In this article, analytic expressions for the frequency wave number spectra are derived for the displacement and rotational components at the ground surface of a micropolar elastic half-space. The ground motion is caused by buried sources described in terms of unit impulsive force and micro-moments. Closed-form analytic expressions for both plane strain and anti-plane strain conditions are established. In the sequel, Green's functions for reduced micro polar half-space where the couple stresses are zero and the stress tensor is nonsymmetric are also presented. Numerical results are presented for anti-plane strain case. The derived expressions can be used to simulate rotational and displacement components of ground motion during earthquakes. © 2015 Elsevier Inc. All rights reserved.

S T G Raghukanth

Department Of Civil Engineering

Earthquake effects

geometry

Hydroelasticity

Shear strain

Strain

ANALYTIC EXPRESSIONS

Displacement components

MICROPOLAR CONTINUUM

MICROROTATION

ROTATIONAL COMPONENT

Seismic ground motions

STRONG GROUND MOTION

WAVENUMBER SPECTRA

Earthquakes

Fulltext

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IIT Madras

Applied Mathematical Modelling

Analytical expressions for displacements and rotations in a homogeneous reduced micropolar half-space subjected to a finite buried source are derived using the method of potentials. Explicit solutions for displacements and rotations are derived for a uniformly distributed force acting over a circular region in the horizontal or vertical direction. The obtained solutions for displacements are validated against those available in literature for a classical elastic half-space. Finally, Green’s functions for displacements and rotations are derived for a unit impulse applied in the horizontal or vertical direction. In addition to analytical solutions, the paper also compares the dispersion phenomenon of compression and&nbsp;shear waves propagating in a reduced micropolar half-space with different material properties. © 2019, Springer Nature Switzerland AG.

Pure and Applied Geophysics

Fundamental Solutions to Static and Dynamic Loads for Homogeneous Reduced Micropolar Half-Space

In this article, spatial variation of ground rotational motions is investigated by modelling the Earth medium as linear elastic and reduced micropolar elastic half-spaces. Ground motions are simulated for an earthquake of magnitude Mw 6 and the simulated results are presented in the form of Peak Translation Velocity (PTV) and Peak Rotational Velocity (PRV) contour maps near the fault plane. Rotations are predominant near the fault plane and decay very fast as moving away from the fault plane. The comparison of results show that the peak amplitude of rotations obtained from reduced micropolar are 80-20 times higher than those obtained from linear elastic theory in the epicentral region. Numerical results have suggested that, asymmetric theory like reduced micro polar theory is more efficient than linear elastic theory to simulate rotational motions. © 2018 Elsevier Ltd

Soil Dynamics and Earthquake Engineering

Spatial variation of ground rotational motions in elastic half-space

This paper explores reduced micropolar theory to simulate ground motion during an earthquake. In this theory, rotational motions are kinematically independent of translational motions. Analytical expressions for ground displacement and rotational motions due to a buried seismic source are presented in this paper. This theory requires two additional material constants which characterise the microstructure of the medium compared with linear elastic theory. Ground motions are simulated for an earthquake of magnitude (Mw) 5.0. The sensitivity of ground motion to these new material constants is reported. It is observed that rotations are sensitive to microstructure of the medium. A comparison with recorded rotations of the Mw 5.2 Izu peninsula, Japan event is also presented in this article. © 2016, Springer Science+Business Media Dordrecht.

Journal of Seismology

Seismic response of reduced micropolar elastic half-space

Bulletin of the Seismological Society of America

Waves in Linear Elastic Media with Microrotations, Part 2: Isotropic Reduced Cosserat Model

Waves in Linear Elastic Media with Microrotations, Part 1: Isotropic Full Cosserat Model

Journal of Geophysical Research

Strong motion compatible source geometry

Classics of Elastic Wave Theory

3l. On the Propagation of Tremors over the Surface of an Elastic Solid by Horace Lamb, F.R.S.

First Comparison of Array-Derived Rotational Ground Motions with Direct Ring Laser Measurements

Seismic ground motion in micropolar elastic half-space

Journal	Data powered by TypesetApplied Mathematical Modelling
Publisher	Data powered by TypesetElsevier Inc.
ISSN	0307904X
Open Access	Yes