Low-Velocity Impact Response of Polyurethane Foam Composite Sandwich Structures

Abstract

Low-velocity instrumented impact tests were carried out on sandwich panels made of glass fiber-reinforced plastic facesheets and polyurethane foam core. The tests were carried out using a drop weight instrumented impact tester, connected to a data acquisition system. Four different types of sandwich samples using polyester/e-glass and epoxy/e-glass facesheet materials and polyurethane foam were considered for investigation. Two different face sheet materials were chosen to experimentally examine the effect of their elastic modulus on the impact response of the sandwich structures. The data acquisition system records the impact data such as impact force, penetration time and depth of penetration, and plots impact force versus depth of penetration and penetration time versus depth of penetration curves. From the recorded data the impact parameters such as maximum impact force, penetration time and depth of penetration versus impact energy were plotted to study the impact behavior. The results show that higher impact energy is required to break the epoxy/e-glass facesheet and backsheet sandwich specimens than other types of specimens examined. The impact damage caused to the facesheet, the core and the backsheet were thoroughly studied experimentally and the extent of damage caused to the facesheets and the core were also compared by finite element analyses.

Low Energy Impact Damage Modes in Aluminum Foam and Polymer Foam Sandwich Structures

“…The main energy absorbing damage modes reported in low-velocity/ low-energy impact studies on various composite skin/polymer foam core combinations include fiber fracture, matrix cracking, core indentation, penetration and perforation, and delamination [2][3][4][5]. A significant point in most of these studies was that the damage was very localized.…”

Production of Metal Wire — Polymeric Foam Composites for Dielectric Applications

“…The nails were impacted with an initial energy (20 J) much greater than the energy absorbed by the foam. Because of the large impact energy, the velocity of the nails should remain constant, and not experience more than a 10-20% deceleration [6].…”

Pre-Programmed Failure Behavior Using Biology-Inspired Structures

“…26 Altering fiber type (glass vs. carbon) and polymer matrix (polyester vs. epoxy) also affects impact resistance. 53 Compression after impact strength can be improved by varying the facesheet and core thicknesses in carbon/aluminum honeycomb systems. 19 Other techniques of improving damage resistance have involved more significant changes to the standard facesheet/core system.…”