Theoretical Analysis of the Buckling Behaviors of Inhomogeneous Shape Memory Polymer Composite Laminates Considering Prestrains

The mismatch in thermal expansion coefficients between the fiber-rich and resin-rich regions of a shape memory polymer composite (SMPC) laminate, along with the residual strain during SMPC fabrication, results in buckling deformation of the inhomogeneous laminate. This paper presents a macroscopic model for buckling of an inhomogeneous SMPC laminate under initial biaxial prestrains. Both linear and nonlinear buckling analyses are carried out using the energy method. The influences of prestrain biaxiality, temperature, and ply angle on the buckling wavelength, critical buckling prestrain, and buckling amplitude are calculated. The results demonstrate that the critical buckling wavelength of the SMPC laminate is independent of the prestrain, while the amplitude is almost independent of temperature. In addition, the optimal fiber stacking configuration with the maximum critical buckling prestrains of inhomogeneous SMPC laminates is determined by a genetic algorithm.