Solving of Partial Differential Equations by Numerical Manifold Method with Partially Overlapping Covers

2014 ◽  
Vol 638-640 ◽  
pp. 1737-1740
Author(s):  
Ya Qi Gong ◽  
Qin Chen ◽  
Yong Feng Qi

Governing equations of 1D high-order numerical manifold method with partially overlapping covers have been deduced by the general method of weighted residuals. By using the proposed method, a highly oscillatory differential equation has been solved. In addition, a posteriori error method is adopted for evaluating the accuracy of the algorithm. Meanwhile, several factors affect the accuracy are also discussed. The results indicate that accuracy of solution increase with the decrease of overlapping ratio and the order of cover function. When higher order cover function such as 6th is used, higher accuracy will matched even for second derivative of unknowns. This paper attempts to enrich the theory and practical field of the NMM.

2012 ◽  
Vol 182-183 ◽  
pp. 1194-1199
Author(s):  
Lei Zheng ◽  
Zheng Zhong Shen

Numerical manifold method (NMM) is based on the blocky theory which absorbed the advantages of finite element method based on the continuum mechanics, discontinuous deformation analysis method based on the non-continuum mechanics and analytic method. According to the finite covering technology of modern manifold analysis method, uniform solving format on continuous-non-continuous problems is established by taking the continuous and discontinuous cover function which can be used for the numerical simulation of large deformation and continuous-discontinuous deformation. The calculation program is worked out based on the method above and it is applied to the actual project.


2007 ◽  
Vol 340-341 ◽  
pp. 365-370 ◽  
Author(s):  
Y.H. Zhang ◽  
Qian Sheng ◽  
Y.M. Cheng

In this paper, three-dimensional(3D) Numerical Manifold Method (NNM) based on hexahedron element cover with full first-order cover function is proposed and the shape function of C8 isoparametric element in FEM is used as the cover weight function. All sub-matrices in equilibrium equations, including stiffness matrix, initial stress matrix, point force matrix, surface force matrix, body force matrix, inertia force matrix, contact matrix and friction matrix, are derived. Different with 2D contact, the direction of shear stiffness and friction force can not be easily defined in 3D contact. A new iterative method based on vector theory to detect the contact direction is developed. The application of 3D NMM in underground excavation is also presented and show good agreement with real engineering.


2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Zhengrong Zhang ◽  
Xiangwei Zhang

Numerical manifold method was applied to directly solve Navier-Stokes (N-S) equations for incompressible viscous flow in this paper, and numerical manifold schemes for N-S equations coupled velocity and pressure were derived based on Galerkin weighted residuals method as well. Mixed cover with linear polynomial function for velocity and constant function for pressure was employed in finite element cover system. As an application, mixed cover 4-node rectangular manifold element has been used to simulate the incompressible viscous flow around a square cylinder in a channel. Numerical tests illustrate that NMM is an effective and high-order accurate numerical method for incompressible viscous flow N-S equations.


2021 ◽  
Vol 133 ◽  
pp. 104070
Author(s):  
Xian-yang Yu ◽  
Tao Xu ◽  
Michael J. Heap ◽  
Patrick Baud ◽  
Thierry Reuschlé ◽  
...  

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