Investigating the strength of adhesively bonded SMC components

Sheet Molding Compound (SMC) has emerged as a compelling alternative to light metal alloys to produce lightweight structural components in several industries. Despite their advantages, the complexity introduced by random short-fiber reinforcement SMC materials makes their mechanical behavior challenging to predict using Finite Element Analysis (FEA) models. These challenges extend to evaluating and predicting the bonding strength of adhesive joints involving such materials, which is critical in many automotive and aerospace applications. This research proposes a methodology for generating accurate material cards for adhesives/joints. The approach integrates experimental testing, numerical modeling, and optimization. A three-phase process was employed, utilizing software such as Hyper Mesh, Abaqus, and Hyper Study. The optimization phase involved the Design of Experiments (DOE) to explore parameter spaces, fitting to construct response surfaces, and optimization algorithms to refine material properties for curve matching. Despite the challenges posed by the brittle nature of SMC substrates, the approach successfully captured the joint’s mechanical behavior, producing a reliable material card for this specific material combination. This study underscores the potential of the proposed methodology to predict joint strength in large-scale simulations, such as full-vehicle assemblies, with improved accuracy and reliability. By addressing the unique challenges of SMC materials, this work provides a robust framework for adhesive characterization and enhances structural designs in composite bonding applications.