Efficient 3-D viscoelastic modeling with application to near‐surface land seismic data

Geophysics ◽  
1998 ◽  
Vol 63 (2) ◽  
pp. 601-612 ◽  
Author(s):  
Tong Xu ◽  
George A. McMechan
Keyword(s):  
Seismic Data ◽  
Three Dimensional ◽  
Elastic Response ◽  
Computational Time ◽  
Near Surface ◽  
Thrust Zone ◽  
Standard Linear Solid ◽  
Standard Linear ◽  
Time Formulation ◽  
Viscoelastic Modeling

Three‐dimensional viscoelastic modeling is implemented by reparameterizing the viscoelastic wave equation for a standard linear solid. The formulation uses weighting factors corresponding to relaxation frequencies and composite memory variables. This novel 3-D formulation requires less computer memory than the traditional relaxation time formulation because one set of relaxation frequencies can be used for all mechanisms for all parts of a model, and only three sets of composite memory variables are needed rather than the seven used in the standard implementation, giving a net reduction of 40% in the total required memory. Computational time is also reduced approximately 25% because of reduced input/output (I/O). The algorithm is applied to 3-D modeling of the viscoelastic response of the near‐surface structure beneath a 3-D reflection survey in the Ouachita frontal thrust zone of southeast Oklahoma. Comparison of the 3-D field data with both viscoelastic and elastic response clearly demonstrates the importance of inclusion of viscoelasticity when accurate amplitude fitting is desired. Observed amplitude and traveltime variations can be explained by shallow velocity and Q distributions obtained independently by 3-D tomography.

Hysteresis and Viscoelastic Modeling of a Piezo-Optic Voltage Sensor

2008 ◽  
Author(s):  
Charles E. Seeley ◽  
Glen Koste ◽  
Craig Stringer
Keyword(s):  
Viscoelastic Model ◽  
Voltage Sensor ◽  
Sensor Technology ◽  
Optical Wave ◽  
Viscoelastic Effects ◽  
Standard Linear Solid ◽  
Standard Linear ◽  
Optical Wave Guide ◽  
Electro Magnetic ◽  
Viscoelastic Modeling

There is growing interest in sensor technology that is immune to electro-magnetic interference. By nature, development of this technology covers multiple physical domains including electronics, optics, mechanics and materials. This paper discusses development of a mathematical model to compensate for the hysteresis and viscoelastic effects of a piezo-optic voltage sensor. The sensor utilizes piezoelectric fibers with interdigitated electrodes coupled to an optical wave guide via a dielectric matrix. The unknown voltage energizes the piezoelectric fibers to deform fiber Bragg gratings (FBGs) on the waveguide. Therefore, a measurable change in wavelength is related to the unknown voltage. The hysteresis model is based on Rayleigh’s Law of magnetization that is adapted for the coupled piezoelectric and optic response, and the viscoelastic model is based on the standard linear solid model using springs and dashpots in combination. Model results compare favorably with experimental results.

scholarly journals On Including Near-surface Zone Anisotropy for Static Corrections Computation—Polish Carpathians 3D Seismic Processing Case Study

Geosciences ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 66
Author(s):  
Mateusz Zaręba ◽  
Tomasz Danek ◽  
Jerzy Zając
Keyword(s):  
Seismic Data ◽  
Three Dimensional ◽  
Seismic Signal ◽  
Surface Zone ◽  
3D Seismic ◽  
Near Surface ◽  
Seismic Surveys ◽  
Geological Interpretation ◽  
Geological Conditions ◽  
Static Corrections

Obtaining the most accurate and detailed subsurface information from seismic surveys is one of the main challenges for seismic data processing, especially in the context of complex geological conditions (e.g., mountainous areas). The correct calculation of static corrections allows for the reliable processing of seismic data. This, in turn, leads to better geological interpretation. A seismic signal passing through a near-surface zone (NSZ) is adversely affected by the high heterogeneity of this zone. As a result of this, observed travel times often show anisotropy. The application of refractive waves and the time delay solution without taking into account the effects caused by the complex anisotropy of an NSZ does not meet the standards of modern seismic surveys. The construction of the NSZ model in mountain regions with the use of refraction may be extremely difficult, as the vertical layers can be observed very close to the surface. It is not sufficient to apply regular isotropic refractive solutions in such conditions. The presented studies show the results of taking into account the anisotropy of an NSZ in the calculations of static corrections. The presented results show that this step is critical for the detailed processing of three-dimensional (3D) seismic data collected in the difficult region of the Carpathians in Southern Poland.

The Study on 3D Incompatible Element in Flexible Multibody System Dynamics

2014 ◽  
Vol 543-547 ◽  
pp. 1282-1285
Author(s):  
Su Bing Liu ◽  
Da Zhi Cao ◽  
Zhi Hui Zhao
Keyword(s):  
Incompatible Element ◽  
Multibody System ◽  
Three Dimensional ◽  
Computational Time ◽  
Flexible Multibody System ◽  
Robust Performance ◽  
Excellent Performance ◽  
Incompatible Elements ◽  
Flexible Multibody ◽  
Standard Linear

In this study the performance of three-dimensional tetrahedron elements has been compared with the background of the simulation of Flexible Multibody System (FMBS). The standard linear tetrahedron element has the least number of nodes, however it has the locking problem. The standard quadratic element has shown precise result and robust performance in many applications, but its high nodes also means large computational time. The incompatible elements integrates the excellence of the linear and quadratic elements and its excellent performance in term of accuracy and time efficiency is presented.

scholarly journals Constitutive Model of Isotropic Magneto-Sensitive Rubber with Amplitude, Frequency, Magnetic and Temperature Dependence under a Continuum Mechanics Basis

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 472 ◽  
Author(s):  
Bochao Wang ◽  
Leif Kari
Keyword(s):  
Constitutive Model ◽  
Continuum Mechanics ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Temperature Dependent ◽  
Nonlinear Constitutive Model ◽  
Measurement Results ◽  
Standard Linear Solid ◽  
Standard Linear ◽  
Main Components

A three-dimensional nonlinear constitutive model of the amplitude, frequency, magnetic and temperature dependent mechanical property of isotropic magneto-sensitive (MS) rubber is developed. The main components of MS rubber are an elastomer matrix and magnetizable particles. When a magnetic field is applied, the modulus of MS rubber increases, which is known as the magnetic dependence of MS rubber. In addition to the magnetic dependence, there are frequency, amplitude and temperature dependencies of the dynamic modulus of MS rubber. A continuum mechanical framework-based constitutive model consisting of a fractional standard linear solid (SLS) element, an elastoplastic element and a magnetic stress term of MS rubber is developed to depict the mechanical behavior of MS rubber. The novelty is that the amplitude, frequency, magnetic and temperature dependent mechancial properties of MS rubber are integrated into a whole constitutive model under the continuum mechanics frame. Comparison between the simulation and measurement results shows that the fitting effect of the developed model is very good. Therefore, the constitutive model proposed enables the prediction of the mechanical properties of MS rubber under various operating conditions with a high accuracy, which will drive MS rubber’s application in engineering problems, especially in the area of MS rubber-based anti-vibration devices.

scholarly journals A Proof-of-Concept Algorithm for the Retrieval of Total Column Amount of Trace Gases in a Multi-Dimensional Atmosphere

2021 ◽  
Vol 13 (2) ◽  
pp. 270
Author(s):  
Adrian Doicu ◽  
Dmitry S. Efremenko ◽  
Thomas Trautmann
Keyword(s):  
Trace Gases ◽  
Three Dimensional ◽  
Principal Component ◽  
Radiative Transfer Model ◽  
Computational Time ◽  
Transfer Model ◽  
Proof Of Concept ◽  
Discrete Ordinate ◽  
Distribution Method ◽  
Total Column

An algorithm for the retrieval of total column amount of trace gases in a multi-dimensional atmosphere is designed. The algorithm uses (i) certain differential radiance models with internal and external closures as inversion models, (ii) the iteratively regularized Gauss–Newton method as a regularization tool, and (iii) the spherical harmonics discrete ordinate method (SHDOM) as linearized radiative transfer model. For efficiency reasons, SHDOM is equipped with a spectral acceleration approach that combines the correlated k-distribution method with the principal component analysis. The algorithm is used to retrieve the total column amount of nitrogen for two- and three-dimensional cloudy scenes. Although for three-dimensional geometries, the computational time is high, the main concepts of the algorithm are correct and the retrieval results are accurate.

Thermomechanical Coupling of a Hyper-viscoelastic Truck Tire and a Pavement Layer and its Impact on Three-dimensional Contact Stresses

2021 ◽  
pp. 036119812110171
Author(s):  
Angeli Jayme ◽  
Imad L. Al-Qadi
Keyword(s):  
Contact Stress ◽  
Contact Area ◽  
Three Dimensional ◽  
Interaction Model ◽  
Rolling Resistance ◽  
Contact Stresses ◽  
Thermomechanical Coupling ◽  
Temperature Profiles ◽  
Near Surface ◽  
Truck Tire

A thermomechanical coupling between a hyper-viscoelastic tire and a representative pavement layer was conducted to assess the effect of various temperature profiles on the mechanical behavior of a rolling truck tire. The two deformable bodies, namely the tire and pavement layer, were subjected to steady-state-uniform and non-uniform temperature profiles to identify the significance of considering temperature as a variable in contact-stress prediction. A myriad of ambient, internal air, and pavement-surface conditions were simulated, along with combinations of applied tire load, tire-inflation pressure, and traveling speed. Analogous to winter, the low temperature profiles induced a smaller tire-pavement contact area that resulted in stress localization. On the other hand, under high temperature conditions during the summer, higher tire deformation resulted in lower contact-stress magnitudes owing to an increase in the tire-pavement contact area. In both conditions, vertical and longitudinal contact stresses are impacted, while transverse contact stresses are relatively less affected. This behavior, however, may change under a non-free-rolling condition, such as braking, accelerating, and cornering. By incorporating temperature into the tire-pavement interaction model, changes in the magnitude and distribution of the three-dimensional contact stresses were manifested. This would have a direct implication on the rolling resistance and near-surface behavior of flexible pavements.

scholarly journals Stable and Efficient Modeling of Anelastic Attenuation in Seismic Wave Propagation

2012 ◽  
Vol 12 (1) ◽  
pp. 193-225 ◽  
Author(s):  
N. Anders Petersson ◽  
Björn Sjögreen
Keyword(s):  
Wave Equation ◽  
Finite Difference ◽  
Half Space ◽  
Material Model ◽  
Second Order ◽  
Finite Difference Approximation ◽  
Difference Approximation ◽  
Space Problem ◽  
Standard Linear Solid ◽  
Standard Linear

AbstractWe develop a stable finite difference approximation of the three-dimensional viscoelastic wave equation. The material model is a super-imposition of N standard linear solid mechanisms, which commonly is used in seismology to model a material with constant quality factor Q. The proposed scheme discretizes the governing equations in second order displacement formulation using 3N memory variables, making it significantly more memory efficient than the commonly used first order velocity-stress formulation. The new scheme is a generalization of our energy conserving finite difference scheme for the elastic wave equation in second order formulation [SIAM J. Numer. Anal., 45 (2007), pp. 1902-1936]. Our main result is a proof that the proposed discretization is energy stable, even in the case of variable material properties. The proof relies on the summation-by-parts property of the discretization. The new scheme is implemented with grid refinement with hanging nodes on the interface. Numerical experiments verify the accuracy and stability of the new scheme. Semi-analytical solutions for a half-space problem and the LOH.3 layer over half-space problem are used to demonstrate how the number of viscoelastic mechanisms and the grid resolution influence the accuracy. We find that three standard linear solid mechanisms usually are sufficient to make the modeling error smaller than the discretization error.

scholarly journals Simulation of Thermal and Electric Field Distribution in Packaged Sausages Heated in a Stationary Versus a Rotating Microwave Oven

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1622
Author(s):  
Wipawee Tepnatim ◽  
Witchuda Daud ◽  
Pitiya Kamonpatana
Keyword(s):  
Temperature Distribution ◽  
Electric Field ◽  
Three Dimensional ◽  
Development Stage ◽  
Microwave Oven ◽  
Computational Time ◽  
Plastic Package ◽  
Heating Uniformity ◽  
The Cost ◽  
Good Agreement

The microwave oven has become a standard appliance to reheat or cook meals in households and convenience stores. However, the main problem of microwave heating is the non-uniform temperature distribution, which may affect food quality and health safety. A three-dimensional mathematical model was developed to simulate the temperature distribution of four ready-to-eat sausages in a plastic package in a stationary versus a rotating microwave oven, and the model was validated experimentally. COMSOL software was applied to predict sausage temperatures at different orientations for the stationary microwave model, whereas COMSOL and COMSOL in combination with MATLAB software were used for a rotating microwave model. A sausage orientation at 135° with the waveguide was similar to that using the rotating microwave model regarding uniform thermal and electric field distributions. Both rotating models provided good agreement between the predicted and actual values and had greater precision than the stationary model. In addition, the computational time using COMSOL in combination with MATLAB was reduced by 60% compared to COMSOL alone. Consequently, the models could assist food producers and associations in designing packaging materials to prevent leakage of the packaging compound, developing new products and applications to improve product heating uniformity, and reducing the cost and time of the research and development stage.

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