Research on a new remeshing method for the 3D FEM simulation of blade forging

A aeronautical blade is one of the most important mechanical components in the aviation industry. A blade manufactured by forging is required to achie ve high precision in shape and to have good mechanical properties. However, the blade has a complicated shape: there is a twist in its shape from the root to the end, and its body is thin and uneven at different positions. Ob viously, blade forging is a process of three-dimensional nature but, until now, most of deformation analyses of blade forging have been made as two-di mensional plane-strain problems. To obtain a more realistic deformed config uration and more precise information about deformation for high precision i n die design and manufacturing, it is necessary to simulate the blade-forgi ng process by using a three-dimensional finite-element method (3D FEM). Not only is the practical process of blade forging of a three-dimensional natu re, but also its deformation is usually large and the forging simulation is usually carried out using the increment method. These cause the FEM mesh t o be distorted to such a degree that a new FEM mesh is necessary for furthe r simulation. There is also another potential problem in the constantly cha nging configuration of the deformed body. The solutions of these problems d epend on a proper remeshing scheme being incorporated into the finite-eleme nt method simulation. One of the most important techniques in remeshing is how to generate the new mesh automatically. Based on the features of the blade and the deformation of blade forging, a new remeshing method of contracting from the boundary to the interior is pr oposed, and a series of procedures and key techniques for realizing the rem eshing method are analyzed and given. The most important characteristic is that it is feasible for a different boundary to mesh and remesh by this new remeshing method because it is based on the boundary of parts. By using th is method, it is possible to generate both a 3D new mesh after degeneracy a nd an initial FEM mesh of complicated parts such as blades, and to generate a 2D FEM initial mesh and a new mesh, not like with modular remeshing, whi ch is only suitable for 3D remeshing and meshing. In addition, it is simple and easy to mesh and remesh by this new remeshing method, without construc ting specific modules and without joining them. (C) 1999 Elsevier Science S .A. All rights reserved.