蠕变压痕实验的计算机模拟

THE SIMULATION OF CREEP INDENTATION TESTING

采用有限元的方法对双相材料的蠕变压痕实验进行了数值模拟，在有限元数值解的基础上，定义了相应于传统单轴蠕变实验的“等效应力”和“等效应变”，建立了蠕变压痕实验同传统单轴蠕变实验之间的关系，给出了确定薄膜蠕变应力指数和蠕变常数的方法；同时数值解的结果表明，实验中通过控制压痕深度不超过薄膜厚度的 ５％～１０％，忽略基体的硬化指数对确定薄膜性能的影响存在一定的误差，但基体的弹性模量对确定薄膜的蠕变性能影响不大。

Finite Element Method(FEM) was used to simulate the creep indentation testing on film/substrate systems. Based on the FEM simulation, a new method is proposed to derive the material creep properties(in Norton equation) from the indention creep experimental results(indentation stress-indenter depth-time) for thin film/substrate systems by the definition of 'effective' stress and 'effective' strain. In the simulation, a steady state was found and the steady state was used to construct the relationship between the traditional uniaxial tensile creep testing and indentation testing. In the simulation of the creep indentation testing, FEM-results showed that the experimental results would have some error from ignoring the influence of the substrates even if the indentation depth did not exceed 5%-10% depth of film.