Study On Numerical Oscillation Of Temperature Field Simulation During Forging Process

As Chinese enterprises are transforming from Made in China to Created in China, great demand for product of high quality, great precision and advanced techniques has been arisen. In order to simulate analytical parameters like temperature field, strain, flowing state and so on, we need a coupling simulation of heat transmission, microstructure transformation and deformation, so as to get a better process design and quality control, a reduction of product design time and cost. Since temperature field is one of the most important factors in coupling simulation, it is of great value to have an intensive study on the temperature field transformation during the forging process, while reducing the numerical oscillation becomes the key factor of accurate temperature field simulations.This paper mainly focus on the numerical oscillation of temperature filed during forging process, discussed the theory basis of heat transmission, proposed the finite element method equations of temperature field. Based on these equations, improved the solver of the temperature field simulation software-TC, and developed a simplified preprocessor and postprocessor for TC.This paper explained the essence of the numerical oscillation of temperature field, and studied several solutions including concentrated heat method, mesh refining method, dynamic time step method and variable differential coefficient method to reduce or avoid this phenomenon. These methods were integrated into the TC simulation program to examine the effect on the numerical oscillation. The results showed that the numerical oscillation can be avoided by these methods, and the stability and efficiency of the finite element simulation program SF2D/3D were improved.Through Using the TC software and comparing with DEFORM, The research on elimination of the numerical oscillations of temperature field is finished, and the following conclusions made: the numerical oscillation of temperature field generally occurs in large temperature gradient surface in initial phase of the simulation. Concentrated heat capacity method can effectively eliminates the numerical oscillations of temperature field, its simulative results and the simulative results of DEFORM are almost the same. The error is quite small; Mesh refining method can, to a certain extent, reduce the numerical oscillation of temperature field, but the effect is not obvious. Mesh refining method is limited by the simulative time as well as the simulative scale. The reducing of the time step can reduce the numerical oscillation of temperature field effectively. The dynamic time step not only can reduce the numerical oscillation of temperature field effectively and also reduce the simulative time greatly. The bigger the differential coefficientβis, the more inhibited the oscillation is. The smallerβis, the less inhibited the oscillation is. The effect used the variable differential coefficient method to reduce numerical oscillations of temperature field is poor.Finally the TC software is used to simulate the two-dimensional and three-dimensional temperature field. The numerical oscillations of temperature field is eliminated and compared with DEFORM, the error is quite small and meets the requirement of engineering application.