Failure Mode Analysis Of Kagome Lattice Structures

Abstract

Ultralight weight structures are today’s essential need in aerospace, marine and automotive industries. Strength and stiffness optimization of load bearing structures is made possible with the evolution of additive manufacturing technologies through shape or topology optimization. Further composite materials and sandwich constructions reduce the design weight. To fully realize the lightweight structure, core designs with low density and high strength are necessary for sandwich panel design. In this study, the performance of the 3D Kagome truss core structure in compression loading is experimentally investigated. These bio-inspired core structures are fabricated by Fused Deposition Modelling (FDM) with Acrylonitrile butadiene styrene (ABS) ABSplus® material for experimental validation purposes. The geometrical parameters of the Kagome structure in terms of its slenderness ratio are varied to study the switch of failure mechanism from yielding dominant behavior to buckling. The effective stiffness of the truss found from finite element modeling and based on experimental results are compared, and the reasons for their discrepancy are explored. The modulus of the Kagome unit-cell is found to be linearly related to its relative density. The result show that with the increase in the slenderness ratio (l/r), the strength of the Kagome structure decreases.