Application of finite element method in production of collar-head screw in suspension arm of motor car vehicle

The subject of analysis is the process of hex cap screws forming designed to fix suspension arm bushing in a motor car. Due to specified requirements set on elements of that type have to meet, both in the scope of size and shape accuracy as well as mechanic properties of material, cold forging closed-die process is applied. Analysis of such process including the application of Finite Element Method in the form of software package DEFORM-3D was conducted. Results of the analysis may help to choose the number and sequence of technological operations, their parameters and the proper shape of tools. The paper presents: suspension arm assembly, computer model presenting screw cold forging technology, work-hardening curve for AISI-1010 (ISO-C10) steel, boundary conditions of simulation, FEM model parameters in the subsequent phases of the process, analysis of accuracy of geometrical measures of screw obtained in simulations of particular phases of the process, discrete and actual model of obtained screw, the form of stained net of the hex cap screw with visible ZY central plane in its section, deformation distribution in screw head after second upsetting process, change in strain rate of the screw in time, filling of pass die, stress fields in screw determined in accordance with Huber's hypothesis, force of screw head upsetting in the function of the travel of the upper die