A Finite Element Model to Analyze Cylinder-Cylinder Intersections

1987 ◽  
Vol 109 (4) ◽  
pp. 411-420 ◽  
Author(s):  
R. Natarajan ◽  
G. E. O. Widera ◽  
P. Afshari
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Finite Element Model ◽  
Internal Pressure ◽  
Pressure Vessel ◽  
Shell Theory ◽  
Element Model ◽  
Pressure Loading

A finite element model is proposed to study the stresses in the neighborhood of a cylinder-cylinder intersection. In particular, diameter ratios greater than 0.5 are focused upon since little information is available in the ASME Boiler and Pressure Vessel Code or in the literature about the stress concentration for these geometries. The aim of the present work is to validate such a model for internal pressure loading. To accomplish this, various parametric finite element studies were conducted. The selected model is then validated by applying it to various available cylinder intersection models and comparing the results. The finite element results are further compared with a solution obtained using a shell theory.

Stress Concentration Factors of Dented Pipelines

2006 ◽  
Author(s):  
Bianca de Carvalho Pinheiro ◽  
Ilson Paranhos Pasqualino ◽  
Se´rgio Barros da Cunha
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Numerical Model ◽  
Finite Element Model ◽  
Internal Pressure ◽  
Element Model ◽  
Small Strain ◽  
Small Scale ◽  
Concentration Factors ◽  
Stress Concentration Factors

A nonlinear finite element model was developed to assess stress concentration factors induced by plain dents on steel pipelines subjected to cyclic internal pressure. The numerical model comprised small strain plasticity and large rotations. Six small-scale experimental tests were carried out to determine the strain behavior of steel pipe models during denting simulation followed by the application of cyclic internal pressure. The finite element model developed was validated through a correlation between numerical and experimental results. A parametric study was accomplished, with the aid of the numerical model, to evaluate stress concentration factors as function of the pipe and dent geometries. Finally, an analytical formulation to estimate stress concentration factors of dented pipelines under internal pressure was proposed. These stress concentration factors can be used in a high cycle fatigue evaluation through S-N curves.

Reduction of Free-Edge Stress Concentration

1985 ◽  
Vol 52 (4) ◽  
pp. 801-805 ◽  
Author(s):  
P. R. Heyliger ◽  
J. N. Reddy
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Free Edge ◽  
Shear Stresses ◽  
Normal Stresses ◽  
Interlaminar Shear ◽  
Three Dimensional Elasticity

A quasi-three dimensional elasticity formulation and associated finite element model for the stress analysis of symmetric laminates with free-edge cap reinforcement are described. Numerical results are presented to show the effect of the reinforcement on the reduction of free-edge stresses. It is observed that the interlaminar normal stresses are reduced considerably more than the interlaminar shear stresses due to the free-edge reinforcement.

scholarly journals Analysis for Wrinkling Behavior of Girth-Welded Line Pipe

1996 ◽  
Author(s):  
Luiz T. Souza ◽  
David W. Murray
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Internal Pressure ◽  
Experimental Test ◽  
Element Model ◽  
Element Analysis ◽  
Line Pipe ◽  
New Era ◽  
Analytical Tools

The paper presents results for finite element analysis of full-sized girth-welded specimens of line pipe and compares these results with the behavior exhibited by test specimens subjected to constant axial force, internal pressure and monotonically increasing curvatures. Recommendations for the ‘best’ type of analytical finite element model are given. Comparisons between the behavior predicted analytically and the observed behavior of the experimental test specimens are made. The mechanism of wrinkling is explained and the evolution of the deformed configurations for different wrinkling modes is examined. It is concluded that the analytical tools now available are sufficiently reliable to predict the behavior of pipe in a manner that was not previously possible and that this should create a new era for the design and assessment of pipelines if the technology is properly exploited by industry.

Detailed Finite Element Modeling of a High Capacity Mooring Steel Wire Rope: Calculation of the Stress Concentration Near the Connection

2020 ◽  
Author(s):  
Michaël Martinez ◽  
Sébastien Montalvo
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Stress Concentration ◽  
Finite Element Model ◽  
Steel Wire ◽  
High Capacity ◽  
Element Model ◽  
Wire Rope ◽  
Contact Forces ◽  
Life Assessment

Abstract The mooring of floating platforms is an important challenge for the offshore industry. It is an important part of the design engineering and, often, a critical point for the fatigue life assessment. A solution that could improve the fatigue life is to directly connect the mooring rope to the platform, without an intermediate chain. However this solution is not widespread and the behavior of a rope near such a connection is little known. The present paper proposes to better understand this behavior, thanks to a detailed finite element model of the rope. The study case is a steel wire rope directly connected to a floating wind turbine. A local finite element model of the rope has been built, where the wires are individually modeled with beam elements. One end of the rope is clamped, simulating the connection, while tension and cyclic bending oscillations are applied to the other end. A localized bending takes place near the connection, leading to stress concentration in the wires. The stress concentration and the local contact forces are calculated for each wire. These data are important entry parameters for a local failure or fatigue analysis. This latter is however not presented here. Despite IFPEN experience in the development of local finite element models of steel wire ropes, it is the first time that such a high capacity rope (MBL = 12 500 kN) is modeled. This is challenging because of the large diameter of the rope and the large number of wires. However this modeling approach is very valuable for such ropes, because the experimental tests are rare and very expensive.

Simulation of Behaviors of a One-Third Scale Containment Model Test

2017 ◽  
Author(s):  
Guopeng Ren ◽  
Rong Pan ◽  
Feng Sun
Keyword(s):  
Finite Element ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Finite Element Model ◽  
Internal Pressure ◽  
Nuclear Power ◽  
Element Model ◽  
Scale Model ◽  
Prestress Losses ◽  
The Finite Element Model

Reactor containment of a nuclear power plant is a structure to ensure the safety of nuclear power plant. It acts as the last barrier to prevent the release of radioactive materials from NPP during accidents. Finite element models were established to simulate a 1/3 scale model of a reactor containment building under leakage test pressure. General finite element software ANSYS were applied. The nonlinear behavior of containment materials, geometric were taken into account in the analysis. The reliability of the finite element model was verified through the comparison of theoretical analysis results with experimental results. In the ANSYS finite element model, the concrete, steel bars and prestress tendons were separated and the prestress tendons were considered by the method of cooling method on the prestress tendon elements. The mechanical properties of the finite element model in the prestress tension process and the absolute internal pressure of 0.52MPa were analyzed. Transient and time dependent losses were taken into account at the same time during the calculation of prestress of tendons, so as to calculate effective prestress at different locations of tendons. Calculation results of prestress losses show that the prestress losses at the hole of equipment hatch are larger than the other areas. The results show that, the deformation of over-all structure of the containment is shrink inward under the action of prestress. And the simulation can achieve the consistent deformation effect between tendons and concrete. The maximum radial displacement of the whole containment structure is located at of 10 ° ∼ 20 °area on the right of the hole of the gate. The effect of expansion deformation of the containment caused by design internal pressure is insufficient to offset the inward shrink effect generated by tendons, and the over-all structure of the concrete containment scale model is mainly under compressive stress. The containment test model is still with a large safety margin under the action of design internal pressure. The largest tensile stress is on the up and down areas of the internal sides of the equipment hatch, dome area close to ring beam, and bottom of perimeter wall close to the base slab. There is possibility of cracking on the concrete in limited local zones. This benchmark can provide a reference for engineering design of containment.

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
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Intensity ◽  
Stress Concentration ◽  
Internal Pressure ◽  
Pressure Vessel ◽  
Pressure Vessels ◽  
Stress Index ◽  
Element Analysis ◽  
Approximate Formulas

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.

The Analysis of the Stiffness about the School Bus Based on Hyper Mesh

2014 ◽  
Vol 912-914 ◽  
pp. 806-809
Author(s):  
Ming Feng Zheng ◽  
Yue Chen ◽  
Ya Lin Yan
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Finite Element Model ◽  
Finite Element Simulation ◽  
Local Structure ◽  
Element Model ◽  
School Bus ◽  
Element Simulation ◽  
As Stress

Established a finite element model of the school bus based on the Hyper Mesh, take a finite element simulation about the various parts of the school bus parameters such as stress, displacement and deformation under 5 conditions. Through the analysis of the school bus to identify conditions displacement of stress more concentrated area as well as in operation, by optimizing improve the local structure of these regions,improve the stress concentration and safety.

Analysis for Wrinkling Behavior of Girth-Welded Line Pipe

1999 ◽  
Vol 121 (1) ◽  
pp. 53-61
Author(s):  
L. T. Souza ◽  
D. W. Murray
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Internal Pressure ◽  
Experimental Test ◽  
Element Model ◽  
Element Analysis ◽  
Line Pipe ◽  
New Era ◽  
Analytical Tools

The paper presents results for finite-element analysis of full-sized girth-welded specimens of line pipe and compares these results with the behavior exhibited by test specimens subjected to constant axial force, internal pressure, and monotonically increasing curvatures. Recommendations for the “best” type of analytical finite element model are given. Comparisons between the behavior predicted analytically and the observed behavior of the experimental test specimens are made. The mechanism of wrinkling is explained and the evolution of the deformed configurations for different wrinkling modes is examined. It is concluded that the analytical tools now available are sufficiently reliable to predict the behavior of pipe in a manner that was not previously possible and that this should create a new era for the design and assessment of pipelines if the technology is properly exploited by industry.

Numerical Investigation of Pressure-Cycling Induced Fatigue Failure of Wrinkled Energy Pipelines

2021 ◽  
pp. 1-38
Author(s):  
Navjot Singh ◽  
Sreekanta Das ◽  
Peter Song ◽  
Nader Yoosef-Ghodsi
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Internal Pressure ◽  
Fatigue Failure ◽  
Fatigue Loading ◽  
Element Model ◽  
Pressure Cycling ◽  
Concentration Factors ◽  
Fatigue Life Analysis ◽  
Stress Concentration Factors

Abstract Wrinkle defects can be complex pipeline deformities to assess and can present the potential to initiate a pipeline release incident as a result of fatigue failure due to pressure cycling, if not dealt with accordingly. Specifically, the stress distribution arising due to applied loads such as internal pressure can vary rapidly due to the complex shape along the wrinkle profile, which may introduce complexities in subsequent assessments such as fatigue life analysis. This paper presents a methodology using numerical simulation for evaluating stress concentration factors of wrinkle defects of varying geometries. A nonlinear finite element model is developed to evaluate stress concentration factors induced by wrinkle defects within steel pipelines subjected to internal pressure. Afterwards, data from full-scale laboratory tests for the wrinkled pipe specimens subjected to cyclic pressure fatigue loading is analyzed to evaluate stress concentration factors for comparable wrinkle profiles. Lastly, a comparison between the results of the stress concentration factors evaluated using finite element method and test data is provided, followed with a brief discussion of potential sources of discrepancies between results obtained from these methods.

Development of B1 and C1 Stress Indices for Trunnion Elbow Supports

1984 ◽  
Vol 106 (2) ◽  
pp. 166-171 ◽  
Author(s):  
D. K. Williams ◽  
G. D. Lewis
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Internal Pressure ◽  
Pressure Vessel ◽  
Pressure Loading ◽  
Empirical Relationships ◽  
Element Analysis ◽  
Stress Indices ◽  
Pressure Stress

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.

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