The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 03, 1995
Filed:
Dec. 21, 1992
Sing C Tang, Plymouth, MI (US);
James C Carnes, Willis, MI (US);
Ford Motor Company, Dearborn, MI (US);
Abstract
Method and system for evaluating sheet metal forming tooling design, for use with a draw die including a punch and binder designed to form the sheet metal into a part, utilizing improved implicit time integration methods that reduce numerical instability, thereby enhancing convergence of numerical solutions. The sheet metal and tool surface of the punch are each represented as a mesh having a plurality of nodes. Contact nodes between the sheet metal mesh nodes and the tool surface mesh can be identified. A first embodiment includes minimizing discontinuities generated by unloading by determining a stress increment of a sampling point in the sheet metal mesh according to an incremental deformation theory of plasticity. A second embodiment includes modelling a draw-bead as a plurality of nonlinear elastic springs to minimize discontinuities in the spring force during unloading. A third embodiment includes filtering a relative velocity vector of at least one contact node with respect to the tool surface, to avoid frictional force oscillations due to the change in direction of the relative velocity vector during formation of the part.