Experimental and numerical investigations on low-velocity impact response of high strength steel/composite hybrid plate

Low-velocity impact tests were carried out on steel/short glass-fiber reinforced thermoplastic hybrid plates fabricated by a direct injection molding process. The impact response such as absorbed energy, peak force, dent depth and damage area was studied. A finite element model based on the data obtained from the dynamic and static tests of the constituent materials has been proposed to predict the response and failure behavior of hybrid plates under low-velocity impact loading, which is validated by comparing experimental results. Using the validated model, the damage process of the thin interface between steel and composite was analyzed conveniently and cost-effectively. It is found that the plastic deformation of steel, the fracture of composite and the interface delamination are three main failure modes. After the minor plastic deformation of constituent materials, the interface delamination occurred and propagated rapidly. In addition, the finite element model is developed successfully to investigate the effects of the impact velocity, the incident angle as well as the constituent material thickness on the impact behavior of hybrid plates. The results obtained in this study can support the design and optimization of load-bearing metal-polymer hybrid (MPH) structures.