FREE VIBRATION ANALYSIS OF A LAMINATED COMPOSITE MINDLIN PLATE BASED ON NEW MODIFIED COUPLE STRESS THEORY

A free vibration model for a composite laminated Mindlin plate (span-depth ratio at 10~20) is established based on new modified couple stress theory for anisotropic material. In this theory, the curvature tensor is asymmetric, while the couple stress bending moment is symmetry. A Hamiltonian principle is employed to derive the governing equations of motion and boundary conditions. This new model can be reduced to the model for a composite laminated thin plate based on modified couple stress theory, and also to the model for a composite laminated Mindlin plate based on classical theory. An example of natural frequencies analysis with a cross-ply simple supported square-plate is used to show the scale effects of natural frequencies. Numerical results show that the present model can capture the scale effects of the free vibration of a micro-scale composite laminated Mindlin plate.