Developments in LS-DYNA for Metal Forming Simulations

One - step simulation with keyword *CONTROL_FORMING_ONESTEP has been widely in use in crash and safety for forming stress and strain initialization. It has also being used for initial estimating of blank size in stamping application. One problem stamping users face is the position of the blank after unfolding can be undesirable. Also, the shifted unfolded blank is not easy to align relative to the tooling position. To address this issue, additional entries are now available in keyword *CONTROL_FORMING_ONESTEP_AUTO_CONSTRAINT to specify three node IDs (NODE1, NODE2 and NODE3) . The unfolded part wi ll be repositioned and re-alligned according to the nodes specified back to the same nodes in the original part. The transformed blank is written in a keyword file “repositioned.k ”. As shown i n Figure 1 , an example of using the N ODE1, NODE2 and NODE3 to transform the unfolded blank back to the original part so the same three nodes defined will be coincident . The three nodes are defined around the edge of two hol es, as Nodes 197, 210 and 171.