Flexural properties of a novel foam core sandwich structure reinforced by stiffeners

The purpose of this paper is to investigate the flexural properties of a novel foam core sandwich structure with stiffeners. 3-point bending tests of two load levels were performed on three stiffened specimens (220 mm x 74 mm x 28.2 mm) and three unstiffened specimens (220 mm x 74 mm x 27.4 mm). Mechanical tests were firstly conducted under 1kN to determine the flexural and shear stiffness, and then under the destructive load to research the ultimate carrying capacity and failure modes. The skins of the specimens are fiberglass and vinyl resin, and the core is PVC foam. The mechanism of this novel structure was studied using Allen's theory on antiplane core and thick faces. Tests indicated that, without increase in weight, shear stiffness of the stiffened specimens increased by 25% and total deflection decreased by 19%. After inserting stiffeners, the failure mode changed from indentation failure to core shear and the ultimate load increased from 2.11kN to 2.74kN. The ultimate load and failure modes obtained from theoretical prediction and FEA both showed good correlations with experimental results. (C) 2019 Elsevier Ltd. All rights reserved.