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

Jnl of Sandwich Structures & Materials

et al. 2010

Self Cite

191

115

This article presents a theoretical analysis for predicting the initial stiffness E*, and plastic collapse strength σ*pl of BCC micro-lattice blocks under compressive loading. This theoretical analysis is based on the observed deformation mechanisms, and can, in principle, be developed to predict the elastic properties of other micro-lattice structures. The analytical solutions are verified by comparing the predictions with FEM data using 1D beam and 3D solid elements and uniaxial compression tests on samples fabricated by selective laser melting. The FEM predictions using the 3D solid elements agree well with the experimental data for a wide range of strut aspect ratios, d/L. In addition, the range of applicability of the analytical model and the FEM predictions using beam elements are clarified.

Section: Prediction Of the Plastic Collapse Strength ã Plmentioning

confidence: 99%

“…Recently, at the University of Liverpool, the rapid prototyping manufacturing process of selective laser melting (SLM) has been used to realize lattice structures at the microscale [11]. Figure 1(a) shows a typical micro-lattice block (termed a body centred cubic, BCC).…”

Section: Introductionmentioning

confidence: 99%

An investigation into the compressive properties of stainless steel micro-lattice structures

Ushijima

Cantwell

Jnl of Sandwich Structures & Materials

et al. 2010

Self Cite

191

115

“…Advanced manufacturing techniques such as the rapid prototyping selective laser melting (SLM) technique [7] has strongly contributed to the initial study on the metallic micro-lattice structure at the University of Liverpool. Work has been carried out in studying the mechanical properties, crush behaviours, as well as impact properties of the SLM SS316L stainless steel and Ti64 titanium alloy micro-lattice [6][7][8][9][10]. However, it should be noted that the mechanical properties of the SLM micro-lattice structures are very much influenced by two processing parameters that are laser power (in Watt [W]) and laser exposure time (in micro seconds [µs]) [11].…”

Section: Introductionmentioning

confidence: 99%

Comparison of the Drop Weight Impact Performance of Sandwich Panels with Aluminium Honeycomb and Titanium Alloy Micro Lattice Cores

Rakhshandeh

Shen

et al. 2010

AMM

Self Cite

Abstract. This paper is a study of the drop weight impact behaviour of small sandwich panels of carbon epoxy skins with aluminium honeycomb and titanium alloy micro-lattice cores. A series of experimental tests have shown that the specific impactor penetration behaviours are similar for both cores. The reasons for this are a result of the detailed deformation and rupture behaviour of the two types of core. The deformation and rupture mechanisms of honeycomb and micro-lattice structures will be discussed in general terms, and these observations will be used to inform discussion of actual deformation and rupture in the panel tests. In this way, micro energy absorbing mechanisms will be related to panel performance, and conclusions on the way forward for improved penetration performance using other core materials and geometries will be identified.

“…In a previous study, it has been shown that the level of impactor penetration for a given impact energy is similar for fully supported and simply supported panels. 24 Figure 13(a) shows typical load versus displacement traces for the SS316L and ALPORAS sandwich panels. The lattice cores were manufactured using two sets of parameters, these being 70 W × 1000 µs and 140 Watts × 1000 µs.…”

Section: Resultsmentioning

confidence: 99%

Low-velocity impact performance of lattice structure core based sandwich panels

Shen

Cantwell

Journal of Composite Materials

et al. 2013

This paper outlines the findings of a study on a range of stainless steel and titanium alloy lattice structures manufactured using the selective laser melting technique. The effect of varying key manufacturing parameters on the properties of lattice strands was studied through a series of single-filament tensile tests. The resulting failure mechanisms were investigated using a scanning electron microscope. The resulting observations have shown that the properties of these lattice strands are determined by the laser energy during the manufacturing process, which in turn is controlled by the laser power and laser exposure time. The quasi-static and low-velocity penetration behaviour of lattice core-based sandwich panels has been examined, and an aluminium foam and an aluminium honeycomb were chosen to benchmark their performance. The impact resistance of the lattice core-based sandwich structures were shown to be dependent on both the manufacturing parameters and lattice unit-cell geometry of the lattice structure. The impact resistances were improved by increasing manufacturing laser energy and lattice core density. A series of drop-weight tests at velocities up to 6 m/s have shown that the penetration behaviour of the titanium alloy lattice cores and the aluminium honeycomb cores is similar.