Ultrasonic wave velocity

Both ultrasonic and radiographic techniques have shown appHcations which ate useful in determining residual stresses (27,28,33,34). Ultrasonic techniques use the acoustoelastic effect where the ultrasonic wave velocity changes with stress. The x-ray diffraction (xrd) method uses Bragg s law of diffraction of crystallographic planes to experimentally determine the strain in a material. The result is used to calculate the stress. As of this writing, whereas xrd equipment has been developed to where the technique may be conveniently appHed in the field, convenient ultrasonic stress measurement equipment has not. This latter technique has shown an abiHty to differentiate between stress reHeved and nonstress reHeved welds in laboratory experiments. 

Fig. 7. Relations between elastic constants and ultrasonic wave velocities, (a) Young s modulus (b) shear modulus (c) Poisson s ratio and (d) bulk...

The permeability of concrete to aqueous liquids is reduced by most air entraining agents [35] and this is illustrated in terms of the depth of penetration of water under a pressure of 8 N mm 2 m 48 h in Fig. 3.31. This is reflected in an improved resistance to attack by sulfate-bearing solutions which is indicated by the loss in ultrasonic wave velocity, as shown in Fig. 3.32 [37]. 

Thus far four composites listed in Table I have been studied. NbTi/Cu is discussed briefly here. From its microstructure and manufacture, a rectangular cross-section bar, it was assumed that this composite has orthorhombic (orthotropic) symmetry in its physical properties. Materials with this symmetry have nine independent elastic constants. While deviations from elastic behavior were small, nine independent elastic constants were verified. Four specimens were prepared (Fig. 16) and 18 ultrasonic wave velocities were determined by propagating differently polarized waves in six directions, (100) and (110). An example cooling run is shown in Fig. 17 for E33, Young s modulus along the filament axis. These data typify the composites studies a wavy, irregular modulus/temperature curve. 

Deformation tests are started at a certain isotropic stress state, the axial strain is increased with a constant strain rate (Fig. 11.40). The related evolution of volume, AE rate, ultrasonic wave velocities, and permeability is... 

Ultrasonic methods have been considered for non-destructive evaluation of compositional changes and mixture uniformity in filled polymers. In principle, it is feasible to determine the size, shape and distribution of filler particles, to detect agglomeration and to assess the extent of filler-matrix interaction, through appropriate application of ultrasonic procedures [48]. The method involves determination of the elastic behaviour of solids by measurement of ultrasonic wave velocity. Propagation of a plane wave in a linear elastic material can be related to its elastic modulus (E) and density (p) according to ... 

Earlier attempts to apply ultrasonic wave-velocity measurements to in-line determination of filler concentration during compounding met with mixed success, however. In one study [51], measurements were undertaken by measuring ultrasonic transit times across... 

The desolvation of nucleoside hydrates in the crystal proceeds along a direction corresponding to one of the crystallographic axes. Ultrasonic methods have been used to study hydration of pyrimidine nucleosides and of D-ribose itself in aqueous-ethanolic solution. Variations in ultrasonic wave velocity with alcohol concentration could be related to the extent of interaction of the sugar hydroxy groups with water. 

By using this method, we measured the anisotropy of ultrasonic wave velocity in axial-radial, axial-tangential and radial-tangential planes in detail (Fig. 3). 

By using sphericahy shaped bovine corhcal bone samples, we experimentally inveshgate the anisotropy of ultrasonic wave velocity and the HAp crystalhtes orientahon in axial-radial, axial-tangenhal and radial-tangenhal planes in... 

The averaging values of density p, longitudinal V] and shear Vi ultrasonic wave velocities, bulk modulus K, shear modulus G, Young s modulus E, and Poisson s ratio a as a function of synthesis temperature T. 

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