Patent ID: 8078442

Claim:
A screw fastening unit analysis model creation method including: a screw fastening unit extracting step of extracting a screw fastening unit, in which at least two or more members are fastened by a screw, from a three-dimensional model; a shape changing step of changing each of circular arc surfaces of the screw, a screw through hole, and a screw hole disposed in the screw fastening unit to a polygonal polyhedron approximating the circular arc surface; a mesh creation step of creating an analysis model which is divided into a meshed analysis unit by allocation of polyhedral meshes along each of the edge surfaces of the screw, screw through hole, and screw hole which is changed to polyhedrons; and a contact definition step of setting the friction of a contact unit of the mesh-divided screw and screw hole to be infinite so as to achieve a fixed state; wherein, in the mesh creation step, mesh data of a unit size composed of a mesh aggregation allocated to each of the polyhedral screw outer shape and hole shapes of the screw through hole and the screw hole after the shape change is prepared in advance, the scale of the mesh data is changed so that the data is matched with the size of the screw, screw through hole, and screw hole, and the mesh aggregations are allocated, wherein the mesh data of the unit size is composed of element data indicating the numbers of elements of the mesh aggregation, nodal point data indicating the total number of connecting vertices of the elements, material data indicating the material of the element, and contact data defining the elements in contact.