Grips

Fatigue tests were performed under load control mode on a Schenck horizontal fatigue testing machine with hydraulic grips and a maximum load capacity of 25 kN. Tension-tension constant amplitude fatigue tests were carried out at three stress levels 60% a , 70% Cu and 80% a at two different stress ratios R = 0.1 and R = 0.5. The test frequency was kept constant (f = 3 Hz) for all the tests. 

Under testing conditions the fuel element to be tested is placed at the stand. Then it is moved into the control unit and gripped with a collet. First the density distribution of the vibro-compacted fuel along the total length of the fuel element is tested. Proceeding from the obtained data the section to be investigated in detail is chosen and a tomogramm of this section is obtained. 

In order to provide the necessary coupling fluid the grip of the probe holder contains a small tank with a mixture of glycerine and water. Thus the operator is able to provide some drops of the liquid to every blade to be inspected. 

Stoppers. Those fitted with 514,519, and 524 cones are useful sizes. Stoppers with flat heads are to be preferred, since they may be stood on end when not in pse, thus avoiding contamination of the ground surface. An additional refinement is the provision of a finger grip as in Fig. II, 56,1. 

Scotchgard Scotch-Grip Scotchguard Scotch-Marine boiler... 

Natural mbber was also used extensively in its oil-extended form in winter tires in the 1970s (57). Use of oil-extended natural mbber treads, found to have excellent traction on ice and snow, superseded studded synthetic mbber treads when studs were banned in certain countries and states owing to the damage they cause to partially cleared roads. This concept has been extended into aH-season tires, which account for over 75% of original equipment and replacement tires in the United States. It has been shown (58) that part replacement of styrene—butadiene mbber (SBR) in the formulation of aH-season tire tread compounds with oil-extended natural mbber increases ice and snow traction, reduces rolling resistance, and has no effect on normal wet grip. Also, there is only a minor trade-off in wear performance, because below a tire surface temperature of approximately 32°C, the wear of natural mbber is superior to SBR, whereas above this temperature the reverse is tme (59). Thus, wear of an aH-season tire ultimately depends on the surface temperature of the tread over its annual cycle of temperatures. 

Plastic deformation is commonly measured by measuring the strain as a function of time at a constant load and temperature. The data is usually plotted as strain versus time. Deformation strain can be measured under many possible loading configurations. Because of problems associated with the preparation and gripping of tensile specimens, plastic deformation data are often collected using bend and compression tests. 

Similarly, for shorter centre distances between the drive and the driven pulleys, the arc of contact will decrease. To ensure a good arc of contact, the centre distance C (Figure 8.10), should be kept as much as possible, otherwise the provision of a jockey pulley, as noted above, will also be necessary. A higher arc of contact will ensure a better grip of the belt on the pulley and hence a smaller slip during transmission of the load. A smaller slip would mean a higher transmission of load and vice versa. 

At constant displacement, creep causes stresses to relax with time. Bolts in hot turbine casings must be regularly tightened. Plastic paper-clips are not, in the long term, as good as steel ones because, even at room temperature, they slowly lose their grip. 

Fig. 26.9. Anti-skid tyres, with a high-loss tread (for maximum grip) and a low-loss wall (for minimum heating up).

The common tests are shown in Fig. 17.2. The obvious one is the simple tensile test (Fig. 17.2a). It measures the stress required to make the longest crack in the sample propagate unstably in the way shown in Fig. 17.3(a). But it is hard to do tensile tests on ceramics - they tend to break in the grips. It is much easier to measure the force required to break a beam in bending (Fig. 17.2b). The maximum tensile stress in the surface of the beam when it breaks is called the modulus of rupture, o for an elastic beam it is related to the maximum moment in the beam, M by... 

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