PSI - Issue 56

Alexandru Isaincu et al. / Procedia Structural Integrity 56 (2024) 167–175 Alexandru Isaincu / Structural Integrity Procedia 00 (2019) 000 – 000

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seen in Fu et al. (2001). The shape of the fibers was presented in Isaincu, Micota and Marsavina (2022) by using a scanning electron microscope. Both materials are part of the thermoplastic branch of polymers. A semi-crystalline structure can be found in both materials. 2.2. Sample preparation Single Edge Crack (SEC) specimens were prepared for the fracture tests. They were obtained by water jet cutting from injected larger plates. The nominal dimensions of 3.2 mm (1/8 of an inch) thick plates are 100 mm length by 100 mm width. The nominal dimensions of 2.0 mm thick plates are 100 mm length by 80 mm width. These plates were directly delivered by the Solvay Group. The plates were obtained by injection molding with the aim of achieving a good and uniform fiber orientation in the middle of the plate. This is required in order to obtain specimens at different fiber orientation angles. The dimensions of SEC specimens, together with the dimensions of the plates from where they were obtained, are presented in Fig. 1.

Fig. 1. Specimen cutting from the original plates considering an orientation angle of (a)/(d) 0°, (b)/(e) 45° and (c)/(f) 90°. The first row of plates corresponds to 2.0 mm thickness. The second row of plates corresponds to 3.2 mm thickness.

For both thicknesses (t), the nominal length (L) of SEC specimen is 80 mm. The width (b) is 25 mm. The notch was manually cut using a vertical bandsaw machine. The depth/length of the notch (a) is 15 mm. A cutter was used to create a sharp indentation insight the specimen (in order to facilitate a better stress concentrator). An important aspect for SEC test specimens is the ratio between a and b. In the current study, this value was kept constant at 0.6 (a=15 mm / b=25 mm). The final shape and dimensions of the specimens are depicted in Fig. 2. Note that there is a difference between the probe fiber orientation angle, relative to the melt flow and probe fiber orientation angle to the crack orientation. In this study, the orientation is described as the angle between fiber