Research Of Determination Method And Software Development On Tube Material Properties

One of the key issues of a successful FEA simulation in tube hydroforming is to obtain reliable data on material properties of the tube, such as the strength coefficient K and the strain-hardening exponent n. since tubular materials during tube hydroforming are under a biaxial even triaxial stress state, which is different from that in the tensile test, other testing method, based on biaxial stretching, are needed.To solve this problem, many analytical models had been suggested by experts worldwide. There is still no standard way to obtain strength coefficient K and strain hardening exponent n. A new method of adaptive FEA inverse solution is proposed in this paper, combined with FEA and analytical methods: first, an initial value of material properties K and n is acquired by the analytical model, which was constructed in this paper; second, according to the adjusting criteria which will be discussed in the following chapters, the material properties that are used in FEA simulation will be substituted from time to time. A visual basic based program is constructed to control the value of K, n after every simulation time by analyzing the OUT files. Comparing to single analytical method or FEA method, the adaptive method proposed in this paper is much more convenient by obtaining the accurate material properties via less computer time and calculations.