The Research on the Stress Concentration Factor of T-Joints Subjected to Axial Load

2010 ◽  
Vol 163-167 ◽  
pp. 460-464 ◽  
Author(s):  
Jia Zhang ◽  
Shu Ying Qu ◽  
Guo Dong Zhang ◽  
Hao Liu

By terms of the numerical modeling of ABAQUS software, the analysis of the stress concentration factor (SCF) of tubular T-joints subjected to axial load is analyzed in this paper. The magnitude and the distribution of the SCF are also obtained. Through the finite element analysis of 816 models, the effect of geometrical parameters on the value and distribution of the SCF is investigated. Then based on these results, the parametric equations of the maximal SCF and SCF distribution for T-joints subjected to axial load are presented. Error analysis of these parametric equations is also carried out.

Author(s):  
Yuhui Huang ◽  
Chengcheng Wang ◽  
Shan-Tung Tu ◽  
Fu-Zhen Xuan ◽  
Takamoto Itoh

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.


2019 ◽  
Vol 8 (3) ◽  
pp. 8546-8556

Many researchers have made attempt to investigate stress concentration factor (SCF) for different discontinuities under different loading conditions and applications, but still failures of components take place which having discontinuities. Number of applications under which the components or parts working under tensile loading. Here, efforts are made to investigate the SCF of flat plate with shoulder fillet under axial tension loading using the approach of Photoelasticity for different D/d ratios. The Finite Element Analysis (FEA) approach used to validate the results of experimentation and found that the results are reasonably at acceptable level. One can utilize the outcome of this research for similar application having same discontinuity and loading condition.


Author(s):  
Jing Zhang ◽  
Jianchun Fan ◽  
Laibin Zhang ◽  
Dong Wen ◽  
Yumei Wang

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.


Author(s):  
Ajay Garg ◽  
Ravi Tetambe

Abstract The elastic stress concentration factor, Kt, is critical in determining the life of machines, especially in the case of notched components experiencing high cycle fatigue. This Kt is defined as the ratio of the maximum stress (σmax) at the notch to the nominal stress (σnom) in the region away from the notch effect. For simple geometries such as, plate with a hole, calculation of Kt from either closed form solution or from making simple but valid assumptions is possible [1,2]. However, for complex machine components such data is usually not available in the literature. Using Kt values from the simple geometries may lead to either over or under estimation of the real Kt for such complex geometries. Such error can then further lead to a substandard product or a product which is overdesigned and expensive. Present paper outlines a methodology for computing reasonably accurate elastic stress concentration factor, Kt, using finite element analysis (FEA) tool. The maximum stress (σmax) is readily available from the finite element analysis. The nominal stress (σnom) near the stress concentration is however can not be directly extracted from the FEA results. A novel approach of estimating reasonably accurate σnom is presented in this paper. This approach is based on selecting the correct path at the stress concentration region, post processing the stress and the stress gradient results along that path and identifying the cut of point where stress concentration effect begins to take place. This methodology is first validated using two examples with known Kt and later applied to a real world problem.


1999 ◽  
Vol 121 (3) ◽  
pp. 252-256 ◽  
Author(s):  
C. S. Sloan ◽  
M. D. Cowell ◽  
T. F. Lehnhoff

Stress concentration factors have been determined for large hole to small hole diameter ratios (D/d) of 10 to 50 for two holes in an infinitely wide tension-loaded panel. Finite element analysis was used to model the system of two holes in a plate that approximates the infinitely wide and tall case. Both the D/d ratio and edge to edge hole spacing were examined for hole placement along an axis perpendicular to the direction of the tension field. It was found for large D/d ratios that the stress concentration factor was only dependent on the distance between the hole edges divided by the large hole diameter. For the configurations analyzed, the stress concentration factors varied from approximately 3 to 11.


1993 ◽  
Vol 20 (2) ◽  
pp. 269-286 ◽  
Author(s):  
D. I. Nwosu ◽  
A. S. J. Swamidas ◽  
K. Munaswamy

The stress distribution along the intersection of offshore tubular T-joints under the action of axial and in-plane and out-of-plane (bending) brace loading has been investigated using degenerated shell elements. The ratios of through-thickness membrane to bending stress and bending to total stress have been obtained using a simple linear interpolation between the stresses on the inner and outer surfaces of the tube. The nominal brace stress and the maximum principal stress values have been used for stress concentration factor determination. The influence of thickness and other geometric parameters on the stress distribution along the intersection was investigated in two ways, viz., increasing the chord thickness while maintaining a constant brace thickness, and keeping the chord thickness constant while reducing the brace thickness.Comparison of the shell finite-element results obtained in this study with the semiloof thin-shell finite-element results of the University College, London (UCL), exhibits good agreement. Good agreement exists between the results of this study and the UCL parametric equations for the chord and the brace of the joint, with a maximum difference of about 7% on the braceside around the saddle position. Comparisons between the finite-element results and other known parametric equations for stress concentration factor with different diametral, wall thickness, and chord thickness and ratios also show good agreement. A comparison of the results obtained from the finite-element analysis and the experimental results of the Canadian Cooperative Fatigue Studies Program, carried out at Memorial University of Newfoundland and University of Waterloo, is also made. Key words: stress distribution, finite-element analysis, stress concentration factors, membrane stress, bending stress, tubular T-joints.


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