INTEGRATIVE SIMULATION FOR ASSESSING THE MECHANICAL PERFORMANCE OF A WELD LINE ON INJECTION MOULDED THERMOPLASTIC PARTS

Weld lines are commonly weak spots in thermoplastic injection-moulded parts. Predicting the healing degree of the polymer matrix at the weld line interface is necessary for enriching the material modelling at the weld line zone. A structural simulation based on such enhanced material modelling would be more accurate and advantageous in terms of product design. In this regard, a physical modelling of the healing degree between polymer interfaces has been developed and used to refine a structural simulation intended to predict the maximal strength of a structure under quasi-static loading. The simulation has been compared to experimental tensile tests performed on specimens injection-moulded with an unreinforced ABS matrix and a 30 wt% glass-fibre reinforced PBT matrix. Strength prediction in the case of the unreinforced polymer has been found satisfactory, proving the capabilities of the model estimating the healing between polymer interfaces. However, large deviations in the strength prediction for the reinforced matrix have been found. Those divergences are probably due to the reduced accuracy of the predicted fibre-orientation at the weld line zone.