Experimental study on the effect of braiding angle on the fracture behavior of 2D braided composite cylinders

Abstract

This research aims to study the fracture mechanism of two‐dimensional (2D) braided glass/epoxy composite cylinders under axial tensile load. For this purpose, three types of composite cylinders were fabricated using braids with three braiding angles, i.e., 30°, 45° and 60° to find out the role of braid angle on the fracture mechanisms of composites. Novel fixtures (jaws) were designed and produced for tensile testing of composite cylinders. Composite cylinders were subjected to the tensile test by applying SANTAM static tensile machine. Macroscopic damage morphologies of samples were provided after the tensile test by using an optical microscope. The results demonstrated that the different fracture modes occur in braided cylindrical composites. Fiber fracture, matrix fracture, and de-bonding were the dominant fracture modes observed in braided composite cylinders proportional to the angle of braids. Fiber fracture was the main mode of fracture in composite cylinders reinforced with braids with angle of 30, while the dominant fracture mode in the composite cylinder reinforced with braids having 60 was matrix fracture. In samples with 45° braiding angle, a combination of fracture modes was observed. In summary, the results indicated that the braiding angle has a significant influence on the fracture behavior of composite cylinders.