钨合金三点弯曲破坏的细观数值模拟

The micro simulation of failure for the three-point bend specimen of tungsten alloy

运用有限元方法模拟了钨合金材料的三点弯曲实验;采用单胞单元计算模型,分析了断口形貌与材料力学性能之间的关系;建立了宏观断裂形式与微观结构参数之间的关联。结果表明:裂纹主要产生在W-W界面、W-M界面,且在基体中向前发展,钨合金材料的破坏可归结为延性材料的破坏;裂纹的尖端始终处于应力集中的状态,随着裂纹的扩展,拉应力集中不断释放,并且转移到新的裂纹尖端;裂纹尖端的单元为拉伸破坏,拉应力是导致裂纹扩展的主要因素。

The three-point bend specimen of tungsten alloy is simulated by using Finite Element code LS-DYNA.And the relation between fractograph and the mechanical properties of tungsten alloy is obtained.The results show that the cracks mainly generate at interface of W-W or W-M,and grow ahead in matrix,so we can consider that the tungsten alloy is a kind of ductile-like material.And the stress always concentrates on the top of crack.The tensile stress releases gradually when the cracks grow.Then the stress concentrates on the new top of crack.The elements which are at the top of crack fail for the effect of tensile stress.So the tensile stress is the mainly power for growth of cracks.