Stress and flexibility factors for multi-mitred pipe bends subjected to internal pressure combined with external loadings

1972 ◽  
Vol 7 (2) ◽  
pp. 97-108 ◽  
Author(s):  
M P Bond ◽  
R Kitching
Keyword(s):  
Internal Pressure ◽  
Large Diameter ◽  
Pipe Bend ◽  
Bending Tests ◽  
Bending Load ◽  
Out Of Plane ◽  
Thin Walled ◽  
Plane Bending ◽  
Internal Pressures ◽  
Stress Patterns

The stress analysis of a multi-mitred pipe bend when subjected to an internal pressure and a simultaneous in-plane or out-of-plane bending load has been developed. Stress patterns and flexibility factors calculated by this analysis are compared with experimental results from a large-diameter, thin-walled, three-weld, 90° multi-mitred bend which was subjected to in-plane bending tests at various internal pressures.

Shakedown Boundary of a 90–Degree Back–to–Back Pipe Bend Subjected to Steady Internal Pressures and Cyclic Out–of–Plane Bending Moments

2014 ◽  
Author(s):  
Hany F. Abdalla
Keyword(s):  
Internal Pressure ◽  
Bending Moment ◽  
Bending Moments ◽  
Pipe Bend ◽  
Structure Comparison ◽  
Out Of Plane ◽  
Plane Bending ◽  
Shakedown Limit ◽  
Elastic Shakedown ◽  
Internal Pressures

Ninety degree back–to–back pipe bends are extensively utilized within piping networks of modern nuclear submarines and modern turbofan aero–engines where space limitation is considered a supreme concern. According the author’s knowledge, no shakedown analysis exists for such structure based on experimental data. In the current research, the pipe bend setup analyzed is subjected to a spectrum of steady internal pressures and cyclic out–of–plane bending moments. A previously developed direct non–cyclic simplified technique, for determining elastic shakedown limit loads, is utilized to generate the elastic shakedown boundary of the analyzed structure. Comparison with the elastic shakedown boundary of the same structure, but subjected to cyclic in–plane bending moments revealed a higher shakedown boundary for the out–of–plane bending loading configuration with a maximum bending moment ratio of 1.4 within the low steady internal pressure spectrum. The ratio decreases towards the medium to high internal pressure spectrum. The simplified technique outcomes showed excellent correlation with the results of full elastic–plastic cyclic loading finite element simulations.

Evaluation of collapse moment of pressurized 30°–180° bend pipes subjected to out-of-plane bending moment

2021 ◽  
pp. 095440622110614
Author(s):  
Manish Kumar ◽  
Pronab Roy ◽  
Kallol Khan
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Plastic Material ◽  
Bending Moment ◽  
Bend Angle ◽  
Pipe Bend ◽  
Geometric Imperfection ◽  
Initial Geometric Imperfection ◽  
Out Of Plane ◽  
Plane Bending

The present paper determines collapse moments of pressurized 30°–180° pipe bends incorporated with initial geometric imperfection under out-of-plane bending moment. Extensive finite element analyses are carried out considering material as well as geometric nonlinearity. The twice-elastic-slope method is used to determine collapse moment. The results show that initial imperfection produces significant change in collapse moment for unpressurized pipe bends and pipe bends applied to higher internal pressure. The application of internal pressure produces stiffening effect to pipe bends which increases collapse moment up to a certain limit and with further increase in pressure, collapse moment decreases. The bend angle effect on collapse moment reduces with the increase in internal pressure and bend radius. Based on finite element results, collapse moment equations are formed as a function of the pipe bend geometry parameters, initial geometric imperfection, bend angle, and internal pressure for elastic-perfectly plastic material models.

Structural Performance of Steel Pipe Tee-Junctions

2014 ◽  
Author(s):  
Theocharis Papatheocharis ◽  
Kalliopi Diamanti ◽  
George E. Varelis ◽  
Philip C. Perdikaris ◽  
Spyros A. Karamanos
Keyword(s):  
Internal Pressure ◽  
Low Cycle Fatigue ◽  
Axial Loading ◽  
Steel Pipe ◽  
Structural Performance ◽  
Finite Element Models ◽  
Bending Tests ◽  
Out Of Plane ◽  
Dimensional Measurements ◽  
Plane Bending

The behavior of steel pipe junctions (Tees) subjected to strong loading in the presence of internal pressure is examined in the present study. The analysis is based on a set of monotonic and cyclic out-of plane bending tests under constant and increasing amplitude displacement-controlled loading schemes leading to low-cycle fatigue failure. Rigorous finite element models are developed to support the experiments, accounting for detailed dimensional measurements and material testing results obtained prior to testing. A parametric analysis is also conducted focusing on the effect of the geometrical characteristics on the overall junction behavior. The performance of the Tee-junctions with varying geometries under out-of plane bending, in-plane bending and axial loading is also examined numerically accounting for the presence of internal pressure.

Stress and flexibility factors for multi-mitred bends subjected to out-of-plane bending

1971 ◽  
Vol 6 (4) ◽  
pp. 213-225 ◽  
Author(s):  
M P Bond ◽  
R Kitching
Keyword(s):  
Theoretical Analysis ◽  
Maximum Stress ◽  
Large Diameter ◽  
Stress Distributions ◽  
Factors Associated ◽  
Out Of Plane ◽  
Thin Walled ◽  
Plane Bending ◽  
Stress Ratios

A theoretical analysis has been developed to predict stress distributions and flexibility factors associated with out-of-plane bending of multi-mitred pipe bends. The estimated range of validity of the analysis is sufficient to include most practical multi-mitred pipe bends. Tests on a large-diameter, thin-walled, three-weld right-angled multi-mitred bend were undertaken and the results closely agreed with computations based on the analysis. Predictions for both flexibility factors and overall maximum-stress ratios from the analysis were almost identical with those given by an in-plane bending theory that had been developed from a similar method of approach.

Effect of Bend Angle on Gross Plastic Deformation of Pipe Bends for Out-of-Plane Bending: A Study Using Plastic Work Curvature Method

2016 ◽  
Author(s):  
Anindya Bhattacharya ◽  
Sachin Bapat ◽  
Hardik Patel ◽  
Shailan Patel ◽  
Michael P. Cross
Keyword(s):  
Plastic Deformation ◽  
Internal Pressure ◽  
Bending Moment ◽  
Plastic Work ◽  
Bend Angle ◽  
Piping System ◽  
Plastic Collapse ◽  
Pipe Bend ◽  
Out Of Plane ◽  
Plane Bending

Bends are an integral part of a piping system. Because of the ability to ovalize and warp they offer more flexibility when compared to straight pipes. Piping Code ASME B31.3 [1] provides flexibility factors and stress intensification factors for pipe bends. Like any other piping component, one of the failure mechanisms of a pipe bend is gross plastic deformation. In this paper, plastic collapse load of pipe bends have been analyzed for various bend parameters (bend parameter = tRbrm2) under internal pressure and out-of-plane bending moment for various bend angles using both small and large deformation theories. FE code ABAQUS version 6.9EF-1 has been used for the analyses. The goal of the paper is to develop an expression for plastic collapse moment for a bend using plastic work curvature method when the bend is subjected to out-of-plane bending moment and internal pressure as a function of bend angle and bend parameter.

Mechanical Behavior of a Branch Pipe Subjected to Out-of-Plane Bending Load

2001 ◽  
Vol 124 (1) ◽  
pp. 7-13 ◽  
Author(s):  
S. Chapuliot ◽  
D. Moulin ◽  
D. Plancq
Keyword(s):  
Experimental Study ◽  
Internal Pressure ◽  
Limit State ◽  
Branch Pipe ◽  
Plastic Behavior ◽  
Bending Load ◽  
Finite Element Calculations ◽  
Out Of Plane ◽  
Plane Bending ◽  
Parameter Influence

A numerical and experimental study on the behavior of a branch pipe is presented in this article. The test is the first one of a series analyzing the behavior of the branch pipe under out-of-plane bending load in the presence of a crack near the junction, a weld or internal pressure. It is performed under bending alone, without weld and without internal pressure, so as to constitute a reference for the series, and thus to estimate each parameter influence. In complement to the experimental study, finite element calculations are performed and presented in this article, so as to analyze the elastic-plastic behavior of the branch pipe and its limit state.

Gross Plastic Deformation of Pipe Bends Under Internal Pressure and In- and Out-of-Plane Bending: A Study on the Sensitivity of the Finite Element Models

2014 ◽  
Author(s):  
Anindya Bhattacharya ◽  
Sachin M. Bapat
Keyword(s):  
Plastic Deformation ◽  
Internal Pressure ◽  
Real Life ◽  
Bending Moment ◽  
Piping System ◽  
Plastic Collapse ◽  
Collapse Load ◽  
Pipe Bend ◽  
Out Of Plane ◽  
Plane Bending

Bends are an integral part of a piping system. Because of the ability to ovalize and warp they offer more flexibility when compared to straight pipes. Piping Code ASME B31.3 [1] provides flexibility factors and stress intensification factors for the pipe bends. Like any other piping component, one of the failure mechanisms of a pipe bend is gross plastic deformation. In this paper, plastic collapse load of pipe bends have been analyzed for various D/t ratios (Where D is pipe outside diameter and t is pipe wall thickness) for internal pressure and in-plane bending moment, internal pressure and out-of-plane bending moment and internal pressure and a combination of in and out-of-plane bending moments under varying ratios. Any real life component will have imperfections and the sensitivity of the models have been investigated by incorporating imperfections as scaled eigenvectors of linear bifurcation buckling analyses. The sensitivity of the models to varying parameters of Riks analysis (an arc length based method) and use of dynamic stabilization using viscous damping forces have also been investigated. Importance of defining plastic collapse load has also been discussed. FE code ABAQUS version 6.9EF-1 has been used for the analyses.

Stresses in Curved, Circular Thin-Wall Tubes

1963 ◽  
Vol 30 (1) ◽  
pp. 134-135
Author(s):  
E. A. Utecht
Keyword(s):  
Thin Wall ◽  
Bending Moments ◽  
Circular Tubes ◽  
Out Of Plane ◽  
Thin Walled ◽  
Plane Bending

Curves are presented which give stress intensification factors for curved, thin-walled circular tubes under various combinations of in-plane and out-of-plane bending moments.

Out-of-Plane Bending (Opb) Test of Large Diameter Mooring Chains

2021 ◽  
Author(s):  
m.r. Karimi ◽  
J. Braun ◽  
E. Gooijer ◽  
P. Barros ◽  
E. Carlberg ◽  
...  
Keyword(s):  
Large Diameter ◽  
Out Of Plane ◽  
Plane Bending
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