Stress-strain test cyclic

Dynamic properties are taken to mean the results from mechanical tests in which the plastic is subjected to a deformation pattern from which the cyclic stress-strain behaviour is calculated. These do not include cyclic tests in which the main objective is to fatigue the material. 

The term dynamic test is used here to describe the type of mechanical test in which the rubber is subjected to a cyclic deformation pattern from which the stress strain behaviour is calculated. It does not include cyclic tests in which the main objective is to fatigue the rubber, as these are considered in Chapter 12. Dynamic properties are important in a large number of engineering applications of rubber including springs and dampers and are generally much more useful from a design point of view than the results of many of the simpler static tests considered in Chapter 8. Nevertheless, they are even today very much less used than the "static" tests, principally because of the increased complexity and apparatus cost. 

E-3 spectrometer. A servo-hydraulic system was built which allowed loading of the samples in a wide variety of modes, and permitted tensile tests to be conducted at constant stress rate, at constant stress (creep), in cyclic fatigue, at constant strain rate, at constant strain or step strain. Provision was made for the simultaneous recording of stress-strain data and ESR spectra and a variable temperature control unit was employed. 

A novel method is the small punch analysis, or pin on disk test, which is used to evaluate the weight loss of friction material. It is performed with a metallic pin in friction contact on a sample (small disk) the pin, moving cyclically, yields a stress-strain curve related to the specimen wear. This test is generally performed on retrieved, or aged, UHMWPE components. 

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.

In order to demonstrate the predictability of the above model, the macroscopic behavior of the SMPF is estimated and the prediction is compared with the test result. In the following, three such predictions and/or comparisons are made. The first one investigates the effect of the heating rate on fully constrained stress recovery. The second one evaluates the effect of the amount of the amorphous phase and the crystalline phase on the stress-strain behavior under cyclic tension. The last one examines the growth of the crystalline phase due to stress induced crystallization. In all cases, the SMPF has a diameter of 0.04 mm. The material parameters for the stress recovery and strain hardening modeling as well as for the amorphous and crystalline subphase modules and for crystalline phase shp systems are summarized in Tables 5.2 to 5.4, respectively. 

Cyclic stress strain n. Repeated loading of a yarn on a tensile testing machine and the determination of the physical properties of the yarn during these cycles. 

Fig. 14 Results of a strain-controlled cyclic, thermomechanical test. Results of strain-controlled cyclic, thermomechanical test of amorphous polymer network LGF2 synthesized from (ohgo[(l-lactide)-ran-glycolide]dimethaycrylates (M = 2,800gmop and Tg = 53 °C) for different Tiow (a) Tiow = 10°C and (b) Flow = 50°C n cycle number, a stress elongation. Taken and modified from ref. [13], Copyright 2007. Reproduced by permission of The Royal Society of Chemistry (RSC). http //dx.doi.oig/10.1039/b702515g...

Fig. 8 Effect of EN and EL loading, respectively, on stress-strain curves in strain-controUed cyclic thermomechanical experiments in air (a), shape-recovery curves upon heating in stress-controUed experiments (b), and stress-strain curves in tensile tests (c). Figures from [39], Copyright 2009, with permission from the Material Research Society...

Figure 6. The complete stress-strain curve of cyclic loading— unloading tests under different confining pressures.

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