Experimental study on the high-velocity impact behavior of sandwich structures with an emphasis on the layering effects of foam core

Abstract

In this study, the effects of the core layering of sandwich structures, as well as arrangements of these layers on the ballistic resistance of the structures under high-velocity impact, were investigated. Sandwich structures consist of aluminum face-sheets (AL-1050) and polyurethane foam core with different densities. Three sandwich structures with a single-layer core of different core densities and four sandwich structures with a four-layer core of different layers arrangements were constructed. Cylindrical steel projectiles with hemispherical nose, 8 mm diameter and 20 mm length were used. The projectile impact velocity range was chosen from 180 to 320 m/s. Considering constant mass and total thickness for the core, the results of the study showed that the core layering increases the ballistic limit velocity of the sandwich structures. The ballistic limit velocity of the panels with a four-layer core of different arrangements, compared to the panel with the single-layer core, is higher from 5% to 8%. Also, for the single-layer core structure, by increasing the core density, the ballistic limit velocity was increased. Different failure mechanisms such as plugging, petaling and dishing occurred for the back face-sheet. The dishing area diameter of back face-sheets was proportional to the ballistic resistance of each sandwich structure.

Two‐step foaming process for fabrication of flexible polyurethane foam composites with spring‐like air‐layer structure

“…36 The core structure design combined with foam composites has the advantages of being lightweight, high strength, and high stiffness; therefore, it is widely used in industrial products. 37 A spring is a type of elastic mechanical component that exhibits the ability to deform when subjected to external forces and return to its original shape once the forces are removed. Springs find wide applications in various fields such as automotive, industrial, and transportation.…”

“…Extensive research has been conducted by scholars on cushioning composites utilizing sandwich structures, which typically consist of a functional core layer sandwiched between upper and lower surface cushioning layers 36 . The core structure design combined with foam composites has the advantages of being lightweight, high strength, and high stiffness; therefore, it is widely used in industrial products 37 . A spring is a type of elastic mechanical component that exhibits the ability to deform when subjected to external forces and return to its original shape once the forces are removed.…”

Mechanical response of sisal/glass fabrics reinforced polyester – polyethylene terephthalate foam core sandwich panels

“…Among the face sheets, light-weight materials, such as aluminum/magnesium alloys [12] and fiber reinforced polymer composites (FRP) [11] are the highlighted ones. FRP may be fabricated by several types of fibers, as glass (GF), carbon, polyethylene, aramid and so one.…”

“…Some liquid molding techniques (LM) may be used, when FRP are employed, to manufacture the SP’s faces, as resin transfer molding (RTM), light-RTM [10,11], vacuum-bag or vacuum infusion (VI) [17]. LM also enable the possibility to in-situ generate the SP’s face-sheets, without the needing later gluing of this component with the core, as when the face is separately supplied [12]. Notwithstanding the benefits in using LM, some inherent characteristics, regarding the face quality need to be taken into account, as the resin distribution and the formation of resin-rich areas on the final composite.…”

Integrated preparation and properties of polyurethane‐based sandwich structure composites with foamed core layer

“…[3][4][5] The sandwich-structure panel is usually composed of top and bottom panels with high strength and stiffness and a light mass-large volume core layer, thus has excellent lightweight, high strength, and some other special functions. For the PU sandwich-structure panel, the upper and lower surface panel materials are usually metal or fiber reinforced composite panel, [6,7] and the core layer is PU-based material. The core layer mainly has the advantages of light weight, good stability, and energy absorption.…”