Ultrasonic Waves propagation

Iwashimizu Yu.. Ultrasonic wave propagation in deformed isotropic elastic materials, Int. 1. Solids Structures, 7 (1971), 419-429. 

Ultrasonic wave propagation Laser Raman scattering Neutron inelastic scattering... 

The velocity is therefore determined by two fundamental physical properties of a material its elastic modulus and density. The less dense a material or the more resistant it is to deformation the faster an ultrasonic wave propagates. Usually, differences in the moduli of materials are greater than those in density and so the ultrasonic velocity is determined more by the elastic moduli than by the density. This explains why the ultrasonic velocity of solids is greater than that of fluids, even though fluids are less dense [1],... 

Three groups of phenomena affect the frequency-dependence of ultrasonic wave propagation classical processes, relaxation, and scattering, of which scattering is likely to dominate in foodstuffs due to their particulate nature. The two classical thermal processes are radiation and conduction of heat away from regions of the material, which are locally compressed due to the passage of a wave they can lead to attenuation but the effect is negligible in liquid materials (Herzfield and Litovitz, 1959 Bhatia, 1967). The third classical process is due to shear and bulk viscosity effects. Attenuation in water approximates to a dependence on the square of the frequency and because of this it is common to express the attenuation in more complex liquids as a()/o or a(f)jf2 in order to detect, or differentiate from, water-like properties. 

Challis, R.E., Tebbutt, J.S., Holmes, A.K. 1998. Equivalence between three scattering formulations for ultrasonic wave propagation in particulate mixtures. J. Phys. D Applied Phys. 31, 3481-3497. 

O Neill, T.J., Tebbutt, J.S., Challis, R.E. 2001. Convergence criteria for scattering models of ultrasonic wave propagation in suspensions of particles. IEEE Trans. Ultrasonics, Ferro-electrics and Frequency Control 48, 419-424. 

Figure 9.4. Different types of Input signal used In ultrasonic detectors to excite the ultrasonic transducer in order to generate an ultrasonic wave propagation Into a sample.

Most ultrasonic material analyses rely on measurements of some characteristic of ultrasonic waves propagating through the sample that provides information on the interaction of ultrasonic waves with the inside of the sample, thus enabling analysis of its physical and chemical properties. 

In most of the cases, an ultrasonic wave propagates adiabatically, so the (20) looks more naturally its right-hand side represents the adiabatic (non-relaxed) modulus and non-adiabatic contribution to the dynamic modulus. Recall that the relaxed (or isothermal) modulus should be regarded as quasi-static one. Figure 1 shows the frequency-dependent factor of non-adiabatic contribution as function of cox. One can see that transformation from isothermal-like to adiabatic-like propagation occurs in the vicinity cox = 1. The velocity of ultrasound is increased in this region, while the attenuation reaches its maximum value. 

The (mean) grain size mainly influences the ultrasonic wave propagation. P-wave velocity and attenuation increases with increasing (mean) grain sizes. 

Rose, J. L. (1985). Ultrasonic wave propagation principles in composite material inspection. Materials Evaluation, April 1985. 43. 4. 481 483. 

In addition to the mechanical tests cited above, ultrasonic wave propagation techniques have been used to measure the anisotropic elastic properties of bone [Lang, 1969 Yoon and Katz, 1976a, b Van Buskirk and Ashman, 1981]. This is possible, since combining Hooke s law with Newton s second law results in a wave... 

Table 47.2 lists the Qj (in GPa) for human (haversian) bone and bovine (both haversian and plexiform) bone. With the exception of Knefs [1978] measurements, which were made using quasi-static mechanical testing, aH the other measurements were made using bulk ultrasonic wave propagation. 

Yoon, H.S. and Katz, J.L. 1976a. Ultrasonic wave propagation in human cortical bone I. Theoretical considerations of hexagonal symmetry. J. Biomech. 9 407. 

Another interesting physical consideration of ultrasonic wave propagation is related to amplitude reduction of an ultrasonic waveform. An amplitude decay curve is illustrated in Figure 12. Lower frequencies can propagate further into a material, since material absorption... 

A. Pilarski, Ultrasonic wave propagation in a layered medium under different boundary conditions. Arch. Acoust. 7, 61 (1982). 

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