Buckling and vibration of composite laminated plates with variable fiber spacing

Buckling and vibration of composite laminated plates with variable fiber spacing were studied by use of finite element method. The formulation of the location-dependent stiffness matrix due to nonhomogeneous material properties was derived. The results indicate that the more fibers distributed in the central portion of the plate may efficiently increase the buckling load and natural frequencies. The fibers distributed in the outer portion of the plate may increase the critical buckling load. However, they will decrease the natural frequencies due to increasing more mass than stiffness. The fiber distribution may change the stiffness and mass of the plate. Therefore, the sequence of the natural mode may be altered.