电磁场计算中一种特殊边界条件及其在波阵解中应用

提出了一种周期边界条件在电磁场有限元方程组中的处理公式，经推导表明，该处理方法的核心是在总体刚度矩阵对有关周期单元系数矩阵的二次叠加，随后着重分析讨论了该公式在波阵解中的实现方法，主要包括建立有关周期边界单元及节点编号数组，建立存贮这些单元系数阵的公用数组，在引应边界节点地上系数矩阵的二次叠加以及改变周期单元节点在“波阵”中的消元次序等。通过这些措施，克服了波阵法不能求解带有约束条件的大型线性方程

Special Boundary Condition in Electromagnetic Field Computation and its Application to Frontal Solution

s: A definition for one periodic boundary condition and its formulation in FEM are presented, of which the key problem is the second-time loading of the boundary element matrix in the global stiffness matrix. The application to frontal solution which is seldom reported is also discussed emphatically. It includes the following steps: (1)Setting up some special arrays for periodic elements;(2)Setting up some arrays for their element matrices and right side terms;(3)Second-time loading of element matrix and the vector of right side term on the corresponding location of those relevant nodes; (4)Changing the node elimination order. In this way the frontal solution may be used to solve large linear equation with contraint conditions.Finally a numerical example of TEAM Workshop Problem shows that the method in this paper is basically correct and can save a lot of computer resource, which is very useful in 3-D magnetic field analysis.