Nonlinear Impact Force Reduction of Layered Polymers with the Damage-Trap Interface

Featured Application The proposed impact force reduction approach using a special material design can reduce the volumes and weights of protective materials such as a plastic phone case. In this paper, a damage-trap material interface design of polymeric materials was proposed. Towards that, baseline and layered Polymethyl methacrylate (PMMA) and Polycarbonate specimens were fabricated with a Loctite 5083 adhesive layer between the interfaces. Out-of-plane impact experiments were conducted and found that the maximum impact force was reduced in layered polymers with so-called "damage-trap material interfaces". At the impact energy of 20 J, the maximum impact force of the layered PMMA specimens with the 5083 adhesive was reduced by 60% compared to the identical specimens without any adhesive bonding. For the layered Polycarbonate specimens with the 5083 adhesive bonding, the maximum impact force was reduced by 20% and energy absorption was increased by 130%. Simplified contact mechanics analysis showed that the low Young's modulus of the 5083 adhesive layers was a key parameter in reducing impact force and damage. Therefore, a simple and effective way to design layered materials with improved impact resistance was proposed.