Evaluation of the interfacial fracture toughness of VARTM sandwich panels using the Mode-I cracked sandwich beam specimen

S. Smith, K. Shivakumar
2000 41st Structures, Structural Dynamics, and Materials Conference and Exhibit   unpublished
Two composite sandwich panels were fabricated using vacuum assisted resin transfer molding (VARTM). One panel was fabricated with face-sheets of woven E-glass/vinyl-ester, the other with woven carbon/vinyl-ester face-sheets. Both panels had closed cell PVC cores with a density of 130 g/cm 3 . Threepoint and four-point bend specimens were machined from the panels and tested to evaluate the quality of the sandwich panels. The load-deflection response of the sandwich beams was in close agreement
more » ... n close agreement with sandwich beam theory. Mode-I cracked sandwich beam (CSB) specimens were also machined from the panels. Fracture tests were preformed to evaluate the fracture toughness of the interface between the face-sheet and core. Load-displacement curves were obtained for loading and unloading of the specimens during crack growth. Three increments of crack growth were monitored. Energy-release rates (ERR) were calculated using the area method and from a finite-element analysis using the virtual crack closure technique (VCCT). The energy-release rates remained constant for the 25.4 mm of crack growth monitored. For the Eglass/PVC sandwich the fracture-toughness values calculated using the area method and the VCCT were 1.88 kJ/m 2 and 1.75 kJ/m 2 , respectively. The values for the carbon/PVC sandwich were 2.00 kJ/m 2 and 1.68 kJ/m 2 , respectively.
doi:10.2514/6.2000-1493 fatcat:u7b52jhdrvbircheejdz2kijpm