Plastic limit loads for pipe bends with circumferential through-wall crack under torsion moment

Li, Jian; Zhou, Changyu; Miao, Xin-Ting; Chang, Le; He, Xin

doi:10.1016/j.ijmecsci.2015.06.022

Cited by 18 publications

(4 citation statements)

References 45 publications

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“…Maximum percentage difference obtained was 5.76% and this was observed for R = 101.6 mm, ø = 30° , C o = 0% and C t = 20% while the minimum of −3.50% was observed for R = 101.6 mm, ø = 30°, C o = 20% and C t = 5%. At the crown region, induced hoop stress is maximum when the pipe bend is exposed to moment loading (Li et al , 2015). In the present analysis, thickness at the crown region was kept constant which was equal to nominal thickness while at the intrados and extrados regions thickness varied from 0% to 20%.…”

Section: Interpretation Of Resultsmentioning

confidence: 99%

Effect of structural deformations and bend angle on the collapse load of pipe bends subjected to in-plane closing bending moment

Silambarasan

Veerappan

Shanmugam

2021

WJE

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Purpose The purpose of this study is to investigate the effect of structural deformations and bend angle on plastic collapse load of pipe bends under an in-plane closing bending moment (IPCM). A large strain formulation of three-dimensional non-linear finite element analysis was performed using an elastic perfectly plastic material. A unified mathematical solution was proposed to estimate the collapse load of pipe bends subjected to IPCM for the considered range of bend characteristics. Design/methodology/approach ABAQUS was used to create one half of the pipe bend model due to its symmetry on the longitudinal axis. Structural deformations, i.e. ovality (Co) and thinning (Ct) varied from 0% to 20% in 5% steps while the bend angle (ø) varied from 30° to 180° in steps of 30°. Findings The plastic collapse load decreases as the bend angle increase for all pipe bend models. A remarkable effect on the collapse load was observed for bend angles between 30° and 120° beyond which a decline was noticed. Ovality had a significant effect on the collapse load with this effect decreasing as the bend angle increased. The combined effect of thinning and bend angle was minimal for the considered models and the maximum per cent variation in collapse load was 5.76% for small bend angles and bend radius pipe bends and less than 2% for other cases. Originality/value The effect of structural deformations and bend angle on collapse load of pipe bends exposed to IPCM has been not studied in the existing literature.

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Section: Interpretation Of Resultsmentioning

confidence: 99%

Effect of structural deformations and bend angle on the collapse load of pipe bends subjected to in-plane closing bending moment

Silambarasan

Veerappan

Shanmugam

2021

WJE

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“…Simultaneously, a distortion in element shape at the nearer region of the crack front, which may lead to selflocking problems, could be avoided by modeling the crack front with more elements. 18,29 It is worth noting that the self-locking problem was not experienced during the analysis of shape-distorted TWCC pipe bends in our analysis. The absence of the self-locking problem was noticed and published by Yahiaoui et al, 7 Balakrishnan et al, 17,18 and Chattopadhyay et al 19 The modeling procedure adopted by Chattopadhyay et al 19 and Li et al 29 was followed in this present study to represent the TWCC at the intrados.…”

Section: Detailed Pcm Analysismentioning

confidence: 90%

“…22–24 The circumferential crack ( 2 θ) at the intrados was taken as 0°, 45°, 60°, and 90° for which the corresponding relative crack lengths ( θ/π) were 0, 0.125, 0.167, and 0.25, respectively. 28,29 The material considered was Type 304 SS, generally used in the piping system, with a 0.26 Poisson's ratio 0.25em false( γ false), yield stress ( σ o false) of 271.93 MPa, and Young's modulus ( E ) of 193 GPa. 17,18,26,28 For the present analysis, the elastic-perfectly plastic (EPP) material model was used, which offers a conservative estimation of the FE results and thus is useful from the standpoint of the pipe bend's design.…”

Section: Fe Analysismentioning

confidence: 99%

“…Also, it is not sensitive to self-locking problems, especially in complicated stress fields where shear-locking does not easily occur when subjected to torsion and bending moments. 17,18,29 Mesh refinement was conducted in all models with three element layers for thickness until the variations in PCM loads at the intervals of two successive models were < 0.1%. 17,22 The mesh study was adequate for the FE analysis since the optimum number of elements and nodes were 4662 and 24,615, respectively.…”

Section: Fe Analysismentioning

confidence: 99%

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Development of an improved structural integrity assessment correlation for circumferential through-wall cracked 90° shape-distorted pipe bends subjected to in-plane opening bending moment

Thulasiraj,

Arunachalam

2023

Proceedings of the Institution of Mechanical Engineers, Part L:

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A detailed and systematic assessment of the plastic collapse load of 90° shape imperfect pipe bends subjected to in-plane opening bending was conducted by implementing three-dimensional non-linear finite element analyses. The material considered in the analysis is the elastic-perfectly plastic type with a large change geometry option. Shape distortions in the pipe's cross-section and through-wall circumferential crack at the intrados region were the defects analyzed in this study. Ovality [Formula: see text] and thinning [Formula: see text] were varied from 0% to 20% with a 5% incrementation, and crack angles of 45°, 60°, and 90° were considered at the intrados. The twice-elastic slope method effectively evaluates the plastic collapse moment as mandated by the ASME B&PV code NB-3213.25, section III. The reaction moment and angular rotation curves were generated for all pipe bend models. The outcomes of the analysis revealed that the plastic collapse moment load of pipe bends was affected by through-wall circumferential crack and [Formula: see text], while thinning produced negligible effect, which was subsequently excluded from the analysis. The combined effect of through-wall circumferential crack and [Formula: see text] produces a consequential influence on the pipe bend at 45° angle, which is severe at 60°, and even more critical at 90°. In the analysis, the plastic collapse moment for short bend radius was reduced, while that of thin-walled pipe bends increased with an increase in thickness and bend radius. The plastic collapse moment of the present analysis was validated using experimental data acquired from open literature. An enhanced structural correlation assessment was proposed for through-wall circumferential crack shape-distorted 90° pipe bends.

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Machine learning for the prediction of problems in steel tube bending process

Görüş,

Bahşı,

Çevik

2024

Engineering Applications of Artificial Intelligence

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Plastic limit loads for pipe bends with circumferential through-wall crack under torsion moment

Cited by 18 publications

References 45 publications

Effect of structural deformations and bend angle on the collapse load of pipe bends subjected to in-plane closing bending moment

Effect of structural deformations and bend angle on the collapse load of pipe bends subjected to in-plane closing bending moment

Development of an improved structural integrity assessment correlation for circumferential through-wall cracked 90° shape-distorted pipe bends subjected to in-plane opening bending moment

Machine learning for the prediction of problems in steel tube bending process

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