动力吸振器对薄板声辐射效率的调控特性

薄(壁)板结构是飞机、高铁、船舶等工程中最常见的结构。薄板结构受到外部动力源的激励不可避免地引起振动噪声超标的问题。动力吸振器相比于表面加筋和敷设阻尼材料等减振降噪方法,具有参数可设计、频率针对性强等优势。然而,目前关于动力吸振器对薄板结构声辐射的调控特性分析并不充分,很多研究人员以及工程师笼统地认为,利用动力吸振器来减小薄板结构振动就可完全达到最好的抑制声辐射效果。实际上,动力吸振器对于薄板结构的声辐射效率的调控会直接影响其抑制声辐射的效果。本文研究了动力吸振器对薄板结构声辐射效率的调控特性,从理论上推导了含有动力吸振器的薄板结构声辐射效率计算方法,并利用数值计算方法分析了动力吸振器的声辐射效率调控特性。动力吸振器的安装,能对薄板结构在吸振器工作频率附近的模态振型和模态频率产生明显的调控作用,从而对声辐射效率产生调控作用。通过调谐动力吸振器的质量和频率,能够降低薄板结构目标模态的频率,或者改变对应的模态振型,实现对声辐射效率的抑制效果。

Tuning Effects of Dynamic Vibration Absorbers on the Sound Radiation Efficiency of Thin Plate Structures

Thin plate structures are the most common structures in aircraft,high-speed track and ship engineering.The undesired excessive noise and vibration can be inevitably generated by the thin plate structures when they are exposed to the external power source.Dynamic vibration absorbers have the advantages of parameter design and frequency pertinence compared with surface reinforcement,laying damping materials and some other vibration and noise control measures.However,the present research about the analysis of the control characteristics of the dynamic vibration absorbers on the acoustic radiation of the thin plate structures is insufficient.Many researchers and engineers generally believe that the best acoustic radiation suppression effect for the thin plate structures can be achieved by using the dynamic vibration absorbers.In fact,the regulation result of the acoustic radiation efficiency of the dynamic vibration absorber will directly affect the suppression effect of the acoustic radiation.In this paper,the control characteristics of dynamic vibration absorbers on acoustic radiation efficiency of thin plate structures are studied.The calculation method of acoustic radiation efficiency of the thin plate structure with dynamic vibration absorbers is deduced theoretically.And the control characteristics of acoustic radiation efficiency of the dynamic vibration absorber are analyzed numerically.The installation of the dynamic vibration absorber can manipulate the modal mode and the frequency of the thin plate structure,resulting in the high acoustic radiation efficiency of the tuning effect in the oscillation frequency band of the absorber.By tuning the mass and the working frequency of the absorber,the target modal frequency of the plate can be reduced,or the corresponding mode shape is regulated.As a result,the manipulating effect on the acoustic radiation efficiency of the plate is realized.