عنوان مقاله [English]
In this paper, the fatigue response of a foam core sandwich composite with unsymmetrical hybrid faces has been investigated. The sandwich laminates were manufactured using the same method for a corresponding selected element in a real composite structure.Two similar woven E-glass fibers (designated by G1\& G2), following unidirectional carbon fibers(C) with Epoxy resin, were used as the face sheet over a PVC foam core. The lamination sequence and angles are, as follows, respectively: [G1/C/C/C/G2/ Foam /G2/C/C/G1], [0/0/0/0/$\pm$ 45/Core/$\pm$45/0/0/0]. Extensive fatigue data were generated for the S-N diagram for such a laminate. Based on static analysis of the two FEM models, critical points in the specimen causing static failure were explained. The effect of using each of the two different proposed designs for specimens were shown.FEA and experiments results both give an improvement in the failure zone and strength values for an oblique type design of the gauge interface. The failure modes, after final failure of the sandwich laminate, have been discussed. From four types of damage recognized
for the laminate, two of them were nucleated and grown in the foam core, first in thickness and then parallel to the length
of the gauge. By increasing the overall stress level, the parallel cracks were shortened.