Abstract
The aim of this work is to evaluate the mechanical properties and failure analysis of cellular core structures with different geometries that were obtained by additive manufacturing. Sandwich panels are widely used in the aerospace and automotive industry. In general, the core of the panels is made of a two dimensional cellular with a honeycomb geometry. With the development of additive manufacturing methods it is possible to produce samples with complex geometries which may compete with conventional designs. Thus an investigation was conducted to evaluate the mechanical behavior of three core geometries, specifically, regular honeycombs, lotus and hexagonal honeycombs with Plateau borders. Samples were produced in PLA (polylactic acid) by fused deposition modelling (FDM). Experimental compressive loading in three different directions, and finite element simulations of the samples permit to evaluate their deformation and failure mechanisms. Load direction angles were found to have a strong influence in the failure mode. Among the three structures, and for the same relative density, the lotus geometry exhibited the highest stiffness and strength. However, the absorbed energy was found to be higher for honeycomb, at two loading directions. Some of the structures studied may be alternative to conventional designs pursuing the strategy of design with low weight and high stiffness.
Highlights
Composite cellular panels are of great potential in the field of transportation, automotive and aerospace industries, among others [1,2,3,4,5,6,7]
S tructural panels made of sandwich composites are common in the fields of automotive and aerospace industries where the combination of high strength and stiffness with low weight are of utmost importance
In general the composite core is made of regular honeycomb structures
Summary
Composite cellular panels are of great potential in the field of transportation, automotive and aerospace industries, among others [1,2,3,4,5,6,7]. There have been several experimental and numerical studies on the behaviour of sandwich structures with different core topologies which include honeycombs with corrugated walls [16,17], with ceramic tiles [18], auxetic cores [15,19], egg-box structures [7,20], truss cores [21,22], and other core designs, such as the ones studied by Araújo et al [23]. The emphasis of the present work is on the study of the in-plane properties measured under compression of three core designs, hexagonal honeycomb, lotus material and hexagonal honeycomb with Plateau borders, which may be used for sandwich core panels These new core designs were previously studied under bending loading conditions by the present authors [23], the in-plane properties were not previously addressed. It was found that the deformation and failure of the several geometries depends, mainly on the loading direction
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