Development and applications of simulation system JS']JSTAMP/NV for Tube Hydro-Forming

Parts created by Tube Hydro-Forming (THF) are increasingly used in automobile bodies because of their high stiffness. THF parts have complex shape with varying cross-sections along its length, therefore, a multi-stage forming process such as bending, pre-forming and hydro-forming is generally necessary to produce them. To understand and to determine the forming conditions before production, simulation technology becomes indispensable. In this paper, firstly, the sheet metal simulation system JSTAW/NV will be briefly introduced, and then its new function for THF simulation will be described in detail. JSTANP/NV was released in 1996 on UNIX platforms and was re-developed on Windows in 2004. It is composed of a pre-post processor for stamping simulation, and uses solvers LS-DYNA, JOH/NIK3D for analysis. The THF function was developed in 2006. It includes a specialized pre-post system for THF simulation and the faster computation program HYTUBE for tube bending, accurate FEM program LS-DYNA for both pre-forming and hydro-forming simulation. By using the THF function in JSTAMP/NV, the simulation can be performed much more efficiently and the design time for THF parts should become shorter. Lastly, application examples will be shown to demonstrate the accuracy and effectiveness of the system JSTAW/NV. Furthermore, ductile damage parameters are applied to evaluate the formability of tube hydro-forming.