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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3. Manufacturing of composite The woven carbon is manufactured by hand lay-up with 6 layers of 2/2 twill carbon fiber to give the required thickness for this test. The resin is mixed with the hardener at the ratio of 2 to 1 and cured at room temperature and left for 12 hours under a medium pressure, a book press was used for this purpose. The pressure can be adjusted to give different thickness and different composite’s fiber volume fraction. The cured parts later were cut and drilled to the right size for the CTS specimen.

4. Experiment 4.1. Tensile Testing

The tensile testing of carbon fiber epoxy was performed to measure its mechanical properties. These properties can be used in the numerical simulation and the design of the parts made of the composite. The testing was performed according to ASTM 3039 [11]. End tabs were used to ensure the fracture at the grips. 4.2. Fracture Testing The tests were done for this study with two composites. The displacement rate was 5mm/min. Both tests were done using Tinius Olsen tensile testing machine (Model 50 ST), the load cell capacity was 50kN (see Fig. 2). For the fracture testing, the clevis of the CTS was fixed on the grips of the device. This fixture applies both tension and shear forces resulting in mode I, mode II and mixed mode loading. Different modes could be adjusted by changing the position of the clevis that is fixed on the holes. The modes vary from 0 degree to 90 degree with an increment of 15 degrees.

(b)

(a)

Fig.2 50kN Tinius Olsen tensile testing machine b)CTS fixture to perform mixed mode testing on plain weave carbon fibre epoxy. The selected pin setup in the picture applies pure mode I loading.