Benefits

• Exceptionally effective: Data show that the passive systems eliminate 90% to 96% of vibration, while the passive-active system achieves vibration isolation exceeding 99.94%. This performance greatly exceeds the 40% to 60% vibration reduction achieved with traditional devices and provides significantly stiffer mounting.
  
  
• Minimal power usage: The combined passive-active system uses a very small amount of electrical power: 0.1–0.2 Hp for a 60-ton aircraft compared to the 40 Hp needed with other devices. The passive systems need no energy input.
  
  
• Lightweight: These technologies are relatively light compared to prior devices.
  
  
• Relatively low cost: These technologies are less expensive than comparable devices.
  
  
• Tunable: These technologies can tune output based on the input received from accelerometers, providing customized vibration isolation response.
  
  
• Easy to implement: The passive technologies are easily transitioned to other products. (The passive-active system has undergone testing with highly successful results.)
  
  
• Reliable: Textron’s LIVE^® vibration components contain no sliding parts to wear, utilize fail-safe design, and operate in harsh production environments without failure.
  

Originally designed for use in Bell helicopters, these technologies can be used in any application where a component must be isolated from harmonic vibration:

• Rotating machinery: Pumps, compressors, turbines
  
  
• Aerospace: Jet engines, airframes, engine mounts
  
  
• Automobiles: Engine mounts
  
  
• Marine applications: Diesel motors, generator sets, power-train gearboxes
  
  
• Power generating equipment: Turbines
  
  
• Military applications: Armament
  
  
• Structural applications: Buildings or floors that hold equipment sensitive to earthquake and climate-control (HVAC) vibrations
  
  
• Large industrial sites: Piping support and systems
  
  
  

Figure 1: Cross-Section of LIVE System

Since the "dynamic" stiffness at the tuned frequency is virtually zero, the degree of vibration reduction is not dependent upon the static stiffness of the mount. This "divide and conquer" approach—that is, separating the oscillatory spring rate from the static spring rate—provides more versatile design options for effective vibration control, allowing the designer to use the optimum mount stiffness needed for the application.

The LIVE^® mount can be tuned by varying the dimensions (e.g., length, area) of the tuning passage or by controlled application of force acting upon the fluid with actuators such as piezoelectric or electromagnetic with associated pistons. The passive-active system combines a passively tuned fluid inertia (to cancel the vibratory stiffness of springs) with an active element that shifts the frequency to track rpm changes and remove any remaining energy/vibration due to internal damping.

Figure 2: Application of Vibration Isolation System Technologies in Textron’s Products

U.S. patent	Description	Vibration reduction	Textron product
Application 09/965,114 (pub. 20020060268): Method and Apparatus for Improved Vibration Isolation	Passive-active technology using either solid or liquid tuning mass	99%	Textron Marine’s Littoral Combat Ship proposal for diesel engine noise control
6,431,530: Vertical Liquid Inertia Vibration Isolator	Passive technology with concentric chambers	96%	Bell Helicopter model 427
6,009,983: Method and Apparatus for Improved Vibration Isolation	Passive technology to enhance vibration reduction with smaller diameter tuning passage	96%	Bell Helicopter models 430 and 427
5,704,596: Vibration Isolation System	Passive technology that tunes isolator by adjusting the cross-sectional area of the tuning passage; used to expedite expensive flight testing	90%	Test only
5,439,082: Hydraulic Inertial Vibration Isolator	Passive technology with solid tuning slug; electromagnetic tuning of LIVE	99%	Test only
5,435,531: Vibration Isolation System	Passive trombone tuner and dual-axis LIVE; used to provide adaptive tuning and expedite expensive flight testing	90%	Test only
4,236,607: Vibration Suppression System	Base technology for Halwes vibration isolator	90%	Bell Helicopter models 430 and 428

Patents

These technologies are protected by U.S. and foreign patents. More information is available on foreign patent protection status upon request. To view the patents, click on the links in Figure 2.

Publications

• The Model 427 Pylon Isolation System, paper presented at the American Helicopter Society 55th Annual Forum (Montréal, Canada; May 25–27, 1999) [1 MB file]
  
  
• P-LIVE™ Vibration Suppression, poster presented at the American Helicopter Society 59th Annual Forum (Phoenix, Arizona; May 6–8, 2003)
  
  
• Results from the Dynamically Tailored Airframe Structures Program, paper presented at the American Helicopter Society 58th Annual Forum (Montréal, Canada; June 11–13, 2002) [1.4 MB file]
  
  
• Dynamically Tailored Airframe Structures Program, paper presented at the American Helicopter Society 57th Annual Forum (Washington, D.C.; May 9–11, 2001) [8 MB file]