Ballistic perforation resistance of thin concrete slabs impacted by ogive-nose steel projectiles

Concrete is a material frequently used in protective structures exposed to extreme loading. In this study, the ballistic perforation resistance of 50 mm thick plain concrete slabs impacted by 20 mm diameter ogive-nose steel projectiles is investigated both experimentally and numerically. Three types of commercially produced concrete with nominal unconfined compressive strengths of 35, 75 and 110 MPa were used to cast material test specimens and slabs. After curing, ballistic impact tests were carried out in a compressed gas gun facility to determine the ballistic limit curve and velocity for each concrete type. Alongside the impact tests, material tests were conducted to assess the mechanical properties of the materials. Finite element models using input from the material tests were established in LS-DYNA. Here, the constitutive behaviour of the three concrete types was predicted by a modified version of the Holmquist-Johnson-Cook (MHJC) model from the literature. Numerical simulations of the ballistic impact tests were finally carried out and the results were found to be in good agreement with the experimental data. The main objective of the study is to reveal the accuracy of the MHJC model in predicting the ballistic perforation resistance of concrete slabs impacted by ogive-nose steel projectiles using standard material tests and two-dimensional digital image correlation to calibrate the constitutive relation.