Complas 2025

COMPLAS 2025

A Cohesive Element-Based and Crystallization-Enhanced Thermomechanical Model for Thermoplastic Overmolding

Li, Xiangfeng (University of Wuppertal)
Liu, Tiansheng (University of Wuppertal)
Tabib, Majd (University of Wuppertal)
Boes, Birte (University of Wuppertal)
Giersberg Sola, Martin (RWTH Aachen University)
Valsecchi, Michele (Columbia University)
Cui, Junhe (Columbia University)
Celik, Hakan (RWTH Aachen University)
Dahlmann, Rainer (RWTH Aachen University)
Hopmann, Christian (RWTH Aachen University)
Kumar, Sanat K (Columbia University)
Fish, Jacob (Columbia University)
Simon, Jaan-Willem (University of Wuppertal)

In session: 1503B - Multiscale And Multiphysics Modelling Of Fibrous Materials And Fibre Reinforced Composites II

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Integrating injection molded thermoplastic compounds with continuous fiber reinforced thermoplastic tapes enables lightweight, high-performance and cost effective composite structures but frequently suffers from inadequate interfacial bonding, potentially leading to premature failure and inefficient design strategies. We address these limitations through a computational multiscale and multiphysics modeling approach that captures the coupled effects of processing conditions, evolving material morphology, and interfacial mechanics. As part of an NSF-DFG collaborative project, this research develops a coupled thermomechanical multiscale framework to address the interfacial and bulk material behavior in overmolded thermoplastic components. The semicrystalline nature of the materials necessitates an advanced multiphysics modeling approach that captures the time-dependent nonlinear response of both the bulk matrix and the interface. To this end, a thermoplastic material model is developed to describe the large-deformation, elastoplastic, and viscoelastic behavior of the bulk material, incorporating bidirectional thermal-displacement coupling. Concurrently, a cohesive zone model (CZM) is employed to characterize damage initiation, interfacial debonding, and failure mechanisms, establishing a direct link between process-dependent crystallinity, interdiffusion, and interface bond strength. This integrated multiscale and multiphysics modeling approach enables the prediction of stress evolution, heat generation, crystallinity distribution, and interfacial fracture under varying processing and loading conditions. By establishing a clear cause-and-effect relationship between processing parameters, mechanical performance and interfacial properties, this research provides critical insights into damage and fracture mechanisms, validated through benchmark simulations and experimental comparisons in fiber-reinforced composites. The developed framework contributes to more reliable and efficient production of fibrous composite materials, minimizing material usage and waste. This research thus supports sustainable and resource-efficient engineering practices, advancing the use of high-performance thermoplastics in structural applications.