Tensile test high speed

In high-speed tensile tests, the rate of loading is substantially increased, often times to a rate of loading that is hundreds—or even thousands—of times faster than in traditional tensile tests. While these rates of loading are quite common in the real world, in the traditional world of material science these rates of loading are unheard of. 

High- speed tensile Test bar Medium- high Minutes 10,000 393.7 36 22.4 Tensile impact at high rates of loading... 

African elephant Charging bull elephant, enraged 11,200 441.0 40.32 25.00 High-speed tensile test... 

Another important material is nylon, which is used in rope and webbing, and also in high-performance sports fabrics. In these the toughness requirement is in pure tension. Tensile impact testing and high-speed tensile testing are useful in these applications. The elongation of the material is often equally important. 

The influence of the fiber orientation can Mso easily be examined in the results of high-speed tensile tests. 

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... 

The mechanical behavior of polymers is well recognized to be rate dependent. Transitions from ductile to brittle mode can be induced by increasing the test speed. The isotactic PP homopolymer with high molecular weight is ductile at low speed tensile tests. It is brittle at tension under high test speeds at room temperature. Grein et al. (62) determined the variation of Kiq with test speed for the a-PP CT samples (Fig. 11.22). The force-displacement (F-J) curves and the schematic diagrams of the fracture surfaces of CT samples are presented in Fig. 11.23. At a very low test speed of 1 mm s , the F-d curve exhibits a typical ductile behavior as expected. At 10 mm s, the F-d curve stiU displays some nonlinearity before the load reaches its maximum value, but this is substantially suppressed as test speeds increase further. The samples fail in brittle mode at test speeds >500 mm s . From Fig. 11.22, the Kiq values maintain at 3.2 MPam at test velocities from 1 to... 

The measurement of mechanical properties is a major part of the domain of characterisation. The tensile test is the key procedure, and this in turn is linked with the various tests to measure fracture toughness... crudely speaking, the capacity to withstand the weakening effects of defects. Elaborate test procedures have been developed to examine resistance to high-speed impact of projectiles, a property of civil (birdstrike on aircraft) as well as military importance. Another kind of lest is needed to measure the elastic moduli in different directions of an anisotropic crystal this is, for instance, vital for the proper exploitation of quartz crystal slices in quartz watches. 

When use conditions differ from those applied to data sheet tests, certain comparative evaluation can be made. Selecting an established high impact plastic such as polycarbonate as the standard, a tensile test would be made on this material at use speeds of strik-... 

High Speed Movie and Tensile Testing. High speed force—elongation material properties were measured on a model 581 Plastechon high speed tester. Experimental details have been describd previously (10). Figure 1 shows a typical force-elongation trace obtained for this class of materials. 

True Tensile Stress-Strain. As indicated above, analysis of high speed motion pictures of material deformation during tensile testing provides a measure of maximum strain change in cross-sectional area and... 

Figure 10. TEM image of stained PA-polybutadiene (15 vol%) after undergoing tough fracture in a notched tensile test at high speed (1 m/s). The section shown is next to the fracture surface (18).

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