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在壳体的弹塑性分析中。当壳体的材料从某一个表面开始进入塑性变形范围时,应力和应力-应变关系沿壳体厚度不再成线性变化,因而不能由显式得到应力沿壳厚的积分值,必须在有限单元法计算中应用数值积分。本文在以直母线锥形单元离散轴对称壳体结构的前提下,进一步以子单元离散锥形单元,使得原来一个必须用三维屈服曲面描述的弹塑性问题能以二维屈服曲面来表征。 本文取用了Prandtle-Ruess塑性坛量理论的等向强化Mises屈服准则的本构方程。非线性结构平衡方程以载荷坛量切线模量法求解。为提高解方程的精度,本文应用了-阶自修正技巧。 为验证理论计算的精度和可靠性,本文把理论计算结果与加劲圆柱壳型性试验值作了比较,两者结果相当一致。
In the elastoplastic analysis of the shell. When the material of the shell enters the plastic deformation range from a certain surface, the stress and the stress-strain relationship no longer change linearly along the thickness of the shell, so the integral value of the stress along the shell thickness cannot be explicitly obtained, and must be in the finite element. Numerical integration is used in the method calculations. In this paper, under the premise of discrete axially symmetric shell structures with straight generatrix tapered elements, the discrete cone elements are further formed in subunits, so that an elasto-plastic problem that must be described by three-dimensional yield surfaces can be characterized by two-dimensional yield surfaces. In this paper, the constitutive equations for the isotropic enhanced Mises yield criterion of the Prandtle-Ruess plasticity algebra theory are used. The nonlinear structural equilibrium equation is solved by the load algebra tangent modulus method. In order to improve the accuracy of the solution equations, we apply the -order self-correction technique. In order to verify the accuracy and reliability of the theoretical calculation, this paper compares the theoretical calculation results with the stiffened cylindrical shell test values. The results are quite consistent.