scholarly journals Analysis of GPR Wave Propagation in Complex Underground Structures Using CUDA-Implemented Conformal FDTD Method

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Jianwei Lei ◽  
Zibin Wang ◽  
Hongyuan Fang ◽  
Xin Ding ◽  
Xiaowang Zhang ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Fdtd Method ◽  
Ladder Approximation ◽  
Fdtd Simulation ◽  
Computational Time ◽  
Underground Structures ◽  
Propagation Law ◽  
Processor Unit ◽  
Ground Penetrating ◽  
Graphics Processor Unit

Ground penetrating radar (GPR), as a kind of fast, effective, and nondestructive tool, has been widely applied to nondestructive testing of road quality. The finite-difference time-domain method (FDTD) is the common numerical method studying the GPR wave propagation law in layered structure. However, the numerical accuracy and computational efficiency are not high because of the Courant-Friedrichs-Lewy (CFL) stability condition. In order to improve the accuracy and efficiency of FDTD simulation model, a parallel conformal FDTD algorithm based on graphics processor unit (GPU) acceleration technology and surface conformal technique was developed. The numerical simulation results showed that CUDA-implemented conformal FDTD method could greatly reduce computational time and the pseudo-waves generated by the ladder approximation. And the efficiency and accuracy of the proposed method are higher than the traditional FDTD method in simulating GPR wave propagation in two-dimensional (2D) complex underground structures.

scholarly journals Analysis of GPR Wave Propagation Using CUDA-Implemented Conformal Symplectic Partitioned Runge-Kutta Method

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Hongyuan Fang ◽  
Jianwei Lei ◽  
Man Yang ◽  
Ziwei Li
Keyword(s):  
Wave Propagation ◽  
Forward Modeling ◽  
Electromagnetic Response ◽  
Acceleration Technique ◽  
Efficient Calculation ◽  
Dense Grid ◽  
Runge Kutta ◽  
Processor Unit ◽  
The Stability ◽  
Ground Penetrating

Accurate forward modeling is of great significance for improving the accuracy and speed of inversion. For forward modeling of large sizes and fine structures, numerical accuracy and computational efficiency are not high, due to the stability conditions and the dense grid number. In this paper, the symplectic partitioned Runge-Kutta (SPRK) method, surface conformal technique, and graphics processor unit (GPU) acceleration technique are combined to establish a precise and efficient numerical model of electromagnetic wave propagation in complex geoelectric structures, with the goal of realizing a refined and efficient calculation of the electromagnetic response of an arbitrarily shaped underground target. The results show that the accuracy and efficiency of ground-penetrating radar (GPR) forward modeling are greatly improved when using our algorithm. This provides a theoretical basis for accurately interpreting GPR detection data and accurate and efficient forward modeling for the next step of inversion imaging.

Numerical Simulation Modeling of GPR on Road Disease

2012 ◽  
Vol 178-181 ◽  
pp. 1463-1468
Author(s):  
Bo Zhai ◽  
Zhi Min Gong
Keyword(s):  
Numerical Simulation ◽  
Wave Propagation ◽  
Simulation Modeling ◽  
Electromagnetic Wave Propagation ◽  
Fdtd Method ◽  
Road Maintenance ◽  
Ground Penetrating ◽  
Radar Wave ◽  
Difference Time ◽  
Propagation Rules

Numerical simulation of ground penetrating radar is an effective way of analyzing and studying high frequency electromagnetic wave propagation rules in the underground media. In this paper, Finite-Difference Time-Domain (FDTD) method is used for numerical simulation to form radar records reflection profile about road disease such as loose disease. The purpose is to study and sum up the radar wave propagation rules and reflection signal characters in this diseases media, in order to provide reliable theory support for road maintenance and evaluation.

scholarly journals Optimising the Complex Refractive Index Model for Estimating the Permittivity of Heterogeneous Concrete Models

2021 ◽  
Vol 13 (4) ◽  
pp. 723
Author(s):  
Hossain Zadhoush ◽  
Antonios Giannopoulos ◽  
Iraklis Giannakis
Keyword(s):  
Refractive Index ◽  
Shape Factor ◽  
Complex Refractive Index ◽  
Fdtd Method ◽  
Air Voids ◽  
Water Fraction ◽  
Index Model ◽  
General Complex ◽  
Ground Penetrating ◽  
Fine Tune

Estimating the permittivity of heterogeneous mixtures based on the permittivity of their components is of high importance with many applications in ground penetrating radar (GPR) and in electrodynamics-based sensing in general. Complex Refractive Index Model (CRIM) is the most mainstream approach for estimating the bulk permittivity of heterogeneous materials and has been widely applied for GPR applications. The popularity of CRIM is primarily based on its simplicity while its accuracy has never been rigorously tested. In the current study, an optimised shape factor is derived that is fine-tuned for modelling the dielectric properties of concrete. The bulk permittivity of concrete is expressed with respect to its components i.e., aggregate particles, cement particles, air-voids and volumetric water fraction. Different combinations of the above materials are accurately modelled using the Finite-Difference Time-Domain (FDTD) method. The numerically estimated bulk permittivity is then used to fine-tune the shape factor of the CRIM model. Then, using laboratory measurements it is shown that the revised CRIM model over-performs the default shape factor and provides with more accurate estimations of the bulk permittivity of concrete.

A Brief Review of Previous Studies on Regularity of Stress Waves Propagation in Micro-Cracks of Rock

2012 ◽  
Vol 170-173 ◽  
pp. 511-515
Author(s):  
Jin Yu ◽  
Yan Yan Cai ◽  
Bo Xue Song ◽  
Xu Chen
Keyword(s):  
Wave Propagation ◽  
Stress Wave ◽  
Mathematic Model ◽  
Practical Significance ◽  
Theoretical Interpretation ◽  
Stress Wave Propagation ◽  
Micro Cracks ◽  
Propagation Law ◽  
Mechanism Research ◽  
Long Time

The research of stress wave propagation law under cracked rock has important theoretical value and practical significance. Because of the discontinuity, nonelasticity and nonlinearity of the cracks, the theoretical interpretation and mechanism research about tress wave propagation law are a great challenge to researchers for a long time. From the establishment of the research method, the determination of mathematic model of micro-cracks and the main solutions, this paper brief reviews the current development of the influence of the complicated micro-cracks on stress wave propagation law.

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.

On the Friction Coefficient in the Numerical Simulation of Tidal Wave Propagation

2010 ◽  
Author(s):  
Z. Y. Song ◽  
C. Cheng ◽  
F. M. Xu ◽  
J. Kong
Keyword(s):  
Numerical Simulation ◽  
Wave Propagation ◽  
Friction Factor ◽  
Tidal Wave ◽  
Computational Time ◽  
Numerical Dissipation ◽  
Courant Number ◽  
Time Step ◽  
Large Time Step ◽  
The Relationship

Based on the analytical solution of one-dimensional simplified equation of damping tidal wave and Heuristic stability analysis, the precision of numerical solution, computational time and the relationship between the numerical dissipation and the friction dissipation are discussed with different numerical schemes in this paper. The results show that (1) when Courant number is less than unity, the explicit solution of tidal wave propagation has higher precision and requires less computational time than the implicit one; (2) large time step is allowed in the implicit scheme in order to reduce the computational time, but the precision of the solution also reduce and the calculation precision should be guaranteed by reducing the friction factor: (3) the friction factor in the implicit solution is related to Courant number, presented as the determined friction factor is smaller than the natural value when Courant number is larger than unity, and their relationship formula is given from the theoretical analysis and the numerical experiments. These results have important application value for the numerical simulation of the tidal wave.

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