The pressure reduction effect in smooth piping elbows—revisited

Lubis, Asnawi; Boyle, James T.

doi:10.1016/j.ijpvp.2003.11.003

Cited by 9 publications

(9 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…These factors were derived for the specific load case of pure in-plane closing moment and internal pressure and are used, usually without modification, for in-plane opening moments and outof-plane loading. The results of an extensive nonlinear finite element study of the pressure reduction effect were recently reported by Lubis and Boyle [9,10]. Both papers dealt with pressure reduction effect for in-plane bending moment.…”

Section: Introductionmentioning

confidence: 94%

Nonlinear Analysis of Pressurized Piping Elbows Subjected to Out-of-Plane Bending

Lubis

Akmal

2006

KEM

Self Cite

View full text Add to dashboard Cite

The behavior of piping elbows under bending and internal pressure is more complicated than expected. The main problem is that the coupling of bending and internal pressure is nonlinear; the resulting stress and displacement cannot be added according to the principle of superposition. In addition, internal pressure tends to act against the effect caused by the bending moment. If bending moment ovalise the elbow cross-section, with internal pressure acting against this deformation, then the ovalised cross section deform back to the original circular shape. It is then introduced the term “pressure reduction effect”, or in some literature, “pressure stiffening effect”. Current design piping code treats the pressure reduction effect equally for in-plane (closing and opening) moment and outof- plane moment. The aim of this paper is to present results of a detailed finite element analysis on the non-linear behavior of piping elbows of various geometric configurations subject to out-of-plane bending and internal pressure. Specifically the standard Rodabaugh & George nonlinear pressure reduction equations for in-plane closing moment are checked in a systematic study for out-of-plane moment against nonlinear finite element analysis. The results show that the pressure stiffening effects are markedly different for in-plane and out-of-plane bending.

show abstract

Section: Introductionmentioning

confidence: 94%

Nonlinear Analysis of Pressurized Piping Elbows Subjected to Out-of-Plane Bending

Lubis

Akmal

2006

KEM

Self Cite

View full text Add to dashboard Cite

show abstract

“…Akan tetapi apabila tekanan internal diberikan pada pipa elbow yang sudah diberi beban bending, maka akan memberikan efek yang berlawanan dengan ovalisasi (pressure reduction effect) [3]. Artinya bahwa tekanan internal mengurangi tegangan akibat beban bending dan menurunkan fleksibilitasnya [4]. Pada kondisi aktual di lapangan, beban yang diterima oleh pipa elbow adalah beban termal.…”

Section: Pendahuluanunclassified

“…Efek pemberian tekanan internal pada pipa elbow dapat menyebabkan perilaku nonlinier apabila penampang pipa tidak lingkaran sempurna, tapi misalnya berbentuk oval akibat beban bending yang diterimanya [4]. Tidak banyak penelitian mengenai pipa elbow yang dilaporkan dalam literature yang membahas perilaku nonlinier pipa elbow yang disebabkan oleh tekanan internal dan beban termal.…”

Section: Pendahuluanunclassified

Perilaku Nonlinier Pipa Elbow Bertekanan dengan Beban Termal dan In-Plane Bending

Nugraha

Lubis

Serjouei

2019

JEM

Self Cite

View full text Add to dashboard Cite

Pipa elbow adalah komponen yang penting pada sistem perpipaan. Pipa elbow memiliki fleksibilitas yang baik, sehingga dapat mengurangi tegangan akibat ekspansi termal. Beban yang diterima oleh pipa elbow adalah beban bending, beban termal dan tekanan internal. Beban bending menyebabkan ovalisasi pada pipa elbow. Jika tekanan internal ditambahkan, maka tekanan internal akan cenderung bertindak melawan efek yang disebabkan oleh beban bending dan menunjukkan perilaku nonlinear. Beban in-plane bending dan tekanan internal yang bekerja secara bersamaan pada ping elbow tidak menunjukkan perilaku nonlinier. Pada kondisi aktual, beban yang diterima oleh pipa elbow adalah beban termal yang memberikan efek cenderung sama seperti beban in-plane bending. Pada penelitian ini dilakukan analisis untuk menilai perilaku nonlinier pipa elbow yang diberikan beban termal dan tekanan internal dibandingkan dengan beban in-plane bending dan tekanan internal. Pada penelitian ini digunakan metode elemen hingga (ANSYS Mechanical APDL). Material yang dipakai adalah titanium alloy (Ti-6Al-4V) dan diasumsikan bersifat elastic-perfectly plastic. Hasil penelitian menunjukkan bahwa perilaku nonlinier hanya terjadi pada pembebanan in-plane bending dan tekanan internal. Sedangkan pada pembebanan termal dan tekanan internal tidak terjadi perilaku nonlinier. Pada pembebanan termal, tekanan internal memberikan efek yang searah dengan perpindahan yang disebabkan oleh beban termal. Pada pembebanan in-plane bending, tekanan internal memberikan efek yang berlawanan dengan perpindahan yang disebabkan oleh beban in-plane bending. Tegangan akibat beban in-plane bending lebih besar dibandingkan beban termal. Tekanan internal meningkatkan tegangan yang disebabkan pembebanan termal dan mengurangi tegangan yang disebabkan pembebanan in-plane bending

show abstract

“…where the coefficients n i are dimensionless; the free term can be easily determined from the equation of equality of axial forces (25). It can be shown that the cross-sectional area F 1 , which is found as an integral of 0 5 1 0 .…”

Section: Idea Of Solution Of the Problemmentioning

confidence: 99%

“…Nevertheless, the nonlinear deformation behavior of pipe bends in such problems is of interest to researchers. As was pointed out in [25], "the stabilizing effect of internal pressure is well known but poorly understood. "…”

mentioning

confidence: 99%

Analytical solution of the Brazier problem for thin-wall pipes with initial cross-sectional shape imperfection in the case of action of pressure

Оrynyak

Radchenko

2008

Strength Mater

View full text Add to dashboard Cite

An analytical method is proposed for the solution of geometrically nonlinear Brazier problem for thin-mall pipes with initial cross-sectional shape imperfection in the case of action of pressure. Geometrical equations relating displacement components to strains and equilibrium equations taking into account change in the curvature of pipe cross section and axis have been derived. A solution in a first approximation for dimensionless flexibility parameter is presented, the exactness of which is illustrated by numerous examples. For the case of joint action of external bending moment and pressure, a limit curve of the critical moment value as a function of pressure value has been obtained.

show abstract

The pressure reduction effect in smooth piping elbows—revisited

Cited by 9 publications

References 10 publications

Nonlinear Analysis of Pressurized Piping Elbows Subjected to Out-of-Plane Bending

Nonlinear Analysis of Pressurized Piping Elbows Subjected to Out-of-Plane Bending

Perilaku Nonlinier Pipa Elbow Bertekanan dengan Beban Termal dan In-Plane Bending

Analytical solution of the Brazier problem for thin-wall pipes with initial cross-sectional shape imperfection in the case of action of pressure

Contact Info

Product

Resources

About