Study of the influence of the skins in the behaviour of sandwich structures subjected to high-velocity impact

Abstract

Sandwich structures made of composite materials, namely glass fibre/polyester, are widely used in  the naval, ground transportation, aerospace and telecommunication industries. Due to the combination of key factors: the good mechanical properties of this kind of materials together with their low specific weight and their permeability to electromagnetic waves. These structures are often subjected to impulsive loads during its service life. Therefore, in order to obtain a safer structural design, a better knowledge of the impact response must be accomplished. It has been demonstrated that the composition of the skins plays a fundamental role in the behaviour of sandwich structures against high-energy ballistic impacts. The structures studied in this work are composed by two E-glass fibre/polyester skins and a PVC core. With the objective of optimising this kind of structures when they are subjected to high-energy impact, a numerical study in the finite element code Abaqus has been carried out. In this study, the number of plies in the front and rear faces varies in order to find the configuration that presents better ballistic performance. To this aim, a VUMAT subroutine previously developed has been used for the skins. The core has been modeled with the crushable foam constitutive model available in the software Abaqus. The influence of the thickness of the skins can be tested by means of this numerical model. The results obtained show that the residual velocity disminishes the more the number of layers in the rear skin increases.