Energy based correlation criteria in the mid-frequency range

Future aircraft concepts utilizing innovative lightweight structures and novel propulsion concepts are a necessity for long term sustainable air travel. These concepts pose new challenges for the vibro-acoustic assessment of cabin structures and the associated noise impact on passengers. Finite Element (FE) models derived from aircraft pre-design data are not optimized for use in acoustic analyses, i.e. the mesh is too coarse to provide meaningful results while setting up Statistical Energy Analysis models for this specific purpose is adding another time-consuming step. A possible alternative, Discrete Energy Analysis (DEA), is evaluated. This method allows to calculate the acoustic behavior of thin-walled structures in higher frequency ranges simply using existing FE meshes. In this paper an experimental lightweight aluminum structure and its respective FE model is investigated for a frequency range up to 5000 Hz. A comparison in terms of vibrational energy between DEA, FE and measurement results are presented. Finally, a lower-bound frequency range is identified in which DEA and FEM correlate and thus allow a substitution for further simulations at higher frequencies.

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“…The following short summary of the ECC was written based on the publication of Biedermann et. al [8].…”

Section: Energy Correlation Criterionmentioning

confidence: 98%

“…Biedermann et. al [8] describe that values above 0.8 indicate a high level of linear dependency between the energy distributions of experiment and simulation. This limit will be adopted here for the following evaluations.…”

Section: Energy Correlation Criterionmentioning

confidence: 99%

Finite element method and dynamical energy analysis in vibro-acoustics - A comparative study

Zettel¹,

Winter²,

Norambuena³

et al. 2021

inter noise

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“…(5) describes the periodicity of the acoustic modes along the circumference while Eqs. (6) and 7represent rigid walls at the axial positions z = 0 and z = L z . Additional damping and absorption effects can be considered utilizing an impedance boundary condition, but are omitted here for clarity.…”

Section: Acoustic Radiation Modesmentioning

confidence: 99%

“…For the studies in this paper, a finite element model of a composite teststructure is assumed. A physical representation of this test-structure is available at the DLR, which is identical to the one investigated by Biedermann et al [6] for the test of a new correlation criterion for model validation. This is considered a first step towards experimental investigations on ASAC systems for composite fuselage type structures.…”

Section: Radiation Efficiencies and Active Controlmentioning

confidence: 99%

“…These structures are shown to exhibit a global vibrational behaviour in the low-frequency range [4,5] where structural waves stretch over a multitude of frames and stringers. In the mid-frequency range a superposition of the global vibration modes as well as local skin segment modes occurs [6]. The high-frequency range exhibits a high modal density and the local modes are statistically distributed.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Active control of composite fuselage type structures with enclosed acoustic cavity

Hesse

2018

Journal of Fluids and Structures

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An active structural acoustic control system for a composite fuselage type structure is developed in this paper. The focus of the active control system is the global reduction of the sound field in an enclosed acoustic cavity using structureintegrated sensors and actuators. Active structural acoustic control systems are commonly designed based on the acoustic radiation modes which diagonalize a radiation operator. In the case of interior sound radiation, this radiation operator is derived in this paper from the coupled acoustic modes, which take into account the boundary conditions of the coupled velocity from the fuselage type structure. This results in frequency-independent radiation modes which do not rely on the validity of the modal interaction approach. The latter one violates the continuity condition of the velocity along the coupling surface. Parameter studies regarding active control implementations are conducted in order to evaluate how many radiation modes need to be considered for achieving a global sound attenuation.

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Asynchronous Modes of Beams on Elastic Media Subjected to Varying Normal Force: Continuous and Discrete Models

Mazzilli

Ribeiro

2019

IUTAM Symposium on Exploiting Nonlinear Dynamics for Engineering Systems

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Energy based correlation criteria in the mid-frequency range

Cited by 10 publications

References 16 publications

Finite element method and dynamical energy analysis in vibro-acoustics - A comparative study

Finite element method and dynamical energy analysis in vibro-acoustics - A comparative study

Active control of composite fuselage type structures with enclosed acoustic cavity

Asynchronous Modes of Beams on Elastic Media Subjected to Varying Normal Force: Continuous and Discrete Models

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