Research of interaction of the deformable designs located in the soil

© 2014 D. V. Berezhnoi et al. In work construction of algorithm of the contact interaction based on introduction between parts of designs of a special contact layer is considered. Different variants of the deformation of the contact layer, for clarity presented by two overlays, depending on the impact of the efforts of substructures at each other. A general governing equation, which is solved on the basis of physically nonlinear problem formulated. To solve the problem, a method of solving problems in increments when iteration step the unknowns are not full of the displacement field, and their increments. It is solved model problems about modeling of stage-by-stage dredging from a foundation ditch with retaining walls

Geometrically nonlinear deformation elastoplastic soil

© 2014 D. V. Berezhnoi, A. A. Sachenkov and M. K. Sagdatullin. In work statement of a problem of numerical modeling of finite deformations elastoplastic soil environments, focused on application FEM is given. Implemented and tested method of solving the problem of elastic-plastic deformation of soil masses on the basis of defining relations between the increments of the true stress and strain, resolved a number of model problems of determining the stress-strain and limiting condition of soils

Empirical analysis of job satisfaction determinants in Russia

© 2015 Canadian Center of Science and Education. All rights reserved. Investigation into job satisfaction determinants is of high practical relevance since it acts as an indicator of particular groups of employees’ willingness to invest in development of professional competencies and skills. The paper presents results of empirical analysis of determinants of job satisfaction, satisfaction with professional advancement prospects as well as concerns over possible job loss carried out using panel data representing working population of Russia. The main results obtained lead us to the following conclusions. Employment functions as well as financial incentives have the strongest influence over job satisfaction and satisfaction with professional advancement prospects, while respondents representing all professions reviewed are generally equally concerned with possible job loss. Age and length of respondent’s employment are nonlinearly related to satisfaction indicators while gender differences are not significant. Residents of large cities are less frequently satisfied with their jobs and professional advancement prospects; however, they are much less concerned about possible job loss. Those employed by state-owned companies and agencies more frequently express satisfaction with their current positions. The analysis also reveals a distinct decline in job satisfaction level and in satisfaction with professional advancement opportunities in the crisis years of 2009 and 2010

Experimental study of evaluation of mechanical parameters of heterogeneous porous structure

© Published under licence by IOP Publishing Ltd. The paper deals with the problem of determining the mechanical macroparameters of the porous material in case of knowing the information about it's structure. Fabric tensor and porosity was used to describe structure of the material. Experimental study presented. In research two-component liquid polyurethane plastics of cold curing Lasilcast (Lc-12) was used. Then samples was scanned on computer tomography. Resulting data was analyzed. Regular subvolume was cut out after analyses. Then mechanical tests was performed. As a result we get information about fabric tensor, porosity, Young's modulus and Poisson ratio of the sample. In the abstract presented results for some samples. Taking into account the law of porosity variation, we considered the problem of evaluating the mechanical macro parameters depending on the nature of the porous structure. To evaluate the macroparameters, we built the dependence of the Young's modules and Poisson ratio of the material on the rotation angle α and the pore ellipticity parameter λ. The sensitivity of the deformations to the elastic constants was also estimated

The evolution of the trabecular bone at a constant combined loading

© 2016, International Journal of Pharmacy and Technology. All rights reserved.This paper deals with the mathematical model of restructured bone tissue under the influence of external forces. The mathematical model has been formed on the basis of Wolff law in the Cowin mathematical formulation. The paper considers a number of model problems: all-around compression with single-direction weakening, the problem of torsion and the problem of uniform compression with stress tensor rotation at a predetermined angle. We have calculated the relative change in the solid volume and the components of the structure tensor (tissue tensor), the solution was considered the convergence of asymptotic behavior of the strain tensor components to the value of - 0.0015, which meant lazy zone. It was noted in the problem of all-around compression that the bone microstructure comes in homeostatic balance regardless of the size and sampling of the parameter of weakening. It was noted in the problem of torsion that an increase in the tangential components of the structure tensor results in significant variation of the behavior of the solid volume and the components of structure tensor. In the problem of stress tensor rotation, the components of structure tensor change first, which is consistent with Wolff law – the bone tissue is rearranged along the lines of principal stresses

Investigation of stress-strain state in the flywheel and estimation their specific energy capacity

© The Authors, published by EDP Sciences, 2017. In this paper, the specific energy intensity of the kinetic energy storage devices, including the flywheel-casing scheme in the potential field, is investigated. The possibilities of using various structural materials in the manufacture of structural elements of a mechanical accumulator are analyzed, the stress-strain state of the flywheel and the casing under quasistatic increase in the rotational speed of the rotor part of the structure is investigated. It is noted that the presence of a potential field in the flywheel-casing system makes it possible to increase the specific energy intensity of the kinetic energy storage

Modelling of deformation of underground tunnel lining, interacting with water-saturated soil

© Published under licence by IOP Publishing Ltd.Built finite element method of calculating the deformation of underground tunnel lining, interacting with dry and water-saturated soils. To simulate the interaction between the lining and soils environments, including physical and non-linear, a special "contact" finite element, which allows to consider all cases of interaction between the contacting surfaces. It solved a number of problems of deformation with the ground subway tunnel lining rings

Determination of muscle effort at the proximal femur rotation osteotomy

© Published under licence by IOP Publishing Ltd.The paper formulates the problem of biomechanics of a new method for treatment of Legg-Calve-Perthes disease. Numerical calculations of the rotational flexion osteotomy have been carried out for a constructed mathematical model of the hip joint, taking into account the main set of muscles. The work presents the results of the calculations and their analysis. The results have been compared with the clinical data. The calculations of the reactive forces arising in the acetabulum and the proximal part of the femur allowed us to reveal that this reactive force changes both in value and direction. These data may be useful for assessing the stiffness of an external fixation device used in orthopedic intervention and for evaluating the compression in the joint

Evaluation of external fixation device stiffness for rotary osteotomy

© Research India Publications. The paper presented the results of strength and stiffness calculation in respect of external fixation device used in the concept of a three-plane spatial correction of proximal femur abnormal orientation taking into account the stage of the disease concerning the localization of degenerative dystrophic process and damage severity. A three-dimensional parametric model of the device was developed and its finite element discretization by four node tetrahedral finite element with a linear approximation and the four node hexagonal finite element with linear approximation. The problem of stress-strain state determination was solved of the structure in the linear formulation on the basis of the finite element method for different values of swivel bracket structure turn. Stress localization zones, the dangerous sections of threaded connections were determined. We obtained the values of maximum shear stress and the stress intensity for various states of construction. On the basis of these data the workloads were determined, the threaded connections of which made 15 Nm by stiffness. The safety margin of the structure by plasticity allows the loads up to 24 Nm. In order to increase the reliability and the hardness of external fixation device the attachment points of pins to rotary brackets were reinforced by locknuts