GFRF' laminated plates have such characteristic that a delamination easily takes place. Therefore, it is important to investigate into the reduction of the compressive strength of GFRR plates caused by the delamination. In this paper, the buckling tests and FEM analyses (FEA) of the GFRR laminated plates with initial delamination under thrust are performed. The GFRP plates which consist of E-glass fibers (Chopped Strand Mat and Balanced Woven Roving) and unsaturated polyester resins are considered. The buckling test is performed for the clamped rectangular plate with the initial delamination at the center or the corner of the plate. The elastic buckling behaviour is simulated by FEA using shell elements, and the energy release rate along delamination tip is calculated to examine the growth of delamination.
FRP laminated plates are widely used in high-speed ships and aircrafts, since: they are characterized by high specific stiffness and strength. In particular, GFRP laminated plates are frequently used because their production costs are relatively cheaper than that of CFRP, etc. However, FRP laminated plates have such characteristic that a delamination easily takes place due to impact force, etc. The presence of the delamination causes significant reduction of the compressive strength, which is known as "Compression After Impact (CAB". Many researchers have investigated the influence of the delamination on the buckling/fracture behaviour both experimentally and analytically. In particular, many research works on FRP laminated beam-columns with initial delamination have been performed (e.g., Johnson and Sridharan, 1999). However, for FRF' laminated plates with initial delamination, large numerical calculations are required when the delamination crack stability is discussed. Therefore, only limited research works (e.g., Suematsu et al., 1998a and 1998b) have been performed, and the investiga investigation into the buckling/fracture behaviour of the delaminated plates is not yet sufficient compared to the beam-columns.
