Theoretical modeling of the interfacial shear and contact stresses of 2D braided composite cylinders

Abstract This research aims to develop an analytical model to predict the interfacial shear stress distribution and contact stress of 2D braided composite cylinders. For this purpose, a tubular structure including a helix braid on a cylindrical mandrel is considered. The interfacial shear stress and axial tensile stress in the composite structure was estimated by applying shear lag assumptions. The contact normal stress and adhesion energy were estimated by applying the assumptions of Johnson‐Kendall‐Robert (JKR) and the Hertzian contact stress theory. The results show that the geometry of the braid and different braid yarn paths have a significant influence on the interfacial shear stress, normal stress in the contact zone, and adhesion energy of composite cylinders. As a novel approach, the proposed model considers the effect of surface roughness in the composite. The results of a parametric study indicated that the composite cylinders with larger braiding angles have lower debonding initiation force. The results also showed that the yarn diameter affected the pullout force in composite cylinders by a large extent. Highlights Normal contact stress and adhesion energy of composite cylinders are affected by the braid yarn path. The 30° composite presented the largest adhesion energy and normal contact stress. Normal tensile stress and interfacial shear stress are influenced by the reinforcement path in the composite. Normal tensile stress and interfacial shear stress in composite cylinders decreased with increased braid angle.