Studies on dynamics and sound transmission loss of thick smart cylindrical composite structures
Loading...
Date
2022-04-07
Authors
Rabbani, Vahid
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
STL describes the accumulated decrease in sound intensity as waves spread outward from a source or through specific areas. To reduce the sound transmission from the cylinder, an acoustic quieting process needs to be implemented. One of the most efficient ways to reduce sound transmission is using piezoelectric materials. Piezoelectric materials can be applied to reduce transmitted noise from different structures versus damping approaches when it is difficult to completely dampen structural vibrations via passive methods.
The aim of the present study is to analyze the dynamic characteristics of piezo-laminated cylindrical structures for vibration suppression and control of sound transmission losses.
Two thick shell models were developed to consider the effects of anisotropicity and piezoelectricity on the STL. In the first model, a 3D piezoelectric model is built to investigate the free vibration of a triclinic piezoelectric cylinder. In the second model, the estimation of STL due to the piezoelectric effects is studied for a piezo-composite cylinder excited by an incident plane wave.
These two initial models enable us to explore deeper and study the effect of feedback control strategy for the enhancement of STL. The active control strategy is achieved by sending the control signal from the distributed piezoelectric sensor layer through a controller to drive the external actuators. The second model was also used to increase STL by using the different sizes and arrangements of piezoelectric electrodes. The study shows that increasing the number of electrodes may not necessarily provide higher soundproofing abilities. However, the level of sound isolation can be adjusted by using the proper size of the electrode.
Finally, to go one more step deeper, considering the fluid-solid shear interaction, a new 3D elastic model incorporating the piezoelectricity and fluid viscosity is developed to simulate the dynamics and STL of a shell submerged in a viscous fluid. Parametric studies are carried out to investigate the effect of fluid viscosity, shell anisotropicity, and piezoelectric boundary conditions on the STL. The results show that the magnitude of STL linearly increases as the value of bulk and dynamic viscosities increases, which results in providing a better soundproofing ability.
Description
Keywords
Exact theory of linear piezoelectricity, Functionally graded piezoelectric, Acoustic transmission loss, Viscous acoustic model, Thick smart composite shell, Active noise control, Triclinic materials