Variational solutions to stresses in cracked cross-ply laminates under bending

• Approximate analytical solutions based on a variational approach are presented for stresses in two cross-ply laminates, [90m/0n]s and [0m/90n]s, with matrix cracks in the 90° layers, subjected to bending. The analysis assumes a plane stress state in longitudinal sections of the laminate and accounts for the lack of symmetry caused by partially closed crack planes or by cracks present on one side of the laminate mid-plane. Comparisons with finite element analysis for laminates of glass/epoxy and graphite/epoxy show that the stress components in the cracked layers in the regions of interest are in good agreement with analytical results. The model is therefore suitable for predicting matrix crack multiplication in addition to estimating the residual flexural stiffness. The results obtained show that the transverse normal stress at the 0/90 interface is compressive for [0/90]s laminate, while this stress is tensile in regions of the interface closer to the crack for the [90/0]s laminate. Thus the analysis suggests that delamination is possible under bending in the [90/0]s laminate.

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)