Experimental and numerical analysis correlation of hail ice impacting composite structures

Many composite aircraft structures such as fuselage and wing skins, engine nacelles, and fan blades are situated such that hail ice impacts are a realistic threat. To investigate this threat, high velocity impact experiments and subsequent numerical analyses were performed to study hail ice impacts on composite structures. As hail ice is not a well characterized impact material, cast ice spheres made to simulate hail ice were projected onto a force measurement transducer system with the motivation of studying and gaining insight into ice as a projectile. Simulated hail ice was then projected onto thin carbon/epoxy composite fabric panels to study their impact damage resistance. Several of the tests involved impacts onto instrumented panels in which no damage occurred. For these test panels, their dynamic response was measured with the intent of future analytical correlation. This paper presents a numerical simulation of impacts onto a force measurement transducer and an instrumented panel impact test in which no damage occurred. The analyses were correlated with the experimental data and have been found to adequately model the impact behavior of ice and the elastic response of a thin composite panel.