Nonlinear Coupling of Pitch and Roll Modes in Ship Motions

Nayfeh, A. H.; Mook, Dean T.; Marshall, Larry R.

doi:10.2514/3.62949

Cited by 240 publications

(148 citation statements)

References 3 publications

Supporting

Mentioning

143

Contrasting

Unclassified

Order By: Relevance

“…The second and third mechanisms are less known [3][4][5] and may result from a nonlinear coupling between heave-roll or pitch-roll motions, respectively. The coupling becomes more and more effective close to the resonant conditions for the vertical motions, thus allowing an energy transfer to the transversal motion [6,7]. Its characteristic features are rather complex and not well established.…”

Section: Introductionmentioning

confidence: 99%

Model simulation of parametrically excited ship rolling

Tondl

Nabergoj²

1990

Nonlinear Dyn

View full text Add to dashboard Cite

Abstract. Two different models for simulating the ship motion in longitudinal or oblique seas are presented and studied in detail. Particular attention is devoted to the parametrically induced rolling which may be established by means of the nonlinear coupling between both heave-roll and/or pitch-roll motions. It is proved that the phenomenon is likely to occur with this mechanism when the roll frequency is subharmonic of the encounter wave frequency and when the vertical motions become resonant.

show abstract

Section: Introductionmentioning

confidence: 99%

Model simulation of parametrically excited ship rolling

Tondl

Nabergoj²

1990

Nonlinear Dyn

View full text Add to dashboard Cite

show abstract

“…The saturation phenomenon was¯rst discovered by Nayfeh, Mook, and Marshall (1973) while analyzing the coupling between the roll and pitch motions of ships. The saturation phenomenon was later experimentally demonstrated by Haddow, Barr, and Mook (1984).…”

Section: Autoparametric Vibration Absorbersmentioning

confidence: 99%

<title>Nonlinear control of plate vibrations</title>

Ashour

Nayfeh

2001

SPIE Proceedings

View full text Add to dashboard Cite

A nonlinear active vibration absorber to control the vibrations of plates is investigated. The absorber is based on the saturation phenomenon associated with dynamical systems with quadratic nonlinearities and a two-to-one internal resonance. The technique is implemented by coupling a second-order controller with the plate's response through a sensor and an actuator. Energy is exchanged between the primary structure and the controller and, near resonance, the plate's response saturates to a small value.Numerical as well as experimental results are presented for a cantilever rectangular plate. For numerical studies,¯nite-element methods as well as modal analysis are implemented. The commercially available software ABAQUS is used in the¯nite-element analysis together with a user-provided subroutine to model the controller. For the experimental studies, the plate is excited using a dynamic shaker. Strain gages are used as sensors, while piezoelectric ceramic patches are used as actuators. The control technique is implemented using a dSPACE digital signal processing board and a modeling software (SIMULINK). Both numerical and experimental results show that the control strategy is very e±cient.A numerical study is conducted to optimize the location of the actuators on the structure to maximize its controllability. In this regard, the control gain is maximized for the PZT actuators. Furthermore, a more general method is introduced that is based on a global measure of controllability for linear systems.Finally, the control strategy is made adaptive by incorporating an e±cient frequency-measurement technique. This is validated by successfully testing the control strategy for a nonconventional problem, where nonlinear e®ects hinder the application of the non-adaptive controller.

show abstract

“…In addition, in order to test the impact of the rotor angular speed and the damping coefficient on the blade, the results proposed by Yan et al [8] are considered. Furthermore, this article presents a system with two degrees of freedom coupled where the transference of energy is studied, being it an additional contribution in the line of the work presented by [9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

“…This energy exchange has been studied before i.e., in the case of a ship. Nayfeh et al [9] formulated and analysed quadratic roll/pitch equations of motions and parametric excitations subject to a 2:1 internal resonance condition where the pitch natural frequency was the double of the roll mode in regular sea conditions. The authors observed that the amplitude of the roll mode was larger than the pitch mode, for large excitations amplitudes.…”

Section: Introductionmentioning

confidence: 99%

Helicopter flap/lag energy exchange study

Castillo-Rivera

Tomás-Rodrı́guez

2017

Nonlinear Dyn

View full text Add to dashboard Cite

This is the accepted version of the paper.This version of the publication may differ from the final published version. Abstract This paper presents a study on the energy exchange taking place on articulated helicopter main rotor blades. The blades are hinged and the flap/lag modes are highly coupled. These dynamical couplings existing between the two degrees of freedom are clearly identifiable as the nonlinear terms that appear in the equations of motion, are key to understand the energy exchange process. The work here conducted is carried out using VehicleSim, a multibody software specialized in modelling mechanical systems composed by rigid bodies. A spring pendulum system is also studied in order to examine its nonlinear behaviour, and to establish existing analogies with the rotor blade nonlinear dynamics. The nonlinear couplings of both systems are compared to each other, and commensurability condition is analysed by means of Short Time Fourier Transform (STFT) methods as well as the flap and lag amplitudes spectrum. Simulations are carried out and the obtained results show clear analogies in the energy exchange process taking place in both systems. The stability of these modes is also studied using Poincare' map method. Permanent repository link

show abstract

Nonlinear Coupling of Pitch and Roll Modes in Ship Motions

Cited by 240 publications

References 3 publications

Model simulation of parametrically excited ship rolling

Model simulation of parametrically excited ship rolling

<title>Nonlinear control of plate vibrations</title>

Helicopter flap/lag energy exchange study

Contact Info

Product

Resources

About