Investigation of the response of an aluminium plate subjected to repeated low velocity impact using a continuum damage mechanics approach.

Experimental investigation of repeated impacts on aluminium plates is performed using drop weights impacting from either constant or variable heights. In repeated impacts of constant and variable heights, the effect of plasticity is noticeable on the specimens in the very first impact. The effect of strain hardening is observed at higher impact numbers. Stiffness of plates is decreased by initiation and propagation of cracks in the specimens. Finally, perforation and penetration occur at the ultimate consecutive impacts. Numerical simulations of repeated impacts are also conducted using continuum damage mechanics by Abaqus software. Lemaitre's model is used as the damage model, and the code is written in Vumat subroutine. The effect of initial uniaxial and biaxial tensile stress on the plates is considered in repeated impacts, and it is concluded that plates with initial tensile uniaxial stress at transverse edges have maximum values of contact force and absorbed energy. [ABSTRACT FROM AUTHOR]