Noise and Vibration Control and Optimization

With its many talented research engineers with advanced degrees in acoustics and vibration, KCF Technologies is an acknowledged leader in developing ingenious noise and vibration controls, whether the task is abatement or converting and refining the noise and vibration into productive sources of usable energy. With funding and support from the Department of Defense, including the US Army and US Naval Air Systems Command, as well as private industry, KCF has made and will continues to make creative strides in these remarkably diverse technologies. Click on a heading below to read selected abstracts of our noise and vibration control and optimization focused research programs.

KCF Technologies is developing a robust and efficient sound generator for separation/isolation of aerosols in HVAC filters. The primary solution is a new, high intensity piezoelectric sound generator combined with a Helmholtz resonator. Conventional piezoelectric sound generators experience degradation in performance over long periods of operation, poor electro-acoustic efficiencies at high amplitude drive levels, and large tolerances in their acoustic performance. KCF is solving these performance limitations with a redesign of the piezo device, boundary condition, acoustic resonator and system housing. Applications include enhancements to HVAC systems and other air filters in industrial processes.

Funding source: Engineer Research and Development Center – Construction Engineering Research Laboratory (ERDC-CERL) SBIR CBD11-108

The military has experienced problems with clogging of air filters on its vehicles when operating in desert conditions such as those in Iraq and Afghanistan. The air filter in military vehicles traditionally needed to be removed periodically and tapped against the vehicle's tire several times to clean it. This operation must be done twice a day in order for the filter to last about 10 days before needing to be replaced. KCF Technologies has developed an acoustic cleaning system for military vehicle air filtration systems. The process involves applying sound vibrations to clean the air filter using a piezoceramic speaker, which is smaller and less bulky than traditional speakers. The technology applies to a variety of applications for high-temperature and high-amplitude applications, including fire alarms, industrial alarms, vehicle back-up alarms, and more.

KCF Technologies has developed a high-temperature piezoelectric sound source for a commercial man-down alarm. This component enables the Personal Alert Safety System (PASS) to sound a loud, piercing alarm whenever a firefighter becomes disabled or lies motionless for 30 seconds. The technology has been in production since 2007 and is available for application in other piezoelectric sound source markets.

Since the first extensive vibration study of EQUAL in 1997, a series of laboratory experiments and road tests have been performed to assess the ability of the product EQUAL to reduce tire vibration for a variety of vehicles, axle loads, and rotational speeds. The laboratory tests show that EQUAL consistently reduces the vertical (Z-direction) vibration magnitude at the fundamental frequency (1/rev). In the tests the average disturbance reduction compared to dual plane balanced wheel assemblies was 29 % in on-vehicle acceleration dynamometer testing and 55 % in fixed axle dynamometer testing. The road and test track measurements show that EQUAL consistently reduces the overall vibration magnitude in a variety of vehicles.

Videos were taken of the EQUAL system moving dynamically within a rotating tire. The videos have aided in understanding the mechanism by which tire vibration is reduced. Initial videos were taken with a modified wheel, and then when wireless camera technology progressed videos were taken with wireless cameras attached inside the wheel. A model describing the dynamics of the particle/tire interaction mechanism was developed to predict the vibration reduction for given operating conditions. These tests have been followed with numerous road and test track measurements.

The technology is an ultra-light, quasiactive noise control method for quieting unmanned aerial vehicles (UAVs). This passive noise reduction method for propellers is tunable to various flight conditions and directions. The design will reduce the acoustic emissions of UAVs without significantly impacting vehicle performance. Reducing UAV acoustic noise can lower the minimum altitude and lower the payload cost. This system can be used on propeller driven fixed wing vehicles and tail rotors of rotary wing aircraft.

Funding source: US Naval Air Systems Command SBIR N101-039

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