Abstract
In this study, the pyramidal lattice stitched foam sandwich composite materials were manufactured by integrating top and bottom panels with pyramidal lattice core to overcome the weak interface between the core and the skins of the sandwich structure. The influence of the reinforcing core rods on the mechanical properties including compressive, shear, and three-point bending performances of the foam sandwich composite materials were revealed through theoretical analysis and comparative experiments. The theoretical predictions were consistent with the experimental results. Compressive test, shear test and three-point bending test were performed. The experimental results show that the core rods can significantly improve the compressive performance and energy absorption efficiency of the pyramidal lattice stitched foam sandwich structure. The effect is related to the diameter of the core rod. The core rod with large diameter has better effect. Compared with the foam sandwich structure, the pyramidal lattice reinforcing foam composites have stronger shear and bending resistance. The failure modes and failure mechanisms of the pyramidal lattice stitched foam sandwich structure under the shear load are given. The failure modes and failure mechanisms of the pyramidal lattice stitched foam sandwich structure under the three-point bending load are also given. The study concludes that compared with the foam sandwich structure, the overall mechanical properties of the lattice stitched foam sandwich structure composites are significantly improved.
Highlights
Sandwich structure composite materials which have the advantages of high strength and lightweight have attracted much attention, especially in the aerospace industry [1–4]
Ac is the compression area of the pyramidal lattice stitched foam sandwich structure; n is the number of carbon fiber core rods; σf is the yield strength of the foam; Foam elastic foundation modulus β represents the basic reaction force in per unit length of the fiber rod based on the elastic foam under the unit lateral deformation
The maximum load of the foam sandwich structure toughened with the 1.4 mm diameter core rods is increased to more than 30,000 N and the strength is as high as 3.17 MPa
Summary
Sandwich structure composite materials which have the advantages of high strength and lightweight have attracted much attention, especially in the aerospace industry [1–4]. Chen et al [26] made a study on mechanical properties of foam sandwich with chopped-glass-fiber/carbon nanotube reinforcing hierarchical structure interlayer It showed the procedure for the preparation of epoxy/glass fiber-PVC foam sandwich composites and conducted a three-point bending test. The quasi-static out-of-plane compressive experiments were carried out to study the stiffness and energy absorption ability of the sandwich construction It demonstrated that the compressive stiffness, the compressive strength and the energy absorption ability of MR-CHC composite structure were higher than those of empty corrugated core sandwich structure as well as single metal rubber material, and increased with the increasing relative density of metal rubber (MR). The study aims to demonstrate a new preparation process for using the highstrength carbon fiber strut to reinforce the low-modulus and lightweight foam sandwich structure composite materials to improve the mechanical properties of the pyramidal lattice stitched foam sandwich structure materials and prepare the samples according to the test standards. The theoretical prediction of the pyramidal lattice stitched foam sandwich structure is given
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