Abstract
In the present paper, effects of titanium skin layer on impact damages in GFRP core of Ti/GFRP laminates as Fibre-Metal Laminates under impact loadings were investigated. Low-velocity impact tests using a drop-weight tower were conducted on Ti/GFRP laminates with single titanium layer as a face sheet. In these tests, the titanium skin or GFRP layer were considered to be as an impact surface, and damages in the GFRP layer after the impact loading were observed in each case. From the experimental evidence, it was found that out-of-plane deformation and internal damages of GFRP layer were constrained by the titanium layer which was set at the opposite side of impact. Furthermore, four-point bending tests were conducted using the GFRP core derived from Ti/GFRP laminates after impact loadings. Experimental results showed that the specimens impacted from the GFRP layer side exhibited superior residual bending strength and bending stiffness compared to those impacted from the titanium layer side. Numerical analyses of impact damages in Ti/GFRP laminates using a finite element method were executed in order to evaluate damage development in the GFRP layer. The calculated damage state in the GFRP layer agreed well with the experimental results. As a consequence, it was revealed that the titanium layer at the opposite side of impact plays a major role in preventing damages in the GFRP core under low-velocity impact loading on Ti/GFRP laminates.
