Dependence of the limit state of composite and polymer materials on the type of the stress state

1988 ◽  
Vol 24 (1) ◽  
pp. 1-7 ◽  
Author(s):  
E. V. Lomakin
Keyword(s):  
Stress State ◽  
Limit State ◽  
Polymer Materials

Dependence of the limit state of composite and polymer materials on the type of stress state

1988 ◽  
Vol 24 (2) ◽  
pp. 194-200 ◽  
Author(s):  
E. V. Lomakin
Keyword(s):  
Stress State ◽  
Limit State ◽  
Polymer Materials ◽  
Type Of Stress State

Elastic-Plastic Finite Element Analysis on the Spillway of a Concrete Gravity Dam

2013 ◽  
Vol 295-298 ◽  
pp. 1870-1875
Author(s):  
Liang Cao ◽  
Hui Min Wang ◽  
Ji Yao ◽  
Shan Guang Qian ◽  
Chun Feng Tang
Keyword(s):  
Finite Element ◽  
Stress State ◽  
Limit State ◽  
Concrete Gravity Dam ◽  
Element Analysis ◽  
Full Account ◽  
Dam Foundation ◽  
Elastic Plastic ◽  
Geological Conditions ◽  
Sliding Stability

The 3-D finite element model of a concrete gravity dam’s spillway was established in this paper, and the elastic-plastic theory was applied, then the deformation and stress state of the dam under various working conditions were analyzed, it was prooved that the deformation and stress state of the dam were in normal condition. After solving the force of the dam foundation surface and taking full account of the complex geological conditions, the dam’s sliding stability was analyzed by capacity limit state design formula. The calculation results showed that, the stability parameter of the dam along foundation surface was bigger than 1.0, the dam’s sliding stability met the requirement.

Numerical modelling of the asymmetric behaviour of concrete

2020 ◽  
Vol 234 (7) ◽  
pp. 988-1000
Author(s):  
Carla V Lopes ◽  
Rui P Cardoso ◽  
Francisco Q Melo
Keyword(s):  
Stress State ◽  
Yield Stress ◽  
Structural Integrity ◽  
Limit State ◽  
Realistic Model ◽  
Biaxial Stress ◽  
Compression Tests ◽  
Finite Element Program ◽  
Limit Stress ◽  
State Criterion

This article analyses the conditions for the yield stress state of concrete subjected to generalised loads. For this purpose, a limit stress state criterion, initially developed for the assessment of magnesium and respective alloys, is here adapted and implemented as a simulation model to assess the structural integrity of concrete components. In fact, materials as magnesium and concrete exhibit a similar mechanical behaviour, presenting a non-symmetric limit state domain for biaxial stress combinations, where it is observed a considerably larger strength to yield or rupture in a compression stress state than in a tensile one. The Cazacu yield stress state criterion has shown to be an accurate and realistic model to define the ultimate strength, either of concrete and magnesium alloys, as mentioned. The Cazacu criterion was implemented in a finite element program as a ‘user-defined’ subroutine. The numerical validation of that criterion was carried out on adjusting its limit stress state points to corresponding ones obtained by experiments of standard tensile or compression tests of concrete test specimens.

scholarly journals Stress-strain state of a borehole determined analytically using drilling-out as a technology of reducing differential settlement

2021 ◽  
Vol 8 (2) ◽  
Author(s):  
Yakov Pronozin ◽  
Mikhail Kajgorodov ◽  
Aleksandr Gerber
Keyword(s):  
Stress State ◽  
Limit State ◽  
Soil Conditions ◽  
Plastic Deformation Zone ◽  
Silt Loam ◽  
Advantages And Disadvantages ◽  
Drilling Parameters ◽  
Pressure Tests ◽  
Soil Destruction ◽  
The Given

The existing approaches for reducing the differential settlements of buildings and structures have their own advantages and disadvantages. Lowering of a building or part of it is one of the promising methods to reduce the differential settlements of shallow foundations resting upon weak silt-loam soils. The effect is achieved by drilling-out vertical boreholes in the immediate vicinity of the foundation from the minimal settlements. Method: Russian and foreign scientists have been involved in the development of calculation procedures for horizontal and inclined drilling-out of boreholes. It has been important to determine drilling parameters when using this technology and how soil characteristics and stress state of soils around the borehole influence the reduction of differential settlements. The paper discusses the influence of the strength characteristics of soils on the stress state of the soil massif around the borehole, as well as the influence of the borehole radius on the formed areas of limit state. The analytical solution is based on the well-known ratio used to determine the stress state around the borehole during pressure tests. Tangential and radial stresses are determined from this ratio; next, they are checked according to the condition of the strength law, and thus, the stress state around the borehole becomes evident. Result: The stress state of the soil around the boreholes has been calculated by the given method; it has made it possible to calculate the areas of soil destruction and determine the parameters of boreholes and their geometry depending on the purposes when regulating the settlements of slab foundations. It has been established that drilling behind the foundation contour in relation to drilling in the foundation contour makes it possible to increase the radius of the plastic deformation zone up to two times under the same soil conditions and well geometry.

Analysis of Small Non-Sand Concrete Pile Grouting Pressure Based on Unified Strength Theory

2012 ◽  
Vol 166-169 ◽  
pp. 3095-3099
Author(s):  
Huai Feng Tong
Keyword(s):  
Stress State ◽  
Principal Stress ◽  
Limit State ◽  
Intermediate Principal Stress ◽  
Plastic State ◽  
Strength Theory ◽  
Unified Strength Theory ◽  
Grouting Pressure ◽  
Concrete Pile ◽  
The Relationship

Analysis of stress state of soil around the pile and grouting pressure of small non-sand concrete pile is given based on the expansion elastic theory of cylindrical cavity and the unified strength theory, the grouting pressure formula is obtained in the elastic limit state and elastic-plastic state of soil around the pile considered the intermediate principal stress, and the relationship is obtained between the grouting pressure and the plastic radius; When the soil around the pile is in different stress state, the correlativity of crack and densification of grouting is analyzed, and the relationship between the grouting pressure and the plastic radius is discussed with the right coefficient of the intermediate principal stress and initial press under different values. The obtained results have provided efficient analysis means for grouting optimal design of post-processing technology with small non-sand concrete pile.

Implementation of Incremental Yield Condition for Continual Problems with Singularity

2019 ◽  
Vol 974 ◽  
pp. 620-626 ◽  
Author(s):  
Sergey Y. Kalashnikov ◽  
Elena Gurova ◽  
Renat Kuramshin ◽  
Vladimir Kharlanov
Keyword(s):  
Stress State ◽  
Plastic Material ◽  
Limit State ◽  
Yield Condition ◽  
Initial Moment ◽  
Elastic State ◽  
Uniform Stress ◽  
Uniform Stress State ◽  
Analytical Expressions ◽  
State Criterion

The limit elastic state of an infinitely large half-plane under the action of concentrated vertical and horizontal forces has been considered. The gradient yield condition specifying the elasto-plastic material yielding initial moment at non-uniform stress state is used as the limit state criterion. The analytical expressions allowing to interpret the result in the singular point have been derived.

scholarly journals THE EFFECT OF MATERIAL STRENGTH ON THE BEHAVIOUR OF CONCRETE‐FILLED STEEL ELEMENTS

2004 ◽  
Vol 10 (3) ◽  
pp. 177-182
Author(s):  
Janis Brauns ◽  
Karlis Rocens
Keyword(s):  
Stress State ◽  
Stress Level ◽  
Composite Structures ◽  
High Performance Concrete ◽  
Limit State ◽  
High Stress ◽  
Material Strength ◽  
Ultimate Limit State ◽  
Concrete Core ◽  
Non Linear

Composite columns and beams are a combination of concrete and steel elements realising the advantages of both types of materials. According to codes for concrete‐filled column, the plastic resistance of the cross‐section is given as a sum of the components and taking into account the effect of confinement in case of circular sections. In this study the stress state in composite column is determined taking into account non‐linear relationship of the modulus of elasticity and Poisson's ratio on the stress level in the concrete core. It has been determined that the effect of confinement occurs at a high stress level when structural steel acts in tension and concrete works in lateral compression. The stress state and load bearing capacity of section in bending is determined taking into account non‐linear dependence on position of neutral axis. Because the ultimate limit state of material is not attained for all the parts simultaneously, to improve the stress state of a composite element and to prevent the possibility of a failure the appropriate strength of concrete and steel should be used. The safety of high-stressed composite structures can be achieved by using ultra‐high‐performance concrete (UHPC).

scholarly journals Numerical and experimental assessment of the long-operated drill pipes destruction conditions

2020 ◽  
pp. 88-97
Author(s):  
O. Yu. Vytyaz ◽  
R. S. Hrabovskyi ◽  
V. I. Artym ◽  
V. V. Tyrlych ◽  
N. R. Hrabovska
Keyword(s):  
Stress Intensity ◽  
Stress State ◽  
Limit State ◽  
Drill Pipe ◽  
Crack Tip ◽  
Experimental Investigations ◽  
Technical Diagnostics ◽  
Drilling Fluids ◽  
Critical Crack ◽  
Drill Pipes

The cause of failures in the elements of the drill string when drilling deep wells is the occurrence and development of crack-like defects in the cross section. The generalized data of defectoscopy of long-term operated drill pipes conducted at the Ukrburgaz drilling rigs from 2015 to 2017, as well as numerous literature data show that such defects are formed at the bottom of corrosion ulcers that occur during operation under the influence of workloads and drilling fluids, in particular during tripping operations, both on the inner and outer surfaces of the drill pipe. During the tripping operations, under the influence of tensile loads, they being developed go up to the surface of the drill pipe, forming scouring, which ultimately leads to the destruction of the pipe. Using known analytical solutions, the stress state in the vicinity of the semieliptic crack located on both the outer and inner surfaces of the hollow cylinder under axial load was estimated and the corresponding stress intensity coefficients at the crack tip of these defects were determined. To predict the limit state of a drill pipe with a semieliptic crack, the analysis of crack parameters reflecting the local stress-strain state near the crack tip is performed. Using the finite-element method, the stress state around the vertex of the semieliptic crack was determined and on this basis the characteristics of fracture mechanics were calculated: J – integral and stress intensity coefficients. Diagrams of fracture risk assessment in the coordinates "depth of crack-like defect - depth of drilling - stress intensity factor" are offered, which make it possible to estimate the safe depth of both internal and external semieliptic crack-like defects detected by technical diagnostics taking into account results of experimental investigations of critical crack resintance. The admissible sizes of the studied defects depending on the depth of drilling are determined.

A New Fully-Detailed Finite Element Model of Spiral Strand Wire Ropes for Fatigue Life Estimate of a Mooring Line

2019 ◽  
Author(s):  
Federico Bussolati ◽  
Martin Guiton ◽  
Pierre-Alain Guidault ◽  
Yann Poirette ◽  
Michael Martinez ◽  
...  
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Stress State ◽  
Finite Element Model ◽  
Limit State ◽  
Element Model ◽  
Offshore Wind Turbine ◽  
Mooring Lines ◽  
Wire Ropes ◽  
The Wire

Abstract Spiral strand wire ropes are commonly used in the mooring system of offshore structures. When dealing with the fatigue limit state, engineers have to consider many different load cases, according to the variability of the environmental state. This usually prevents the use of any detailed numerical model of the mooring lines. In this paper, we propose a new method to evaluate with an affordable computational cost the detailed mechanical stress state in different parts of the wire ropes used for mooring a floating offshore wind turbine. We first compute tension and bending history in the mooring, with the hydrodynamic software Deeplines™, assuming for simplification stationary aerodynamic loads on the floater. These time series are then accounted for in a novel Finite Element Model of the spiral strand, with small sliding among the wires. The obtained kinematics and stress state of the wires can then feed a fatigue law based on fretting fatigue, which has been experimentally evidenced to condition the fatigue life of spiral strand wire ropes. The potential of this method is illustrated with an application to a cylinder-like shape floater equipped with 3 pairs of catenary mooring lines. It is shown that bending and tension histories do not significantly depend on the wire rope bending stiffness.

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