Experimental and numerical investigation on the effect of projectile nose shape in low-velocity impact loading on fiber metal laminate panels

In this paper, low-velocity impact responses of 2/1 GLARE 3 (a commercial type of fiber metal laminate) specimens were studied experimentally and numerically. The effects of indenter's nose shape (flat, conical, and hemispherical) on energy absorption and failure mechanisms were thoroughly investigated. Drop weight testing machine with different impact energies was used for experimental tests and numerical simulation was also carried out. Failure mechanisms, such as delamination, debonding, aluminum sheet rupture, and composite laminate fracture, were discussed by sectioning the tested specimens. The results indicate that maximum and minimum contact force occurred with flat and conical indenters, respectively. Also, the target absorbs the utmost energy under the penetration of flat indenter and least energy during conical indenter perforation. It is depicted that the deflection at the peak load represents the main failure of the panel. Consequently, front aluminum sheet failure is determinant in fiber metal laminate panels impacted by flat and hemispherical indenters where back aluminum sheet is more significant for fiber metal laminate panels impacted by the conical indenter. Numerical simulation verified by experimental results is extended to lower impact weights and more velocities, which are discussed.