Model uncertainties of flexible structures vibrations induced by internal flows

Ritto, T.G.; Sampaio, Rubens; Rochinha, Fernando A.

doi:10.1590/s1678-58782011000300014

“…For instance, the reader can see [14,11,10], in the context of drillstring dynamics, as well as the work of [19] in hydraulic fracturing. Other studies applying stochastic techniques to describe the random dynamics of flexible structures are [12,13] and [3]. The analysis of the stochastic dynamics of a highly nonlinear system, with three degrees of freedom, can be seen in [6].…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Nonlinear Stochastic Dynamics of an Elastic Bar With an Attached End Mass

Cunha¹,

Sampaio²

2014

Proceedings of the 3rd South-East European Conference on Computational Mechanics (SEECCM III)

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0

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Abstract. This work studies the nonlinear dynamics of a one-dimensional elastic bar, attached to discrete elements, with viscous damping, random elastic modulus, and subjected to a Gaussian white-noise distributed external force. The system analysis uses the maximum entropy principle to specify the elastic modulus (gamma) probability distribution and uses Monte Carlo simulations to compute the propagation of uncertainty in this discrete-continuous system. After describing the deterministic and the stochastic modeling of the system, some configurations of the model are analyzed in order to characterize the effect of a lumped mass in the overall behavior of this dynamical system. The simulation results show that the system response presents multimodal probability distribution, irregular distribution of energy throughout the spectrum of frequencies, and a limit behavior, for large values of the lumped mass, similar to a mass-spring system. 682

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“…For instance, the reader can see [14,11,10], in the context of drillstring dynamics, as well as the work of [19] in hydraulic fracturing. Other studies applying stochastic techniques to describe the random dynamics of flexible structures are [12,13] and [3]. The analysis of the stochastic dynamics of a highly nonlinear system, with three degrees of freedom, can be seen in [6].…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Nonlinear Stochastic Dynamics of an Elastic Bar With an Attached End Mass

Cunha¹,

Sampaio²

2013

Proceedings of the 3rd South-East European Conference on Computational Mechanics – SEECCM III

Self Cite

2

1

0

View full text Add to dashboard Cite

Abstract. This work studies the nonlinear dynamics of a one-dimensional elastic bar, attached to discrete elements, with viscous damping, random elastic modulus, and subjected to a Gaussian white-noise distributed external force. The system analysis uses the maximum entropy principle to specify the elastic modulus (gamma) probability distribution and uses Monte Carlo simulations to compute the propagation of uncertainty in this discrete-continuous system. After describing the deterministic and the stochastic modeling of the system, some configurations of the model are analyzed in order to characterize the effect of a lumped mass in the overall behavior of this dynamical system. The simulation results show that the system response presents multimodal probability distribution, irregular distribution of energy throughout the spectrum of frequencies, and a limit behavior, for large values of the lumped mass, similar to a mass-spring system. 682

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“…Variability analysis plays an important role to study uncertainties in dynamical models. For instance, uncertainties related to structures excited by internal flow have been recently investigated by Ritto et al (2011), uncertainties for hearing protector noise attenuation apparatus by Lima et al (2010) and electrical uncertainties of passive/active structural vibration control have been numerically and experimentally studied by Santos and Trindade (2011).…”

Section: Variability Analysismentioning

confidence: 99%

Loudness scattering due to vibro-acoustic model variability

Oliveira¹,

Silva²,

Sánchez³

et al. 2012

J. Braz. Soc. Mech. Sci. & Eng.

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The use of numerical simulation in the design and evaluation of products performance is ever increasing. To a greater extent, such estimates are needed in an early design stage, when physical prototypes are not available. When dealing with vibro-acoustic models, known to be computationally expensive, a question remains, which is related to the accuracy of such models in view of the well-known variability inherent to the mass manufacturing production techniques. In addition, both the academia and industry have recently realized the importance of actually listening to a products sound, either by measurements or by virtual sound synthesis, in order to assess its performance. In this work, the scatter of significant parameter variations on a simplified vehicle vibro-acoustic model is calculated on loudness metrics using Monte Carlo analysis. The mapping from the system parameters to sound quality metric is performed by a fully-coupled vibro-acoustic finite element model. Different loudness metrics are used, including overall sound pressure level expressed in dB and Specific Loudness in Sones. Sound quality equivalent sources are used to excite this model and the sound pressure level at the driver's head position is acquired to be evaluated according to sound quality metrics. No significant variation has been perceived when evaluating the system using regular sound pressure level expressed in dB and dB(A). This happens because of the third-octave filters that average the results under some frequency bands. On the other hand, Zwicker Loudness presents important variations, arguably, due to the masking effects.

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Model uncertainties of flexible structures vibrations induced by internal flows

Cited by 10 publications

References 9 publications

Analysis of the Nonlinear Stochastic Dynamics of an Elastic Bar With an Attached End Mass

Analysis of the Nonlinear Stochastic Dynamics of an Elastic Bar With an Attached End Mass

Analysis of the Nonlinear Stochastic Dynamics of an Elastic Bar With an Attached End Mass

Loudness scattering due to vibro-acoustic model variability

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