A Full Quadrilateral Meshes Generation Algorithm And Its Application In Ship Finite Element Method

Mesh generation is one of the most important steps in foundation of Finite Element Model. Too many questions must be considered and too much time must be spent during this process. The form of mesh has directly effect on calculation precision and calculation scale. In the time of Finite Element Method using in Naval Architecture and Ocean Engineering, some Finite Element Mesh Auto generation Methods are needed urgently. The theoretical and realistic experience demonstrates that quadrilateral element is more precise than triangular element, so some quadrilateral mesh algorithms are needed. Nowadays, triangular mesh algorithms have already matured to some extent, but quadrilateral mesh algorithms are rare. The main problems of existing quadrilateral mesh algorithms are the worse adaptation to the complex domains and the lower auto degree. Its special inside structure and restriction of generated elements cause quadrilateral mesh have such shortcoming, itself.This paper has reviewed and compared of all kinds of mesh generation algorithms and concluded their advantages and disadvantages especially have some details on triangular mesh generation algorithms. On the basis of that, this paper ameliorates to form an improved method, namely, ameliorated advancing front approach (AAFA) as the algorithm of triangular mesh generation. This method makes full use of mapping method and other methods, which generate mesh in given domain directly according to some rules. So it can avoid their shortcomings and acquire high quality meshes quickly.Compare high quality quadrilateral mesh with the same dimension's triangular meshes, high quality quadrilateral mesh can acquire more precise value, so in the shell structure's Finite Element Analysis, the first choice is quadrilateral mesh. After triangular meshes are formed in the ship Finite Element Method Pre-process,, they should be transferred to quadrilateral meshes. In this paper, quadrilateral mesh generation algorithm is based on triangular meshes. The triangular element merges with the adjoin element optionally or decomposes to become three quadjilateral elements. The merge and decomposition are irrelevant with the triangular mesh generation algorithm. Therefore this method is suitable for any triangle meshes generated by any methods.