Harnessing buckling response to design lattice structures with improved buckling strength

Abstract

Lattice structures (LSs) are suitable for engineering structures because of their exceptional mechanical properties. However, strut based LSs suffer from a low buckling strength that limits their effectiveness in structural applications requiring high stiffness and strength. We propose a novel method for designing buckling-resistant strut-based LS by harnessing the buckling response of the base LS. A simple cubic strut LS with square cross-section struts was investigated with its buckling modes as a guide to design modified stiffened LS while maintaining the same relative density and stiffness. The weak regions in the LS were modified using conventional geometries, such as hollow rectangular, hollow hexagonal and angle designs. Experimental analysis of additively manufactured LS demonstrates increase in the buckling strength of up to 35% can be achieved without compromising the stiffness of the LS. The numerical simulations are further validated with experimental results with discrepancy below 10%. Finally, it was also found that the trends in the buckling strength were consistent for samples based on different relative densities and independent of material type. These results demonstrate that the current methodology can be further extended to other LSs to enhance their buckling resistance without reducing the stiffness of the base LSs.

Keywords

• Simple cubic
• Strut-lattice
• Buckling
• Mechanical properties
• Finite element analysis
• Additive manufacturing