An evaluation of data reduction methods for opening mode fracture toughness of sandwich panels

The interfacial bond toughness between the face sheet and the core continues to be a limiting parameter in the design of sandwich structures. An accurate method of measurement and data reduction of interfacial fracture toughness is essential to minimize the potential for errors and uncertainty. The cracked sandwich beam (CSB) specimen along with compliance calibration (CC) method is commonly used to measure the opening mode fracture toughness of sandwich panels. In this paper two alternative methods, namely modified beam theory (MBT) and modified compliance calibration method (MCC) are validated for data reduction of the CSB specimen. Both MBT and MCC were found to be valid and gave almost identical results. The simplicity of MBT method compels it to be recommended for data reduction of CSB test.