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The effect of geometrical dispersion on stress wave propagation
Hora, Petr
The effect geometrical dispersion is that the energy in a wave-packet propagates at different speeds depending on its frequency. It is shown that duration of a wave-packet increases linearly with propagation distance and also that the duration of a wave-packet after a given propagation distance depends on the input signal. Some conclusions are made concerning the Lamb wave propagation in a steel plate.
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The effect of geometrical dispersion on stress wave propagation
Hora, Petr
The effect geometrical dispersion is that the energy in a wave-packet propagates at different speeds depending on its frequency. This manifests itself as a spreading of the wave-packet in space and time as it propagates through a structure. It is show that duration of a wave-packet increases linearly with propagation distance and also that the duration of a wave-packet after a given propagation distance depends on the input signal.
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Non-destructive material evaluation by non-contact ultrasound
Landa, Michal
The paper presents new non-invasive ultrasonic methods have been developed for physical properties evaluation of namely non-porrous materials. Two non-invasive ultrasonic methods (laser ultrasound, ultrasound with air-coupling) were described and advages and limitations are shown on the experimental results.
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Generation of elastics waves by moveing source
Ježdík, Roman ; Landa, Michal
Principle of elastic waves generation by moving source realized by transducer array is performed. Numerical model of this generation technique is used for studying reflection and refraction coefficient on planar water-glass interface. Comparison with retical values of coefficients is done. Differences between numerical model and theory are discussed.
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Comparison of the matrix techniques for modeling stress waves in multilayered media
Hora, Petr
This paper describes the development of a general purpose model for wave propagation in Cartesian system. When isotropic materials are used, the model can account for elastic and visco-elastic isotropic materials, single or multi-layered structures, free or leaky systems. Model determines what resonances can exist in order to satisfy the boundary conditions and the bulk wave propagation characteristics in each of the layers.
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