Increase in transmission loss of single panels by addition of mass inclusions to a poro-elastic layer: Experimental investigation

Sound transmission loss of metamaterial-based thin plates with multiple subwavelength arrays of attached resonators

“…1(b) represents a periodic extension of the system reported by Howard [35], while that sketched in Fig. 1(c) comes from work of Kidner et al [33,45] and Idrisi et al [34,46]. In the present work, we only address the simplified model shown in Fig.…”

“…More recently, dynamic vibration absorbers have been implemented for the reduction of sound radiation from vibrating structures [29][30][31]. Some researchers also apply distributed vibration absorbers to improve the STL of thin structural partitions [32][33][34][35]. In their investigations a finite master structure is always specified and the resonance frequencies of the attached vibration absorbers are commonly tuned to some selected structural modes to suppress the structural vibration and in turn to reduce the sound transmission.…”

“…In his investigation [35], the beam-like absorbers are all tuned to slightly different natural frequencies and they are modeled as single degree of freedom spring-mass resonators. In contrast, Kidner et al [33,45] and Idrisi et al [34,46] develop the idea of using heterogeneous blankets attached to a thin plate. Such heterogeneous blankets are made of poro-elastic layers with embedded masses, and they are commonly treated as an array of spring-mass resonators to simplify the modeling and design process [33,34,45,46].…”

Numerical investigation of active porous composites with enhanced acoustic absorption

“…Recent experimental investigations report a significant improvement of the insertion loss of standard acoustic blankets at lower frequencies by the addition of randomly placed masses to the poroelastic layers [1]. They show that the improvement by distributed masses (inclusions) tend to be greater than the one due to the mass effect alone.…”

Chamber Core Structures for Fairing Acoustic Mitigation

“…Some of the passive noise control approaches investigated by the U.S. Air Force Research Laboratory include damped Helmholtz resonators, composite blankets (incorporating distributed vibration absorbers), and a combined structural-acoustic damper called a "passive vibroacoustic attenuation device" [1][2][3]. In laboratory experiments, these approaches typically provided 6 dB of narrowband attenuation, and 2-3 dB broadband attenuation.…”