On the Characterisation of Foam and Micro‐lattice Materials used in Sandwich Construction¹

Abstract

The paper gives an overview of issues relating to the characterisation of the progressive collapse of core cellular materials used in sandwich construction. The specific structural application addressed is foreign object impact, and in this case the core cellular material is subject to multi‐axial stresses, progressive collapse and possible rupture. The paper gives an overview of various theoretical and modelling issues, which are then related to experimental materials and structural tests for model development, calibration and validation. Most discussion concerns polymeric crushable foam, metal foam and metallic lattice structures.

Plate-impact loading of cellular structures formed by selective laser melting

“…The powder experiences local surface melting and welding, resulting in features on the scale of hundreds of micrometres, with the limiting factor being the size of the region of powder which is melted by the laser. Mines [17] and Smith et al [18] have used SLM to form body-centredcubic structures. Wang et al [19] have studied a structure designated Kagome which has a three-fold axis of symmetry and McKown et al [20] have studied an octahedral lattice.…”

Local Effects during Indentation of Fully Supported Sandwich Panels with Micro Lattice Cores

“…Each strut is modeled using three Hughes Liu beam elements. In the longer term, other micro-lattice geometries [1] will be studied with a view to improving perforation performance.…”

“…Mines [1] has identified five behaviours for perforation of a sandwich panel, namely: global elastic response, local core skin debonding, perforation core crushing, boundary response and post impact response. This paper focuses on perforation core crushing.…”

“…Mines [1] discusses the new manufacturing technique of selective laser melting to realize stainless steel micro lattice structures, which have strut diameters of 200 microns and strut lengths of 3mm. In the manufacturing process a bed of fine powder (15 to 30 microns) is selectively melted using a laser.…”

Skin-core adhesion in high performance sandwich structures

“…Work has been carried out in studying the mechanical properties, crush behaviours, as well as impact properties of the selective laser melting (SLM) SS316L stainless steel and Ti64 titanium alloy micro-lattice (Santorinaios et al, 2006;McKown et al, 2007;2008;Mines, 2008;Mines et al, 2008;Shen et al, 2010;2013). This study aims to discuss the interfacial fracture properties of a stainless steel lattice core-based sandwich structure in order to improve the damage tolerance of sandwich structures and increase the toughness between skin and core.…”