Post-buckling analysis of composite plates under combined compression and shear loading using finite strip method

• Similar to the end shortening strain commonly used for compression, the skewed angle strain is uniquely proposed for the first time to control the in-plane shear action in the finite strip method.
• The post-buckling analysis of laminated composite plates under combined compression and in-plane shear action is controlled using the end shortening and skewed angle strains.
• When the ratio of skewed angle strain vs. end shortening strain is large enough, the average tensile section forces along the longitudinal direction are produced due to the large out-of-plane deflection.
• For the pure shear action, the resulting average longitudinal and transverse section forces cannot be ignored when compared to the average shear section force.

The post-buckling analysis of laminated plates under combined shear and compression is presented using the nonlinear finite strip method. Similar to the end shortening strain for compression, the skewed angle strain is uniquely proposed for in-plane shear action. The nonlinear governing equations under the skewed angle and end shortening are solved numerically using the Newton–Raphson method. The numerical finite element analysis is conducted to validate the proposed method, and a parametric study is performed to show the post-buckling behavior of composite plates. It is noted that the resulting average longitudinal and transverse section forces induced by the out-of-plane deflection or so called the non-linear strains cannot be ignored when compared to the average shear section force for the case of pure shear action. Also, when the out-of-plane deflection becomes large enough under combined compression and shear action, the average compression section force will transit to the average tensile section force in the longitudinal direction. The present analysis is capable of simulating the post-buckling behavior under the combined shear and compression action.