Analysis of Two Actual Problems of Interlaminar Fracture Assessment of Layered Composite

Two types of specimens were studied based on applying the nonlinear theory of flexible plates to obtain the interlaminar fracture toughness of layered composites. For a specimen of the thin sub-layer type, a theoretical solution was obtained in relation to the determination of the interlaminar fracture toughness for a mixed II/I mode. The fundamental possibility of using this solution in test practice was confirmed. The application of the nonlinear theory of flexible plates to the well-known standard specimen of the double-cantilever beam (DCB) was studied in more detail.  A theoretical solution was obtained, an iterative algorithm for processing test results based on MATLAB code was developed, highly flexible glass fiber reinforced polymer (GFRP) specimens were tested and their comparison with the results of processing according to the ASTM D 5528-01 standard with correction of the linear solution was given.