CRAHVI D 3.2.4: Stochastic methodology for hail and stone impact

Abstract

This report describes a methodology developed for stochastic impact simulations with ice (hailstone) and stone (concrete, runway debris) on the composite HTP. A previous report D3.1.8 discussed a deterministic model for stone and ice impact, which is used here as the basis for stochastic impact simulations. This showed that impact damage is very localised, requiring a fine FE model of the impact region, so that attention is restricted to a vulnerable element in the HTP which is the sandwich stiffened LE shell between 2 ribs. The stochastic tool in PAM-OPT is used to investigate the influence of composites properties and impact conditions on simulated impact damage in a CFRP/honeycomb sandwich with carbon fabric/epoxy skins. In this report a stochastic methodology is defined with PAM-OPT and demonstrated by investigating damage from a rigid impactor. It is shown how a stochastic analysis may be used to define limiting conditions for panel damage when impactors will just penetrate the sandwich skin. In further work a second report D3.3.2 considers the stochastic analysis of wider range of impact scenarios and discusses the design implications for sandwich panels in aircraft structures.