Strength characterization of assemblies of polymers, made by laser welding

Abstract

We experimentally establish a plastic and breaking intrinsic stress criterion for welded joints made by laser radiation using the TWISTr configuration. This welding is used in junction of two plastics materials, one laser transparent, one no laser transparent as control panels. Two types of plastic materials have been studied, ABS and PA66 polymers. The yield surface which characterize the limit of elasticity and the rupture surface have been described by a modified Drucker-Prager criterion identified in the case of complex mixed modes state of stresses coupling tensile and shear stresses. The conclusion is that ABS is a good candidate for laser welding application, whereas PA66 presents lower mechanical properties in the welding area. For design purpose of welded zones, the proposed Drucker-Prager criterion has been used for the calculation and the simulation of breaking welded ABS plates and welded PA66 step plates. The comparison between experimental and numerical simulation values shows a relatively good agreement.