Wong W O, Fan R P, Cheng F
Department of Mechanical Engineering, The Hong Kong Polytechnic University, 11 Yuk Choi Road, Hung Hom, Kowloon, Hong Kong Special Administrative Region, China.
J Acoust Soc Am. 2018 Feb;143(2):1064. doi: 10.1121/1.5024506.
A viscoelastic dynamic vibration absorber (VDVA) is proposed for suppressing infrasonic vibrations of heavy structures because the traditional dynamic vibration absorber equipped with a viscous damper is not effective in suppressing low frequency vibrations. The proposed VDVA has an elastic spring and a viscoelastic damper with frequency dependent modulus and damping properties. The standard fixed-points theory cannot be applied to derive the optimum design parameters of the VDVA because both its stiffness and damping are frequency dependent. A modified fixed-points theory is therefore proposed to solve this problem. H design optimization of the proposed VDVA have been derived for the minimization of resonant vibration amplitude of a single degree-of-freedom system excited by harmonic forces or due to ground motions. The stiffness and damping of the proposed VDVA can be decoupled such that both of these two properties of the absorber can be tuned independently to their optimal values by following a specified procedure. The proposed VDVA with optimized design is tested numerically using two real commercial viscoelastic damping materials. It is found that the proposed viscoelastic absorber can provide much stronger vibration reduction effect than the conventional VDVA without the elastic spring.
提出了一种粘弹性动力吸振器（VDVA）来抑制重型结构的次声振动，因为配备粘性阻尼器的传统动力吸振器在抑制低频振动方面效果不佳。所提出的VDVA具有一个弹性弹簧和一个具有频率相关模量和阻尼特性的粘弹性阻尼器。由于其刚度和阻尼都与频率有关，标准的定点理论不能用于推导VDVA的最佳设计参数。因此，提出了一种改进的定点理论来解决这个问题。针对由谐波力激发或由于地面运动引起的单自由度系统的共振振动幅度最小化，推导了所提出的VDVA的H设计优化。所提出的VDVA的刚度和阻尼可以解耦，这样通过遵循特定程序，吸振器的这两个特性都可以独立调整到其最佳值。使用两种实际的商用粘弹性阻尼材料对优化设计的VDVA进行了数值测试。结果发现，所提出的粘弹性吸振器比没有弹性弹簧的传统VDVA能提供更强的减振效果。
