Papers by Keyword: Triangular Element

Abstract: A method of analysis for calculating a precise distribution of a stress intensity factor alonga front of 3D crack was improved by introducing a closed-form integral. In the present study, the crackface is discretized with number of triangular boundary elements on which the weighting function ofbody force doublet varies linearly with coordinate variables. A closed form solution of a resultant forceover an arbitrary planar-triangular area due to a presence of an isolated point force was derived andused to satisfy a stress boundary condition of a creased crack problem. In principle, arbitrary shaped3D cracks which may contain asperities and multiple creased lines in its face can be solved by presentapproach.

Abstract: Utilising the strain based approach with exact representation of rigid body motion, an efficient way of constructing membrane elements will be proposed. The major problem encountered in practice is generally the compatibility between degrees of freedom of various elements [1-3]. A simple and efficient triangular and sector element are developed by the use of the strain based approach. They are based on the assumed independent functions for the various components of strain insofar as it is allowed by the compatibility equations. Theses elements produce results which are acceptable within practical engineering accuracy even when few elements are employed.

Abstract: Using a weighed decomposition of the stiffness matrix and the weighed generalized inverse theory, a reanalysis method is presented for the topological modification of plane structures, and a set of formulae of elementary topology change are obtained. These formulae are explicit one and using them one can reanalyze the modified structures in topological optimal design. Finally an example is given to verify the valid of this method.

Abstract: In reverse engineering, in order to analyze the accuracy of formed work-piece, the shape error between the formed work-piece and its CAD model need to be calculated. In this paper, a matching method on the basis of triangle mesh is proposed. This matching method includes three parts: pre-positioning, rough registration and fine registration. Firstly, the maximum projective plane of cloud data is designed to parallel to the xy plane through translation and rotation, and cloud data is translated by a vector which can be obtained with the point with the maximum z coordinate and the origin of coordinates. Secondly, cloud data is gradually rotated 360 degree around z axis confirm the angle making the error minimum. In this way, an initial value of ICP algorithm can be obtained, which can avoid the local convergence in the algorithm. Finally, ICP algorithm can be applied to calculate the surface error further. After matching, the error between work-piece and the CAD model can be calculated by interpolation based on triangle mesh. The results show that the matching method can obtain the higher matching accuracy.

Abstract: A new triangular element of Hermitian type, i.e., the degrees of freedom includes differentiation of value as well as value itself, is proposed and XFEM formulation is demonstrated. Some numerical examples are also shown.