Design of distributed dynamic absorbers for vibration suppression of panel structures

用于壁板结构减振的分布式动力吸振器的设计

Distributed dynamic absorbers have many advantages such as wide frequency bandwidth for vibration suppression,strong detuning adaptability,and high system stability,making them very suitable for the vibration and noise control of continuous structures.Therefore,they have broad application prospects in various fields such as transportation,aviation,and aerospace.However,there are still many challenges in the engineering applications of distributed dynamic absorbers for vibration suppression,including the engineering realization of the optimal damping of traditional optimal coherence dynamic absorbers,and the engineering applicability of the finite periodic array dynamic absorbers.Based on the damping material properties obtained by the dynamic mechanical analyzer tests,this paper establishes the finite element model of the cantilever-beam-type dynamic absorber with constrained damping layers,aiming to realize the accurate determination of the optimal damping.Experiments are conducted by attaching the traditional dynamic absorbers with the optimal damping to a thin-walled panel with four clamped edges.Results show that the vibration of the panel is well suppressed,with the reduction of the frequency response peak larger than 14 dB and the reduction ratio of RMS larger than 58%within 500 Hz.Afterwards,the periodically arrayed dynamic absorbers are designed according to the bandgap regulation method.The tuning behavior of the arrayed dynamic absorbers by changing designing parameters is investigated.The vibration reduction effect of arrayed dynamic absorbers is compared with that of the traditional dynamic absorbers under the same mass ratio through experiments.Results indicate that the arrayed dynamic absorbers are easier to design,and have a similar reduction effect on the modal vibration of the thin panel as the traditional dynamic absorbers within a narrow frequency range near the natural frequency,while they perform unsatisfactory in a broad band.Significantly,if the appropriate frequency and damping of the arrayed absorbers are chosen,a relatively wide bandgap can also be generated,which shows high engineering applicability.The research work in this paper provides beneficial reference for the design of distributed dynamic absorbers suitable for vibration suppression of thinwalled panel structures.

分布式动力吸振器具有减振频带宽、失谐适应性强、系统稳定性高等诸多优点,非常适合于连续体结构的振动与噪声控制,在交通运输、航空航天等诸多领域拥有广泛的应用前景.然而,分布式动力吸振器在工程减振应用方面仍然存在许多问题,如传统最优同调动力吸振器设计中最优阻尼的工程匹配问题,以及阵列化动力吸振器在有限周期条件下的工程适用性问题等.基于动态机械分析仪(DMA)测试得到的阻尼材料特性参数,本文建立了敷设约束阻尼层的悬臂梁式动力吸振器的有限元模型,以实现最优阻尼的精确匹配.实验中以四边固支的薄壁板结构为研究对象,在壁板上安装了最优同调的动力吸振器进行减振.实验结果表明:在随机激励下,壁板的振动得到了很好的抑制,其各阶频响峰值降低量均高于14 dB,在500 Hz内的RMS值降低比在58%以上.此外,本文基于带隙调控方法进行了周期阵列化动力吸振器的设计,并分析了设计参数对阵列化动力吸振器带隙特性的调控规律.通过实验对比相同质量比条件下传统动力吸振器和阵列化动力吸振器的减振效果可以发现:阵列化动力吸振器设计便捷,在吸振器固有频率附近的窄带范围内具有和传统动力吸振器相似的减振效果,但是其宽带减振效果较差.值得注意的是,若选取合适的吸振器频率和阻尼,阵列化动力吸振器也可以产生较宽的带隙,表现出良好的工程适用性.本文的研究工作为适用于薄壁板结构减振的分布式动力吸振器的设计提供了有益的参考.