Mechanical Responses of Symmetric Straight and Curved Composite Microbeams

Purpose: The mechanical behaviors of general microbeams are presented, including the lateral forced vibration of a symmetric straight microbeam subjected to transverse excitation and the buckling and postbuckling of a symmetric curved composite microbeam subjected to axial and thermal loads. Methods: To achieve this, the nonlocal elasticity theory is taken into account and the small scale parameter is involved to modeling the symmetric straight microbeam. The nonlinear partial differential equation governing microbeam lateral motion is derived due to the axial elongation, and a set of linear ordinary differential equations are derived by the method of multiple scales. The lateral displacement is determined and the amplitude-frequency relation is presented and discussed. Subsequently, the in-plane instability of functionally graded carbon nanotube reinforced composite curved microbeams in thermal environment is examined. Results: It is showed that an increase in carbon nanotube volume fraction improves the critical buckling load of the composite microbeams. The temperature-induced tensile loading and displacement also have remarkable effects. Furthermore, geometrical parameters can be used to determine the buckling mode of the composite microbeam due to its significant effect on critical buckling loads. Conclusions: The solutions of critical geometrical parameters are determined and they are affected by the temperature change, carbon nanotube distribution and volume fraction, respectively.