Strength prediction and experimental damage investigations of plain woven CFRPs with interacting holes using multi-instrument measurements

Official URL: https://dx.doi.org/10.1002/pc.27347

Composite structures with holes have been utilized in different applications, for example, swash plates, adaptor plates, and repair patches. These notches reduce the structural performance of the composite plates. In a woven composite plate with two interacting holes, the orientation of the holes affects the stress concentration factor (SCF) and strength of the laminate. The SCF determined by finite-element method (FEM) shows that the structural performance of the sample with a single hole is improved through drilling one more hole along the loading direction. The main purpose of this article is to investigate, numerically and experimentally, the interaction between two holes, oriented at different angles, when the plate is subjected to tension. The location of the critical region depends on the configuration of the holes. The critical region and characteristic distances are established for each sample combining the FEM and digital image correlation (DIC) techniques. Point stress criterion (PSC) and extended-PSC (EPSC) methods are utilized to predict the final failure strength of specimens. The failure progression under the influence of interaction between the two holes is investigated by infrared thermography (IRT). Moreover, to complement the IRT and mechanical results, fractographic analysis is conducted and it is concluded that a delamination dominated fracture along loading direction takes place in samples with two holes while a transversal matrix dominated failure is observed for the single notch specimen.