Analysis on the Influence Factors of Casing Collapse Resistance Strength

2011 ◽  
Vol 415-417 ◽  
pp. 2121-2125 ◽  
Author(s):  
Qi Lou ◽  
Wei Du ◽  
Xin Li Han ◽  
Dong Feng Li ◽  
Guang Lu Zhang

Casing collapse resistance strength is an important parameter for its properties in using. Specification, geometry accuracy, material properties, and many other reasons can influence casing collapse resistance property. Study each factors influence for casing collapse resistance strength based on full scale collapse test results of seventeen Φ177.80mm casings and there geometry and material properties test results. The results show that casing collapse resistance strength was influenced by geometry accuracy, yield strength and residual stress together. Ovality greater than 0.5% and fluctuated more than 0.5%, or eccentricity more than 10%, casing collapse resistance strength will be reduced obviously. Casing with excellent collapse resistance strength will be produced through making yield strength in appropriate level, controlling the geometry accuracy and reducing residual stress.

2020 ◽  
Vol 20 (3) ◽  
pp. 1-10
Author(s):  
Sung Bae Kim ◽  
Sang Seup Kim ◽  
Ki Youl Baek

Steel elements exhibit varying characteristics during site installation after shop manufacturing. There may be a mix-up owing to unclear management methods for transport, and deformation might occur during field installation. Moreover, the technical basis for evaluating repair methods is narrow. In this study, variations in material properties after performing mechanical calibration were determined for widely used steel types, such as SS400 and SM490, in which thicknesses of 30 mm and less are frequently used on sites. The test results showed that the mechanical calibration in unheated and thermal heating cases increased the yield strength and tensile strength of steel, and the Korea Standard value was satisfied. A yield ratio of approximately 85% or less was obtained, indicating sufficient toughness. In addition, variations owing to thermal heating did not occur when temperatures below 650 °C were applied.


2019 ◽  
Vol 85 (1(I)) ◽  
pp. 49-56 ◽  
Author(s):  
A. M. Lepikhin ◽  
V. V. Moskvichev ◽  
A. E. Burov ◽  
E. V. Aniskovich ◽  
A. P. Cherniaev ◽  
...  

The results of unique experimental studies of the strength and service life of a metal-composite high-pressure tank are presented. The goal of the study is to analyze the fracture mechanisms and evaluate the strength characteristics of the structure. The methodology included tests of full-scale samples of the tank for durability under short-term static, long-term static and cyclic loading with internal pneumatic pressure. Generalized test results and data of visual measurements, instrumental and acoustic-emission control of deformation processes, accumulation of damages and destruction of full-scale tank samples are presented. Analysis of the strength and stiffness of the structure exposed to internal pneumatic pressure is presented. The types of limiting states of the tanks have been established experimentally. Change in the stress-strain state of the tank under cyclic and prolonged static loading is considered. Specific features of the mechanisms of destruction of a metal-composite tank are determined taking into account the role of strain of the metal liner. The calculated and experimental estimates of the energy potential of destruction and the size of the area affected upon destruction of the tank are presented. Analysis of test results showed that the tank has high strength and resource characteristics that meet the requirements of the design documentation. The results of the experiments are in good agreement with the results of numerical calculations and analysis of the stress-strain state and mechanisms of destruction of the metal-composite tank.


1992 ◽  
Vol 35 (3) ◽  
pp. 977-985 ◽  
Author(s):  
K. G. Gebremedhin ◽  
J. A. Bartsch ◽  
M. C. Jorgensen

Author(s):  
Ying Hong ◽  
Xuesheng Wang ◽  
Yan Wang ◽  
Zhao Zhang ◽  
Yong Han

Stainless steel 304 L tubes are commonly used in the fabrication of heat exchangers for nuclear power stations. The stress corrosion cracking (SCC) of 304 L tubes in hydraulically expanded tube-to-tubesheet joints is the main reason for the failure of heat exchangers. In this study, 304 L hydraulically expanded joint specimens were prepared and the residual stresses of a tube were evaluated with both an experimental method and the finite element method (FEM). The residual stresses in the outer and inner surfaces of the tube were measured by strain gauges. The expanding and unloading processes of the tube-to-tubesheet joints were simulated by the FEM. Furthermore, an SCC test was carried out to verify the results of the experimental measurement and the FEM. There was good agreement between the FEM and the experimental results. The distribution of the residual stress of the tube in the expanded joint was revealed by the FEM. The effects of the expansion pressure, initial tube-to-hole clearance, and yield strength of the tube on the residual stress in the transition zone that lay between the expanded and unexpanded region of the tube were investigated. The results showed that the residual stress of the expanded joint reached the maximum value when the initial clearance was eliminated. The residual stress level decreased with the decrease of the initial tube-to-hole clearance and yield strength. Finally, an effective method that would reduce the residual stress without losing tightness was proposed.


Author(s):  
Ines Gilch ◽  
Tobias Neuwirth ◽  
Benedikt Schauerte ◽  
Nora Leuning ◽  
Simon Sebold ◽  
...  

AbstractTargeted magnetic flux guidance in the rotor cross section of rotational electrical machines is crucial for the machine’s efficiency. Cutouts in the electrical steel sheets are integrated in the rotor sheets for magnetic flux guidance. These cutouts create thin structures in the rotor sheets which limit the maximum achievable rotational speed under centrifugal forces and the maximum energy density of the rotating electrical machine. In this paper, embossing-induced residual stress, employing the magneto-mechanical Villari effect, is studied as an innovative and alternative flux barrier design with negligible mechanical material deterioration. The overall objective is to replace cutouts by embossings, increasing the mechanical strength of the rotor. The identification of suitable embossing geometries, distributions and methodologies for the local introduction of residual stress is a major challenge. This paper examines finely distributed pyramidal embossings and their effect on the magnetic material behavior. The study is based on simulation and measurements of specimen with a single line of twenty embossing points performed with different punch forces. The magnetic material behavior is analyzed using neutron grating interferometry and a single sheet tester. Numerical examinations using finite element analysis and microhardness measurements provide a more detailed understanding of the interaction of residual stress distribution and magnetic material properties. The results reveal that residual stress induced by embossing affects magnetic material properties. Process parameters can be applied to adjust the magnetic material deterioration and the effect of magnetic flux guidance.


Coatings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 670
Author(s):  
Preeda Chaturabong

Chip seal bleeding is influenced by many factors, including design inputs, material properties, and project-specific conditions. It reduces the surface texture of the pavement and thus compromises the safety of the traveling public. Even though factors that bring about premature bleeding are known, currently, no laboratory test methods for evaluating bleeding in chip seals have been specified. The objective of this paper is to present the results of an investigation of the influence factors of asphalt emulsion residue properties measured by the ASTM D7405 multiple stress creep and recovery (MSCR) test, as well as other factors related to chip seal bleeding resistance as measured by the modified loaded wheel test (MLWT). In this study, the MSCR test was used as a tool for evaluating the performance of asphalt emulsions because it has been identified as a potential test related to bleeding in the field. In addition, MLWT was selected as a tool for evaluating chip seal bleeding performance in the laboratory. The results of the MLWT showed that the emulsion application rate (EAR), aggregate gradation, and emulsion properties were significant factors affecting bleeding. The MSCR test was found to be a promising tool for the performance evaluation of asphalt emulsion residue, as the test was able to differentiate between emulsion chemistries and modifications in terms of sensitivity to both temperature and stress. In relation to chip seal bleeding resistance, only the creep compliance (Jnr) obtained from the MSCR test results was identified as a significant property affecting potential for bleeding.


2001 ◽  
Vol 357-360 ◽  
pp. 1241-1244 ◽  
Author(s):  
M. Däumling ◽  
C.N. Rasmussen ◽  
F. Hansen ◽  
D.W.A. Willén ◽  
O.E. Schuppach ◽  
...  

1983 ◽  
Vol 105 (4) ◽  
pp. 574-579 ◽  
Author(s):  
J. R. Fowler ◽  
E. F. Klementich ◽  
J. F. Chappell

This paper describes testing and analysis which demonstrates that collapse specimens tested in short testers with rigid end seals give artificially high collapse values. It also compares the API collapse formulas with conventional strength of materials collapse criteria which incorporate ovality and finds the two approaches give very similar results. A statistical analysis indicates that ovality, while not nearly as important as yield strength and D/t, is important to collapse. Finally, it shows that pipe with lower ovality exhibits better collapse resistance.


Sign in / Sign up

Export Citation Format

Share Document