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

Abstract

A aeronautical blade is one of the most important mechanical components in the aviation industry. A blade manufactured by forging is required to achieve 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. Obviously, blade forging is a process of three-dimensional nature but, until now, most of deformation analyses of blade forging have been made as two-dimensional plane-strain problems. To obtain a more realistic deformed configuration and more precise information about deformation for high precision in die design and manufacturing, it is necessary to simulate the blade-forging process by using a three-dimensional finite-element method (3D FEM). Not only is the practical process of blade forging of a three-dimensional nature, but also its deformation is usually large and the forging simulation is usually carried out using the increment method. These cause the FEM mesh to be distorted to such a degree that a new FEM mesh is necessary for further simulation. There is also another potential problem in the constantly changing configuration of the deformed body. The solutions of these problems depend on a proper remeshing scheme being incorporated into the finite-element 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 proposed, and a series of procedures and key techniques for realizing the remeshing 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 this method, it is possible to generate both a 3D new mesh after degeneracy and 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, which 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 constructing specific modules and without joining them.