Abstract
This paper describes the results of analysis and testing conducted on the in-plane shear modulus and strength of laminated carbon fiber reinforced plastics (CFRP) aluminum honeycomb sandwich panels. The analytical method for the fracture strength of the sandwich panel was as follows : the primary load carrying members are the face sheets stabilized by low-density core material. The stress components analysis showed a normal stress in the directions parallel and perpendicular to the fiber and a shear stress along the fiber was determined in the laminate of each layer, taking into account the elastic failure prior to overall fracture. This was then compared with the fundamental strength in relation to the aforementioned kind of fracture mechanisms of the unidirectional CFRP. The sandwich panels make use of the facing laminated angles of 25°, 0°, 90°, -25° and 45°, 0°, 90°, -45°. The panel was loaded in shear by applying a tensile load to a picture frame test fixture having diagonally opposite corners. The test results on the fracture strength and fracture modes have a good correspondence with the analytical results. Holographic interference techniques were applied to non-destructive inspection at the delamination of the interlaminar in CFRP laminate or CFRP laminate-honeycomb core interface. Through this process one of the serious defects in the sandwich panel became apparent.
