PSI - Issue 33

10

Jamaloddin Jamali et al. / Procedia Structural Integrity 33 (2021) 832–842 Author name / StructuralIntegrity Procedia 00 (2019) 000–000

841

Fig15: The calculated fracture toughness for some of the CT specimens made of polyester in MPa.  m

Fig. 16 shows the comparison between the average values of fracture toughness specimen measured using SENB and CT test along with their standard deviation. The result correlates to the literature review of this research paper in which CT has lower fracture toughness than SENB; the results of CT fracture test provided less discrepancy and smaller value of standard deviation.

Fig. 16 Comparison between the average values of fracture toughness polyester specimens measured using SENB and CT test along with their standard deviation.

7. Conclusion In conclusion, the mechanical behavior of polyester in response to tensile and fracture was studied. The fracture study of polymers helps to study fracture properties of polymer matrix composite made of these polymers. Two testing methods, CT and SENB, were applied to investigate polyester specimens’ mode I fracture properties. Tensile testing was performed to provide the required data for calculation of fracture toughness using CT and SENB methods. For SENB, the effect of thickness on fracture testing was explored to ensure state of plain strain. Finally, a comparison between measured CT fracture toughness and SENB fracture toughness showed that a more precise results as well as lower values of fracture toughness can be obtained using CT specimen.