Elastic Wave Propagation from Point Excitations on Thin-Walled Cylindrical Shells

1990 ◽  
Vol 112 (3) ◽  
pp. 399-406 ◽  
Author(s):  
A. D. Pierce ◽  
Hyun-Gwon Kil
Keyword(s):  
Wave Propagation ◽  
Dispersive Medium ◽  
Circular Cylindrical Shell ◽  
Exciting Force ◽  
Cylinder Surface ◽  
Two Dimensional ◽  
Phase Velocities ◽  
Unbounded Medium ◽  
Thin Walled ◽  
Analytical Expressions

The circular cylindrical shell is described by equations that govern wave propagation in a two-dimensional homogeneous, but anisotropic and dispersive, medium. The idealization of an unbounded medium is applicable if the source is replaced by a periodic array of forces, the repetition distance being the cylinder circumference. Analytical expressions and calculations are presented for wavefront patterns, amplitude distributions, polarizations, and phase velocities for waves on the cylinder surface. The analysis includes all three possible directions of the exciting force and gives fundamental results that can be superimposed to predict vibration fields resulting from arbitrary excitations.

Acoustic wave propagation in two dimensional sheared ducted flows

1997 ◽  
Author(s):  
E. Longatte ◽  
P. Lafon ◽  
S. Candel ◽  
E. Longatte ◽  
P. Lafon ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Acoustic Wave ◽  
Two Dimensional ◽  
Acoustic Wave Propagation

CALCULATION OF THE DEPENDENCE OF THE DISTANCE TO THE LOCATED OBJECT FROM THE CORNER POSITION OF THE VEHICLE LINE

2018 ◽  
pp. 14-18
Author(s):  
V. V. Artyushenko ◽  
A. V. Nikulin
Keyword(s):  
Real Time ◽  
Statistical Physics ◽  
Angular Position ◽  
Three Dimensional ◽  
Line Of Sight ◽  
Two Dimensional ◽  
Radar Station ◽  
Flight Mode ◽  
Vector Algebra ◽  
Analytical Expressions

To simulate echoes from the earth’s surface in the low flight mode, it is necessary to reproduce reliably the delayed reflected sounding signal of the radar in real time. For this, it is necessary to be able to calculate accurately and quickly the dependence of the distance to the object being measured from the angular position of the line of sight of the radar station. Obviously, the simplest expressions for calculating the range can be obtained for a segment or a plane. In the text of the article, analytical expressions for the calculation of range for two-dimensional and three-dimensional cases are obtained. Methods of statistical physics, vector algebra, and the theory of the radar of extended objects were used. Since the calculation of the dependence of the range of the object to the target from the angular position of the line of sight is carried out on the analytical expressions found in the paper, the result obtained is accurate, and due to the relative simplicity of the expressions obtained, the calculation does not require much time.

scholarly journals Study on X-ray Induced Two-Dimensional Thermal Shock Waves in Carbon/Phenolic

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3553
Author(s):  
Dengwang Wang ◽  
Yong Gao ◽  
Sheng Wang ◽  
Jie Wang ◽  
Haipeng Li
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Wave Propagation ◽  
Thermal Shock ◽  
Anisotropic Material ◽  
Energy Deposition ◽  
X Rays ◽  
Two Dimensional ◽  
X Ray ◽  
Deposition Depth

Carbon/Phenolic (C/P), a typical anisotropic material, is an important component of aerospace and often used to protect the thermodynamic effects of strong X-ray radiation. In this paper, we establish the anisotropic elastic-plastic constitutive model, which is embedded in the in-house code “RAMA” to simulate a two-dimensional thermal shock wave induced by X-ray. Then, we compare the numerical simulation results with the thermal shock wave stress generated by the same strong current electron beam via experiment to verify the correctness of the numerical simulation. Subsequently, we discuss and analyze the rules of thermal shock wave propagation in C/P material by further numerical simulation. The results reveal that the thermal shock wave represents different shapes and mechanisms by the radiation of 1 keV and 3 keV X-rays. The vaporization recoil phenomenon appears as a compression wave under 1 keV X-ray irradiation, and X-ray penetration is caused by thermal deformation under 3 keV X-ray irradiation. The thermal shock wave propagation exhibits two-dimensional characteristics, the energy deposition of 1 keV and 3 keV both decays exponentially, the energy deposition of 1 keV-peak soft X-ray is high, and the deposition depth is shallow, while the energy deposition of 3 keV-peak hard X-ray is low, and the deposition depth is deep. RAMA can successfully realize two-dimensional orthotropic elastoplastic constitutive relation, the corresponding program was designed and checked, and the calculation results for inspection are consistent with the theory. This study has great significance in the evaluation of anisotropic material protection under the radiation of intense X-rays.

Effects of geometric and refractive index disorder on wave propagation in two-dimensional photonic crystals

2000 ◽  
Vol 62 (4) ◽  
pp. 5711-5720 ◽  
Author(s):  
A. A. Asatryan ◽  
P. A. Robinson ◽  
L. C. Botten ◽  
R. C. McPhedran ◽  
N. A. Nicorovici ◽  
...  
Keyword(s):  
Refractive Index ◽  
Wave Propagation ◽  
Photonic Crystals ◽  
Two Dimensional

A CALIBRATED MODEL SEISMIC SYSTEM

Geophysics ◽  
1972 ◽  
Vol 37 (3) ◽  
pp. 445-455 ◽  
Author(s):  
C. N. G. Dampney ◽  
B. B. Mohanty ◽  
G. F. West
Keyword(s):  
Wave Propagation ◽  
Elastic Wave ◽  
Elastic Waves ◽  
Critical Examination ◽  
Two Dimensional ◽  
Linear Filtering ◽  
Analog Model ◽  
Basic Assumptions ◽  
Electronic Circuitry ◽  
Seismic System

Simple electronic circuitry and axially polarized ceramic transducers are employed to generate and detect elastic waves in a two‐dimensional analog model. The absence of reverberation and the basic simplicity. of construction underlie the advantages of this system. If the form of the fundamental wavelet in the model itself, as modified by the linear filtering effects of the remainder of the system, can be found, then calibration is achieved. This permits direct comparison of theoretical and experimental seismograms for a given model if its impulse response is known. A technique is developed for calibration and verified by comparing Lamb’s theoretical and experimental seismograms for elastic wave propagation over the edge of a half plate. This comparison also allows a critical examination of the basic assumptions inherent in a model seismic system.

Investigation of Contact Conditions During Stamping of a Thin Plate

2020 ◽  
Author(s):  
Harshal Y. Shahare ◽  
Rohan Rajput ◽  
Puneet Tandon
Keyword(s):  
Wave Propagation ◽  
Material Properties ◽  
High Speed ◽  
Fdtd Method ◽  
Propagation Model ◽  
Transmitted Wave ◽  
Two Dimensional ◽  
Contact Conditions ◽  
Simulation Based ◽  
Difference Time

Abstract Stamping is one of the most used manufacturing processes, where real-time monitoring is quite difficult due to high speed of the mechanical press, which leads to deterioration of the accuracy of the products In the present work, a method is developed to model elastic waves propagation in solids to measure contact conditions between die and workpiece during stamping. A two-dimensional model is developed that reduces the wave propagation equations to two-dimensional equations. To simulate the wave propagation inside the die-workpiece model, the finite difference time domain (FDTD) method and modified Yee algorithm has been employed. The numerical stability of the wave propagation model is achieved through courant stability condition, i.e., Courant-Friedrichs-Lewy (CFL) number. Two cases, i.e., flat die-workpiece interface and inclined die-workpiece interface, are investigated in the present work. The elastic wave propagation is simulated with a two-dimension (2D) model of the die and workpiece using reflecting boundary conditions for different material properties. The experimental and simulation-based results of reflected and transmitted wave characteristics are compared for different materials in terms of reflected and transmitted wave height ratio and material properties such as acoustic impedance. It is found that the numerical simulation results are in good agreement with the experimental results.

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