Technical Discussion、
Natural Frequency自然频率
Pneumatic isolators consist of a volume of air (air chamber) that is aled with a reinforced, flexible diaphragm. When pressurized, the isolator supports its payload using a piston, which is located on top of the diaphragm. (Fig 3)
气浮式减震器由一个空气室（气囊）由一个加固的、柔韧的隔膜密封。当受压时，减震器通过位于隔膜上方的一个Piston（锤头）支撑载荷。
The effective area of the diaphragm and the pressure on the diaphragm define the load capacity of the isolator. The pressure in the isolator is controlled by a leveling valve that controls both the internal pressure and “float” height of the isolator.
有效的隔膜面积和隔膜上的压力确定了减震器承载载荷的能力。减震器内的压力由一个能控制内部气压和减震器浮起高度的高度调节阀来控制。
The typical pneumatic isolator design incorporates dual air chambers, a spring chamber and a damping chamber. In the Fabreeka design, the damping chamber is parated from the spring chamber and connected by pneumatic tubing (e Damping). This design concept can take different shapes, since only the total or “effective” volume is critical to the natural frequency of the isolator (Eq 1). Note that the pressure (P) is proportional to the load (W), thus maintaining a constant natural frequency even when the load changes.
典型的气浮减震器设计包含双重气囊（一个弹簧室和阻尼室）。在Fabreeka的设计中，阻尼室与弹簧室分离，通过一气管连接（见阻尼）。这个设计观念可以得到不同的形状，因为只有总的或有效的体积对于减震的自然频率才是关键的（见Eq 1）。注意压力（P）与载荷是成比例的，所以可以维持在一个恒定的自然频率即使当载荷发生变化的时候。
Where: Fn = natural frequency (Hz)自然频率（固有频率）
g = gravity (in/c2)重力加速度
n = rate of specific heat of gas at constant pressure and volume (1.4 for air) 在恒定的压力和体积下，气体的比热率
W = weight of supported load (lbs) 支持载荷的重量
Aeff = effective area of diaphragm(in2)隔膜的有效面积
兔爷儿V = air volume空气体积
Pabs= absolute pressure (psig)绝对气压
韩国研究生几年
The stiffness of pneumatic isolators comes primarily from the pressure and volume of a given air col
umn. The stiffness of a pneumatic spring can be derived from the pressure-volume relationship of gas laws, assuming:
梦见妹妹(a) Adiabatic compression
(b) Any change in volume is small relative to the initial volume
气浮减震器的刚度主要从气压和给定空气圆柱的体积。气动弹簧的刚度可能得到“气压-容积”关系气体定律，假设：
豆豉鲮鱼的做法
假设：
（a）绝热的压缩
（b）体积上任何改变是轻微的联系初始体积
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契机的近义词
Where:
K = stiffness (lbs/in)刚度
n = ratio of specific heat for the gas (n = 1.0 for air at low frequencies less than
1 Hz.)气体的比热率
Pabs= absolute gas pressure of air column (psi)空气柱的绝对气压
Aeff = area of air column (in2)空气柱的面积
From this expression it can be en that the respon of a mass supported by an undamped air spring is determined by the volume of air.
从这个表达式能够看出，无阻尼的空气弹簧支承的质量块的响应由空气的体积决定。
Note that even when using a thin, flexible diaphragm, the elastomeric material will exhibit an added stiffness at very low pressures. This added stiffness affects the pneumatic contribution of the isolator. To reduce this stiffness contribution, operating pressures should be higher than 3 bar. Valve stiffness can also have an effect on the overall stiffness of a pneumatic isolator.
注意即使当使用一个薄的、柔性的薄膜，弹性材料在低气压时将展示一个额外的刚度。这种额外的刚度影响减震器的气动贡献。为了减少这个刚度贡献，运行气压需要比3 bar 高。阀的刚度对气浮减震器的全部刚度起作用。
Damping衰减
The purpo of damping in an isolator is to reduce or dissipate energy as rapidly as possible. Damping is also beneficial in reducing vibration amplitudes at resonance. Resonance occurs when the natural frequency of the isolator coincides with the frequency of the source vibration.
减震器内衰减的目的是为了尽可能快地减少和消耗能量。衰减在共振时减少振动强度
是有利的。共振发生在当减震器的固有频率与源振动的频率一致。
The ideal isolator would have as little damping as possible in its isolation region and as much as possible at the isolator's natural frequency to reduce amplification at resonance. Damping however can also lead to a loss of isolation efficiency. (Fig 5)
理想的减震器在它的减震范围有尽可能少的衰减越好，并且在减震器的自然频率上时尽可能多的在共振时减少放大。衰减不管怎样会导致减震效率的损失。
To provide vertical damping for a system, a damping chamber is connected to the spring chamber using pneumatic tubing. (Fig 4) An expression for the damping can be obtained by analyzing the rate of change of energy, which occurs when the air flows between chambers. This expression is a function of the tubing and the volume ratio between the spring and damping chambers.
为了给系统提供垂直方向的减震，一个衰减室通过气管连接到弹簧室。（Fig 4）衰减的表达式可以通过分析发生在两个气室间气体流动产生的能量变化的速率来确定。这个表达式是气管和弹簧室和阻尼室间的体积比的函数。
相思风雨中吉他谱Damping is looked at carefully to give the best effective isolation that can be achieved. For air spring-mass systems, damping is esntial to stop transient vibrations following a disturbance such as a stage or bridge moving and to limit the amplitude
of forced vibration at the isolator’s natural frequency. The length and diameter of the tubing are chon for a given volume ratio to create laminar flow in the damper. This design concept allows for a wide range of damping values to be ud depending on the application. Damping is optimum when the air flow in the tubing is laminar for both large and small disturbances.
慎重考虑衰减来给予最有效的减震器是可能达到的。对于空气弹簧-质量块系统，衰减是必不可少的用来停止尾随的干扰引起的瞬变的振动例如一个阶段或者桥梁移动，并且可用来限制在减震器的固有频率上受迫振动的振幅。导管的长度和直径被选为一个给定的体积比在衰减室内创造层流。这个设计观念考虑到使用的大范围的衰减值是取决于应用。当对于大和小的干扰，管子中的气流是薄片式的，衰减是最佳的。
Transmissibility传递率
The natural frequency (dynamic stiffness) and damping properties of an isolator determine the isolator’s transmissibility.
减震器的自然频率（动态刚度）和衰减特性确定了减震器的传递率
The ratio of vibration transmitted after isolation to the disturbing vibration is described as "transmissibility" and is expresd in its basic form in Equation 3, where Fd is the disturbing frequency of vibration and fn is the natural frequency of the isolator.
对干扰振动减震后振动传递的比率称之为“传递率”并且按公式3的基本格式表示，Fd 是振动的干扰频率，fn是减震器的自然频率。
青春快乐When considering damping, the equation is rewritten (Eq 4), where ξ reprents the damping of the isolator.
当考虑衰减时，改写后的公式4，ξ表示减震器的阻尼。
Maximum transmissibility of an isolator occurs at resonance when the ratio of the disturbing frequency to the natural frequency is equal to 1 (Fd / Fn = 1). At resonance the transmissibility is given by equation 5. Note that the magnitude of an isolator's amplification at resonance is a function of that isolator’s damping.
减震器的最大的传递率出现在共振时，即当干扰频率与自然频率相等时(Fd / Fn = 1)。共振时传递率给定在公式5。注意在共振时减震器放大的震级是减震器衰减的作用。
Fig 5 graphically shows the transmissibility of an isolator as a function of the frequency ratio. Several
percentages of critical damping are displayed to show the effect of damping in the isolation region and the amplification region, including the maximum amplification at resonance.
Fig 5生动地显示减震器的传递率是根据频率比率的作用。在减震区域和放大区域，关键衰减的几个比例显示衰减的影响，包括在共振区的最大放大。
At frequencies greater than the square root of 2 (1.41) times the isolator’s natural frequency, isolation (reduction in transmissibility) begins. Isolation improves as a function of the frequency ratio. The primary benefit of a pneumatic isolator is
its low natural frequency and corresponding transmissibility at low frequencies. 80% to 90% reduction can be achieved below 10 Hz even with high damping.
当“频率比”大于1.41倍减震器的自然频率，减震（减少传递率）开始。减震改善随着频率比的函数。一个气浮减震器的主要得意于在低频率时它的低自然频率频率和相应的传递率。80% 到90%的衰减能取得在10Hz下面与高衰减一样。
Note that as damping is incread, the curve of transmissibility is flattened, so that in the region near to resonance (ratio = 1.0) the curve is reduced, but in the region where isolation is required, the curv
e is incread. The curves show that if there is a significant amount of damping in an isolator, its natural frequency has to be reduced to retain the desired degree of isolation at the frequency ratio of concern.
既然随着衰减增加，传递率的曲线趋向于扁平，所以在靠近共振（ratio = 1.0）的区域内曲线下降，但是在该区域内，减震需要的地方，曲线提高。曲线显示如果在一个减震
