Impact Protective Performance and Theoretical Analysis of Polyvinyl Chloride/Thermoplastic Polyurethane Foam Composite Structure via Finite Element Simulation

Polymer foams are widely used as cushioning and impact protective materials, while the single foam is susceptible to densification by concentrating pressure at the point of impact, thus reducing the protection effect. Herein, inspired by the tortoise shell, a composite structure composed of a poly(vinyl chloride) (PVC) hard layer and a thermoplastic polyurethane (TPU) foam soft layer was developed, which demonstrated significantly enhanced impact protection and energy absorption performance. The numerical model and finite element model were developed by adopting the Storakers model and the Rayleigh damping model to represent the hyperelastic behavior and energy dissipation of the elastic foam. Macroscopic and mesoscopic theoretical analyses revealed the mechanism of excellent cushioning and protection performance. The model is also capable of simulating the effects of the foam thickness, the modulus of the rigid plate, and the free-falling sphere on the cushioning performance. Therefore, this work provides a rational design of the buffering material and a numerical model that is capable of directing the material selection, design, and optimization of the composite material configuration depending on the requirements of different impact protection situations.