Contact stress analysis and contact surface design of multibody elastic system an application to spot welder electrode design

Abstract

A resistance spot welding mechanism is modeled as a multibody elastic contact problem to investigate the contact stress distribution and to design an optimal shape of the electrode. Contact stress is analyzed using a quadratic programming approach neglecting friction and thermal effect. Maximum contact stress is appeared at the edge of the electrode. SAP IV program was used to generate flexibility matrices of electrode and base metal plates. An optimal contour of the electrode tip for a minimum peak contact stress was suggested using a sequential linear programming technique and presented graphically for a particular geometry. Contrary to the conventional shape, the designed shape of the electrode is convex around the edge and concave at the center of the electrode tip.