Study on the Stress Concentration at the Round Corners of Flat Heads in Pressure Vessels Subjected to Internal Pressure

1996 ◽  
Vol 118 (4) ◽  
pp. 429-433
Author(s):  
H. Chen ◽  
J. Jin ◽  
J. Yu

Results from finite element analysis were used to show that the stress index kσ and the nondimensionalized highly stressed hub length kh of a flat head with a round corner in a pressure vessel subjected to internal pressure are functions of three dimensionless parameters: λ ≡ h/dt, η ≡ t/d, and ρ ≡ r/t. Approximate formulas for estimating kσ and kh from λ, η, and ρ p are given. The formulas can be used for determining a suitable fillet radius for a flat head in order to reduce the fabricating cost and to keep the stress intensity at the fillet under an acceptable limit.

2012 ◽  
Vol 538-541 ◽  
pp. 3253-3258 ◽  
Author(s):  
Jun Jian Xiao

According to the results of finite element analysis (FEA), when the diameter of opening of the flat cover is no more than 0.5D (d≤0.5D), there is obvious stress concentration at the edge of opening, but only existed within the region of 2d. Increasing the thickness of flat covers could not relieve the stress concentration at the edge of opening. It is recommended that reinforcing element being installed within the region of 2d should be used. When the diameter of openings is larger than 0.5D (d>0.5D), conical or round angle transitions could be employed at connecting location, with which the edge stress decreased remarkably. However, the primary stress plus the secondary stress would be valued by 3[σ].


2014 ◽  
Vol 889-890 ◽  
pp. 1406-1409 ◽  
Author(s):  
Ming Jian Jian ◽  
Guang Cheng Zhang ◽  
Du Qing Zhang

By finite element software ANSYS a model of GIS busbar tube was established for investigating the effect of the gas pressure on the shell. The results shows that the stress concentration degree is higher on the shoulder between the main tube and the branch pipes under the internal pressure and the gravity, and the highest value is 44.92MPa which is far lower than the admissible stress. Stress changed along the thickness direction, and its value decreased gradually from the inside out. The distributions of the strain and deformation are similar to that of the stress.


Author(s):  
Curtis Sifford ◽  
Ali Shirani

Abstract This paper presents the application of the rules from ASME Section VIII, Division 3 of the ASME Boiler and Pressure Vessel Code for a fracture mechanics evaluation to determine the damage tolerance and fatigue life of a flowline clamp connector. The guidelines from API 579-1 / ASME FFS-1 Fitness-For-Service for the stress analysis of a crack-like flaw have been considered for this assessment. The crack tip is modeled using a refined mesh around the crack tip that is referred to as a focused mesh approach in API 579-1 / ASME FFS-1. The driving force method is used as an alternative to the failure assessment diagram method to account for the influence of crack tip plasticity. The J integral is determined using elastic-plastic finite element analysis and converted to an equivalent stress intensity factor to be compared to the fracture toughness of the material. The fatigue life is calculated using the Paris Law equation and the stress intensity factor calculated from the finite element analysis. The allowable number of design cycles is determined using the safety factors required from Division 3 of the ASME Pressure Vessel Code.


Author(s):  
Curtis Sifford ◽  
Ali Shirani

This paper presents the application of the rules from ASME Section VIII, Division 3 of the ASME Boiler and Pressure Vessel Code for a fracture mechanics evaluation to determine the damage tolerance and fatigue life of a flowline clamp connector. The guidelines from API 579-1 / ASME FFS-1 Fitness-For-Service for the stress analysis of a crack-like flaw have been considered for this assessment. The crack tip is modeled using a refined mesh around the crack tip that is referred to as a focused mesh approach in API 579-1 / ASME FFS-1. The driving force method is used as an alternative to the failure assessment diagram method to account for the influence of crack tip plasticity. The J integral is determined using elastic-plastic finite element analysis and converted to an equivalent stress intensity factor to be compared to the fracture toughness of the material. The fatigue life is calculated using the Paris Law equation and the stress intensity factor calculated from the finite element analysis. The allowable number of design cycles is determined using the safety factors required from Division 3 of the ASME Pressure Vessel Code.


1984 ◽  
Vol 106 (2) ◽  
pp. 166-171 ◽  
Author(s):  
D. K. Williams ◽  
G. D. Lewis

A finite element analysis of a trunnion elbow support is presented for the case of a long radius elbow subjected to an internal pressure loading. The stress results are categorized as average and linearly varying (through the thickness) stresses. The resulting stresses are then interpreted per Section III of the ASME Boiler and Pressure Vessel Code from which the primary and secondary (B1 and C1) pressure stress indices are developed. Several analysis were performed on various structural geometries in order to determine empirical relationships for the stress indices as a function of dimensionless ratios.


2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Christopher J. Evans ◽  
Timothy F. Miller

This paper investigates using nonlinear finite element analysis (FEA) to determine the failure pressure and failure location for pressure vessels. The method investigated by this paper is to predict the pressure-vessel failure point by identifying the pressure and location where the total mechanical strain exceeds the actual elongation limit of the material. A symmetrically shaped component and a nonsymmetric shaped component are analyzed to determine the failure pressure and location. Data were then gathered by testing each pressure vessel to determine its actual failure pressure. Comparing the FEA results with experimental data showed that the fea software predicted the failure pressure and location very well for the symmetric shaped pressure vessel, however, for the nonsymmetrical shaped pressure-vessel, the fea software predicted the failure pressure within a reasonable range, but the component failed at a weld instead of the predicted location. This difference in failure location was likely caused by varying material properties in both the weld and the location where the vessel was predicted to fail.


2011 ◽  
Vol 65 ◽  
pp. 281-284 ◽  
Author(s):  
Cai Li Zhang ◽  
Fan Yang

According to pressure vessel material waste problem in the traditional design, the finite element technique is used to pressure vessel optimization design in this paper. Firstly, the finite element analysis is applied to carry out stress calculation, and we extracted the related results parameters for following calculation. Then we conducted the quantitative calculation after choosing optimization design method, and got the best design parameters which meet performance indexes. At last, we conducted the optimization design of pressure vessels using this technology. Practical results prove the validity and the practicability of this method in the pressure vessels design.


Author(s):  
Michael W. Guillot ◽  
Jack E. Helms

Finite element analysis is widely used to model the stresses resulting from penetrations in pressure vessels to accommodate components such as nozzles and man-ways. In many cases a reinforcing pad is required around the nozzle or other component to meet the design requirements of Section VIII, Division 1 or 2, of the ASME Pressure Vessel Code [1]. Several different finite element techniques are currently used for calculating the effects of reinforcing pads on the shell stresses resulting from penetrations for nozzles or man-ways. In this research the stresses near a typical reinforced nozzle on a pressure vessel shell are studied. Finite element analysis is used to model the stresses in the reinforcing pad and shell. The commercially available software package ANSYS is used for the modeling. Loadings on the nozzle are due to combinations of internal pressure and moments to simulate piping attachments. The finite element results are compared to an analysis per Welding Research Council Bulletin 107 [2].


Author(s):  
Hee-Tae Lee ◽  
Sang-Beom Shin ◽  
Sung-Hoon Ko

The purpose of this study is to develop the integrated design system of supports, which are turning roller, dent pad and bracing pipe to control distortion of the pressure vessel. The optimum design condition for each support was established by analytical solution and finite element analysis with simple model and verified by comparing with the results of FEA for actual model. Based on the results, the Window-based computer program was developed using Visual C++. The program supports component feature-based modeling. In addition, user can easily determine the condition of supports and jigs during manufacturing of pressure vessels with user-friendly functions such as the material database of ASME, easy input, and detail output.


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