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中国物理学会期刊

黏弹性问题的插值型无单元Galerkin方法

CSTR: 32037.14.aps.68.20191047

Interpolating element-free Galerkin method for viscoelasticity problems

CSTR: 32037.14.aps.68.20191047
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  • 基于改进的移动最小二乘插值法, 提出了黏弹性问题的插值型无单元Galerkin方法. 采用改进的移动最小二乘插值法建立形函数, 根据黏弹性问题的Galerkin弱形式建立离散方程, 推导了相应的计算公式. 与无单元Galerkin方法相比, 本文提出的黏弹性问题的插值型无单元Galerkin方法具有直接施加本质边界条件的优点. 通过数值算例讨论了影响域、节点数对计算精确性的影响, 说明了该方法具有较好的收敛性; 将计算结果与无单元Galerkin方法和有限元方法或解析解比较, 说明了该方法具有提高计算效率的优点.

     

    In this paper, based on the improved interpolating moving least-square (IMLS) approximation, the interpolating element-free Galerkin (IEFG) method for two-dimensional viscoelasticity problems is presented. The shape function constructed by the IMLS approximation can overcome the shortcomings that the shape function of the moving least-squares (MLS) can-not satisfy the property of Kronecker function, so the essential boundary conditions can be directly applied to the IEFG method. Under a similar computational precision, compared with the meshless method based on the MLS approximation, the meshless method using the IMLS approximation has a high computational efficiency. Using the IMLS approximation to form the shape function and adopting the Galerkin weak form of the two-dimensional viscoelasticity problem to obtain the final discretized equation, the formulae for two-dimensional viscoelasticity problem are derived by the IEFG method. The IEFG method has some advantages over the conventional element-free Galerkin (EFG) method, such as the concise formulae and direct application of the essential boundary conditions, For the IEFG method of two-dimensional viscoelasticity problems proposed in this paper, three numerical examples and one engineering example are given. The convergence of the method is analyzed by considering the effects of the scale parameters of influence domains and the node distribution on the computational precision of the solutions. It is shown that when dmax = 1.01−2.00, the method in this paper has a good convergence. The numerical results from the IEFG method are compared with those from the EFG method and from the finite element method or analytical solution. We can see that the IEFG method in this paper is effective. The results of the examples show that the IEFG method has the advantage in improving the computational efficiency of the EFG method under a similar computational accuracy. And the engineering example shows that the IEFG method can not only has higher computational precision, but also improve the computational efficiency.

     

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