The results of experimental mechanics research methods come directly or indirectly from the measured data, which reduces or avoids many assumptions about deformation conditions and material properties. Its outstanding advantage is that the result is reliable, but at the same time, it has high cost, long cycle and great limitations, which is not convenient for further forming limit analysis and process parameter optimization.
The advantage of numerical analysis method is that it overcomes the mathematical difficulties encountered in solving the triple nonlinear partial differential equation in plastic theory by using the achievements in numerical analysis in the field of mathematics, and can give the numerical solution of complex metal plastic forming problems. In recent years, with the development of finite element method and computer technology, this kind of method has become one of the most powerful tools to analyze metal plastic forming process. The finite element method can be used to simulate and analyze the whole forming process from the blank of spur bevel gear to the part during plastic machining on the computer. The load and energy required for stress field, strain field and deformation can be obtained. The changes of geometry, size and performance of spur bevel gear blank in the forming process can be given, the generation of defects can be predicted and the forming quality can be analyzed. The advantages of finite element simulation are strong function, high precision and wide range of problem solving. It can describe the deformation of any shape with different shapes, sizes and types of elements. It is suitable for any speed boundary conditions. It can easily and reasonably describe the shape of the die, deal with the friction between the spur bevel gear blank and the die, and consider the influence of various process parameters such as material hardening effect and temperature on the forming process, The mechanical information and flow information at any time in the forming process can be obtained, such as strain field, velocity field, stress field, displacement field and temperature field, and the generation and expansion of defects can be predicted. The forming process can be realized virtually on the computer, repeatedly demonstrated, calculated and optimized, which is unmatched by other research methods. At present, the finite element method has become one of the powerful tools to study the plastic forming law, material deformation behavior and various physical fields, and has been widely used.
Plastic finite element method can be divided into two categories: one is flow plastic finite element method, including rigid plastic finite element and rigid viscoplastic finite element; The other is solid plastic finite element, including elastic-plastic finite element and elastic viscoplastic finite element. Elastoplastic finite element can effectively deal with the unloading problem and calculate the residual stress and residual strain. It is often used in the analysis of Engineering bearing problems, but the workload is large and the mathematical treatment is complex. Rigid plastic finite element is often used to simulate the plastic machining process of large deformation metals because it simplifies the finite element calculation formula, greatly simplifies the calculation process and has high calculation efficiency.