Size-dependent buckling instability and recovery of beam-like, architected microstructures

Beam-like, architected microstructures (BAMs) can be used in various functional applications, such as microelectro-mechanical systems (MEMS), energy harvesting, actuation, etc. Designing with high aspect ratios under large deformations, BAMs typically experience severe buckling instability. Therefore, it is of necessity to investigate the mechanical behaviors with respect to the geometric and material nonlinearities. This paper proposes a bilinear size-dependent model using the modified couple stress theory to full formulate the buckling response of the BAMs. Buckling-induced large deformation is studied using the geometric nonlinearity, and the recoverability is investigated based on the material nonlinearity. Experiments and numerical simulations are conducted to validate the theoretical results at the macroscale and microscale, respectively, and satisfactory agreements are obtained. Parametric studies are carried out to study the effects of the material length scale faclor-lo-thickness ratio x = (i.e., geometric nonlinearity) and plastic factor eta (i.e., material nonlinearily). chi and g are further discussed with respect. W the effective bending sliffness (B) over bar (PAM) and volume (V) over bar (PAM) of the microsiruclures. The theoretical model presented in this study can be used to predict. and Lune the mechanical response of BAMs with different. architected webbing pallems. (C) 2018 The Author(s). Published by Elsevier Ltd.