PSI - Issue 62

Paolo Zampieri et al. / Procedia Structural Integrity 62 (2024) 446–453

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Paolo Zampieri/ Structural Integrity Procedia 00 (2019) 000 – 000

3. Experimental results

The results from shear lap tests on the impregnate fiber and without S.A. are presented in Fig. 3 to Fig. 5. Based on the test results, the stress σ yy was calculated as follows: σ ›› ൌ  ∙ † ∙ – (1) Where P is the applied load, n is the number of fiber bundles, and d and t are the equivalent fiber bundle height and width. As Fig. 3a illustrates, the maximum fiber axial force for these specimens actually decreases with specimen curvature. Instead, tensile rupture in the textile is the predominant failure mode in the specimens with l b ≥ 250 mm. Since the rupture in this case is limited to the fiber, the results are unaffected by curvature. Additionally, the related σ yy – S g curves (Fig. 3d) exhibit a linear branch at first, followed by a non-linear behavior until the maximum force associated with the fiber's tensile failure is reached.

a)

b)

c)

d)

Fig. 3 Fibre axial stress vs global slip for each specimen at: a) lb=150 mm; b) lb=200 mm; c) lb=250 mm; lb=350 mm.

The σ yy – S g curves for the impregnate fiber (l b =350 mm and R 2 ) with single and double S.A. are shown in Fig. 4. In this case, it can be shown that, in comparison to the scenario without S.A. (Fig. 3d), the S.A. do not increase the maximum axial force.