3-D numerical study on the bending of symmetric composite laminates

In this paper, the composite, laminates subjected to pure bending are modelled by using 3-D anisotropic finite elements and the distributions of stress and strain along the thickness are presented. The numerical results show that there is a stress concentration near the bonding interface in the central region (far from traction boundaries and free edges) of symmetric angle-ply laminates, which should be called “interlaminar effect”. The abrupt change of the mechanical behavior of material on the interfaces causes interlaminar stresses. The laminates are in 3-D stress state near the interfaces. The strain distribution of the 3-D numerical model is different from the strain hypothesis of the classical laminate theory based on the Kirchhoff-Love hypotheses of straight inextensional normals.