Residual compressive strength of aluminum alloy honeycomb sandwich panel in the presence of multiple impact dents

The present article discusses the effect of impact damage on residual compressive strength of aluminum alloy honeycomb sandwich panel (HSP). Multiple dents were created in HSP by penetrating indenters of different diameters through quasi-static indentation technique. The damaged samples were compressed edge-wise for determination of in-plane compression after impact (CAI) strength. The failed samples were macroscopically examined to reveal the underlying damage mode. Experimental results showed that the presence of multiple dents of 5 mm size or less do not appreciably affect the CAI strength of aluminum alloy HSP. However, moderate reduction in CAI strength was observed in case of multiple dents of 10 mm. Compressive strength was reduced by 18% in presence of four dents of 10 mm diameter. The maximum reduction in CAI strength of up to 30% was observed in samples impact damaged by 15 mm indenter. Examination of failed HSP showed that the maximum load was sustained taken by aluminum facesheet whereas the contribution of honeycomb core was insignificant. Research findings exhibit that the CAI strength of aluminum alloy honeycomb structure is not sensitive to impact damages size less than 5 mm diameter however dents above 5 mm size can seriously impair mechanical performance and structural integrity.