PSI - Issue 32

A.S. Smirnov et al. / Procedia Structural Integrity 32 (2021) 321–325 Author name / Structural Integrity Procedia 00 (2019) 000–000

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Fig. 2. Experimental scheme to determine the effect of an interdeformation pause on the change in the fracture stress of the fiberglass.

Figure 3 shows the test temperature dependence of the fracture stress after 30-minute holding and the fracture stress without interdeformation holding. The data in Fig. 3 show that intermediate annealing between the deformations has a non-monotonic effect on the fracture stress of the fiberglass. Thus, at 70 and 140 ºC, 30-minute fiberglass holding after a load of 90% of the fracture stress decreases the stress after reloading, whereas this effect is not observed at a test temperature of 110 °C.

Fig. 3. The effect of temperature and time pause on fiberglass fracture stress degradation under conditions of compressive stress perpendicular to the fiberglass sheet plane.

Figure 4 shows a typical image of the fracture surface of the specimen compressed by a load perpendicular to the sheet plane. The specimen fracture is chaotic, and it occurs in the fibers, in the zones with lower adhesive strength between the binder and fiber, and in the matrix.