In this study, “L” shape curved laminate beam were tested to investigate the interlaminar tensile strength by bending load. The test specimens were made of Cytec MXB 7701-7781 (fiberglass/epoxy) fabric prepreg. The specimens were designed to have four different thicknesses with the initial flaw of 0.5-inch square in the mid-plane and to be compared with the results of sound specimens. The laminated beam specimens were loaded via a fixture to make a radius opening bending moment, producing a through the thickness tensile stress in the bend region.
The first ply delamination in the specimens with initial flaw occurred at about 30% of the loads for the sound specimens. The final failure occurred at approximately 40% higher values than the first delamination loads except for 10-ply specimens. In the 10-ply specimens, no more loads were carried after the first ply failure.
As a result the tests, the typical values are given as linear functions of the lay-up thickness in both of initial flawed and unflawed test specimens.