Li Bu-Yun, Shuai Chang-Geng, Ma Jian-Guo
Institute of Noise & Vibration, Naval University of Engineering, Wuhan, 430030, People's Republic of China.
National Key Laboratory on Ship Vibration & Noise, Wuhan, 430030, People's Republic of China.
Sci Rep. 2024 Apr 8;14(1):8195. doi: 10.1038/s41598-024-58469-x.
Large floating raft vibration isolation systems (FRVISs) based on high-static-low-dynamic stiffness (HSLDS) technology offer excellent low frequency vibration isolation performance with broad application prospects. However, the design process for these complex high-dimensional coupled nonlinear systems remains poorly developed, particularly when applied for ocean-going vessels that experience rolling and pitching motions. The present work addresses this issue by establishing a six-degree-of-freedom HSLDS vibration isolation model for FRVISs composed of eight isolators, and the model is applied to fully analyze the swing stability and multidimensional vibration isolation performance of these systems. The influence of nonlinearity on the mechanical properties of the vibration isolators is analyzed more clearly by assuming that each vibration isolator realizes nonlinear HSLDS characteristics in the z direction and linear characteristics in the x and y directions. The results demonstrate that the swing displacement responses of the system are greatly reduced under weak nonlinearity, which reflects the high static stiffness and high static stability characteristics of an HSLDS system. The multidimensional vibration isolation performance of the system is evaluated according to the impacts of nonlinearity, the installation height H of the isolators, and the relative position D of the two middle isolators. The results of analysis demonstrate that applying a value of H = 0 produces the best vibration isolation performance overall under strong nonlinearity by avoiding unnecessary secondary peaks in the force transmission rate under harmonic mechanical excitation and ensuring a maximum high-frequency vibration isolation effect. However, applying a weak nonlinearity is better than a strong nonlinearity if H is not zero. In contrast, D has little effect on the vibration isolation effect of the raft in the x, y, and z directions. Therefore, an equidistant installation with D = 0.5 would be considered ideal from the standpoint of installation stability.
基于高静低动刚度（HSLDS）技术的大型浮筏隔振系统（FRVISs）具有出色的低频隔振性能，应用前景广阔。然而，这些复杂的高维耦合非线性系统的设计过程仍不完善，特别是应用于经历横摇和纵摇运动的远洋船舶时。本文通过建立一个由八个隔振器组成的FRVISs的六自由度HSLDS隔振模型来解决这个问题，并将该模型用于全面分析这些系统的摆动稳定性和多维隔振性能。通过假设每个隔振器在z方向上实现非线性HSLDS特性，在x和y方向上实现线性特性，更清楚地分析了非线性对隔振器力学性能的影响。结果表明，在弱非线性下系统的摆动位移响应大大降低，这反映了HSLDS系统的高静刚度和高静稳定性特性。根据非线性、隔振器的安装高度H以及两个中间隔振器的相对位置D的影响来评估系统的多维隔振性能。分析结果表明，通过避免谐波机械激励下力传递率中不必要的二次峰值并确保最大高频隔振效果，在强非线性下应用H = 0的值总体上产生最佳隔振性能。然而，如果H不为零，则应用弱非线性比强非线性更好。相比之下，D对筏体在x、y和z方向上的隔振效果影响很小。因此，从安装稳定性的角度来看，D = 0.5的等距安装将被认为是理想的。
