Calculation Of Stress-strain State Research Articles

Расчет напряженно-деформированного состояния многослойных комбинированных сосудов давления

Расчет напряженно-деформированного состояния многослойных комбинированных сосудов давления

Calculation of stress-strain state of stamp rigging elements

В статье предложен подход к исследованию напряженно-деформированного состояния элементов штамповой оснастки с учетом контактного взаимодействия. Задача сводится с привлечением теории вариационных неравенств к проблеме минимизации функционала полной внутренней энергии системы. При этом определяется распределение контактного давления по контактным поверхностям. Также определяется напряженно-деформированное состояние штампов.

Strength Calculation Method for Cross-Section of Reinforced Concrete Flexural Member Using Curvilinear Concrete Stress Diagram of EN-2

This article is continuation of earlier work of the author. Apractical method for cross-section strength calculation of flexural reinforced concrete members with rectangular compression zone using curvilinear concrete stress-strain diagrams of Eurocode 2 (EN-2) is presented in this article. The method can be used for strength calculation of members with flanges and reinforcement in compression zone as well. Curvilinear EN-2 stress diagrams are readily superseded by polynomials that can be easily integrated are proposed by the author. It gives opportunity for mathematically accurate, without changing of curvilinear diagram by arbitrary diagrams, determination of value and location for resultant of concrete compression zone stresses and location of neutral axes as well. Calculation is performed for any chosen strain of the layer subjected to the maximum compression. The said strain may be of greater or less value in comparison to that corresponding to the concrete strength. In this way the maximum strength of the member can be estimated when the compression zone strain value varies within chosen interval. The method is suitable in both cases for the members which are commonly (not abundantly) and abundantly reinforced if the neutral axes is located within the cross-section, i. e. within the interval up to the centre of the tensile reinforcement cross-sectional area. Strength of members reinforced with high strength reinforcement which is not sufficiently prestressed or not prestressed at all can be determined by calculation. Formulae can be used for calculation of stress-strain state in persistent situations (not ultimate ones) and for calculation of steel prestress value as well. Rectangular compression zone parameters required for member strength calculation using curvilinear stress diagram are presented in the article. Results obtained by the proposed method are compared with the results obtained using EN-2 formulae.

Topical problems in ensuring safe operation of gas pipelines in the far north environment

The methods and results of the technical state inspection of gas pipelines in the Far North environment are considered. The stress-strain state calculations for gas pipelines in operation as well as metallographic and strength investigations of metal after operation have been performed.

Experimental and computational analysis of stress-strain state of pneumatics in breaker zone under mechanical effects

The paper is devoted to the calculation of the stress-strain state of interior regions of laminated composite structures (pneumatic tires) with the application of the finite element method. It is shown that the approaches to modeling of the rubber-cord structure of a tire (using rod, membrane, or three-dimensional isotropic elements simulating the separate cord threads and the rubber matrix) affect the calculation results. For this reason, the results of calculations need to be correlated with the experimental data. The polarization-optical method is used as the experimental method for determining the stresses in the interior regions of a tire. An experimental and computational method of determining the stress-strain state of pneumatic tires is proposed. The method is intended for the selection of a technique for simulating the laminated structure of pneumatic tires in terms of the correlation with the experimental data on standard tires.

Life prediction of titanium and aluminum alloys under fretting fatigue conditions using various crack propagation criteria. Part 2. Application of the technique to cylindrical specimens with semi-elliptical crack and account of the residual stresses

In order to simulate the operating fretting-fatigue conditions in cylindrical structural components, we have performed experimental studies on fretting fatigue of cylindrical specimens with clamped concave cylindrical pads of bridge type. Using the known solutions for stress intensity factors in the semi-elliptical cracks growing in cylindrical specimens, we predict the kinetics of propagation of fretting-fatigue cracks according to the two-parameter model described in Part 1. A close correlation of calculated and experimental fretting-fatigue life values is observed for AMg6N alloy for varied experimental fretting conditions (contact load, slip amplitude and friction coefficient). For alloy VT9 we have provided approbation of the technique, which takes into account distribution of the residual stresses in the material subsurface during calculation of stress-strain state and life under fretting-fatigue conditions.

The inclusion of rheological properties of rocks to calculation of stress-strain state of an undermined rock mass

The procedure proposed for calculation of deformation and collapse of underworked strata is based on using the stiffness calculation matrix, representing the pre-mining state of rocks. The initial stress method is employed to account for variations in elastic constants in the deformation area in terms of the linear viscosity-elasticity. Potentialities of the described approach are considered. A number of solutions to the research problems are presented.

Investigation of the possibility and conditions for passing inspection gauges through the section of cable-stayed aerial pipeline crossing

We have performed calculations of stress-strain state of cable-stayed aerial pipeline crossing in the operation state and of the additional effect of the inspection gauge application. In order to assess efforts in the pipe and cable stays of the aerial crossing, we apply analytical solutions combined with numerical simulations using the 3D PipeMaster software system. This comprehensive analysis allows one to assess stresses in the critical zones of the crossing, as well as to develop recommendations on strengthening the structure of the aerial crossing before its in-line inspection.

Calculation of stress-strain state for an over-goaf rock mass

The stress state of a rock mass over a goaf is analyzed by using the mathematical modeling. The initial stress method is used to consider caving and failure zones within overlying rocks and makes it possible to derive an effective estimation algorithm for the undermined rock state.

A study of suitability of various criteria for fracture toughness prediction on small-sized specimens

A three-dimensional stress-strain state calculation is performed by the finite-element method for precracked Charpy specimens side grooves of different depths. Based on the calculated results, the paper addresses the suitability of various brittle fracture criteria to describe experimental data on fracture toughness of these specimens.

Calculation of stress-strain state in a rock mass with an oil formation

The papers considers the problems on deformation in a rock mass with an oil formation under condition of uncertain data on this rock mass. The pre-derived systems of integral equations are solved, and the results are discussed.

Computational estimate of the dynamical response of TUK-84 in tests under accident conditions during shipment

A computational finite-element model of TUK-84 is described. The expected results are presented for the parameters of the first five impacts on TUK-84 when it is dropped from a height of 9 m and data from calculations of the dynamical stress-strain state of the structure which correspond to the maximum stresses and strains in the vessel and cover under a prescribed action. The computational model of the container is described for the case where the container is dropped from a height onto a pin, and the boundary conditions and expected maximum flexing in the impact zone are shown.

Application of Finite-Element Method to Investigate Interaction between Slide-Prone Soils and Piles

An analytical scheme using the finite-element method is proposed for interaction between slide-prone soils and piles in single-row anti-slide structures. Results are presented for calculation and analysis of the stress-strain state of slide-prone soils interacting with the piles.

Energy consumption for deformation to fracture of a circular-clamped thin plate under impact loading

An experimental procedure for evaluating energy spent for fracture of a circular-clamped sheet structural element upon transverse flexure, induced by impact loading of a spherical head-face body, is briefly outlined. Flexure test results for two sheet metals (a 20 mild steel and a D16T aluminum alloy 1.0 and 0.75 mm thick, respectively) and a 2.0-mm PA6 shock-resistant composite are cited. Experimental data analyses and stress-strain state calculations for a plate material within the circular boundary upon flexure made it possible to establish the relation between the work of deformation and the dynamic strength and plasticity. Sheet structural element materials are comparatively evaluated by their specific energy spent for deformation under transverse static and impact loading.

Automated calculation of the stress-strain state of two-tier collectors

Automated calculation of the stress-strain state of two-tier collectors

Analysis of the stress-Strain state of components of the lock joint of a compressor disk in a gas turbine engine in the three-dimensional elastic statement. Report 1

The stress-strain state (SSS) of the lock joint in a “dovetail-type” compressor disk is investigated. The effect of type of loading and geometric parameters on the distribution of stress intensity is established. Surfaces of elastic-stress concentration are obtained as a function of the relationship between nominal stresses and the slope of the groove. It is demonstrated that consideration of torsion is a determining factor in performing SSS calculations for the real operating conditions of the type of lock joint under consideration.

Application of the finite-element method in calculating seepage in the foundations of hydraulic structures

1. The information obtained by the finite-element method contains a complete set of data on seepage, and may be directly used to facilitate the interpretation of the calculation findings. 2. No major technical difficulties are encountered in calculating the heterogeneity and anisotropy of the filtering medium, the arbitrary shape of the reference area, and the hydraulic conditions along its boundaries. 3. The use of a simple layout of elements makes it possible to carry out a successive calculation of the seepage flow under a structure and a concurrent calculation of the stress-strain state of the structure and foundation. The hydrodynamic pressure and hydrostatic forces, determined during the course of seepage calculation are introduced as force components during statics calculations.