Effects of Perforation on the Collapsing Strength of Casing

2013 ◽  
Vol 395-396 ◽  
pp. 881-886
Author(s):  
Yu Guang Cao ◽  
Shi Hua Zhang ◽  
Xin Ren

In this study, three-dimensional mechanical model of the perforated casing was simplified as flat plate mechanical model. The theoretical equation for the calculation of collapsing strength factor for a perforated casing under squeeze was derived as per elasticity theory. Three-dimensional FEM model of a perforated casing was built using ANSYS and analysis was performed. The stress concentration factor (SCF) was discussed for perforated casing in this paper and the effects of aperture on SCFs were analyzed in detail.

2002 ◽  
Vol 37 (3) ◽  
pp. 259-264 ◽  
Author(s):  
Q. Z Wang

First, based on an approximate analysis, simple closed-form expressions of the stress concentration factor (SCF) for two- or three-dimensional models with a circular hole or a spherical cavity in a finite domain are derived. Then, an asymptotic method is adopted to improve the accuracy of the derived solutions for an extremely large circular hole or spherical cavity, when the remaining ligament approaches zero. Exact limit SCF values for these two kinds of models were given by Koiter; these values are used for the adjustment of the coefficients in the SCF expressions. Finally, simple SCF formulae for these finite domain problems are obtained, their accuracy is demonstrated to be very good by comparison with the available data from the literature, and the asymptotic validity is guaranteed.


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.


2007 ◽  
Vol 353-358 ◽  
pp. 74-77
Author(s):  
Zheng Yang ◽  
Chong Du Cho ◽  
Ting Ya Su ◽  
Chang Boo Kim ◽  
Hyeon Gyu Beom

Based on detailed three-dimensional finite element analyses, elastic stress and strain field of ellipse major axis end in plates with different thickness and ellipse configurations subjected to uniaxial tension have been investigated. The plate thickness and ellipse configuration have obvious effects on the stress concentration factor, which is higher in finite thickness plates than in plane stress and plane strain cases. The out-of-plane stress constraint factor tends the maximum on the mid-plane and approaches to zero on the free plane. Stress concentration factors distribute ununiformly through the plate thickness, the value and location of maximum stress concentration factor depend on the plate thickness and the ellipse configurations. Both stress concentration factor in the middle plane and the maximum stress concentration factor are greater than that under plane stress or plane strain states, so it is unsafe to suppose a tensioned plate with finite thickness as one undergone plane stress or plane strain. For the sharper notch, the influence of three-dimensional stress state on the SCF must be considered.


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.


1993 ◽  
Vol 115 (1) ◽  
pp. 47-52 ◽  
Author(s):  
M. Guagliano ◽  
A. Terranova ◽  
L. Vergani

The paper deals with the bending stress concentration evaluation of a marine diesel engine crankshaft. Experimental strain gauge tests were conducted on a full scale single crank to measure the stress concentration near the crank fillet. A three-dimensional finite element schematization of the crankshaft and the linear elastic calculations conducted show the stress field along the most overstressed zone and how it is influenced by different load conditions. It is now possible to calculate accurately the stress concentration factor Kt. However, a mesh of a mechanical element with a complex geometry like crankshaft is very expensive and difficult. Therefore a bidimensional model of the crankshaft has been also considered: experimental tests and numerical analyses under different load conditions were also carried out in this case. The agreement between the results obtained from these different kinds of analyses is good. The values of the stress concentration factors obtained from bidimensional and three-dimensional analysis with the same boundary and load conditions are similar. A plane model of crankshaft can be utilized to determine the theoretical stress concentration factor Kt with considerable saving of calculation time.


2013 ◽  
Vol 03 (03) ◽  
pp. 153-159 ◽  
Author(s):  
Murilo Augusto Vaz ◽  
Julio Cesar Ramalho Cyrino ◽  
Gilson Gomes da Silva

2012 ◽  
Vol 13 (2) ◽  
Author(s):  
Nitin Jain ◽  
MOON Banerjee ◽  
Shubhashish Sanyal

ABSTRACT: A number of analytical and numerical techniques are available for the two dimensional study of stress concentration around the hole(s) in isotropic and composite plates subjected to in-plane or transverse loading conditions. The information on the techniques for three dimensional analyses of stress concentration factor (SCF) around the hole in isotropic and composite plates subjected to transverse loading conditions is, however, limited. The present work emphasizes on the effect of fibre orientation (q) on the stress concentration factor in fibrous composite plates with central circular hole under transverse static loading condition. The work is carried out for cantilever fibrous composite plates. The effects of thickness -to- width (T/A) and diameter-to-width (D/A) ratios upon SCF at different fibre orientation are studied. Plates of four different composite materials were considered for hole analysis in order to determine the sensitivity of SCF with elastic constants. Deflections in transverse direction were calculated and analysed. All results are presented in graphical form and discussed. The finite element formulation and its analysis were carried out using ANSYS package.ABSTRAK: Terdapat pelbagai teknik analitikal dan numerical untuk kajian tumpuan tegasan dua dimensi di sekeliling lubang-lubang dalam komposit isotropik dan plat pada satah atau keadaan bebanan melintang. Bagaimanapun, maklumat mengenai kaedah analisis tiga dimensi untuk faktor ketumpatan tegasan (SCF) sekitar lubang dalam komposit isotropik dan plat pada keadaan bebanan melintang adalah terhad. Kertas ini menekankan kesan orientasi gentian (q) pada faktor tumpuan tegasan dalam komposit plat bergentian dengan lubang berpusat di bawah keadaan bebanan melintang. Kajian ini dilkukan untuk cantilever plat komposit bergentian. Kesan ketebalan terhadap kelebaran plat (T/A) dan diameter terhadap kelebaran komposit (D/A) dengan SCF pada orientasi gentian berbeza telah dikaji. Plat komposit bagi empat bahan komposit berbeza telah diambilkira bagi kesemua analisis untuk mendapatkan kesensitifan SCF dengan konstan elastic. Defleksi pada arah melintang telah dikira dan dianalisa. Kesemua keputusan telah disembahkan secara grafik dan dibincang. Fomulasi unsur finit dan analisis telah dilaksanakan menggunakan pakej ANSYS.KEYWORDS:          finite element method; stress concentration factor; composites; transverse loading; deflection; elastic constants


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