Effect of the elliptical perforation on the stress/strain concentration in the self‐reinforced polyethylene terephthalate composites

Abstract The four distinct hole samples of self‐reinforced poly(ethylene terephthalate) composites (srPET) have been fabricated. All samples were tested under uniaxial loading, and tensile mechanical properties were reported. The line and plane strain and stress distribution were analyzed using digital image correlation (DIC). The results showed that the strength of the srPET composites increased as the hole diameter ratio increased. The highest tensile and yield strength of 116.62 and 65.2 MPa were found at a diameter ratio of 2. The DIC results showed that the local yield point moved to the lower average strain, the yield point moved to a marginally higher average strain, and the total yield point substantially moved towards the higher average strain value. The line strain and plane strain distribution were found to show that the growth of the yielding in the elliptical hole was slower and had a more substantial area far away from the hole to withstand transferred stress, which caused an increase in the entire deformation process and showed better tensile strength and strain as it moved towards the sharper elliptical hole. Applying srPET with bolted joints, such as the elliptical holes, is recommended rather than circular ones. Highlights SrPET composites were studied for different hole sizes. Strength and strain of srPET increased as the elliptical holes became sharper. Yielding in the elliptical hole grew more slowly than in the circular hole. srPET did not break instantly due to its tough and ductile behavior.