Impacts of porous material fluid bulk properties on noise attenuation performance of cylinder shell structure based on finite element model

Abstract

SummaryThe noise control method of laying acoustic blanket is adopted to construct a cylinder cell noise experimental device; a typical porous material, melamine foam (MF), is used for noise attenuation experiments in aluminum (Al) and aluminum/melamine foam (Al/MF) cylinder shells and to achieve corresponding in‐shell noise response spectrograms. Based on the Virtual Lab acoustics software, a finite element model has established for the analysis of noise in the Al/MF cylinder shell and numerical simulation computation has been conducted for the acoustic mode and in‐shell acoustic response; the correctness of the finite element model is verified via comparison with theoretical and measured data. On this basis, the impacts of porous material fluid bulk properties on the noise attenuation effect of the Al/MF cylinder shell are further studied within the frequency range of 0 ∼ 1000 Hz. It is suggested that fluid bulk properties changes pose relatively high impacts on internal noise response of a cylindrical cavity. Within low‐frequency and high‐frequency ranges, the response value of sound pressure increases with flow resistivity, while the response value of sound pressure decreases with the increases of tortuosity, porosity, flow resistivity (only for the medium frequency range), and viscous characteristic length in the medium and high frequencies ranges.

State-Difference Feedback Control for Discrete-Time Takagi–Sugeno Fuzzy Descriptor Systems with Parameter Uncertainties and External Noises

“…Furthermore, sensors and actuators in control systems may be affected by various noise sources [20,21], so we need to establish effective noise reduction methods to ensure accurate and reliable control of dynamic systems. In this article, passivity constraints will be presented to reduce unnecessary damaging noise in systems, equipment, or processes [22].…”

Acoustic radiation performance investigation of a double-walled cylindrical shell equipped with annular plates and porous foam media

“…Therefore, based on these discretization techniques, various mature software such as ANSYS, COMSOL, Abaqus, and LMS SYSNOISE have been developed to study the sound radiation responses of mechanically excited isotropic flat panels with uniform 48 and varying thickness 49 and cylindrical shells with porous foam. 50, 51 Noteworthily, LMS SYSNOISE, an advanced software for vibro-acoustic design and structure optimization, is capable of analyzing the acoustic radiation from vibration source and computing radiation sound field of structural surface or any point requested. In addition to employing sound pressure (SP), sound power (SW) is adopted to inspect the acoustic radiation performance of structure.…”

Simulation Analysis of the Sound Transmission Loss of Composite Laminated Cylindrical Shells with Applied Acoustic Coverings

“…Lane et al [2] experimentally investigated the noise reduction effect of a thermal protection system on MF materials in composite fairings at three test bandwidths, but the noise reduction law of the MF materials in low and medium frequency fairings was less involved. Li Bin et al [10][11][12] studied the noise reduction of melamine foam-lined cylindrical cavities in the low and medium frequency bands (100-400 Hz), and they analyzed the influence of the acoustic parameters of melamine foam pores and different laying rates on the acoustic resonance response in the low and medium frequency bands of 100-400 Hz. Yan Wenjie et al [13,14] used finite element simulation to study the influence of the laying scheme, laying thickness, and Helmholtz resonator on the noise response of a cylindrical shell acoustic cover layer.…”