scholarly journals Strains analysis at the wave propagation throught he contact layer of the elastic solids

2020 ◽  
pp. 89-96
Author(s):  
N.B. Chertova ◽  
◽  
Yu.V. Grinyaev ◽  
Keyword(s):  
Wave Propagation ◽  
Strain Distribution ◽  
Strain State ◽  
Strain Analysis ◽  
Contact Layer ◽  
Reflection Coefficients ◽  
Block Medium ◽  
Elastic Solids ◽  
Elastic Parameters ◽  
Analytical Expressions

The stress-strain state on the interface of the elastic solids is investigated. The studied interface presents a contact layer which is characterized by dimension and the set of physics mechanical parameters. The models of layered and block medium are used for the description this boundary. In the framework of these models the problem of elastic wave propagation through the interface is considered. Analytical expressions for the refraction and reflection coefficients allowing us to determine the strains on the interface and strains distribution in the contact layer are found. Corresponding strains amplitudes depending on the layer thickness are calculated at the different elastic parameters of contacting solids and boundary. The strain laws on the interface which is described by the layered and block medium models are analyzed. The regions of equivalent use these models are determined in the case of strain analysis on the boundary and the strain distribution in the contact layer.

scholarly journals X-ray diffraction strain analysis of a single axial InAs1–xPxnanowire segment

2015 ◽  
Vol 22 (1) ◽  
pp. 59-66 ◽  
Author(s):  
Mario Keplinger ◽  
Bernhard Mandl ◽  
Dominik Kriegner ◽  
Václav Holý ◽  
Lars Samuelsson ◽  
...  
Keyword(s):  
Strain Distribution ◽  
Strain State ◽  
Strain Analysis ◽  
Statistical Information ◽  
Core Region ◽  
X Ray Diffraction ◽  
Ensemble Averaging ◽  
X Ray ◽  
Inhomogeneous Strain ◽  
Zinc Blende

The spatial strain distribution in and around a single axial InAs1–xPxhetero-segment in an InAs nanowire was analyzed using nano-focused X-ray diffraction. In connection with finite-element-method simulations a detailed quantitative picture of the nanowire's inhomogeneous strain state was achieved. This allows for a detailed understanding of how the variation of the nanowire's and hetero-segment's dimensions affect the strain in its core region and in the region close to the nanowire's side facets. Moreover, ensemble-averaging high-resolution diffraction experiments were used to determine statistical information on the distribution of wurtzite and zinc-blende crystal polytypes in the nanowires.

Effect of pipe expansion on the redistribution of residual stresses after molding

2020 ◽  
Vol 10 (2) ◽  
pp. 122-126
Author(s):  
Nikolay A. Makhutov ◽  
◽  
Dmitry A. Neganov ◽  
Eugeny P. Studenov ◽  
◽  
...  
Keyword(s):  
Residual Stresses ◽  
Strain Distribution ◽  
Strain State ◽  
Stress And Strain ◽  
Cylindrical Shape ◽  
Pipe Material ◽  
Pipe Expansion ◽  
Calculation Results ◽  
Residual Deformations ◽  
Stress And Strain Distribution

In the factory, pipes for trunk oil and oil product pipelines are obtained by molding and welding. To ensure a cylindrical shape and reduce technological residual stresses, expansion technology is used. Pipe expansion causes a significant change in the values of residual deformations and stresses. The article presents both the calculation results and graphs regarding stress and strain distribution during bending of the stock and their redistribution after expansion. Based on the calculation results, the final total values of residual stresses and residual deformations caused by bending and expansion were stated to be important components of the stress-strain state observed in pipelines being operated under cyclic loading, as well as those used in assessing how degradation affects the ductility of the pipe material. These factors were concluded as being reasonably taken into account when performing verification calculations regarding long-running pipelines if, based on their diagnostics and analysis, their state does not meet modern strength requirements.

Boundary conditions for the numerical solution of wave propagation problems

Geophysics ◽  
1978 ◽  
Vol 43 (6) ◽  
pp. 1099-1110 ◽  
Author(s):  
Albert C. Reynolds
Keyword(s):  
Wave Propagation ◽  
Reflection Coefficient ◽  
Finite Difference ◽  
Boundary Conditions ◽  
Numerical Solution ◽  
Neumann Boundary ◽  
Synthetic Seismograms ◽  
Neumann Boundary Conditions ◽  
Numerical Calculations ◽  
Reflection Coefficients

Many finite difference models in use for generating synthetic seismograms produce unwanted reflections from the edges of the model due to the use of Dirichlet or Neumann boundary conditions. In this paper we develop boundary conditions which greatly reduce this edge reflection. A reflection coefficient analysis is given which indicates that, for the specified boundary conditions, smaller reflection coefficients than those obtained for Dirichlet or Neumann boundary conditions are obtained. Numerical calculations support this conclusion.

Constitutive inequalities for isotropic elastic solids under finite strain

1970 ◽  
Vol 314 (1519) ◽  
pp. 457-472 ◽  
Keyword(s):  
Scalar Product ◽  
Finite Strain ◽  
Strain Analysis ◽  
Stress And Strain ◽  
Elastic Solids ◽  
Intrinsic Interest ◽  
Typical Member ◽  
Rates Of Change ◽  
Constitutive Inequalities ◽  
Strain Measures

Possible restrictions on isotropic constitutive laws for finitely deformed elastic solids are examined from the standpoint of Hill (1968). This introduced the notion of conjugate pairs of stress and strain measures, whereby families of contending inequalities can be generated. A typical member inequality stipulates that the scalar product of the rates of change of certain conjugate variables is positive in all circumstances. Interrelations between the various inequalities are explored, and some statical implications are established. The discussion depends on several ancillary theorems which are apparently new; these have, in addition, an intrinsic interest in the broad field of basic stress—strain analysis.

scholarly journals Interaction of outer hull structures with flexible lines

2019 ◽  
pp. 123-129
Author(s):  
Sergey Bratelev ◽  
Igor Rozоv
Keyword(s):  
Finite Length ◽  
Strain State ◽  
Stress Strain ◽  
Stress Strain State ◽  
Software Packages ◽  
Loading Patterns ◽  
Analytical Expressions

This paper investigates stress-strain state of hull with longitudinal and transverse stiffeners under compression due to flexible lines (straps). Architecturally, two hull variants have been studied: rectangular with roundings at bilges and cylindrical. The problem was solved as per well-known analytical expressions, whereas stress-strain parameters of “hullstrap” system, depending on strap stiffness and presence of “loose” contact with the strap and the plating, were updated in ANSYS and LS-DYNA software packages. The study yielded the following data: stress-strain parameters of plating taking into account longitudinal and transverse stiffeners; loading patterns for separate hull elements (plate, stiffener) depending on strap stiffness; and loading patterns for separate hull elements in case of “loose” contact with straps in the areas of finite length.

scholarly journals Frequency-Dependent Tensile and Compressive Effective Moduli of Elastic Solids With Randomly Distributed Two-Dimensional Microcracks

2015 ◽  
Vol 82 (8) ◽  
Author(s):  
Youxuan Zhao ◽  
Yanjun Qiu ◽  
Laurence J. Jacobs ◽  
Jianmin Qu
Keyword(s):  
Wave Attenuation ◽  
Two Dimensional ◽  
Effective Moduli ◽  
The Finite Element Method ◽  
Elastic Solids ◽  
Frequency Dependent ◽  
Micromechanics Models ◽  
Dynamic Case ◽  
Crack Faces ◽  
Analytical Expressions

This paper develops micromechanics models to estimate the tensile and compressive elastic moduli of elastic solids containing randomly distributed two-dimensional microcracks. The crack faces are open under tension and closed under compression. When the crack faces are closed, they may slide against one another following the Coulomb's law of dry friction. The micromechanics models provide analytical expressions of the tensile and compressive moduli for both static and dynamic cases. It is found that the tensile and compressive moduli are different. Further, under dynamic loading, the compressive and tensile moduli are both frequency dependent. As a by-product, the micromechanics models also predict wave attenuation in the dynamic case. Numerical simulations using the finite element method (FEM) are conducted to validate the micromechanics models.

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