Compression/tension test

Pipes and Cole [2-25] measured the interaction term F,2 in various off-axis tests for boron-epoxy. They reported significant variation of F,2 for off-axis tension tests and acceptable variation for off-axis compression tests. However, compression tests are much more difficult to perform than simple off-axis tension tests on a flat specimen with a high length-to-width ratio. A compression specimen with a high length-to-... 

Fig.4. The dependence of flow stress on deformation temperature in tension test (left) and in compression test (right) of the A12n78 alloy after heat treatment.

Compression/tension failure in the short beam shear test. 

The stress field which is developed at the center of this test specimen is compression-tension, and taking the y axis to be the compression axis the compressive stress, oy, is given by (32, 44) ... 

Uniaxial tension testing with superposed hydrostatic pressure has been described by Vernon (111) and Surland et al. (103). Such tests provide response and failure measurements in the triaxial compression or tension-compression-compression octants. 

ASTM D429 also has another direct tension procedure as Method D, which is for test pieces bonded after vulcanization (normally the bond is formed during curing of the rubber). Curiously, this differs from method A in that a compression set test piece is specified, but which one is not stated, and the speed is 0.83 mm/s. 

The failure characteristics of a food or food material can be measured using compression, tension, or torsion. Of all the available deformation tests, possibly the most common is uniaxial compression (Lelievre et al, 1992). Bulk compression is another type of compression test, but it is seldom used due to the difficulty inapplyingforceby means of hydraulic pressure (Bourne,, 1982). The experimental... 

The most common dynamic method is oscillatory testing, in which the sample is subjected to a sinusoidal oscillatory strain, and the resulting oscillatory stress measured. The more sophisticated rotational viscometers have the additional capability of dynamically testing liquid-like materials using small angle oscillatory shear. A parallel disc viscometer can be set up for testing solid-like materials (e.g., butter), in oscillatory shear. Some UTM-type solids rheometers, in which the moving crosshead can be made to reciprocate sinusoidally, can be used to test solid-like materials in oscillatory deformation in compression, tension or shear. 

A number of highly sophisticated commercial rheometers, rather different in design from the traditional UTM, are now available in which dynamic and static tests on solids in compression, tension, shear and bending can all be carried out using the same instrument. 

Compression set of rubbers at ambient and elevated temperatures Tension testing of gasket materials... 

Compression tests, as well as tension tests, were carried out on the samples of varying AN content. All samples exhibited a compressive yield stress, and with further increase of strain, a subsequent drop in stress, occurred before the stress again started to rise. From the test data, the elastic modulus and the yield strength were determined as a function of nitrile content and the results are shown in Fig. 29. 

The results of tension tests upon refractories in the hot state are not available in the literature nor are data relating to the transverse strength of bricks and tiles. This is to be regretted since in many furnace constructions transverse loads must be considered. Again, it seems very probable that the compression test of firebricks will ultimately be replaced by one involving transverse stress. 

Pure torsion tests were performed on ice single crystals at a constant imposed external shear stress". Softening was evidenced as the creep curves revealed a strain-rate increase, up to a cumulated plastic strain of 7%, see figure 1. Note that such a behaviour was also observed during compression and tension tests. ... 

Stress-strain curves developed during tensile, flexural and compression tests may be quite different from each other. The moduli determined in compression are generally higher than those determined in tension. Flaws and sub-microscopic cracks significantly influence the tensile properties of brittle polymeric materials. However, they do not play such an important role in compression tests as the stresses tend to close the cracks rather than open them. Thus, while tension tests are more characteristic of the defects in the material, compression tests are characteristic of the polymeric material as it is. The ratio of compressive strength to tensile strength in the case of polymers is in the range 1.5 to 4.0 [Dukes, 1966]. 

The mechanical behavior of these Be-rich phases and its variation with temperature has been studied by means of hardness tests, bending stress-rupture tests, tension tests and compression tests (Ryba, 1967 Marder and Stonehouse, 1988 Fleischer and Zabala, 1990 c Nieh and Wadsworth, 1990 Bruemmer etal., 1993). The observed brittle-to-ductile transition temperatures are of the order of 1000°C. The low-temperature fracture toughness has been found to be between 2 and 4 MN/m with practically no macroscopic ductility (Bruemmer et al., 1993), though there are indications of local plasticity at... 

Shear-like compression is a more important mode of deformation for engineering applications than tension. Testing in shear is not more difficult than testing in tension, and the only practical difficulty comes from the necessity to bond the rubber test piece to rigid members to provide attachments for applying the shearing force. 

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