Stress analysis in symmetric composite laminates subjected to shearing loads

• An analytical solution is proposed to determine the interlaminar stresses in long symmetric laminated composite plates subjected to a shearing load.
• The interlaminar stresses demonstrate high stress gradient near the free edge.
• The numerical values of the interlaminar normal and shear stresses are established by using Reddy’s layerwise theory.
• The effects of fiber orientation angles as well as the stacking sequence of the layers on the interlaminar stresses are obtained.

In the present study, an analytical solution is proposed to determine the interlaminar stresses in long symmetric laminated composite plates subjected to shearing loads. An improved first-order shear deformation theory (IFSDT) and a simplified IFSDT (SIFSDT) are utilized to calculate the unknown constants appearing in the reduced elasticity displacement field which actually demonstrate the global deformations of the plate. Then the numerical values of the interlaminar normal and shear stresses are established through the laminates by using Reddy’s layerwise theory. Finally, several numerical examples are presented to study the interlaminar stresses in the interfaces of the layers and through the thickness of the laminates. The effects of fiber orientation angles as well as the stacking sequence of the layers within the laminates on the interlaminar stresses are obtained and discussed. All results specify high stress gradients of the interlaminar normal and shear stresses near the edges of the laminates.