In tensile test

Plastic Stra.ln Ra.tlo. The plastic strain ratio is the ratio of strains measured in the width over the thickness directions in tensile tests. This ratio characterizes the abhity of materials to resist thinning during forming operations (13). In particular, it is a measure of the abhity of a sheet material to resist the thinning and failure at the base of a deep drawn cup. The plastic strain ratio is measured at 0°, 45°, and 90° relative to the rolling direction. These three plastic strain ratios Rq, R, and R q, are combined to obtain the average strain ratio, cahed the R or the R value, and its variation in strain ratio, cahed... 

Although the glassy resins form the continuous phase quite high extensions are possible in tensile tests, particularly at high strain rates. 

Figure 2. Ductility of Ti-a H alloys in dependence on temperature. Here ductility is a logarithmic function of the area reduction in tensile tests. Hydrogen contens are 0 (curve 1), 0.16 (2), 0.35 (3), 0.50 (4), 0.61 (5), 1.25 (6) and 1.54 wt.%.

The basic alloy at atmospheric pressure and T = 20°C demonstrated the per cent elongation <5 = 31% and the per cent reduction ip = 65% while plastic properties of the hydrogenated alloy were close to zero. But an opposite relation was observed in tensile tests under a pressure of 6.5 kbar. The plastic properties of the hydrogenated alloy increased to <5 = 33% and /> = 83% at P = 6.5 kbar and T = 20°C while those of the basic alloy changed only slightly (Fig. 11). 

Young s moduli were determined in tensile tests using samples of 4 mm thickness. Slow cyclic loading (frequency 0.01 Hz) with small strain amplitudes (s < 3%) was used for the tests in order to maintain the thermal equilibrium as much as possible. The temperature range was limited to 260 °C as thermal decomposition became noticeable above this temperature [11],... 

Young s moduli of the polymers were determined in tensile tests [53] using samples of 4 mm by 10 mm cross-section and a gauge length of 50 mm. The results of the... 

Fig. 5.2. Young s modulus E, as determined in tensile tests, is plotted against 1/Ktc, that is the inverse molecular mass between crosslinks. Test temperature 23 °C...

Yield strength as determined in tensile tests [53] at ambient temperature was plotted in Fig. 6.1 against M 1, the inverse molecular mass between crosslinks. All the samples of polymer A (the most crosslinked polymer) failed before the polymer started to yield. Therefore, load-extension-curves were extrapolated up to a hypothetical yield strain in this case. The extrapolated tensile is marked by brackets (Table 6.1). 

Polymer A with GIC = 160 J m-2 is typical for thermoset materials which are expected to be brittle [78]. At the other end of the series, polymer E and Phenoxy with G,c > 1 kJ m 2 are tougher than several wellknown thermoplastics (PMM A, PS, PES). In contrast to the more crosslinked polymers, polymer E and Phenoxy PKHJ show necking after yielding in tensile tests with draw ratios A = 1.7 and A = 2.1, respectively (Table 2.1). 

It may be pointed out that the term yield point is sometimes erroneously used as a synonym for elastic limit and proportional limit As it has been described in the paragraphs above it is actually a phenomenon that occurs in only a very small number of cases in tensile testing. As it has also been observed in the description that graphically and experimentally, it is an anomalous behaviour in which there is a strain occurring with no increase in stress. 

In tensile testing of rubber, elongation is the increase in the distance between bench marks on a dumbbell strip or the distance apart of the grips holding a ring test piece, on the application of a load to the test sample. It is expressed as a percentage of the original distance between the marks. 

In tensile testing of rubber, another term for elongation. 

The change in dimensions resulting from the application of a stress. In tensile testing of rubber strain is synonymous with elongation. 

In tensile testing of mbber, the elongation reached by the sample at its breaking point also... 

In our own recent low temperature studies45 of ultra high drawn polyethylene, a change in the background level of tan 6 in tensile tests when the environmental gas is changed, is attributed to thermoelastic effects resulting from the different heat transfer characteristics of the gases used. 

The relationship between craze initiation and propagation, and crack initiation and propagation, is not well understood (31). Crazing clearly precedes formation of unstable cracking. For example, in tensile tests on Lustran A-21 S/AN, crazing occurred at 1.8-2.0% elongation, whereas... 

Fiber Fractography and Morphology. Fibers broken in tensile tests were examined in the scanning electron microscope to gain a better understanding of their failure mechanism. Such insight can be used to guide the development of consolidants that prevent such failures. 

In tensile tests at strain-rates of e = 2 x 10 -2 x 10" s" intrinsic crazing of PC has been observed in a temperature range of 120-135 °C, i.e. about 15-30 °C below the glass transition temperature Figure 2 shows a nominal stress-strain curve... 

This latter reaction would rmih in an increase in ESR intensity and hence would explain the anomalous decay. Son doubt exists whether this proposed mechanism can explain the anomalous decay experienced in tensile tested samples. Firstly the friction effects to produce the tribo-electricity charge are not so clearly present. Secondly, Mead et al have dtown that the peroxy radical content decreases as... 

In short, a typical readout in tensile tests is elongation of the specimen, which is a stretch, or extension of the specimen. The elongation is typically expressed in percent of the stretch related to gage length (the distance between two reference points within the center section of the dogbone. In other words, percent of elongation equals to lOOX tensile strain. 

Two types of mechanical tests have been used the low rate of deformation tensile, compressive or bending tests and the high speed impact tests. Immiscibility of polymers is reflected in both. For example, in tensile tests the maximum strain at break (or the maximum elongation), and the yield stress (or the maximum strength) can be... 

Tensile strength - In tensile testing, the ratio of maximum load a body can bear before breaking to original cross-sectional area. Also called ultimate strength. [11]... 

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