Journals Proceedings

Abstract

The focus of current investigation is on adhesively bonded joints of glass/epoxy skin- rigid unfilled thermoset foam core material sandwich composite structures to study their shear failure properties. Rigid foam cores of Polyurethane (PUF) or Polyisocyanurate (PIR) of four different densities – 64,125,250 and 500 kg/m3 were used with uniform thicknesses. Plain weave glass fabric and a room temperature epoxy GY 257 withA140 hardener were used for the skin design. The lap shear and peel test specimens were prepared by vacuum bagging technique. The double lap shear properties were compared with the single lap shear properties evaluated earlier and a detailed comparative analysis was made on the influence of different foam densities and their adhesion to the skin on the failure behaviour of otherwise identical sandwich composite samples. The peel properties of the skin were also evaluated in Mode I cantilever set up against foams of different densities. The highlight of this work is in the comparison of porosity levels of foams, their influence on adhesive and cohesive fracture, failure mode property correlation and the usefulness of the obtained data in the design of sandwich joints.