On improvement of the interlaminar shear strength of carbon fiber/epoxy laminates with magnetically guided steel particles

To enhance the interlaminar shear strength of carbon fiber/epoxy resin laminate, stainless steel particles were filled between laminas and uniformly arranged along the thickness direction by the outside magnetic field during manufacturing the composites. Specimens with five particle densities of 15 g/m2, 30 g/m2, 45 g/m2, 60 g/m2, and 75 g/m2 were prepared for testing. The interlaminar shear strength was obtained by short beam shear test and compared with the one of specimens without particles and with the randomly distributed particles between layers. Both modified equivalent stiffness predicting model and bridging model were established. A segmented prediction model was proposed by combining the two models. The error between results obtained by the proposed model and test was less than 10%. Results showed that the interlaminar shear strength of all specimens filled with particles was improved except for the one with particle density of 15 g/m2. The interlaminar shear strength of the specimens with randomly distributed particles between layers increased by 6.12%, 7.29%, 7.43%, and 6.01% for specimens with particle densities of 30 g/m2, 45 g/m2, 60 g/m2, and 75 g/m2. The interlaminar shear strength of the specimens with magnetically guided particles aligned along the thickness direction increased by 9.78%, 14.39%, 17.93%, and 20.39% for the four particle densities. This indicated that the interlaminar shear strength of the carbon fiber/epoxy laminate could be effectively enhanced by aligning the particles between laminas along the thickness direction using the outside magnetic field guidance during manufacturing the composites.