Papers by Author: Liang Chu

Abstract: Cam mechanism is the most important equipment of the automotive panel die for flanging, lateral punching processes etc. The product is required to higher precision, so the various components of cam mechanism are required to higher safety and usability. The paper focuses on the structure of cam mechanism that can be simulated by finite element simulation program on working conditions. It analyses the variation of deformation, stress and strain for cam mechanism.

Abstract: Hot forming is a method to make products with ultra high strength steels which typically used in automotive sector. 22MnB5 is one of the most typical hot forming steels. In this paper, hot forming process of 22MnB5 steel is simulated by thermo-mechanical coupled FE software Pam-stamp 2011. Through the simulation the temperature distribution and martensite phase fraction of hot forming part can be obtained. Besides, a hot forming experiment was set up. The tensile strength and Vickers hardness of hot samples which take from the hot formed part are measured. The experimental results indicate that the value of Vickers hardness in side wall is higher. The microstructure investigations have shown that the part after hot forming mostly fully martensitic microstructures. The result from simulation show good agreement with experimental results.

Abstract: Dual phase (DP) steel is a high strength steel for auto-panel. In this paper, mechanical property, forming ability, baked-hardening and work hardening properties of high strength steel DP450 are studied by experiments, and compared with those of steel MS6000.And theoretical research on predicting the forming limit of steel DP450 by the NADDRG model. The established mathematic model for relativity is of practical usefulness. Experimental results reveal that the yield strength of steel DP450 is about 7.2% lower than the MS6000,and the break strength increases by 18.9%,while the elongation increases by 19%.The strain hardening exponent of steel DP450 are superior to those of MS6000.The results show that mechanical property of high strength steel DP450 is better than that of MS6000,while forming ability of DP450 is not lower than that of MS6000.And baked-hardening and work hardening properties of steel DP450 are better than those of MS6000.The steel sheet DP450 owned a good forming ability.

Abstract: In this paper, the spinning process of automotive wheel rim is simulated with the finite element software DEFORM-3D. The forming of the automotive wheel rim based on finite element method is completed by the improvement of the spinning process. it can be divided into three different stages: spinning stage, flattening stage and shaping stage. The reference data for technological parameter of spinning process is achieved.The results are useful to the further research of the spinning process of automotive wheel rim.

Abstract: Bending process is one of the important methods to form thick hull plate, whose accuracy is directly related to the quality of hull plate forming.In this paper, bending process of thick hull plate is simulated by using finite element software ANSYS, and some simulation results on bending deformation of thick hull plate such as the deformation of meshes in deformation zone, the distributions of the Von Mises stress and effective strain are obtained.

Abstract: In this paper, the nosing process of metal tube with a conical die is investigated using the finite element method, and a series of simulations on the tube nosing process by using the program ABAQUS is carried out. The concrete process of tube nosing deformation is described. Some simulation results on tube nosing deformation such as the distributions of the Von Mises stress and effective strain, the material thickness variation of deformation zone are obtained and analyzed.

Abstract: Based on actual production, the each mould in the production line of containment of nuclear power reactor and the frame of THP22-4000 hydraulic press was modeled by coupling method. By using the finite element analysis simulation software ANSYS Workbench, the stiffness and strength of each coupling models were analyzed by node-coupling method. According to the results having been analyzed formerly, the distribution of stress and strain of each coupling models were studied, and the influence rules of assembly area of mould on workbench and close-height of mould on coupling stiffness were drawn, so as to guide the mold and the hydraulic structure design and optimization. Under the prerequisite of ensuring the forming precision of containment, it would be possible to configure and optimize scientifically and rationally the structure of forming molds and equipments, lower the costs of productions, and obtain higher economic benefits.

Abstract: Based on analyzing the stress-strain characters of material in nosing deformation zone, and considering two influencing factors, i.e. material thickness variation and material work-hardening, according to ignoring and considering the influence of additional bending stress at the entrance of die, and the different forms of work-hardening of metal materials, a new set of mathematical models of deformation force calculated for tube nosing with conical die are set up by utilizing slab method that belongs to one of the theoretic methods solving the problems of metal plastic forming. Furthermore, the scope of the application of every mathematical model of deformation force calculated for tube nosing with conical die is classified from conical die semi-angle and work-hardening of metal material point of view in theory.

Abstract: Hydraulic press is important pressure processing equipment, which has a wide range of applications in production and manufacturing industry. The structure of hydraulic press frame has an extremely significant effect on safety and usability. Against the structure of frame-type hydraulic press in this paper, a solid model has been built with CAD program Pro/E and the hydraulic press frame under working conditions is simulated by finite element simulation program ANSYS. This paper analyses the variation of stress, strain and frame deformation under working conditions, and the dangerous sections of hydraulic press frame can be found under the maximum work load. The research results show: The maximum value of effective strain and effective stress can be found in the screw holes of cylinder port, the maximum value of stress and strain in the direction of hydrocylinder force can be found in the confluence of upright column and lower beam, the maximum value of effective displacement and the displacement in the direction of hydrocylinder force can be found in cylinder port and part of upper beam.

Abstract: FEM simulations of squashing and bending process of large diameter elbow was applied to analyze the influence of squashing velocities, one of the key process parameters, on the deformation of the tube. In this study the squashing distance of first step is 300mm after several simulation attempts, corresponding to different squashing speeds and different bending velocities of second step. The simulation results of different velocities are compared and discussed. In the end the final velocities of the two steps are given.