金属试件变形断裂过程的计算模拟分析——组合功密度模型的应用

COMPUTER SIMULATED ANALYSES ON DEFORMATION AND FRACTURE OF NON CRACKED AND CRACKEDSPECIMENS

本文作者已建立了一个既适用于裂纹体亦适用于无裂纹体的统一损伤断裂模型——组合功密度模型。在本文中,作者应用该模型并结合大应变弹塑性有限元方法对40Cr制的圆棒光滑拉伸试件、圆棒切口拉伸试件和三点弯曲裂纹试件的变形和断裂过程进行了计算模拟。模拟结果很好地再现了两种圆棒拉伸试件的实验过程;而对于三点弯曲试件,模拟得到的载荷——加载位移关系曲线、裂纹扩展量——加载位移关系曲线、J_R阻力曲线和断裂韧性J_(IC)值等均与实测结果相当吻合。证实了该模型既能用于模拟预测无裂纹体中的裂纹萌生和扩展,也能模拟预测裂纹体中的裂纹起裂和稳定扩展过程。

A unified damage and fracture model, the combinatory work density model, which is suitable for both non-cracked body and cracked body has been su-ggested[5-7] by the authors of this paperIn the present paper, the deformation and fracture of the two kinds of tensile specimen and TPB specimen made of Steel 40Cr have been simulated by using the new model combined with large elastic-plastic deformation finite element method. The results represent the whole deformation and fracture processes of the specimens in e-xperiments; especially, the results on the TPB specimen present the relationships of the loading with the displacement at loading point P-A, the crack extension with the displacement at loading point Aa-A, the resistance curve JR-Δa and the fracture toughness J1c. All the results are in remarkable agreement with those obtained by expe. srimerus. Therefor it is confirmed that the model suggested by the authors can be used to simulate crack initiation and propagation in non-cracked body or fracture initiation, as well as stable crack propagation in cracked body.