scholarly journals Interaction among neighbouring rectangular finite strike slip faults in a linear viscoelastic half space representing lithosphere-asthenosphere system

MAUSAM ◽  
2021 ◽  
Vol 71 (4) ◽  
pp. 699-708
Author(s):  
DEBNATH PAPIYA ◽  
SEN SANJAY
Keyword(s):  
Half Space ◽  
Correspondence Principle ◽  
Integral Transform ◽  
Active Regions ◽  
Fault System ◽  
Model Parameters ◽  
Seismic Events ◽  
Linear Viscoelastic ◽  
Earthquake Faults ◽  
Stress Accumulation

There are seismically active regions consisting of fault system with a number of neighbouring earthquake faults. A movement across any one of them may affect the nature of stress accumulation near the others. Mathematical models may be developed to study these interactions and the pattern of interseismic stresses during the aseismic period in between two consecutive seismic events. In this paper, the lithosphere-asthenosphere system is being represented by a linear viscoelastic half space. The material of the half space is expected to possess the properties of both Maxwell and Kelvin type materials. It is assumed that the system is under a steady shear stress generated by some tectonic phenomena. For obtaining the solution for displacement, strain and stresses from the resulting boundary value problem, Integral transform, Green’s function techenique and correspondence principle have been used. Appropriate estimates of the model parameters were used in carrying out the numerical computations for investigating the nature of interactions among the faults.

scholarly journals Pattern of Stress-Strain Accumulation due to a Long Dipslip Fault Movement in a Viscoelastic Layered Model of The Lithosphere–Asthenosphere System

2013 ◽  
Vol 18 (3) ◽  
pp. 653-670 ◽  
Author(s):  
S.K. Debnath ◽  
S. Sen
Keyword(s):  
Mantle Convection ◽  
Integral Transformation ◽  
Active Regions ◽  
Viscoelastic Layer ◽  
Seismic Events ◽  
Strain Accumulation ◽  
Fault Movement ◽  
System A ◽  
Earthquake Faults ◽  
Stress Accumulation

Abstract The process of stress accumulation near earthquake faults during the aseismic period in between two major seismic events in seismically active regions has become a subject of research during the last few decades. In the present paper a long dip -slip fault is taken to be situated in a viscoelastic layer over a viscoelastic half space representing the lithosphere-asthenosphere system. A movement of the dip-slip nature across the fault occurs when the accumulated stress due to various tectonic reasons, e.g., mantle convection etc., exceeds the local friction and cohesive forces across the fault. The movement is assumed to be slipping in nature, expressions for displacements, stresses and strains are obtained by solving the associated boundary value problem with the help of integral transformation and Green's function method. A detailed study of these expressions may give some ideas about the nature of stress accumulation in the system, which in turn will be helpful in formulating an earthquake prediction programme

Coupled FEM-BEM Approach for Axisymetrical Heat Transfer Problems

2008 ◽  
Vol 273-276 ◽  
pp. 740-745
Author(s):  
Gennady Mishuris ◽  
Michał Wróbel
Keyword(s):  
Heat Transfer ◽  
Half Space ◽  
Integral Transform ◽  
Transfer Problem ◽  
Mixed Boundary ◽  
Nonlocal Boundary ◽  
Fem Analysis ◽  
Nonlocal Boundary Conditions ◽  
Problem Solution ◽  
Infinite Domain

This work deals with a stationary axisymmetrical heat transfer problem in a combined domain. This domain consists of half-space joined with a bounded cylinder. An important feature of the problem is the possible flux singularity along the edge points of the transmission surface. Domain decomposition is used to separate the subdomains. The solution for an auxiliary mixed boundary value problem in the half space is found analytically by means of Hankel integral transform. This allows us to reduce the main problem in the infinite domain to another problem defined in the bounded subdomain. In turn, the new problem contains a nonlocal boundary conditions along the transmission surface. These conditions incorporate all basic information about the infinite sub-domain (material properties, internal sources etc.). The problem is solved then by means of the Finite Element Method. In fact it might be considered as a coupled FEM-BEM approach. We use standard MATLAB PDE toolbox for the FEM analysis. As it is not possible for this package to introduce directly a non-classical boundary condition, we construct an appropriate iterative procedure and show the fast convergence of the main problem solution. The possible solution singularity is taken into account and the corresponding intensity coefficient of the heat flux is computed with a high accuracy. Numerical examples dealing with heat transfer between closed reservoir (filled with some substance) and the infinite foundation are discussed.

Test of Strain-Time Correspondence Principle with Gel-Containing Elastomers

1986 ◽  
Vol 59 (2) ◽  
pp. 305-314 ◽  
Author(s):  
N. Nakajima ◽  
E. R. Harrell
Keyword(s):  
Large Deformation ◽  
Correspondence Principle ◽  
Small Deformation ◽  
Complex Viscosity ◽  
Shear Stresses ◽  
Growth Data ◽  
Stress Growth ◽  
Linear Viscoelastic ◽  
The Difference ◽  
Linear Viscoelastic Theory

Abstract With four NBR samples and one EPR, oscillatory measurements and stress-growth measurements were performed, the former being at very small deformation and the latter leading to large deformation. The Rheometrics mechanical spectrometer was used with a cone-plate fixture. The temperature was 100°C. The stress-growth data of NBR's, converted to complex viscosity-frequency data through the application of stress-time correspondence principle, were in good agreement with those observed in the oscillatory measurement. Thus, the stress-growth data including the large deformation were “linearized” to form a master curve. With the EPR sample, such a linearization was not necessary. The stress-growth data were adequately treated with the linear viscoelastic theory up to shear stresses approaching the steady state. The difference in behavior between the NBR's and EPR is caused by differences in type and extent of long branching and gel present in the samples.

Time Effects on Settlement of Rigid Pile Composite Foundation: Simplified Models

2018 ◽  
Vol 15 (07) ◽  
pp. 1850066 ◽  
Author(s):  
Meijuan Xu ◽  
Pengpeng Ni ◽  
Guoxiong Mei ◽  
Yanlin Zhao
Keyword(s):  
Numerical Integration ◽  
Half Space ◽  
Unsaturated Soils ◽  
Pressure Coefficient ◽  
Closed Form Solution ◽  
Elastic Half Space ◽  
Composite Foundation ◽  
Model Parameters ◽  
Time Effects ◽  
Rigid Pile

The behavior of pile composite foundation is studied using the flexibility method. During the analysis, determination of the flexibility matrix (settlement) is critical. However, conventional methods of Winkler and elastic half-space foundation models are incapable of considering the time effects of soil consolidation and creep. The foundation model of Zaretsky and Tsytovich [1965] can be used to evaluate settlement for unsaturated soils, but the complexity of numerical integration over an arbitrary loading area hinders its application. In this paper, a novel scheme is proposed for numerical integration by rotating the loading surface using the equiareal transformation technique. Therefore, a simplified closed-form solution is developed to calculate time dependent settlement for foundation soils. The efficacy of the proposed technique is demonstrated using illustrative examples of an elastic half-space, a rigid raft foundation without piles, and rigid pile composite foundations with multiple piles under surface loading. Furthermore, parametric study is conducted to evaluate the sensitivity of model parameters. The permeability [Formula: see text] and Poisson’s ratio [Formula: see text] are found to be important, whereas pore pressure coefficient [Formula: see text] and degree of saturation [Formula: see text] are less significant in the calculation.

Isolated Triggered Tremor Spots in South America and Implications for Global Tremor Activity

2019 ◽  
Author(s):  
Kevin Chao ◽  
Zhigang Peng ◽  
William B. Frank ◽  
Germán A. Prieto ◽  
Kazushige Obara
Keyword(s):  
South America ◽  
Seismic Station ◽  
Plate Boundary ◽  
Active Regions ◽  
Fault System ◽  
Southern Chile ◽  
Tectonic Tremor ◽  
Single Station ◽  
Chile Triple Junction ◽  
Triggered Tremor

ABSTRACT We report new observations of triggered tectonic tremor in three regions in South America along the plate boundary between the Nazca and South America plates: southern Chile, Ecuador, and central Colombia. In these regions, tremor was observed during the passage of large‐amplitude surface waves of recent large earthquakes, which occurred in South America and around the world. In southern Chile, triggered tremor was observed around an ambient tremor active zone in the Chile triple junction region. In Ecuador and central Colombia, only one seismic station in each region recorded triggered tremor. With a single‐station approach, we are able to estimate potential tremor sources in these regions. Triggered tremor in Ecuador is likely associated with an inland fault near the volcanic region. In central Colombia, triggered tremor may be associated with the Romeral fault system rather than the subduction zone interface. In addition, we summarize global observations of tremor‐triggering stress and background ambient tremor activity in 24 tremor‐active regions. Based on the global summary of triggered and ambient tremor activity, the relative lack of triggered tremor in central and northern Chile and Peru is consistent with the lack of background tremor activity in these regions, suggesting tectonic tremor occurs only in isolated regions along major faults.

Extraction of Quasi-Linear Viscoelastic Parameters for Lower Limb Soft Tissues From Manual Indentation Experiment

1999 ◽  
Vol 121 (3) ◽  
pp. 330-339 ◽  
Author(s):  
Y. P. Zheng ◽  
A. F. T. Mak
Keyword(s):  
Lower Limb ◽  
Soft Tissues ◽  
Model Parameters ◽  
Viscoelastic Parameters ◽  
Fitting Procedure ◽  
Ultrasound Indentation ◽  
Initial Modulus ◽  
Linear Viscoelastic ◽  
Young Subjects ◽  
Three Body

A manual indentation protocol was established to assess the quasi-linear viscoelastic (QLV) properties of lower limb soft tissues. The QLV parameters were extracted using a curve-fitting procedure on the experimental indentation data. The load-indentation responses were obtained using an ultrasound indentation apparatus with a hand-held pen-sized probe. Limb soft tissues at four sites of eight normal young subjects were tested in three body postures. Four QLV model parameters were extracted from the experimental data. The initial modulus E0 ranged from 0.22 kPa to 58.4 kPa. The nonlinear factor E1 ranged from 21.7 kPa to 547 kPa. The time constant τ ranged from 0.05 s to 8.93 s. The time-dependent material parameter α ranged from 0.029 to 0.277. Large variations of the parameters were noted among subjects, sites, and postures.

Transient Compressional Waves in an Infinite Elastic Plate or Elastic Layer Overlying a Rigid Half-Space

1962 ◽  
Vol 29 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Julius Miklowitz
Keyword(s):  
Half Space ◽  
Elastic Layer ◽  
Integral Transform ◽  
Formal Solution ◽  
Equations Of Motion ◽  
Low Frequency ◽  
Frequency Equation ◽  
Point Load ◽  
Phase Method ◽  
Stationary Phase Method

The problem treated is that of an infinite free plate excited symmetrically by two equal and normally opposed step point-loads on its faces. The problem is equivalent to that of the surface normal point-load excitation of an infinite elastic layer, half the thickness of the plate, overlying a rigid half-space with lubricated contact. The formal solution is obtained from the equations of motion in linear elasticity with the aid of a double integral transform technique and residue theory. The stationary phase method, and known characteristics of the governing Rayleigh-Lamb frequency equation, are used to analyze and evaluate numerically the far field displacements. It is shown that the head of the disturbance is composed predominantly of the low-frequency long waves from the lowest mode of wave transmission.

Axisymmetric contact with friction of a rigid sphere with an elastic half-space

2009 ◽  
Vol 465 (2108) ◽  
pp. 2565-2588 ◽  
Author(s):  
O. I. Zhupanska
Keyword(s):  
Contact Problem ◽  
Half Space ◽  
Integral Transform ◽  
Elastic Half Space ◽  
Rigid Sphere ◽  
Analytical Treatment ◽  
Normal Contact ◽  
Exact Analytical Solutions ◽  
Single Integral ◽  
Toroidal Coordinates

The problem of normal contact with friction of a rigid sphere with an elastic half-space is considered. An analytical treatment of the problem is presented, with the corresponding boundary-value problem formulated in the toroidal coordinates. A general solution in the form of Papkovich–Neuber functions and the Mehler–Fock integral transform is used to reduce the problem to a single integral equation with respect to the unknown contact pressure in the slip zone. An analysis of contact stresses is carried out, and exact analytical solutions are obtained in limiting cases, including a full stick contact problem and a contact problem for an incompressible half-space.

The Effect of Refrigerated Storage on the Rheological Properties of Three Commercial Mozzarella Cheeses

2008 ◽  
Vol 4 (4) ◽  
Author(s):  
Edward B Muliawan ◽  
Savvas G Hatzikiriakos
Keyword(s):  
Rheological Properties ◽  
Viscoelastic Properties ◽  
Elevated Temperatures ◽  
Maxwell Model ◽  
Model Parameters ◽  
Refrigerated Storage ◽  
Mozzarella Cheese ◽  
Relaxation Dynamics ◽  
Generalized Maxwell Model ◽  
Linear Viscoelastic

The linear and non-linear viscoelastic properties and the effect of refrigerated storage on the rheological properties of three commercial mozzarella cheeses was studied. The linearity of the rheological behavior of mozzarella cheese increases with temperature because of the ability for the cheese to flow easier at higher temperatures as well as the lack of yield stress at elevated temperatures. The generalized Maxwell model parameters obtained from the linear viscoelastic data were found to describe the linear relaxation dynamics of the mozzarella cheese satisfactorily. It is also shown that the damping function of mozzarella cheese, which is a measure of the degree of non-linearity, can be described by a generalized Zapas model. Although, the different commercial mozzarella cheeses do not exhibit linear viscoelastic differences at room temperature, they do show significant differences at 60°C. The effect of refrigerated storage on the linear viscoelastic properties is brand-dependent and indicates structural differences among cheese samples. Finally it is shown that the dynamic moduli decrease with longer refrigerated storage due to proteolysis activities and/or weakening of the casein matrix.

scholarly journals Tidal bending of glaciers: a linear viscoelastic approach

2003 ◽  
Vol 37 ◽  
pp. 83-89 ◽  
Author(s):  
Niels Reeh ◽  
Erik Lintz Christensen ◽  
Christoph Mayer ◽  
Ole B. Olesen
Keyword(s):  
Laboratory Experiments ◽  
Viscoelastic Model ◽  
Elastic Beam ◽  
Beam Theory ◽  
Model Parameters ◽  
Beam Model ◽  
Glacier Ice ◽  
Linear Viscoelastic ◽  
Reasonable Choice ◽  
Linear Viscoelastic Model

AbstractIn theoretical treatments of tidal bending of floating glaciers, the glacier is usually modelled as an elastic beam with uniform thickness, resting on an elastic foundation. With a few exceptions, values of the elastic (Young’s) modulus E of ice derived from tidal deflection records of floating glaciers are in the range 0.9–3 GPa. It has therefore been suggested that the elastic-beam model with a single value of E ≈ 1GPa adequately describes tidal bending of glaciers. In contrast, laboratory experiments with ice give E = 9.3 GPa, i.e. 3–10 times higher than the glacier-derived values. This suggests that ice creep may have a significant influence on tidal bending of glaciers. Moreover, detailed tidal-deflection and tilt data from Nioghalvfjerdsfjorden glacier, northeast Greenland, cannot be explained by elastic-beam theory. We present a theory of tidal bending of glaciers based on linear viscoelastic-beam theory. A four-element, linear viscoelastic model for glacier ice with a reasonable choice of model parameters can explain the observed tidal flexure data. Implications of the viscoelastic response of glaciers to tidal forcing are discussed briefly.

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