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1

Reflection and transmission in non-local couple stress micropolar thermoelastic media

Gupta Deepa, Malik Sangeeta, Kumar Krishan, Sharma Raj Kumar

International Journal of Applied Mechanics and Engineering

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2022

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Vol. 27, no. 2

53--76

EN

We have studied the problem of homogenous, isotropic non-local couple stress micropolar thermoelastic solid in the absence of body forces, couple density and heat resources. The reflection and transmission of waves at the interface of two distinct media have been investigated. It is observed that amplitude ratios of various reflected and transmitted waves are functions of wave number of incident waves and are affected by the non-local parameter of thermoelastic solid.

2

The Effects of Trunk Cavity and Air-Gaps in the Acoustic Response of a Passenger Vehicle

Oktav A.

Archives of Acoustics

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2017

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Vol. 42, No. 3

433--440

EN

The effects of additional cavities and air-gaps in the acoustic response of a passenger vehicle are investigated. It is observed that the cabin cavity and the trunk cavity of the passenger vehicle are connected through an aperture in the rear seat. In the trunk cavity of the vehicle, there are two more air-gaps which are designed as countermeasures to trunk lid slam noise. It is established that acoustic modes and acoustic eigenfrequencies of the vehicle are altered through the trunk cavity and its air-gaps. To develop an analytical solution, the actual acoustic cavity is simplified into a rectangular shape. In the analytical solution, the coupling of trunk and cabin cavities is considered. It is shown that the computational analysis results match well with the results of the analytical solution proposed. Further, the resonator effect of air-gaps present in the trunk cavity is examined.

3

Guided circumferential waves in layered poroelastic cylinders

Shah S. A., Apsar G.

International Journal of Applied Mechanics and Engineering

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2016

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Vol. 21, no. 4

933--950

EN

The present paper investigates the propagation of time harmonic circumferential waves in a two-dimensional hollow poroelastic cylinder with an inner shaft (shaft-bearing assembly). The hollow poroelastic cylinder and inner shaft are assumed to be infinite in axial direction. The outer surface of the cylinder is stress free and at the interface, between the inner shaft and the outer cylinder, it is assumed to be free sliding and the interfacial shear stresses are zero, also the normal stress and radial displacements are continuous. The frequency equation of guided circumferential waves for a permeable and an impermeable surface is obtained. When the angular wave number vanish the frequency equation of guided circumferential waves for a permeable and an impermeable surface degenerates and the dilatational and shear waves are uncoupled. Shear waves are independent of the nature of surface. The frequency equation of a permeable and an impermeable surface for bore-piston assembly is obtained as a particular case of the model under consideration when the outer radius of the hollow poroelastic cylinder tends to infinity. Results of previous studies are obtained as a particular case of the present study. Nondimensional frequency as a function of wave number is presented graphically for two types of models and discussed. Numerical results show that, in general, the first modes are linear for permeable and impermeable surfaces and the frequency of a permeable surface is more than that of an impermeable surface.

4

Pomiar prędkości fazowej fal ultradźwiękowych w nasyconym materiale porowatym. Metoda widma amplitudowego

Kochański J., Kubik J.

Zeszyty Naukowe. Mechanika / Akademia Techniczno-Rolnicza w Bydgoszczy

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2004

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Z. 54(243)

179-186

PL

W pracy przedstawiono metodę wyznaczania prędkości fazowej fal ultradźwiękowych w oparciu o przebieg widm amplitudowych sygnałów odbitych od badanej próbki. Metodę zilustrowano przykładami wyznaczając prędkość fazową dla dwóch rodzajów materiałów: aluminium i spieku granulatu szklanego.

EN

The paper presents a combined experimental and analytical amplitude spectrum method for the measurement of phase velocity of longitudinal ultrasonic waves propagating between the boundaries of the tested sample.