scholarly journals Theory of Propagation of Elastic Waves in a Fluid‐Saturated Porous Solid. I. Low‐Frequency Range

1956 ◽  
Vol 28 (2) ◽  
pp. 168-178 ◽  
Author(s):  
M. A. Biot
Keyword(s):  
Elastic Waves ◽  
Low Frequency ◽  
Porous Solid ◽  
Frequency Range ◽  
Propagation Of Elastic Waves

An identification problem related to the Biot system

2014 ◽  
Vol 0 (0) ◽  
Author(s):  
Viatcheslav I. Priimenko ◽  
Mikhail P. Vishnevskii
Keyword(s):  
Elastic Waves ◽  
Existence And Uniqueness ◽  
Direct Problem ◽  
Low Frequency ◽  
Identification Problem ◽  
Scalar Function ◽  
Uniqueness Result ◽  
Frequency Range ◽  
Biot Equations ◽  
Propagation Of Elastic Waves

Abstract.In this paper, we study the propagation of elastic waves in porous media governed by the Biot equations in the low frequency range. We prove the existence and uniqueness result both for the direct problem and the inverse one, which consists in identifying the unknown scalar function

Elastic Waves in Pipe Resting on Two-Parameter Foundation

2010 ◽  
Vol 163-167 ◽  
pp. 2857-2861 ◽  
Author(s):  
Zhi Rong Lin ◽  
Akira Kasai
Keyword(s):  
Wave Propagation ◽  
Elastic Waves ◽  
Low Frequency ◽  
Curvilinear Coordinates ◽  
Complex Field ◽  
Frequency Range ◽  
Wave Propagation Problem ◽  
Propagating Waves ◽  
Foundation Parameter ◽  
Two Parameter

A method based on Hamiltonian system in complex field is presented in curvilinear coordinates to study elastic waves in pipes of various shapes on two-parameter foundation. The method and its computer program are verified and applied to analyze the axial wave propagation problem of elliptical pipe embedded in foundation. Numerical results show the dispersion changes of varying degree in the presence of foundation and reveal significant influences of the second foundation parameter especially in the low frequency range. The promising and effective way of controlling propagating waves by adjusting the shear ability of foundation is also indicated in the results.

scholarly journals Vibration Isolation of a Rubber-Concrete Alternating Superposition In-Filled Trench for Train-Induced Environmental Vibration Based on 2.5D Indirect Boundary Element Method

2021 ◽  
Vol 9 ◽  
Author(s):  
Liguo Jin ◽  
Jingya Wang ◽  
Xujin Liu ◽  
Qiangqiang Li ◽  
Zhenghua Zhou
Keyword(s):  
Elastic Waves ◽  
High Speed ◽  
Vibration Isolation ◽  
Soft Soil ◽  
Low Frequency ◽  
Isolation Effect ◽  
High Speed Train ◽  
Frequency Range ◽  
The Impact ◽  
Rubber Concrete

A new train-induced vibration isolation measure of rubber-concrete alternating superposition in-filled trench is presented in this paper. For analyzing the vibration isolation effect of the new measure, this paper establishes a 2.5D train-track-layered foundation-filled trench model to analyze the dynamics of track and layered foundation with the in-filled trench. The correctness of the model is verified by using the measured data of the Sweden X-2000 high-speed train. The vibration isolation effect of the rubber-concrete alternating superposition in-filled trench is calculated by using the actual soft soil foundation parameters of the X-2000 high-speed train, and the vibration isolation effect is also compared with that of the empty trench, rubber in-filled trench, and concrete in-filled trench. The results show that the vibration isolation effect of the rubber-concrete alternating superposition in-filled trench proposed in this paper is better than that of the C30 concrete in-filled trench, especially the impact on displacement. Compared with low-frequency vibrations generated by the lower train speed, the rubber-concrete alternating superposition in-filled trench has a better vibration isolation effect on high-frequency vibrations caused by higher-speed trains. The rubber-concrete alternately superposition in-filled trench has the frequency band characteristics of elastic waves. Elastic waves in the passband frequency range can propagate without attenuation, while the elastic waves in the forbidden frequency range will be filtered out.

The effect of boundaries on wave propagation in a liquid-filled porous solid

1960 ◽  
Vol 50 (4) ◽  
pp. 599-607
Author(s):  
H. Deresiewicz
Keyword(s):  
Wave Propagation ◽  
Free Boundary ◽  
General Solution ◽  
Elastic Waves ◽  
Body Waves ◽  
Porous Solid ◽  
Field Equations ◽  
Reflected Waves ◽  
Three Body ◽  
Propagation Of Elastic Waves

ABSTRACT A general solution is deduced of the differential equations which describe the propagation of elastic waves in a nondissipative liquid-filled porous solid. The solution is then used to examine some of the phenomena which arise when each of the three body waves predicted by the field equations is, in turn, incident on a plane traction-free boundary. It is found, for example, that an obliquely incident wave of each type in general gives rise to reflected waves of all three types.

Evaluation of Special Hearing Aids for Deaf Children

1971 ◽  
Vol 36 (4) ◽  
pp. 527-537 ◽  
Author(s):  
Norman P. Erber
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Low Frequency ◽  
Acoustic Stimulation ◽  
Deaf Children ◽  
Frequency Range ◽  
Frequency Limit ◽  
Unpublished Studies ◽  
Published Research

Two types of special hearing aid have been developed recently to improve the reception of speech by profoundly deaf children. In a different way, each special system provides greater low-frequency acoustic stimulation to deaf ears than does a conventional hearing aid. One of the devices extends the low-frequency limit of amplification; the other shifts high-frequency energy to a lower frequency range. In general, previous evaluations of these special hearing aids have obtained inconsistent or inconclusive results. This paper reviews most of the published research on the use of special hearing aids by deaf children, summarizes several unpublished studies, and suggests a set of guidelines for future evaluations of special and conventional amplification systems.

Dynamic Damping and Stiffness Characteristics of the Rolling Tire

2001 ◽  
Vol 29 (4) ◽  
pp. 258-268 ◽  
Author(s):  
G. Jianmin ◽  
R. Gall ◽  
W. Zuomin
Keyword(s):  
Dynamic Behavior ◽  
Variable Parameter ◽  
Low Frequency ◽  
Vertical Load ◽  
Frequency Range ◽  
Inflation Pressure ◽  
Vehicle Simulation ◽  
Dynamic Damping ◽  
Speed Range ◽  
Stiffness Characteristics

Abstract A variable parameter model to study dynamic tire responses is presented. A modified device to measure terrain roughness is used to measure dynamic damping and stiffness characteristics of rolling tires. The device was used to examine the dynamic behavior of a tire in the speed range from 0 to 10 km/h. The inflation pressure during the tests was adjusted to 160, 240, and 320 kPa. The vertical load was 5.2 kN. The results indicate that the damping and stiffness decrease with velocity. Regression formulas for the non-linear experimental damping and stiffness are obtained. These results can be used as input parameters for vehicle simulation to evaluate the vehicle's driving and comfort performance in the medium-low frequency range (0–100 Hz). This way it can be important for tire design and the forecasting of the dynamic behavior of tires.

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