Analytical Study of the Effects of Delamination in Glare Fiber-Metal Laminate using Modified Virtual Crack Closure Technique (MVCCT)

Abstract

Progression in the field of materials used in an aircraft, has seen resurgence in a relatively successful Fiber-Metal Laminate called GLARE, which is composed of several layers of very thin metal (often aluminium), along with layers of uni-directional Glass Fiber pre-pregs. All the layers are bonded to each other with the use of matrix such as epoxy-resin system. The major advantage of this material is that it can be tailored to fit the stress condition by varying the orientation of the Glass Fiber layers. Furthermore, other advantages include better damage tolerance, corrosion resistance, fire resistance and low specific weight. Although GLARE is a composite material, its material properties and fabrication techniques are considered to be homogeneous aluminium like. In this paper, we try to approach this material as a composite, and determine the effect of delamination that occurs due to various reasons. To achieve this, a finite element model of size of 200 mm x 200 mm plate is generated and a compressive load in terms of initial displacement is applied. Various crack sizes at the centre of the plate along the stacking sequence is modelled and analysed. The corresponding Strain Energy Release Rates (SERR) are computed along with various other parameters such as Elemental Stress, Displacement and Contact Stresses. Modified Virtual Crack Closure Technique (MVCCT) is used to obtain the SERR values in all three modes of failure, and their direct effect on the structural integrity of the model is studied and reported.