论文部分内容阅读
本文用两种数值方法,非线性长波分析和刚粘塑性有限元方法研究了孔洞敏感的超塑性材料在单向拉伸和园板涨形中的不均匀变形和断裂过程。分析表明,这种过程是不均匀几何失稳与内部孔洞长大的结合与相互作用的结果。材料的应变速率敏感性指数与孔洞长大速率通过不同的变形机理图控制着这种过程。叠加的静水压力能够改变孔洞敏感材料的断裂模式,从常压下没有宏观颈缩的孔洞断裂到无内部孔洞的外部颈缩断裂。
In this paper, two kinds of numerical methods, nonlinear long-wave analysis and rigid visco-plastic finite element method are used to study the inhomogeneous deformation and fracture process of hole-sensitive superplastic materials in uniaxial tension and circular plate. The analysis shows that this process is the result of the combination and interaction of uneven geometric instability and internal cavity growth. The material’s strain rate sensitivity index and hole growth rate control this process through different deformation mechanism diagrams. The superimposed hydrostatic pressure can change the fracture mode of the hole-sensitive material, from the hole without macroscopic neck under atmospheric pressure to the external neck with no internal hole.