Aiming to isolate disturbance vibration for heavy payloads with low frequency, a novel hydro-pneumatic near-zero frequency vibration isolator is proposed, which possesses high-static and low-dynamic (HSLD) stiffness. And different from most isolators existing previously, a nonlinear damping strategy realized by fluid damping mechanism is implemented into the device in order to enhance vibration isolation performance. Due to that the natural frequency of isolation system is close to zero and loading capacity can be adjusted by the gas pressure, the proposed device is termed as pneumatic near-zero frequency (NZF) vibration isolator. To obtain the primary resonance response for the harmonically forced nonlinear system, the averaging method is employed first and verified numerically. A direct current (d. c.) term is added in the analytical trial solution, which reflects the asymmetry existed in dynamic response. As a result, multiple steady solutions are observed and the induced amplitude jump appears. Then the stability of periodic response is carried out by using the Jacobin matrix approach. It is concluded that increases of all types damping including linear, square and friction damping are able to shrink the unstable region and further reduce the possibility of occurrence of amplitude sudden-jump in primary resonance. More accurately, the critical border which can separate the jump and none jump zones is found analytically and numerically, and design criterion for avoidance of sudden-jump is developed. After that, equivalent damping analysis gives a new insight into how nonlinearity effects of each damping dominate vibration isolation transmissibility in resonance and effective isolation frequency band. It is shown that the square type damping based on fluid mechanism can suppress the resonance response and transmissibility and does not decrease the effectiveness in isolation band, which will bring the favorable advantage for NZF isolator in practical application.

为了隔离低频重载的干扰振动，提出了一种新型的具有高静动态低刚度的液-气近零频振动隔离器。与以往大多数隔离器不同，该装置采用了流体阻尼机制实现的非线性阻尼策略，以提高隔振性能。由于隔离系统的固有频率接近零，并且可以通过气压来调节负载能力，因此该装置被称为气动近零频率（NZF）隔振器。为了获得谐波强迫非线性系统的初级共振响应，首先采用平均方法并进行了数值验证。直流电 ）术语添加到分析试验解决方案中，反映了动态响应中存在的不对称性。结果，观察到多个稳态解并且出现了引起的幅度跳跃。然后利用雅可比矩阵方法实现了周期响应的稳定性。结论是，包括线性阻尼，平方阻尼和摩擦阻尼在内的所有类型的阻尼的增加能够缩小不稳定区域，并进一步降低一次共振中出现振幅突然跳跃的可能性。更准确地说，通过分析和数值分析找到了可以将跳跃区和非跳跃区分开的临界边界，并制定了避免突然跳跃的设计准则。之后，等效阻尼分析为共振和有效隔离频带中每个阻尼的非线性效应如何主导振动隔离传递性提供了新的见解。结果表明，基于流体机制的方型阻尼能够抑制共振响应和传递性，并且不会降低隔离带的有效性，这将为NZF隔离器的实际应用带来有利的优势。