A modified spring-mass model of low-velocity-impact on composite laminate including shearing deformation at delaminated region and reduction on membrane stiffness

Abstract

A modified spring-mass model for response prediction of composite laminate subjected to destructive large mass impact was developed based on perturbation analysis on membrane stiffness and modified subsection superposition of bending stiffness. The reduction of the membrane effect caused by impact induced intraply matrix failure was evaluated by substituting the perturbated elastic modulus into the membrane stiffness. The subsection superposition method for calculating the bending stiffness of delamination-damaged laminate was modified by considering the transverse shear effect. According to the results of the finite element simulation, the accuracy of the first-order shear deformation theory (FSDT)-based subsection superposition method in evaluating the bending stiffness of delaminated laminates is obviously higher than the classical plate theory (CPT)-based one with the increase of laminate thickness. Destructive drop weight impact tests on the FRP laminate were conducted to validate the proposed model. The results show that the FSDT-based model is more accurate than the CPT-based one in destructive large mass impact response analysis.