Recent advancements in space exploration, the transportation industry, and the demand for specific properties in the component led the researcher to switch from traditional materials to composite materials. Composite material classification is very vast, but among all the classes sandwich composite occupies a very important place owing to its high bending stiffness and light weight. The sandwich structure consists of two facesheet and a low-density core. Sandwich structure can fail in various ways but most frequently debonding between facesheet and core is observed. During the Mode I testing, it was observed that crack propagation is not along the interface. Crack moves into the core and propagates in the core known as crack kinking. Tilted Sandwich Debond (TSD) specimen counters this problem and leads to interfacial debonding. This study highlights the importance of TSD specimens in the evaluation of mode I fracture toughness. Five sandwich specimens having different foam and facesheet combinations are taken into consideration. The numerical simulation is done using the finite element software ABAQUS®. 2-D finite element modeling is done to determine strain energy release rate (SERR) using the J-Integral approach and compared with the analytical results in the literature. The effect of mesh size on the SERR is analyzed.