Mechanical properties and deformation behavior under compressive loading of selective laser melting processed bio-inspired sandwich structures

Abstract

Sandwich structures are widely used in aviation and aerospace applications because of their outstanding characteristics of light-weight, excellent energy absorption and continuous compression behaviors. Nature has provided us with extraordinary resources to meet the demanding for modern industry. In this study, inspired by the microstructures of the Norway spruce stem, four light-weight sandwich structures were designed and manufactured by selective laser melting (SLM). The structures had good formability using an optimized laser processing parameter setting. The uniaxial compression tests of SLM-processed bio-inspired sandwich structures were conducted to evaluate their specific compressive strength and energy absorption performance. Finite element analysis was employed to study stress distributions in structures during compression tests and analyze fracture mode combining with the observation of fracture surface morphology. The experimental and numerical results indicated that the gradient structure, with tube size gradually decreasing from top and bottom plate towards the center, exhibited the highest specific absorption energy, ultimate strength and specific strength, which was 5.73 J/g, 214.8 MPa and 98.99 MPa/(g/cm3), respectively. The FEA results revealed that the arrangement of tubes significantly affected the stress distribution and fracture locations of structures. The gradient structure, with the highest specific absorption energy and ultimate strength, had the most uniform stress distributions, contributing to its excellent compressive performance.