Stress Concentration at the Root of Bolt Thread Under Twist With Deformable Flanges

2011 ◽  
Author(s):  
Yasumasa Shoji ◽  
Toshiyuki Sawa
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Numerical Methods ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Finite Element Analyses

Bolts and Nuts are required to fasten objects, such as flanges in various types of plants. It is known that stress concentration at the root is relevant for its strength for both static integrity and fatigue. A lot of investigations were carried out to understand the behavior of the bolt using experimental and numerical methods. Recently, finite element analyses have been used to examine the detailed behavior of the bolt root successfully. The authors reported such example in a recent study [13] using submodelling (or so-called zooming) technique that handled only bolt tension with rigid fastened surface; some factors were missing. In this paper, the twist of the bolt was taken into account and the fastened object is replaced by deformable plates. The stress concentration factor has been reconsidered.

scholarly journals Parametric Formulae for Elastic Stress Concentration Factor at the Weld Toe of Distorted Butt-Welded Joints

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 169 ◽  
Author(s):  
Yuxiao Luo ◽  
Renle Ma ◽  
Seiichiro Tsutsumi
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Fatigue Test ◽  
Stress Concentration Factor ◽  
Welded Joints ◽  
Concentration Factor ◽  
Angular Distortion ◽  
Large Set ◽  
Finite Element Analyses ◽  
Weld Toe

The evaluation of the stress concentration factor (SCF) at the notches of welds is of importance, especially for butt-welded joints that are widespread in the industry. Some empirical formulae can be found in the literature to estimate the SCF at the weld toes of butt-welded joints, while few solutions are available for the distorted joints under tensile fatigue test conditions. In the present study, the existing SCF formulae for butt-welded joints loaded in tension are examined and discussed. The influence of the weld width on SCF, which is commonly ignored or misestimated by existing solutions, is investigated comprehensively based on a large set of two-dimensional (2D) finite element analyses. Consequently, a new precise parametric formula for the elastic SCF at the weld toe of geometrically symmetric butt-welded joints under tension is proposed, together with a wide application range. Moreover, the analysis is also extended to consider joints with angular distortion. A two-step finite element analysis is employed to simulate the clamping and loading procedures in the fatigue test. Similarly, the parametric formulae for the assessment of clamping-induced stress and SCF caused by angular distortion are carried out as well based on the results from finite element analyses. The formulae proposed by this paper are finally tested and proved to be valid and precise.

Numerical Investigation of Stress Concentration Factor at Irregular Corrosion Pit Under Tension-Torsion Loading

2014 ◽  
Author(s):  
Yuhui Huang ◽  
Chengcheng Wang ◽  
Shan-Tung Tu ◽  
Fu-Zhen Xuan ◽  
Takamoto Itoh
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
Aspect Ratio ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Three Dimensional ◽  
Element Analysis ◽  
Stress Concentration Factors ◽  
Local Dissolution

Finite element analysis is adopted to study the stress concentration of pit area under tension-torsion loading. The stress concentration factors under regular evolution and irregular evolution of pits are investigated by conducting a series of three-dimensional semi-elliptical pitted models. Based on the finite element analysis, it can be concluded that pit aspect ratio (a/2c) is a significant parameter affecting stress concentration factor (SCF) for regular evolution pits. Pits, having higher aspect ratio, are very dangerous form and can cause significant reduction in the load carrying capacity. When local dissolution occurs in the pitting area, SCF will have a sharp increase, it is more probable for a crack to initiate from these areas compared with pits for regular evolution. Furthermore, local dissolution coefficient is proposed to study effect of local dissolution within the pit on SCF.

Stress Concentration Factor Calculation for the Hooks in Lifting Appliance of Spent Fuel Well Cover

2014 ◽  
Author(s):  
Xiang Liu ◽  
Yue Li ◽  
Jinhua Wang ◽  
Bin Wu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Spent Nuclear Fuel ◽  
Curved Beam ◽  
Spent Fuel ◽  
The Finite Element Method ◽  
High Temperature Reactor

The spent nuclear fuel of HTR-PM (High Temperature Reactor–Pebblebed Modules) will be dry stored in wells. In the mouth of each well, there is a cover weighing 11 tons. A lifting appliance with three hooks is used to open and close the covers. The hooks are L-shaped with fillet at the inside corner. The stress concentration at the corner has a significant impact on the strength and fatigue life of hooks. For optimizing the structure of the hook, the stress concentration factor related to the radius of fillet is calculated by both theoretical and numerical methods. The theoretical calculation is based on the Saint-Venant’s Principle and the analytical solution of a curved beam. The result is consistent with the numerical calculation performed by the finite element method.

Theoretical Analysis and Experimental Verification of the Stress Concentration Factor at the Steel Tube-Welded Hollow Sphere Connection Node

2016 ◽  
Vol 851 ◽  
pp. 739-744
Author(s):  
Bo Li ◽  
Hong Gang Lei ◽  
Xu Yang
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Theoretical Analysis ◽  
Hollow Sphere ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Hot Spot ◽  
Steel Tube ◽  
Element Analysis ◽  
Hot Spot Stress

In this paper, the author uses ANSYS, the software of finite element analysis, to establish the finite element model, the hot spot stress value of different connection structures of steel tube-welded hollow sphere under uniaxial elongation has been analyzed, the theoretical stress concentration factor of this joint has been obtained. Through the static test on the four typical test-piece, 26 steel tube-welded hollow spherical nodes in total, the actually measured stress concentration factor of the joints has been obtained. The theoretical analysis basically coincides with the law of stress concentration factor obtained from the test results.

scholarly journals Stress Concentration Factor of Expanded Aluminum Tubes Using Finite Element Modeling

2013 ◽  
Vol 10 (1) ◽  
pp. 88
Author(s):  
L Mhamdi ◽  
AC Seibi ◽  
A Karrech ◽  
S El-Borgi ◽  
I Barsoum
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Plastic Material ◽  
Structural Response ◽  
Perfectly Plastic ◽  
Empirical Relations ◽  
Aluminum Tubes ◽  
Semi Empirical

 This paper discusses the development of semi-empirical relations for the maximum stress concentration factor (SCF) around circular holes embedded in aluminum tubes under various expansion ratios and mandrel angles. Finite element models were developed to study the expansion of a typical aluminum tube with embedded holes of various sizes. An elastic perfectly-plastic material behaviour was used to describe the structural response of the tubes under expansion. Various hole-diameter-to-tubewall- thickness ratios, tube expansion ratios, and mandrel angles were considered to determine the stress state around the hole at zero and 90 degree locations from which the maximum SCF was determined. Semi-empirical relations for the maximum SCF using the Lagrange interpolation formulation were developed. The developed relations were found to predict the SCFs accurately. 

Finite Element Analysis on Stress Concentration of Well Casing With Corrosion Pits

2010 ◽  
Author(s):  
Jing Zhang ◽  
Jianchun Fan ◽  
Laibin Zhang ◽  
Dong Wen ◽  
Yumei Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Spherical Cavity ◽  
High Stress ◽  
Orifice Diameter ◽  
Element Analysis ◽  
Corrosion Pits

Corrosion-induced pits will disturb the original stress distribution of casing and appear local high stress area. Through 3-D finite element analysis on casing with spherical and cylindrical corrosion cavity, the stress concentration degree and the influences of cavity shape, size and orifice diameter on stress concentration factor are determined and analyzed. The results show that the depth and shape of corrosion cavities are major factors impacting the stress concentration factor. For the casing with corrosion pits, the smaller orifice diameter, the more obvious influence of hemisphere effect on stress concentration factor. With the transition from shallow-spherical cavity to exact hemispherical cavity or from exact hemispherical cavity to deep-spherical cavity or from exact hemispherical cavity to cylindrical cavity, the changes of stress concentration factor show different characteristics.

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