Vibration damping of platform structures excited by distributed loads using modified acoustic black holes

Abstract

In industries, vibrations generated from machinery propagate in structures causing noise and failures of systems. To prevent the propagation of vibrations from a source to another component, platforms and anti-vibration mounts are used as a combined form. Here, a platform is a component supporting a machine and an anti-vibration mount is a component, which prevents the propagation of vibrations. In an isolated platform, which consists of a platform and anti-vibration mounts, the mounts block the transmission of vibrations, whereas vibrations remaining in the platform causes vibration-induced noise. Therefore, there is a need to reduce vibrations in isolated platforms. The aim of this study is to reduce vibrations remaining in isolated platforms using acoustic black holes that absorb flexural waves. Unlike a method to attach acoustic black holes to a thin plate based on 2D structural intensity analysis, this study investigates a method to attach acoustic black holes to a structure based on 3D structural intensity fields. Next, considering that actual excitations are typically frequency-dependent, the study finds improved locations and directions for attaching acoustic black holes in platforms excited by frequency-dependent forces. Lastly, considering real industrial environments, it proposes an improved method for applying acoustic black holes on platforms where the available space for attachment is restricted due to machinery installed on top. Through this process, the feasibility of applying acoustic black holes in industrial environments is enhanced.