任意形状要素による3次元力学解析法と関連技術(<小特集>ボリュームデータ,ボクセルデータなどに基づくものつくり支援システム)  [in Japanese] Analysis of 3-D Mechanics Using an Arbitrarily-Shaped Element with Associated Techniques(<Special Feature>Computer Aided Design and Production System Based on Voxel or Volume Data Structure)  [in Japanese]

A novel formulation of contmua featured by arbitrarily-shaped elements is outlined The formulation uses generalized coordinates chosen to be the coefficients of the polynomial with arbitrary degree interpolating the element configuration, thus dispensing with nodal variables Hence there is no restriction on the geometry of elements, and objects with large deformations and rigid-body modes can be modeled easily The variable-gain error correction method bonds the elements and imposes boundary conditions in a unified manner Techniques useful for implementation of the methodology are also introduced The first one is a high precision description of object boundary based on a simple and efficient algorithm interpolating a surface from position and normal vectors given at vertices of its mesh. A theory for optimization of numerical integration over domains with arbitrary dimension and geometry is also presented. After showing a procedure to incorporate the techniques into the arbitrarily-shaped element formulation, validity of the approach is demonstrated through numerical examples.