Buckling and pattern transformation of modified periodic lattice structures

The prior buckling modes of conventional square lattice structures are always global buckling other than local buckling (i.e., pattern transformation). Interestingly, we found that the preferential buckling mode can be altered to pattern transformation by modifying the sections of the frame in conventional square lattice structures, and there exists an effective modifying region. In order to predict the pattern transformation of this kind of modified structures and to determine the corresponding critical buckling conditions, the theoretical analyses are carried out, and we found that the theoretical results agree well with numerical simulations and experimental studies. This study provides an effective way to achieve pattern transformation based on conventional lattice structures. The presented theoretical approach for predicting critical buckling conditions may shed useful insights on the design and application of lattice metamaterials.