Wavy-ply sandwich with composite skins and crushable core for ductility and energy absorption

Abstract

Conventional composite materials offer high specific stiffness and strength, but suffer from low failure strains and failure without warning. This work proposes a new design for sandwich structures with symmetrically-wavy composite skins and a crushable foam core, aiming to achieve large strains (due to unfolding of the skins) and energy absorption (due to crushing of the foam core) under tensile loading. The structure is designed by a combination of analytical modelling and finite element simulations, and the concept is demonstrated experimentally.When loaded under quasi-static tension, wavy-ply sandwich specimens with carbon-epoxy skins and optimised geometry exhibited an average failure strain of 8.6%, a specific energy dissipated of 9.4 kJ/kg, and ultimate strength of 1570 MPa. The scope for further developing the wavy-ply sandwich concept and potential applications requiring large deformations and energy absorption are discussed.

Modelling of a novel strong and ductile FRP composite

“…Currently, numerical modelling of the composite with stiff skins and inner cores is relatively few in number. In those available studies, stiff skins have been modelled as either an orthotropic [15] or isotropic [20] material with linear-elastic properties. Nevertheless, numerous computational models have successfully applied either orthotropic [1,2,5] or isotropic [21][22][23][24] elements to simulate the tensile behavior of FRP material in strengthening concrete structures.…”

“…Few differences were found between those two methods if those FRP composites were under pure tensile loading [25]. On the other hand, inner cores have been modelled as an isotropic material with corresponding material properties [15,20]. In this study, inner systems consisting of columns and various cores have been printed by Acrylonitrile Butadiene Styrene (ABS) or Polylactic Using a 15mm width FRP strip to make skins Core material is ABS Fig.…”

“…The proposed composite was therefore expected to suffer from less thermal [13] and UV [14] impacts than existing composites in exclusive usage of epoxy resin to bond their elements [15][16][17][18]. Compared with available composites relying on either epoxy bond [15] or stitches [19,20] to connect outer skins with inner cores, those helically twisted skins were also expected to resist much higher opening stresses concentrated at the core edges due to the core stiffness. Then, notable nonlinear composite responses could be stably achieved at high stresses, unfolding remarkably shaped skins to develop large composite deformation.…”

Design, Simulation and Manufacturing of an Integrated Composite Material Parabolic Trough Solar Collector

“…It is a combination of two or more different materials in order to take advantage of positive properties of each constitutive material [20]. It has high strength to weight ratio (specific strength) [21], stiffness to weight ratio (specific stiffness) [22], and high resistance to heat [23] and corrosion due to chemicals. The most common composite materials used for industrial applications are carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer (CFRP).…”

Can tailored non-linearity of hierarchical structures inform future material development?

“…Many mechanisms for introducing ductile-like qualities into composite components have been proposed and are often reliant upon plastic deformations and damage mechanisms [1][2][3][4][5][6][7], with the inherent limitation of causing non-recoverable loss of stiffness/performance. Non-linear elastic behaviour offers a clear benefit as an alternative by providing repeatable deformations.…”