽w越小、裂纹长度a越大,这种作用就越明显.

Taking the aluminum/steel composite plate with explosive welding and subjected to two-way u- niformed tension as investigation object, the propagation direction of I-type crack at surface symmetric center and propagation to the juncture of the composite plate is analyzed with strain-energy density factor theory and the influence of Poisson＇s ratio μ and crack size on the crack propagation path is discussed. The result shows that the propagation of the I-type crack in above-mentioned composite plate and perpendicu- lar to the surface symmetric center and propagating to the juncture of composite plate will have two possi- ble directions, one being that the crack continues to grow along the direction perpendicular to the juncture of composite plate and the other being that the crack extends along the direction of the juncture of the com- posite plate. The poisson＇s ratio of melting layer materials at the junction will play a decisive role. The larger the ｜μ-0. 25 ｜, the shorter the width and the longer the length of crack is, the more obvious this effect will be.