Relaxation of residual stresses caused by external cyclic loads on the basis of a kinetic approach

1985 ◽  
Vol 21 (1) ◽  
pp. 53-57
Author(s):  
A. P. Babichev ◽  
V. V. Sibirskii ◽  
S. N. Shevtsov
Keyword(s):  
Residual Stresses ◽  
Kinetic Approach ◽  
Cyclic Loads

Residual stresses in samples with a hole under the action of static and cyclic loads

1978 ◽  
Vol 10 (12) ◽  
pp. 1478-1480
Author(s):  
N. A. Vishnyakov ◽  
G. D. Gringauz ◽  
G. F. Rudzei
Keyword(s):  
Residual Stresses ◽  
Cyclic Loads ◽  
Static And Cyclic Loads

scholarly journals Modèle numérique pour l’étude des structures fissurées soumises à des contraintes résiduelles

2007 ◽  
pp. 627-642
Author(s):  
Zohra Gaiech ◽  
Hocine Kebir ◽  
Laurent Chambon ◽  
Jean-Marc Roelandt
Keyword(s):  
Residual Stress ◽  
Boundary Element Method ◽  
Stress Field ◽  
Residual Stresses ◽  
Specific Treatment ◽  
Cyclic Loads ◽  
Residual Stress Field ◽  
Principle Of Superposition ◽  
Compressive Stresses ◽  
Improve Fatigue

During their operational use the aeronautic structures can be submitted to relatively moderate cyclic loads and more rarely to stern loads. These last can generate residual stress field, which will influence the in-service behaviour. Otherwise, residual stress field can be created in a voluntary way by a specific treatment (compressive stresses). They permit to improve fatigue tolerance behaviour. This illustrates the importance of the study of the structure behavior under residual stresses, and the need to consider them in numerical simulations. The objective of this work is to develop a numerical method, based on the boundary element method and the principle of superposition, to assess the influence of residual stresses on fracture mechanics parameters.

A Direct Method on the Analysis of Steady State Residual Strains in a Steel Joint Subjected to Cyclic Loads

2003 ◽  
Author(s):  
C.-C. Yu ◽  
C.-T. Wu ◽  
T.-P. Chang
Keyword(s):  
Steady State ◽  
Residual Stresses ◽  
Direct Method ◽  
Direct Analysis ◽  
Cyclic Loads ◽  
Pipe Length ◽  
Study Results ◽  
Residual Strains ◽  
Residual Stresses And Strains ◽  
Fixed End

The thick plate element of Mindlin type combined with the plane stress element is adopted in the direct analysis method. The numerical process is pretty efficient with respect to the speed of the calculation of final steady state residual quantities resulted in by cyclic loads. Two pipes joined together with a concentric reducer are employed as an example. The steady state residual stresses and strains after pipes experience cyclic anti-symmetric deflections, simulating the seismic loads, are illustrated. The diameter, the length of the pipes, and properties of material are the parameters evaluated in the present study. Results indicate that shorter pipe has higher shear effect at the fixed end. The ratio of pipe diameter to pipe length does not significantly differ the residual profile while the existence of a concentric reducer disturbs the distribution of the residual stresses and residual plastic strains dramatically.

The Effect of Temperature and Load Cycling on the Relaxation of Residual Stresses

1976 ◽  
Vol 20 ◽  
pp. 309-319 ◽  
Author(s):  
J. M. Potter ◽  
R. A. Millard
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Cyclic Load ◽  
Stress Measurement ◽  
Thermal Exposure ◽  
Effect Of Temperature ◽  
Cyclic Loads ◽  
Load History ◽  
Stress Concentrations ◽  
Aircraft Structures

The Fastress automatic residual stress measurement system was used to measure residual stress in unnotched shot peened 7075-T6 aluminum alloy specimens for a study of the effect of load and thermal exposure on residual stresses. Cyclic loads at zero and high mean stress conditions at stress levels in excess of those used in aircraft structures gave no apparent change in residual stress. Thermal exposure above 200°F resulted in significant changes in residual stress; at 225°F, 30 to 50 hours were required to cause the residual stress to reduce to onehalf the original value and less than 15 hours at 250°F was sufficient to cause a 50Z reduction. The data indicate that the cyclic load history that may be expected in aircraft structures is not sufficient to cause residual stress relaxation in areas remote from fasteners and other stress concentrations but that thermal exposure can cause significant relaxation.

Method to evaluate residual stresses in the laser cutting process

2002 ◽  
Vol 12 (1) ◽  
pp. 27-41 ◽  
Author(s):  
Y. Zamachtchikov ◽  
F. Breaban ◽  
P. Vantomme ◽  
A. Deffontaine
Keyword(s):  
Residual Stresses ◽  
Laser Cutting ◽  
Cutting Process

Prediction of residual stresses and springback after bending of a textured aluminium plate

2003 ◽  
Vol 105 ◽  
pp. 175-182 ◽  
Author(s):  
L. Delannay ◽  
R. E. Logé ◽  
Y. Chastel ◽  
P. Van Houtte
Keyword(s):  
Residual Stresses

Theoretical study of the prestressing strand's stress by computer modeling methods

2020 ◽  
Vol 76 (11) ◽  
pp. 1139-1148
Author(s):  
A. G. Korchunov ◽  
E. M. Medvedeva ◽  
E. M. Golubchik
Keyword(s):  
Residual Stresses ◽  
High Strength ◽  
Pearlitic Steel ◽  
Internal Stresses ◽  
Steel Microstructure ◽  
Compressive Stresses ◽  
Wide Range ◽  
Prestressing Strands ◽  
Increasing Temperature ◽  
Wire Strand

The modern construction industry widely uses reinforced concrete structures, where high-strength prestressing strands are used. Key parameters determining strength and relaxation resistance are a steel microstructure and internal stresses. The aim of the work was a computer research of a stage-by-stage formation of internal stresses during production of prestressing strands of structure 1х7(1+6), 12.5 mm diameter, 1770 MPa strength grade, made of pearlitic steel, as well as study of various modes of mechanical and thermal treatment (MTT) influence on their distribution. To study the effect of every strand manufacturing operation on internal stresses of its wires, the authors developed three models: stranding and reducing a 7-wire strand; straightening of a laid strand, stranding and MTT of a 7-wire strand. It was shown that absolute values of residual stresses and their distribution in a wire used for strands of a specified structure significantly influence performance properties of strands. The use of MTT makes it possible to control in a wide range a redistribution of residual stresses in steel resulting from drawing and strand laying processes. It was established that during drawing of up to 80% degree, compressive stresses of 1100-1200 MPa degree are generated in the central layers of wire. The residual stresses on the wire surface accounted for 450-500 MPa and were tension in nature. The tension within a range of 70 kN to 82 kN combined with a temperature range of 360-380°С contributes to a two-fold decrease in residual stresses both in the central and surface layers of wire. When increasing temperature up to 400°С and maintaining the tension, it is possible to achieve maximum balance of residual stresses. Stranding stresses, whose high values entail failure of lay length and geometry of the studied strand may be fully eliminated only at tension of 82 kN and temperature of 400°С. Otherwise, stranding stresses result in opening of strands.

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