Damage Mechanism Evaluation of Polymer Matrix Composite Reinforced with Glass Fiber via Modified Arcan Test Specimens

Damage mechanism evaluation of polymer matrix composites reinforced with glass fibers via Arcan test has become a very vital research area for determining the weak part of composite structures in aircraft segments. So, the objective of the present article is to study the effect of changing different load angles as: α = 0°, 15°, 30°, 45°, 60°, 75°, and 90° of unidirectional glass-fiber-reinforced polymer matrix composite specimens by Arcan test. In this study, modified Arcan test specimens (butterfly shaped) are used to study the mechanical properties and the resulting fracture mode of unidirectional glass-fiber-reinforced polymer matrix composite under combined tension and shear stresses. Two cases of applied Arcan test specimens of unidirectional glass-fiber-reinforced polymer matrix composite specimens were evaluated: (1) notch-to-notch perpendicularly oriented fiber specimens are referred to as group A1, and (2) notch-to-notch longitudinally oriented fiber specimens are group A2. The results revealed that the shear modulus of A1 specimens is found to be G12 = 5.5 GPa ± 18%, which is close to the value calculated using the elastic properties of the composite components. On the other hand, the shear modulus of A2 specimens is found to be G21 = 4.2 GPa ± 8%, which is relatively close to calculated G23 value. It is observed that the fracture mode of A2 specimens is almost not affected by the loading direction. However, the number of cracks and its direction relative to the notch-to-notch line decreases as the test angle increases. Moreover, the strength of A1 specimens is much higher than that of A2 specimens at all applied loading angles, except for pure shear loading.