3-D Numerical Study on the Bending of Symmetric Composite Laminates

In this paper,the composite laminates subjected to pure bendinq are modelled by using 3-D anisotropic finite elements and the distributions of stress and strain alongthe 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 onthe interfaces causes interlaminar stresses.The laminates are in 3-D stress state nearthe interfaces. The strain distribution of the 3-D numerical model is different from thestrain hypothesis of the classical laminate theory based on the Kirchhoff-Love hypotheses of straight inextensional normals.