Experimental investigation of the dynamic fracture of a class of RT-PMMAs under impact loading

The present work aims to investigate experimentally the crack arrest capability and dynamic fracture mechanisms under impact loading of three commercial, rubber-toughened (RT) PMMA grades differing by their rubber nano-particle concentration and resulting Charpy impact toughness. For that purpose, Kalthoff and Winkler (KW)-like impact tests were performed using gas launcher considering impact velocities ranging between 20 and 100 m/s. A high-speed camera was used to record the projectile/specimen interaction and the progressive failure of the specimen. The fracture surfaces of the fragments were observed using a scanning electron microscope (SEM). It is seen that the higher the impact velocity the larger the number of fragments. On the other hand, it is shown that increasing the rubber nano-particle concentration favors the crack arrest capability under impact loading by promoting inelastic deformation, reducing the crack propagation velocity, limiting crack multi-branching, and reducing the number of fragments.