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The damping performance of lightweight steel/polymer/steel sandwich composites has been typically studied without considering the interface between the heterogeneous materials. Herein, the interface between the steel and polymer layers was investigated experimentally for various steels and polymers. Impact hammer tests revealed that the interfacial adhesion strength between steel and polymer did not significantly affect the loss factor of the sandwich cantilever beam composites. However, although very thin, the adhesive layer itself greatly influenced the vibration-damping performance of the composite. As such, previous three-layered (skin-core-skin) sandwich model without considering the properties of adhesive layer predicted different results from experiments. To accurately predict the loss factor of the sandwich, a five-layered sandwich model consisting of two skins, two adhesives, and a core layer was proposed and validated with experiments.

Steel-polymer sandwich composites are relatively strong and lightweight materials. However, accurately predicting the mechanical properties of these materials has been challenging, presumably due t...

This study reports on the prediction of the delamination of steel-polymer composites. To characterize the adhesive properties from peeling tests, a simple model was derived based on peeling mechanics, in particular considering plastically dissipated energy of polymer film due to bending. Peeling tests were performed at two angles so that the adhesive properties were determined in both normal and tangential directions. Then, peel strength at arbitrary angle was predicted and compared with experiments, showing that the peel strength at only two angles and peeling mechanics considering the bending of polymer film can accurately describe the adhesive properties of steel-polymer interface. Finally, finite element simulations based on the cohesive zone model were performed to predict the delamination between steel-polymer sandwich composites, demonstrating the validity of cohesive zone model equipped with necessary properties determined using peeling tests and the developed model in this study.

Steel-polymer composites have low density, high specific flexural stiffness and vibration damping properties over other metal materials. However, the weak interfaces between steel and polymer sheet are the typical locations where the failure occurs. Furthermore, interfacial failure is a fatal reason of the degradation of mechanical properties. Therefore, predicting interfacial failure of the final product is an important technology in commercialization of steel-polymer composites. In this study, we built forming limit diagram (FLD) based on two different failure modes: failure of the bottom skin steel and interfacial failure between the skin steel and core polymer. Acoustic emission (AE) technique was conducted to observe the interfacial failure moment. Peak frequency was found to be the key feature to distinguish interfacial failure. Peak frequency band that indicates interfacial failure was from 300 kHz to 500 kHz. This peak frequency band made it possible to build FLD considering the interfacial failure.