Experimental Study on the Characteristics of Bolted Pipe Flange Connection Under Bending Moment and Internal Pressure

2021 ◽  
Author(s):  
Xing Zheng ◽  
Toshiyuki Sawa ◽  
Mei Feng ◽  
Honggui Ding
Keyword(s):  
Experimental Study ◽  
Internal Pressure ◽  
Bending Moment ◽  
Flange Connection

Experimental Study on the Characteristics of Bolted Pipe Flange Connection Under Bending Moment and Internal Pressure

2020 ◽  
Author(s):  
Xing Zheng ◽  
Toshiyuki Sawa ◽  
Mei Feng ◽  
Honggui Ding
Keyword(s):  
Experimental Study ◽  
Internal Pressure ◽  
Bending Moment ◽  
Wind Load ◽  
Force Distribution ◽  
Flange Connection ◽  
Special Cases ◽  
Minimum Residual ◽  
Spiral Wound

Abstract After a bolted gasketed pipe flange connection is assembled, the pipe flange connection is usually subjected to some additional loads such as bending moment, own weight, wind load and so on. These additional loads will lead to changing the axial bolt force distribution of the pipe flange connection and the distribution will become more and more scattered. As a result, the minimum residual axial bolt force will be much smaller and the minimum contact gasket stress will decrease, so a leakage is easy to occur in the connection. In special cases such as earthquakes, the bolted pipe flange connection is usually subjected to a high bending moment. Then sometimes leakage accidents occur. In order to promote the safety of the connections and to avoid them being broken under the earthquakes, in the present paper, the equivalent pressure and the assembly efficiency in the pipe flange connection of class 150 4″ are measured experimentally. The leak rates of the connection using spiral-wound gasket when a bending moment was applied or not applied were measured to elicit the equivalent pressure. Moreover, some tightening procedures such as JIS B 2251, ASME PCC-1 Legacy and GB/T 38343 were applied to tighten the pipe flange connection. The axial bolt force distribution, the assembly efficiency based on the target axial bolt force and the assembly efficiency based on tightness parameter of the connection when bending moment was applied or not applied were measured, and the results are compared. As a result, the equivalent pressure under a given bending moment is obtained, and a difference of the equivalent pressure between our results and Kellogg’s results is demonstrated. In addition, the new assembly efficiency based on the tightness parameter is also measured under a given bending moment as well as internal pressure. Using the equivalent pressure and the assembly efficiency obtained in the present paper, a new design will be possible for pipe flange connections under bending moment.

Effect of External Bending Moment on the Sealing Performance of Pipe Flange Connection

2010 ◽  
Author(s):  
Yoshio Takagi ◽  
Hiroyasu Torii ◽  
Toshiyuki Sawa ◽  
Yuya Omiya
Keyword(s):  
Stress Distribution ◽  
Internal Pressure ◽  
Deformation Characteristic ◽  
Bending Moment ◽  
Displacement Curve ◽  
Linear Deformation ◽  
Flange Connection ◽  
Sealing Performance ◽  
Non Linear ◽  
The Difference

Since an external bending moment affects the sealing performance of pipe flange connection, it is important to investigate this effect. This paper analyzed the contact gasket stress distribution of pipe flange connections and evaluates the effect of external bending moment on the sealing performance from the viewpoint of changes in contact gasket stress. The study includes the FE analyses and the experimental leakage tests. The FE analyses suggested the large decrease of contact gasket stress at tension side and small increase at compression side. The difference in change in contact gasket stress was caused by the non-linear hysteresis characteristics of stress-displacement curve of gasket. The FE analyses also suggested that the loading order, internal pressure and external bending moment, also affected the sealing performance due to the non-linear deformation characteristic of the gasket. The sealing performance when the external bending moment applied prior to the internal pressure was degraded more than when the internal pressure was applied prior to the external bending moment. The experimental leakage tests using helium (He) gas were analyzed by the finite element method and discussed. This paper also evaluated the stress distribution in the pipe flange under external bending moment. The results suggested that the hub stress dominated the flange structure and the most important factor in designing the flange.

FEM Stress Analysis and Sealing Performance in Pipe Flange Connections With Gaskets Subjected to Internal Pressure and External Bending Moment

2002 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Mitsuhiro Matsumoto
Keyword(s):  
Internal Pressure ◽  
Strain Curve ◽  
Bending Moment ◽  
Stress Distributions ◽  
Stress Strain Curve ◽  
Flange Connection ◽  
Leakage Test ◽  
Sealing Performance ◽  
Calculated Average ◽  
Good Agreement

This paper deals with the characteristics of a pipe flange connection with a compressed asbestos sheet gasket (JIS) subjected to an internal pressure and a bending moment. The contact gasket stress distributions at the interfaces between pipe flanges and a gasket are calculated by the elasto-plastic finite element method taking account a hysteresis and a non-linearity in the stress-strain curve of the compressed asbestos sheet gasket. In addition, measurements of a change in axial bolt force and leakage test were conducted using an actual pipe flange connection with the gasket subjected to the internal pressure and the bending moment. The new gasket constants are calculated by using the results of the leakage test and the calculated average contact gasket stress. The values of the new gasket constants obtained by the present study are in a fairly good agreement with those from ROTT (PVRC). It is found that the value of the tightness parameter is increased as the bending moment is increased. This is because the average contact gasket stress under the bending moment is increased, while it is decreased under the internal pressure.

Study on steel wire reinforced thermoplastic pipes under combined internal pressure and bending moment at various temperatures

2021 ◽  
Vol 169 ◽  
pp. 108381
Author(s):  
Jianfeng Shi ◽  
Sijia Zhong ◽  
Xinyu Nie ◽  
Jun Shi ◽  
Jinyang Zheng
Keyword(s):  
Internal Pressure ◽  
Steel Wire ◽  
Bending Moment

Ratcheting assessment of corroded elbow pipes subjected to internal pressure and cyclic bending moment

2021 ◽  
pp. 030932472198989
Author(s):  
Ali Salehi ◽  
Armin Rahmatfam ◽  
Mohammad Zehsaz
Keyword(s):  
Growth Rate ◽  
Stainless Steel ◽  
Internal Pressure ◽  
Bending Moment ◽  
Axial Direction ◽  
Hoop Strain ◽  
Cyclic Bending ◽  
High Fatigue ◽  
The Impact ◽  
Cyclic Bending Moment

The present study aimed to study ratcheting strains of corroded stainless steel 304LN elbow pipes subjected to internal pressure and cyclic bending moment. To this aim, spherical and cubical shapes corrosion are applied at two depths of 1 mm and 2 mm in the critical points of elbow pipe such as symmetry sites at intrados, extrados, and crown positions. Then, a Duplex 2205 stainless steel elbow pipe is considered as an alternative to studying the impact of the pipe materials, due to its high corrosion resistance and strength, toughness, and most importantly, the high fatigue strength and other mechanical properties than stainless steel 304LN. In order to perform numerical analyzes, the hardening coefficients of the materials were calculated. The results highlight a significant relationship between the destructive effects of corrosion and the depth and shape of corrosion, so that as corrosion increases, the resulting destructive effects increases as well, also, the ratcheting strains in cubic corrosions have a higher growth rate than spherical corrosions. In addition, the growth rate of the ratcheting strains in the hoop direction is much higher across the studied sample than the axial direction. The highest growth rate of hoop strain was observed at crown and the highest growth rate of axial strains occurred at intrados position. Altogether, Duplex 2205 material has a better performance than SS 304LN.

Elastic-plastic bending of the pipeline under combined loading

2021 ◽  
pp. 372-377
Author(s):  
Виктор Миронович Варшицкий ◽  
Евгений Павлович Студёнов ◽  
Олег Александрович Козырев ◽  
Эльдар Намикович Фигаров
Keyword(s):  
Internal Pressure ◽  
Limit State ◽  
Bending Moment ◽  
Axial Direction ◽  
Longitudinal Force ◽  
Combined Loading ◽  
Dimensional Problem ◽  
Elastic Plastic ◽  
Pipeline Section ◽  
Thin Walled Pipe

Рассмотрена задача упругопластического деформирования тонкостенной трубы при комбинированном нагружении изгибающим моментом, осевой силой и внутренним давлением. Решение задачи осуществлено по разработанной методике с помощью математического пакета Matcad численным методом, основанным на деформационной теории пластичности и безмоментной теории оболочек. Для упрощения решения предложено сведение двумерной задачи к одномерной задаче о деформировании балки, материал которой имеет различные диаграммы деформирования при сжатии и растяжении в осевом направлении. Проведено сравнение с результатами численного решения двумерной задачи методом конечных элементов в упругопластической постановке. Результаты расчета по инженерной методике совпадают с точным решением с точностью, необходимой для практического применения. Полученные результаты упругопластического решения для изгибающего момента в сечении трубопровода при комбинированном нагружении позволяют уточнить известное критериальное соотношение прочности сечения трубопровода с кольцевым дефектом в сторону снижения перебраковки. Применение разработанной методики позволяет ранжировать участки трубопровода с непроектным изгибом по степени близости к предельному состоянию при комбинированном нагружении изгибающим моментом, продольным усилием и внутренним давлением. The problem of elastic plastic deformation of a thin-walled pipe under co-binned loading by bending moment, axial force and internal pressure is considered. The problem is solved by the developed method using the Matcad mathematical package by a numerical method based on the deformation theory of plasticity and the momentless theory of shells. To simplify the solution of the problem, it is proposed to reduce a twodimensional problem to a one-dimensional problem about beam deformation, the material of which has different deformation diagrams under compression and tension in the axial direction. Comparison with the results of numerical solution of the two-dimensional problem with the finite element method in the elastic plastic formulation is carried out. The obtained results of the elastic-plastic solution for the bending moment in the pipeline section under combined loading make it possible to clarify criterion ratio of the strength of the pipeline section with an annular defect in the direction of reducing the rejection. Application of the developed approach allows to rank pipeline sections with non-design bending in the steppe close to the limit state under combined loading of the pipeline with bending moment, longitudinal force and internal pressure.

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