Cyclic tensile tests

The bond length of the specimens under cyclic tensile test was 20mm. Cyclic tensile tests were performed under the condition of stress ratio 7 = 0.1 and a loading frequency / = 5 Hz. Cyclic tensile loads applied to the co-cured single lap joint specimens were 30%, 40%, 50%, 60%, and 70% of the tensile load bearing capacity obtained from the static tensile load test. 

Figure 6. Stress-strain curves obtained from cyclic tensile tests. Samples of soybean flour protein and pectin containing without PEO (A) and with PEO (B). For the PEO free films, the loop created in the first cycle is larger than following cycles. For the PEO included films, the size of loops gradually decreased as cycled, then became constant in the last two cycles.

A peroxide-induced reactive compounding of PP/GRT blends in a corotating twin-screw extruder was carried out to prepare thermoplastic elastomer alloys (Wiessner et al., 2012). The extrusion experiments showed that the width of the residence time distribution was the key parameter determining the mechanical properties of elastomer alloys, whereas the mean residence time had little effect. This was confirmed by performing both quasi-static and cyclic tensile tests. 

The polymers in the form of films were subjected to uniaxial tensile tests at constant nominal strain-rate (0.03 s ). In addition, to investigate mechanical hysteresis, cyclic tensile tests were carried out, cycling between a fixed strain limit (300%) and zero load, with the same magnitude of strain-rate for loading and unloading. 

Cyclic tensile testing was done after exposure durability testing [16]. The as-received and an exposed curve (similar time and stress of exposed fiber push out sanqile) are shown in Figure 10. As can be seen from the cyclic tensile tests performed at room temperature both as received and post exposed that the exposed sample has a smaller hysteresis consistent with scenario 2 above. 

Figure 3.3 Deformation cycle to demonstrate the water-sensitive shape memory effect. is the maximum strain applied in the cyclic tensile testing, is the strain in the unloading dry state, and e is the residual strain values of the two successive cycles after shape recovery was triggered by water immersion. Reproduced with permission from [40].

In the thermo-mechanical cyclic tensile tests, the shape recovery of the segmented polyurethanes occurs at + 20°C. To examine the influence of T on... 

As a type of smart material, precise control of the SME is essential for the application of SMPs. In the thermo-mechanical cychc tensile tests of the segmented polyurethanes, the third loading curve is close to the second loading curve. In other words, the segmented polyurethanes turn completely elastic after the first deformation. This led to enhancing the shape recovery of the segmented polyurethanes by a pre-deformation treatment. In this study, the segmented polyurethanes were extended to 120% of strain on the tensile tester at + 20°C. Afterwards, the specimens were removed from the tensile tester and kept at + 20°C for 15 minutes for shape recoveiy. Then the recovered specimen was viewed as a new sample to perform the thermo-mechanical cyclic tensile tests with 100% of deformation amplitude. 

The segmented polyirrethane without hard domains shows over 90% of shape recovery in the thermo-mechanical cyclic tensile tests with 50% of elongation. This suggests that the molecular interactions can also play the role of physical cross-finks and enable the segmented polyurethane to show the SME under some... 

Thermo-mechanical cyclic tensile tests of the polymers with HSC = 30%. 

Figure 4.16 illirstrates the thermo-mechanical cyclic tensile tests of the IPDl-based T -SMPUUs from which the shape fixity and shape recovery of the polymers can be calculated via Eqs [3.1] and [3.2]. As shown in Fig. 4.16(a),... 

Shape memory properties of T-type high performance shape memory polyurethane thermo-mechanical cyclic tensile tests... 

Table 7.2 Cyclic tensile testing results of BIN-SMPU with various MB contents...

The cyclic strain-stress curves of fiber obtained by thermo-mechanical cyclic tensile testing are shown in Fig. 9.14. The fiber has a fixity ratio of more than 85.8% and a recovery ratio of more than 95.4%. The detailed shape fixity ratios and recovery ratios are recorded in Table 9.3. At 60°C, in the first cycle, the maximum stress at full elongation is 0.07 cN/dtex. 

Figure 11.5 illustrates the stress-strain behaviors of the SMF by drawing at high temperature and thermal recovery cyclic tensile testing, and the data of the fixity ratio, recovery ratio and stress at 100% strain are tabnlated in Table 11.2. 

A load-strain crrrve of rrrrtreated PBA-based SMPU fibers under a cyclic tensile test is shown in Fig. 11.17. As the shape fixity and recovery ratios could change... 

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