Natural Frequencies and Mode Shapes of Statically Deformed Inclined Risers

Feras Alfosail; Ali H. Nayfeh; Mohammad I. Younis

doi:10.1016/j.ijnonlinmec.2016.09.007

Natural Frequencies and Mode Shapes of Statically Deformed Inclined Risers

Feras Alfosail, Ali H. Nayfeh, Mohammad I. Younis

Research output: Contribution to journal › Article › peer-review

21 Scopus citations

Abstract

We investigate numerically the linear vibrations of inclined risers using the Galerkin approach. The riser is modeled as an Euler-Bernoulli beam accounting for the nonlinear mid-plane stretching and self-weight. After solving for the initial deflection of the riser due to self-weight, we use a Galerkin expansion employing 15 axially loaded beam mode shapes to solve the eigenvalue problem of the riser around the static equilibrium configuration. This yields the riser natural frequencies and corresponding exact mode shapes for various values of inclination angles and tension. The obtained results are validated against a boundary-layer analytical solution and are found to be in good agreement. This constitutes a basis to study the nonlinear forced vibrations of inclined risers.

Original language	English (US)
Pages (from-to)	12-19
Number of pages	8
Journal	International Journal of Non-Linear Mechanics
Volume	94
DOIs	https://doi.org/10.1016/j.ijnonlinmec.2016.09.007
State	Published - Oct 19 2016

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This research made use of the resources of the IT Research Computing at King Abdullah University of Science & Technology (KAUST) in Thuwal, Saudi Arabia. In addition, the first author acknowledges the support of Saudi Aramco.

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10.1016/j.ijnonlinmec.2016.09.007

https://repository.kaust.edu.sa/bitstream/10754/621052/1/10.1016-j.ijnonlinmec.2016.09.007.pdf

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title = "Natural Frequencies and Mode Shapes of Statically Deformed Inclined Risers",

abstract = "We investigate numerically the linear vibrations of inclined risers using the Galerkin approach. The riser is modeled as an Euler-Bernoulli beam accounting for the nonlinear mid-plane stretching and self-weight. After solving for the initial deflection of the riser due to self-weight, we use a Galerkin expansion employing 15 axially loaded beam mode shapes to solve the eigenvalue problem of the riser around the static equilibrium configuration. This yields the riser natural frequencies and corresponding exact mode shapes for various values of inclination angles and tension. The obtained results are validated against a boundary-layer analytical solution and are found to be in good agreement. This constitutes a basis to study the nonlinear forced vibrations of inclined risers.",

author = "Feras Alfosail and Nayfeh, {Ali H.} and Younis, {Mohammad I.}",

note = "KAUST Repository Item: Exported on 2020-10-01 Acknowledgements: This research made use of the resources of the IT Research Computing at King Abdullah University of Science & Technology (KAUST) in Thuwal, Saudi Arabia. In addition, the first author acknowledges the support of Saudi Aramco.",

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doi = "10.1016/j.ijnonlinmec.2016.09.007",

language = "English (US)",

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AU - Alfosail, Feras

AU - Nayfeh, Ali H.

AU - Younis, Mohammad I.

N1 - KAUST Repository Item: Exported on 2020-10-01 Acknowledgements: This research made use of the resources of the IT Research Computing at King Abdullah University of Science & Technology (KAUST) in Thuwal, Saudi Arabia. In addition, the first author acknowledges the support of Saudi Aramco.

PY - 2016/10/19

Y1 - 2016/10/19

N2 - We investigate numerically the linear vibrations of inclined risers using the Galerkin approach. The riser is modeled as an Euler-Bernoulli beam accounting for the nonlinear mid-plane stretching and self-weight. After solving for the initial deflection of the riser due to self-weight, we use a Galerkin expansion employing 15 axially loaded beam mode shapes to solve the eigenvalue problem of the riser around the static equilibrium configuration. This yields the riser natural frequencies and corresponding exact mode shapes for various values of inclination angles and tension. The obtained results are validated against a boundary-layer analytical solution and are found to be in good agreement. This constitutes a basis to study the nonlinear forced vibrations of inclined risers.

AB - We investigate numerically the linear vibrations of inclined risers using the Galerkin approach. The riser is modeled as an Euler-Bernoulli beam accounting for the nonlinear mid-plane stretching and self-weight. After solving for the initial deflection of the riser due to self-weight, we use a Galerkin expansion employing 15 axially loaded beam mode shapes to solve the eigenvalue problem of the riser around the static equilibrium configuration. This yields the riser natural frequencies and corresponding exact mode shapes for various values of inclination angles and tension. The obtained results are validated against a boundary-layer analytical solution and are found to be in good agreement. This constitutes a basis to study the nonlinear forced vibrations of inclined risers.

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EP - 19

JO - International Journal of Non-Linear Mechanics

JF - International Journal of Non-Linear Mechanics

ER -

Natural Frequencies and Mode Shapes of Statically Deformed Inclined Risers

Abstract

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