TC4钛合金在准静态拉伸下的本构模型及失效参数

CONSTITUTIVE MODEL AND FAILURE PARAMETERS OF TC4 TITANIUM ALLOY UNDER QUASI-STATIC TENSILE

高速碰撞有限元模拟中经常涉及材料的大变形和断裂过程。基于Johnson-Cook断裂失效模型,设计了不同缺口尺寸的TC4钛合金试件,采用试验和有限元模拟相结合的方法研究了试样的断裂应变和应力三轴度。试验中制作了散斑,利用二维数字图像相关(DIC)技术获取试件在室温准静态拉伸条件下的断裂应变;利用Abaqus软件对准静态拉伸过程进行模拟,获取各试件的平均应力三轴度。将断裂应变与平均应力三轴度进行拟合,得到了Johnson-Cook断裂失效模型参数。将断裂失效模型参数带入Pamcrash软件中进行仿真,对比试验和Pamcrash仿真的断裂形貌和载荷位移曲线,两者均呈现出较好的一致性,验证了失效模型参数的正确性。

Large deformation and fracture processes of materials are often involved in the finite element simulation of high-speed collision. Based on the Johnson-Cook fracture failure model, TC4 titanium alloy samples with different notch sizes were designed, and the fracture strain and stress triaxiality of the samples were studied by combining test and finite element simulation. Speckle was produced during the experiment. The fracture strain of the sample under quasi-static tensile condition was obtained by using two-dimensional digital image correlation(DIC) technique at room temperature. The software Abaqus was used to simulate the quasi-static tensile process and obtain the average stress triaxiality of each sample. The parameters of Johnson-Cook fracture failure model were obtained by fitting the fracture strain with average stress triaxiality. The parameters of the fracture failure model were brought into the Pamcrash software for simulation, the fracture morphology and load-displacement curves of the test and Pamcrash simulation showed good consistency, which verified the correctness of the parameters of the failure model.