scholarly journals To the study of the natural seismic tension of geological massifs

2020 ◽  
pp. 124-130
Author(s):  
Марина Валерьевна Зарецкая
Keyword(s):  
Contact Stress ◽  
Mechanical Characteristics ◽  
Block Structure ◽  
Equations Of Motion ◽  
Integral Representations ◽  
Structure Modeling ◽  
Block Element ◽  
Geological Medium ◽  
Stress Variation ◽  
Isotropic Elastic Medium

Методом блочного элемента проведено исследование блочной структуры, моделирующей геологический массив. Состояние геологической среды описывается уравнениями движениями для однородной, изотропной упругой среды в форме Ляме. Выписаны функциональные и псевдодифференциальные уравнения, получены интегральные представления блочного элемента. Установлены основные тенденции изменения контактных напряжений в зависимости от значений механических характеристик материала блоков и геометрических параметров структуры. The block structure method is used to study the block structure modeling a geological massif. The state of the geological medium is described by equations of motion for a homogeneous, isotropic elastic medium in the form of a Lame. Functional and pseudo-differential equations are written out, and integral representations of the block element are obtained. The main tendencies of contact stress variation are established depending on the values of the mechanical characteristics of the material of the blocks and the geometric parameters of the structure.

Analysis and Assessment of Seismic Hazard for the Azov-Black Sea Recreation Area

2020 ◽  
Vol 11 (7) ◽  
pp. 1672
Author(s):  
Marina ZARETSKAYA
Keyword(s):  
Block Structure ◽  
Property Values ◽  
Factorization Method ◽  
Geological Medium ◽  
Geological Structures ◽  
Motion Equations ◽  
Recreation Area ◽  
Isotropic Elastic Medium ◽  
Block Based ◽  
Block Element Method

One of the geological structures accountable for the implementation of seismic potential of the region is the largest vertical faults in the Earth’s interior, where earthquake foci are usually located. This article is aimed at developing a better method for calculation of stresses and strains that occur in such seismogenic areas. According to the results of the analysis of data collected during the expeditionary work, the geophysical medium is modeled by a block structure in the form of a half-space with a cut rectangular parallelepiped, which is divided into five block elements. The state of material in the geological medium is described in each block by motion equations for a homogeneous, isotropic elastic medium in the Lamé form. Following the block element method, the algorithm of the differential factorization method is implemented in each block. Based on the numerical analysis results, the main trends in contact stresses and dynamics of displacement amplitudes were determined depending on the mechanical property values of the block material and the geometric parameters of the structure.

scholarly journals Laminar momentum jets in a stratified fluid

1971 ◽  
Vol 45 (3) ◽  
pp. 561-574 ◽  
Author(s):  
E. J. List
Keyword(s):  
Fourier Transforms ◽  
Equations Of Motion ◽  
Finite Thickness ◽  
Three Dimensional ◽  
Stratified Fluid ◽  
Integral Representations ◽  
Return Flow ◽  
Horizontal Flows ◽  
Creeping Flows ◽  
Finite Distance

Solutions are presented for creeping flows induced by two-and three-dimensional horizontal and vertical momentum jets in a linearly stratified unbounded diffusive viscous fluid. These linear problems are solved by replacing the momentum jet by a body force singularity represented by delta functions and solving the partial differential equations of motion by use of multi-dimensional Fourier transforms. The integral representations for the physical variables are evaluated by a combination of residue theory and numerical integration.The solutions for vertical jets show the jet to be trapped within a layer of finite thickness and systems of rotors to be induced. The horizontal two-dimensional jet solution shows return flows above and below the jet and a pair of rotors. The three-dimensional horizontal jet has no return flow at finite distance and the diffusive contribution is found to be almost negligible in most situations, the primary character of the horizontal flows being given by the non-diffusive solution. Stokes's paradox is found to be non-existent in a density-stratified fluid.

scholarly journals Dispersion and Attenuation for an Acoustic Wave Equation Consistent with Viscoelasticity

2014 ◽  
Vol 22 (03) ◽  
pp. 1450006 ◽  
Author(s):  
A. Hanyga
Keyword(s):  
Wave Equation ◽  
Acoustic Wave ◽  
Equations Of Motion ◽  
Asymptotic Properties ◽  
Integral Representations ◽  
Acoustic Wave Equation ◽  
Completely Monotonic ◽  
Acoustic Equation ◽  
Viscoelastic Equations ◽  
Dispersion And Attenuation

An acoustic wave equation for pressure accounting for viscoelastic attenuation is derived from viscoelastic equations of motion. It is assumed that the relaxation moduli are completely monotonic (CM). The acoustic equation differs significantly from the equations proposed by Szabo (1994) and in several other papers. Integral representations of dispersion and attenuation are derived. General properties and asymptotic behavior of attenuation and dispersion in the low and high-frequency range are studied. The results are compatible with experiments. The relation between the asymptotic properties of attenuation and wavefront singularities is examined. The theory is applied to some classes of viscoelastic models and to the quasi-linear attenuation reported in seismology.

Research on Parameterized Modeling Technology for the Bolted Joints Structure

2014 ◽  
Vol 565 ◽  
pp. 211-216 ◽  
Author(s):  
Xue Zhai ◽  
Qing Gang Zhai ◽  
Jian Jun Wang ◽  
Xu Guang Fu
Keyword(s):  
Mechanical System ◽  
Mechanical Characteristics ◽  
Modeling Method ◽  
Bolted Joints ◽  
Structure Modeling ◽  
Theoretical Derivation ◽  
Turbofan Engine ◽  
Modeling Technology ◽  
Parameterized Modeling ◽  
Improve Calculation

Bolted joints structures exist in modern mechanical system, it is difficult to simulate the characteristics of the bolted joints accurately and effectively because of their complexity and diversity, which bring a great challenge to the whole structure modeling. Based on theoretical derivation of the bolted joints mechanical characteristics, the parameterized simulation technology and modeling method was used to equivalent simulate the bolted joints and with the example of a certain type of modern turbofan engine to elaborate the application of the parameterized modeling method. The research results have shown that the parameterized modeling method can not only simulate the true characteristics of bolted joints but also can improve calculation efficiency and saving computing cost effectively.

Dynamics of a Vibrating Micro Three-Axis Ring Gyroscope

2006 ◽  
Vol 306-308 ◽  
pp. 1241-1246
Author(s):  
Chang Boo Kim ◽  
Chong Du Cho ◽  
Hyeon Gyu Beom
Keyword(s):  
Angular Velocity ◽  
Dynamic Characteristics ◽  
Mechanical Characteristics ◽  
Equations Of Motion ◽  
Measuring Method ◽  
Plane Motion ◽  
Main Body ◽  
Cyclic Symmetry ◽  
Natural Modes ◽  
Angular Velocities

This paper presents electro-mechanical characteristics of a micro-machined vibrating silicon ring gyroscope which can measure angular velocity components about three orthogonal axes. The ring gyroscope has a ring connected to the gyroscope main body by support ligaments that are arranged with cyclic symmetry. The natural modes of its vibration can be distinguished into the in-plane motion and the out-of-motion that are coupled by the gyro-effect due to the rotation of the gyroscope main body. The motions of the ring are electro-statically driven, sensed and balanced by electrodes. The equations of motion are formulated with considering the electrostatic effects of electrodes. The measuring method of angular velocities of the gyroscope main body by force-torebalance is proposed. The dynamic characteristics of the ring gyroscope are discussed.

scholarly journals ASSESSMENT OF GEOECOLOGICAL CONSEQUENCES OF SUBDUCTION PROCESSES

2021 ◽  
Vol 1 (6) ◽  
pp. 79-83
Author(s):  
M.V. Zaretskaya ◽  
◽  
V.V. Lozovoy ◽  
Keyword(s):  
Diffusion Equation ◽  
Volcanic Activity ◽  
Model Problem ◽  
Block Structure ◽  
Three Dimensional ◽  
Factorization Method ◽  
Integral Representations ◽  
Transport And Diffusion ◽  
Numerical Analytical Method ◽  
And Diffusion

t. The aim of the work is to develop a numerical-analytical method for assessing the geoecological consequences of volcanic activity accompanying the subduction process. The boundary problem was formulated, including the three-dimensional transport and diffusion equation and boundary conditions at the bottom and surface of the water. For research, a block structure with quasi-homogeneous layers is introduced. In each block, a differential factorization method is implemented and integral representations of solutions are obtained. Calculations for a model problem are carried out, conclusions are formulated about the features of the behavior of the heavy and light fractions of volcanic ejections depending on the speed of currents, intensity and duration of the eruption.

The Fundamental Mechanical Characteristics Evaluation for Bolted Pipe Flange Connections With RTJ Gaskets Under Internal Pressure

2019 ◽  
Author(s):  
Kenshiro Nakade ◽  
Koji Sato ◽  
Toshiyuki Sawa
Keyword(s):  
Plastic Deformation ◽  
Contact Stress ◽  
Inflection Point ◽  
Mechanical Characteristics ◽  
Design Method ◽  
Leak Rate ◽  
Bolt Preload ◽  
Higher Temperature ◽  
Sealing Mechanism ◽  
Better Than

Abstract Bolted pipe flange connections with metallic flat gaskets or ring type joint (RTJ) gaskets are used under higher pressure and higher temperature. However, a sealing mechanism is not known and a design method is not established how to determine bolt preload for preventing leakage from the connection with metallic gaskets. In addition, the characteristics of the connection are not known when oval and octagonal gaskets are used. In previous paper, when the contact stress of metallic flat gasket reaches the stress at plastic deformation inflection point, the leak rate is decreased rapidly. However, the leak rate could be measured up to 1.0 × 10−5 Pa · m3/s level. The objectives of the paper are to measure the leak rate of the metallic flat gasket of which the contact stress is over the stress at plastic deformation inflection point, and to measure the leak rate of 1.0 × 10−9∼10 Pa · m3/s level in the flat metallic gasket in the platen tests and the connection with RTJ gaskets. In addition, the characteristics of the connection are examined when oval and octagonal gaskets are used. As a result, it is found that the leak rate for the metallic flat gasket can be measured around 1.0 × 10−9∼10 Pa · m3/s in the platen tests when the contact stress of aluminum gasket reaches the stress at plastic deformation inflection point and more while the leak rate of SUS 304 flat gasket is around 1.0 × 10−7∼8 Pa · m3/s even if the contact stress is over 1.3 times of the stress at plastic deformation inflection point. In addition, the sealing characteristics of the connection with oval gasket are shown to be better than that with octagonal gasket. From a laser microscope observation, it is found that the contact area of oval gasket in the connection is smaller than that of octagonal gasket in the connection.

Analysis on Mechanical Characteristics of Flexible Membranous Disc Coupling

2013 ◽  
Vol 655-657 ◽  
pp. 506-510
Author(s):  
Shang Yang ◽  
Hui Qun Yuan ◽  
Yan Li
Keyword(s):  
Finite Element ◽  
Working Conditions ◽  
Dynamic Characteristics ◽  
Mechanical Characteristics ◽  
Finite Element Models ◽  
Stress Variation ◽  
3D Finite Element ◽  
Harmonic Response ◽  
Design Requirements ◽  
Element Theory

Using the basic finite element theory, 3D finite element models of flexible membranous disc coupling with different disc thickness is built by ANSYS ，and then the dynamic characteristics are analyzed in working conditions. In particular, the analysis of static stress and harmonic response to the thickness of 0.85 model is done for getting the stress variation under a rated condition. The date calculated by dynamic characteristics and stress analysis can satisfy the design requirements. Those researches and analysis provide a theoretical consideration for complex vibration situation of flexible membranous disc coupling and for the improvement and optimization of coupling product.

A LATTICE SOLID MODEL FOR THE NONLINEAR DYNAMICS OF EARTHQUAKES

1993 ◽  
Vol 04 (06) ◽  
pp. 1059-1074 ◽  
Author(s):  
PETER MORA ◽  
DAVID PLACE
Keyword(s):  
Equations Of Motion ◽  
Ductile Material ◽  
Solid Model ◽  
Interacting Particles ◽  
Stick Slip ◽  
Nonlinear Dynamical ◽  
Initial Work ◽  
Isotropic Elastic Medium ◽  
Lattice Solid Model ◽  
Lattice Solid

A lattice solid model is presented that is capable of simulating the nonlinear dynamical processes (friction and fracture) associated with earthquakes. It is based on molecular dynamics principles to model interacting particles by numerically solving their equations of motion. Particles represent indivisible units of the system such as grains and interactions are described through effective potential functions. In this initial work, particles interact through radial pairwise potentials and the solid is made of particles arranged in a two–dimensional triangular lattice which corresponds to an isotropic elastic medium in the macroscopic limit. Simple and tractable potentials are specified to model brittle and ductile material. Numerical experiments of flawed brittle and ductile blocks subjected to uni–axial compression yield mode II fracturing behavior and characteristic stress–strain curves. In another experiment involving brittle blocks with rough surfaces being dragged past one another, stick–slip frictional behavior is observed. These results suggest that earthquakes can be simulated using the particle based modeling approaches even when the particles and their interactions are highly simplified.

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