Experimental finding of dynamic deformation fields in metal and composite plates under impact

The purpose of research is to develop and verify methods of experimental determination of the dynamic strain fields in the study of impact damage and destruction of the plates. An experimental rig that realizes dynamic load of the studied plate at high-speed impact with a projectile and determination of dynamic strain fields on the plate surface is developed. The method is based on digital image correlation procedure in combination with a high-speed video recording that implemented using hardware-software Vic-3D complex. The investigation is performed in two series of experiments with different materials and dimensions of the test plates and with different materials and speed of the projectile. The experimentally obtained fields of the dynamic strain for the high-speed impact of the aluminum plate and a spherical steel projectile and for the carbon fiber plate and ice projectile are presented. The results are presented in the form of time-lapse recording of the tensor component fields of dynamic deformation and time dependences of deformations at certain points of the plate. The implemented deformation rate is up to 1,.5· * 103 sec --1. The state of strain for carbon-fiber composite during high speed destruction is obtained. The reliability of the digital image correlation method results is confirmed by direct measurement of residual deformations in the plate. The described method provides detailed experimental data about the processes of high-speed deformation for metals and composite materials. This data is of interest for experimental verification of deformation and destruction models behavior of materials at high strain rates. In particular, it provides an opportunity to obtain the necessary data for verification of deformation models and failure criteria of deformation under biaxial stress state. This method can be used for mathematical models testing and experimental investigation of the ballistic damage and destruction dependences of critical structural elements in cases of foreign objects damage of aircraft and engines parts or armor piercing.