Abstract: Compared with the straight fiber placement composite laminates, variable-stiffness laminates can achieve the designability of composite materials. And, the optimization of placement pathsof variable-stiffness laminates can increase the buckling load of the laminates. Firstly, expanding the composite laminate fiber placement paths of which orientation angle is linearly changed with the coordinate axis, and then four kinds of nonlinear changed placement paths had been proposed. And these five kinds of placement paths were regarded as the reference paths of the composite laminates to build layers by shifted method. Secondly, the variable-stiffness composite laminates were divided into five types according to the five different placement paths,and those laminates were modeled and analysedby ANSYS software without regard for overlap and gap caused by shifted method. Finally, under the uniaxial and biaxial compression load, the buckling loadsof the variable-stiffness composite laminates were calculated and compared with the fixed fibrous orientation angle laminated plates. The results show that the buckling load of variable-stiffness composite laminates had been considerably increased by the design optimizationof fiber placement paths of laminated plates.

Key words: variable-stiffness, fiber curve placement, reference path, placement path design, buckling analysis