轴对称弹塑性大变形有限元法在断裂局部方法中的应用

Application of Finite Elment Method of Axisymmetric Elastic-Plastic Large Deformation in Fracture Local Approach

研究了断裂局部方法中测定材料的临界解理应力σ_u和威布尔指数m的方法。进行了16Mn钢的光滑试件和缺口试件的低温拉伸试验。测定了材料的应力-应变曲线和缺口试样的断裂载荷,编制了轴对称弹塑性大变形有限元分析程序。程序中大变形的分析采用了完全的拉格朗日方法,非线性方程组的求解采用了修正的牛顿法。计算了缺口试件的应力-应变场,编制了根据缺口试件的断裂载荷和有限元计算中得到的应力、应变场,计算m和σ_u的程序,测定了16Mn钢的临界解理应力σ_u和威布尔指数m。

Studies the method to measure the critical cleavage stress σ_μ and Weibull exponent m in fracture local approach. Tensile tests are carried out with the axisymmetric notched tensile sppecimens and common tensile specimens of steel 16Mn at low temperatures. The stress-strain laws and breaking load of notch specimens are obtained. Finite element programs related to axisymmetric elastic-plastic and large deformation problem are developed, in which the Total Lagrange method is used. Revised Newton-Raphson method is used in the solution of non linear equations. The stress-strain field of notch specimens is calculated. The calculation of m and σ_μ is programed according to the breaking load of notch specimens and stress-strain field calculated by means of finite element method. The local cleavage paramters m and σ_μ of steel 16Mn are determined.