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Abstract
Hemming adhesive has an important influence on the dimensional accuracy and structural stability of autobody closure panels, especially when lightweight dissimilar materials are used. Therefore, detailed material models are urgently needed for reliable bonding quality prediction in the industry. In this study, multi-physics modeling of one-component hemming adhesive during the curing process is proposed, considering the change of curing degree and mechanical properties. Material properties related to temperature and time are measured and analyzed to determine the model parameters. Then, taking a cylindrical adhesive as the research object, the thermal-chemical-structural coupling process is simulated based on the material model. The mechanical response under oscillatory shear load and temperature cycle is investigated, and the simulation results are verified by experiments. Finally, the approach is applied to a typical convex-edge hemming assembly with dissimilar materials, and the simulation deformation accuracy is verified by non-contact measurement. The results show that the predicted reverse torque and normal force of the cylindrical adhesive based on the multi-physics modeling are well correlated with the experimental values, which can reflect the curing process of gel, chemical shrinkage and stress relaxation. The assembly deformation is related to the curing kinetics of the adhesive in the heating stage and slightly rebounds due to chemical shrinkage in the holding stage. It provides an important reference for the bonding quality prediction and performance optimization of hemming adhesive.
Disclosure statement
No potential conflict of interest was reported by the author(s).