Numerical Simulation of Progressive Lancing Operation in Sheet Metal Forming

摘要

Systems and methods of conducting a time-marching simulation of manufacturing a sheet metal part that requires progressive lancing operation (PLO) are disclosed. The time-marching simulation is conducted with a connection-separation scheme for nodes along the lancing route to ensure a smooth timely separation of a lancing cut. The scheme includes creating a set of surrogate lancing route nodes by duplicating nodal coordinates of the existed nodes located along the lancing route. Nodal constraints to initially link together the existed nodes and the corresponding surrogate nodes are then created. The nodal constraint is removed in accordance with a separation time schedule established using start and end locations of the lancing route and corresponding start and end time for making the lancing cut. The nodal constraints can also be removed based on the zones of the lancing route defined by a user.

主权项

1. A method of conducting a time-marching simulation of manufacturing a sheet metal part that requires progressive lancing operation, said method comprising:
receiving, in a computer system, a finite element analysis (FEA) model representing a blank sheet metal and a die face definition that includes a lancing route of a progressive lancing operation (PLO), wherein the FEA model and the die face definition are used in a time-marching simulation of manufacturing a sheet metal part, the FEA model contains a plurality of nodes connected by a plurality of finite elements, and the lancing route is defined by a series of coordinates that includes start and end locations of the lancing route and corresponding start and end times of the PLO in reference to simulation time of the time-marching simulation; conducting the time-marching simulation until the simulation time reaches the start time of the PLO, wherein the nodes and the finite elements of the FEA model have deformed due to contacts with the die face; identifying those of the finite elements within close proximity of the lancing route as a group of lacing route elements by comparing the coordinates of the lancing route with the deformed FEA model; adjusting nodal positions of the lancing route elements' corner nodes to respective particular locations on the lancing route when said nodal locations are determined to be within close proximity of the lancing route based on a proximity criterion; dividing each of the lancing route elements crossed by the lancing route into two finite elements, said two finite element having shared nodes located on the lancing route; creating a set of surrogate lancing route nodes by duplicating respective nodal coordinates of the existed nodes along the lancing route of the deformed FEA model; updating the lancing route elements such that those lancing elements located on one side of the lancing route are redefined by replacing the existed node with said corresponding surrogate lancing route node, while those lancing elements located on opposite side of the lancing route are left unmodified; creating respective nodal constraints to initially link together said each of the existed nodes along the lancing route with the corresponding one of the surrogate lancing route nodes; associating a separation time schedule with said nodal constraints, wherein the separation time schedule is established using the start and the end times in conjunction with the start and the end locations of the lancing route; and conducting remaining of the time-marching simulation, in which each of the nodal constraints is removed in accordance with the separation time schedule to achieve numerical simulation of the PLO.