PSI - Issue 25

Jamaloddin Jamali et al. / Procedia Structural Integrity 25 (2020) 180–185 Author name / Structural Integrity Procedia 00 (2019) 000–000

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5. Displacement Tracking To study and measure the displacement of different points of the notch and how crack is propagating, a simple displacement tracking methodology was followed. Here, the change in the displacement in each point is measure using the photos taken during the test. The time of the photos were matched by the time of the measured values of the force to give force-displacement curve. 6. Results 6.1. Tensile testing results The values of some mechanical properties derived from stress strain curve is shown in table 1. The specimen dimension was 200x3.1x26.3 with the gage length of 130 mm.

6.2. Fracture testing result The crack mouth opening force vs displacement is shown in Fig.3.

Fig.3 Force displacement of the CTS woven carbon fibre epoxy specimen Based on the values of the force vs crack tip vertical displacement (Fig. 3) for two specimens, fracture toughness can be obtained. The value of fracture toughness can be calculated using [7]: K � � P√ w π t a . � co � s w α a � �.�� � �.��� � w a � a � � � �.�� � w a � a � � �.�� � w a � a � � (1) K �� � P√ w π t a . � si � n α wa � ��.�� � �.� � w a � a � � � �.�� � w a � a � � �.�� � w a � a � � (2)