Micro-composite films constrained by irregularly bilateral walls: A size-dependent post-buckling analysis

Post-buckling analysis of micro-composite films (MCF) has been extensively investigated in recent years. However, the literature of composite elements at micro/nanoscale has been mainly focused on buckling response without lateral confinements. This paper takes one step forward to theoretical studying of static and dynamic post-buckling response of MCF constrained by irregularly bilateral walls using the modified couple stress theory. A discretization algorithm is developed to convert the irregular constraints into normalized gap vectors. An energy method is presented to solve the proposed model by minimizing the total energy with respect to the gap vectors. Numerical simulations are carried out to validate the theoretical model. Satisfactory agreements are obtained between the theoretical and FE results. The proposed theoretical model is used to study the effect of the material length factor ς on the buckling mode transition force P and highest achievable buckling mode of the irregularly constrained micro-films. The presented model can be used to predict and tune the post-buckling response of the axially loaded MCF subjected to irregularly bilateral constraints.