Vibratory stress

L.C. Rogers, and M.L. Parin, "Additive Damping for Vibratory Stress Reduction of Jet Engine Inlet Guide Vanes," presented at the 47th Shock and Vibration Symposium, Albuquerque, NM, 1976, published in the 47th S V Bulletin. 

The maximum vibratory stress in the base material of the strip hybrids due to periodic excitations with three different fi-equencies is plotted versus reinforcing strip modulus in Figure 6.14. The maximum vibratory stress in the base material varies nonlinearly and decreases... 

Prevention and minimization of corrosion is achieved by a combination of design (steady and vibratory stresses, heat flux, and flow), feedwater and boiler water treatment (control of pH tmd corrosion potential, and control of impurity concentration), and operation (control of impurity ingress and stress and temperature conditions) (Fig. 3). These corrosion control measures are discussed in Refs 4—6 and 9-19. 

Steam turbines are also selected as drivers for pumps and compressors that generally require variable speed. Process compressors as large as 60,000 hp (44,800 kW) are in service with variable-speed steam turbine drives. Special robust buckets are required for these turbines to withstand the vibratory stresses inherent with continuous operation over a wide speed range. In other respects, large multistage/multivalve mechanical-drive steam turbines are similar to corresponding turbine-generator sets. 

Practice for making and using U-bend stress corrosion test specimens Recommended practice for laboratory immersion corrosion testing of metals Method for vibratory cavitation erosion test Practice for recording data from atmospheric corrosion tests of metallic-coated steel specimens... 

Post-installed bolts will be required at times for attachment of equipment which may be subjected to large accelerations during a blast. Expansion anchors should be avoided for most blast design applications unless the load levels are low. Typically "wedge" type anchors are qualified for dynamic loads although most of these ratings are for vibratory loads and are based on cyclic tests at low stress levels. These should only be used where ultimate loads are less than the rated capacity with a margin of safely. Epoxy anchors have shown excellent dynamic capacity and may be considered for critical applications. 

FIGURE 8.36 Comparison of variation of permeate flux with mean waU shear stress two-phase flow. Dean, and vibratory shear-enhanced process (VSEP) system. (From Figure 6 in Al-Akoum, O., Mercier-Bonin, M., Ding, L., Fonade, C., Aptel, P., and Jaffrin, M.Y., Desalination, 147, 31, 2000. With permission.)... 

In one study 38% of patients undergoing dobutamine stress echocardiography developed hypotension. Increases in blood pressure are more in hne with what one would expect. Although dobutamine does not as a rule cause a marked increase in systolic blood pressure in normotensive patients, hjrpertensive patients can develop marked systolic hypertension during an infusion of the drug. When stress echocardiography with dobutamine is performed in subjects who prove to be entirely healthy, an audible Still s-like vibratory systolic ejection murmur is nevertheless produced. 

Occasionally, long slender fractionating columns undergo periodic sway from the action of winds of moderate velocity. Sometimes the sway significantly stresses the shell or skirt at the base of the column. Since most vessels are designed to resist static loads caused by winds of over 100 mph, large vibratory sways caused by winds of low or... 

Cavitation corrosion of cylinder liners is not caused by high velocity water flow, nor by impingement of coolant streams. Rather, it appears that vibratory effects are primarily responsible. Under the tremendous stresses of fuel compression and combustion in the Diesel cycle, these 3/4 inch thick cylinder liners vibrate or "ring" at frequencies estimated to be in the range of 7,000 to 8,000 cycles per second, and higher. 

Development of specific penetration devices, either incorporated into the CPT or individually used, have further expanded the capabilities of penetration tests, resulting in subsequent refinement of soil profiling. They include the dilatometer (DMT [Marchetti, 1975,1980 Marchetti and Crapps, 1981 Lutenegger, 1988]), seismic cone (Campanella and Robertson, 1984 Campanella et al., 1986 Baldi et al., 1988), acoustic cone (Villet et al., 1981, Massarch, 1986), lateral stress cone and lateral stress cell (measurement of lateral stress on the cone shaft—Morrisson, 1984 Huntsman, 1985 Huntsman et al., 1986 Baligh et al., 1988), vibratory cone (evaluation of susceptibility of cohesionless soils to liquefaction— Sasaki et al., 1984), and pressure-cone (Jezequel et al., 1982 Hughes and Robertson, 1985 Whiters et al., 1986). 

Taking into account the use of solid-state ESs in applications involving vibration (e.g., electric vehicles), the development of load-bearing solid-state electrolytes (structural electrolytes) has received growing interest [899-902]. Westover et al. [902] used PEO/[EMIM][BF4] infiltrated into nanoporous silicon to assemble load-bearing solid-state ESs. This ES could maintain the energy density of nearly 10 Wh kg under the tensile stress at 300 kPa and 80 g vibratory accelerations. 

Cracking has occurred in PWR piping systems as a result of stress corrosion, vibratory and thermal fatigue and dynamic loadings. All incidents of cracking have been detected and corrective actions taken prior to any catastrophic failures. (Pipe thinning due to erosion has caused catastrophic failure, but that mechanism is considered separate from cracking.)... 

Therefore, degradation of rigid, crystalline or amorphous polymers requires application of some shock stresses on them, such as vibratory milling. 

The mechanical stress in semicrystalline polymers, especially the shock and friction forces developed through vibratory milling, results, as an effect of the presence of macroradicals, in a continuous formation of some new surfaces, extremely rich in energy and. 

The amorphous polymers are proeessed only in the visco-elastie or flowing state. However, quite frequent are the situations in which, prior to their proeessing the polymers are subjected, at inferior temperatures, either to vibratory milling or ultrasonic irradiaton, in view of their homogenization from the viewpoint of the particle size. Also, vibratory milling under T is applied for the recovery of wastes that is why, knowledge of the chemical transformations suffered - under such conditions - by the amorphous polymers and, respectively, activation of certain chemical reactions under the action of mechanical stresses, may result in significant practical applications. 

The intense mechanical stress of rigid polymers, especially by vibratory milling, determines morphological changes materialized in the considerable dispersion of the material. The process consists in the reduction of the grain s geometrical dimensions and the forma-... 

Thus, in vibratory milling of the PS in a gaseous medium, the molecular weight decrease is produced only at the same time with specific surface increase and with the grain dimensions decrease, respectively, while the established function is determined by the working temperature, the frequency of the mechanical stress, and the nature of the medium [694],... 

The molecular weight decrease and the possibility of obtaining some reactions of the PVC with the aromatic diamine-type radical acceptors are conclusive arguments for a radical destructive mechanism of the polymers under vibratory milling conditions. Consequently, mechanodispersion is a mechanochemical-type process, developing itself according to the general laws of polymer fracture under stress. 

Dynamic Modulus. The ratio of stress to strain under vibratory conditions (calculated frdata obtained from either free or forced vibration tests, in shear, compression, or elongation). 

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