Fracture toughness and crack growth resistance of sandwich panels with grooved cores

Abstract

The delamination phenomenon in sandwich panels occurs in the form of face/core debonding. The grooved foams are usually employed in curved sandwich structures for easier formability and better adhesion. In this research, the debonding toughness of facesheet to the core in a sandwich beam with grooved core is investigated using numerical and experimental methods. The sandwich beam consisted of two Kevlar 49/polyester facesheets and a polyurethane foam core. To obtain the values of strain energy release rate, the Cracked Sandwich Beam (CSB) specimen along with the Modified Beam Theory (MBT) method was used for the data reduction of the test results. In the numerical part, a model based on the cohesive zone theory was employed to simulate the crack growth in the specimens. Comparison of the numerical and experimental load–displacement curves indicated that the proposed model can reasonably predict the behavior of the structure under similar loading conditions. The effect of foam-related parameters such as the number and width of core grooves on crack growth resistance was examined numerically. The results showed that increasing the number and width of the grooves enhanced the resistance of the sandwich beams against the growth of interfacial cracks.

Fiber bridging mechanism in moisture‐induced mode I delamination in carbon/epoxy composites: Finite element analysis and experimental investigation

“…The application of BTS law has also been implemented in cracked sandwich beam (CSB) specimens, where the debonding between Kevlar/polyester facesheets and a polyurethane foam core were characterized. [ 38 ] Satisfactory agreement was obtained when comparing the experimental and numerical force‐displacement curves.…”

The effect of manufacturing methods on the interface debonding and flexural behavior of sandwich structures: Thermography approach and three‐point‐bending experiments

“…[11][12][13][14] The influence of a face-to-core interface debonding on the strength of a FCS panel was evaluated analytically using elastic fracture mechanics in their works. In the article of Gholami et al, [15] the debonding toughness of the face sheet to the core in a sandwich beam with cellular core was studied using numerical and experimental methods. Their results indicated that increasing the number and width of the grooves enhanced the resistance of the sandwich beams against the growth of interfacial cracks.…”