Determination of effective stress concentration coefficient using the results of fatigue testing of shafts

1986 ◽  
Vol 22 (7) ◽  
pp. 323-325
Author(s):  
A. I. Abdullaev ◽  
A. S. Guseinov ◽  
R. D. Gashimov
Keyword(s):  
Stress Concentration ◽  
Effective Stress ◽  
Fatigue Testing ◽  
Concentration Coefficient ◽  
Stress Concentration Coefficient

scholarly journals Mining-Induced Redistribution of the Abnormal Stress under the Close Bearing Coal Pillar for Entry Design

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Xudong Liu ◽  
Wenlong Shen ◽  
Jianbiao Bai ◽  
Rui Wang ◽  
Jizhong Kang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Stress Concentration ◽  
Simulation Model ◽  
Lateral Pressure ◽  
Pressure Coefficient ◽  
Stress Gradient ◽  
Coal Pillar ◽  
Concentration Coefficient ◽  
Stress Concentration Coefficient

Underground space is vulnerable to large deformation influenced by the abnormal stress induced by the bearing coal pillar. A numerical simulation model was established to determine the redistribution of the abnormal stress induced by the mining activities. The double-yield model, the strain softening model, the interface model, and the Mohr–Coulomb model were determined to simulate the gob compaction effect, the pillar strength reduction effect, the structure plane discontinuity effect, and the rock mechanical behavior, respectively. This numerical simulation model is reliable to predict the abnormal stress under the bearing coal pillar by the comparison of the abutment stress from this model and the existing theoretical model as well as the entry roof surface displacement from this model and the field measuring method. The results from the validated numerical model indicate that the abnormal stress including stress concentration coefficient, stress gradient, and lateral pressure coefficient will redistribute to another state that the stress concentration coefficient and stress gradient increase gradually and then decrease, and the lateral pressure coefficient decreases gradually, then increases, and finally decreases sharply with the approach of the mining working face. Their maximum increasing rates are calculated as 121.05%, 198.56%, and 236.82%, respectively. This predicted mining-induced redistribution of the abnormal stress is available for designing the underground entry layout in the determination of the entry position, determination of the driving operation time, mining disturbing range warning, and the prediction of the strengthening support area.

Use of methods of high-frequency loading for accelerated determination of the effective stress concentration factors

1988 ◽  
Vol 20 (8) ◽  
pp. 1040-1044
Author(s):  
L. E. Matokhnyuk ◽  
A. V. Voinalovich
Keyword(s):  
Stress Concentration ◽  
Effective Stress ◽  
High Frequency ◽  
Concentration Factors ◽  
Stress Concentration Factors

Influence of Stress Concentration on Fatigue Property of Welded Joints of 5083 Aluminum Alloy

2013 ◽  
Vol 456 ◽  
pp. 451-455
Author(s):  
Jun Yang ◽  
Bo Li ◽  
Qiang Jia ◽  
Yuan Xing Li ◽  
Ming Yue Zhang ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Aluminum Alloy ◽  
Fatigue Strength ◽  
Stress Concentration ◽  
Welded Joints ◽  
Weld Zone ◽  
Fatigue Property ◽  
Concentration Coefficient ◽  
5083 Aluminum Alloy ◽  
Stress Concentration Coefficient

Fatigue test of the welded joint of 5083 aluminum alloy with smooth and height of specimen and the weld zone than the high test measurement and theoretical stress concentration coefficient calculation, the weld reinforcement effect of stress concentration on the fatigue performance of welded joints. The results show that: Smooth tensile strength of specimens for 264MPa, fatigue strength is 95MPa, the tensile strength of the 36%. Higher tensile strength of specimens for 320MPa, fatigue strength is 70MPa, the tensile strength of the 22%. Higher specimen stress concentration coefficient is 1.64, the stress concentration to the weld toe becomes fatigue initiation source, and reduces the fatigue strength and the fatigue life of welded joints.

scholarly journals Stress strain state of elastic plate with elliptical cut-out

2020 ◽  
pp. 3-8
Author(s):  
E.E. Deryugin ◽  
Keyword(s):  
Plastic Deformation ◽  
Stress Concentration ◽  
Driving Force ◽  
Strain State ◽  
Mechanical State ◽  
Concentration Coefficient ◽  
Stress Strain ◽  
Crack Driving Force ◽  
Stress Strain State ◽  
Stress Concentration Coefficient

The article considers a crack in the form of a narrow cut with a certain cfn at the cut out in an unbounded plate. The characteristics of the mechanical state of this system under uniaxial loading are determined: the stress concentration coefficient, the crack-driving force, and the energy of a solid with a crack. The elastic energy expenditure during crack propagation is determined. The general regularities of the mechanical state of a solid with a crack, not necessary having the form of an ellipse, are revealed. An important parameter of a crack is the curvature at the tip. It is shown that the Griffiths crack does not actually have a singularity at the tip. The stress strain state of the plate with an elliptical crack is identical to the same of the plate with a focus of homogeneous plastic deformation.

A new method of measuring the stress concentration coefficient

2012 ◽  
Vol 28 (6) ◽  
pp. 436-440
Author(s):  
Krzysztof Kwieciński ◽  
Robert Jachym ◽  
Krzysztof Krasnowski
Keyword(s):  
Stress Concentration ◽  
New Method ◽  
Concentration Coefficient ◽  
Stress Concentration Coefficient

scholarly journals Study on Temporal and Spatial Characteristics of Overlying Strata in Deep Coal Mining Process

2021 ◽  
Author(s):  
Bang-an Zhang ◽  
Yang yushun ◽  
Dong-ming Zhang
Keyword(s):  
Stress Concentration ◽  
Coal Seam ◽  
Coal Mining ◽  
Three Dimensional ◽  
In Situ Stress ◽  
Three Dimensional Model ◽  
Concentration Coefficient ◽  
Working Face ◽  
Stress Concentration Coefficient

Abstract This paper adopts the stress relief method to test the in-situ stress in the field to obtain the in-situ stress distribution characteristics of No. 2+3# coal seam. A three-dimensional model was established with the No. S3012 working face as the engineering background, and the measured in-situ stress values ​​were applied to the three-dimensional model, and the spatial-temporal evolution characteristics of coal and rock mass around the stope during coal seam mining were studied. The specific conclusions are as follows: the three-dimensional stress distribution map in front of, behind and on both sides of the working face in the process of coal mining are obtained. As the working face goes on, the maximum value of the supporting stress formed in front of, behind and on both sides of the working face shifts to the corner, presenting a “hump-like” distribution. The stress concentration coefficient of front, back and both sides of stope increases linearly with the increase of mining size. Under the same mining size, the stress concentration coefficient in front of stope is the smallest, and the stress concentration coefficient on both sides is the largest. The three-dimensional displacement field distribution nephogram of overlying strata in the process of coal mining is obtained. With the continuous advance of the working face, the roof strata of coal seam undergo continuous dynamic subsidence process, and the roof subsidence increases continuously, showing the shape of "bowl" with sharp bottom. In the process of working face mining, the roof displacement of coal seam showed an "O" shape evolution characteristic. The three-dimensional distribution cloud map of the plastic zone of coal and rock mass in the process of working face mining was obtained, and the failure volume of the plastic zone gradually increases with the continuous progress of the working face.

Calculation about the Effect of Stress Concentration Coefficient on the Fatigue Properties for Welded Cruciform Joints of 16MnR Steel

2012 ◽  
Vol 189 ◽  
pp. 350-354
Author(s):  
Ying Xia Yu ◽  
Bo Lin He ◽  
Xiao Dong Zhang
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Stress Concentration ◽  
Welded Joints ◽  
Fatigue Properties ◽  
Concentration Coefficient ◽  
Cruciform Joints ◽  
Welded Structures ◽  
Line Angle ◽  
Stress Concentration Coefficient

Stress concentration coefficient of welded joints has a crucial influence on mechanical properties of welded structures. Geometrical parameters of welded joints seriously affect the stress concentration coefficient. In order to increase the mechanical properties and safety of welded structures, it has great significance for reducing stress concentration coefficient and improving the mechanical properties of welded structures by researching and improving the geometry of welded joints. In this paper, the effect of stress concentration coefficient on the fatigue properties for welded cruciform joints of 16MnR steel was analyzed by using ABAQUS finite element and MSC.Fatigue programe, and the change rule of stress concentration coefficient with the variation of the parameter was studied and the fatigue life changed with the stress concentration coefficient was also researched. The calculation results indicate that reducing the weld tangent line angle θ can effectively decrease the stress concentration coefficient of welded cruciform joints, and the fatigue life of welded cruciform joints can be improved succesfully. In order to obtain the safety welded structures, the true weld tangent line angle θ should be controlled in the angle smaller than 20o.

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