Effects of the core density on the quasi-static flexural and ballistic performance of fibre-composite skin/foam-core sandwich structures

Abstract

Polymeric foams are extensively used as the core materials in sandwich structures and the core material is typically bonded between relatively thin fibrecomposite skins. Such sandwich structures are widely used in the aerospace, marine and wind-energy industries. In the present work, various sandwich structures have been manufactured using glass-fibre-reinforced polymer (GFRP) skins with three layers of poly(vinyl chloride) foam to form the core, with the densities of the foam layers ranging from 60 to 100 kg/m 3. This study has investigated the effects on the quasi-static flexural and high-velocity impact properties of the sandwich structures of: (a) the density of the polymeric-foam core used and (b) grading the density of the foam core through its thickness. The digital image correlation technique has been employed to quantitatively measure the values of the deformation, strain and onset of damage. Under quasistatic three-point and four-point bend flexural loading, the use of a low-density layer in a graded-density configuration reduced the likelihood of failure of the sandwich structure by a sudden force drop, when compared with the core configuration using a uniform (i.e. homogenous) density layer. The high-velocity impact tests were performed on the sandwich structures using a gas-gun facility with a compliant, high-density polyethylene projectile. From these impact experiments, the graded-density foam core with the relatively lowdensity layer located immediately behind the front (i.e. impacted) GFRP skin was found to absorb more impact energy and possess an increased penetration resistance than a homogeneous core structure.

Mechanical properties of PLA based closed porous structures manufactured using FDM process

“…, 1998), aerospace applications (Dangal et al ., 2021; Marx et al ., 2020) and automotive industry (Moon et al ., 2019; Romero et al ., 2021; Yavuz et al ., 2016). Porous structures can be used in ballistics for military areas (Ahmadi et al ., 2020; Kaboglu et al ., 2018; Marx et al ., 2019), shock absorbers and heat exchangers for vehicles (Chin et al ., 2022; Fiedler et al. , 2021; Kuruneru et al ., 2020).…”

Study on impact behavior of glass fiber/PVC curved sandwich structure composites

“…There are many studies on the impact behavior and CAI behavior of sandwich composites at home and abroad. [5][6][7][8] Some researchers investigated the quasi-static indentation behavior of fiber reinforced with composite. Luo et al [9] studied the damage of composite materials in the quasi-static indentation and found that the specimen size and support conditions have little influence on the maximum load.…”

Preparation and properties of expandable epoxy foam prepreg for sandwich composites prepared via thermal expansion molding process

“…The quality of the molding process is evaluated based on the metallographic microstructures 37 . The lightweight foam core with various foam hybrid structures endows the core with a higher structure and function designability 38,39 . The development and applications of expandable foam have the ability for overcoming the molding challenges of various hybrid and reinforced sandwich composites 40,41 .…”

“…37 The lightweight foam core with various foam hybrid structures endows the core with a higher structure and function designability. 38,39 The development and applications of expandable foam have the ability for overcoming the molding challenges of various hybrid and reinforced sandwich composites. 40,41 Moreover, the epoxy foam will provide a better interface performance between the foam core and composite skin, and expand the application potential of sandwich composites.…”