WEST BETHESDA, Md. –
A new
1,000-pound inertial actuator, the AMA1000, is giving engineers at Naval
Surface Warfare Center, Carderock Division (NSWCCD) unprecedented capability in
full-scale testing.
Dr.
John Miesner, an engineer assigned to Carderock Division’s Acoustic Signatures
Technology Division, said the Navy has used actuators like the AMA1000 in a wet
environment for many years, but the shakers, as they are called, were not
capable of producing high forces at a broad range of frequencies until
2014. That is when the Carderock
Division Shaker Lab developed a wet-capable shaker called the MA400
specifically for this purpose. The
installed MA400s are performing well and produce about 400 pounds of
force.
Dr.
Miesner recognized that the MA400 design could be improved to produce 1,000
pounds within the same volume by replacing the rectangular magnetic laminations
with axisymmetric components that better fill the cylindrical vessel. This also reduces the number of parts
required and simplifies the manufacture and assembly of the shaker. “This shape
naturally fills the cylindrical volume and allows all of the moving mass to be
used for generating magnetic forces for higher acceleration of the inertial
mass and increased output force” Miesner said.
Shakers
are rooted in Isaac Newton’s second law of motion (F=MA) and researchers use
them at Carderock Division to predict how a ship will respond to vibration
sources including motors, pumps and other rotating equipment. The shaker does
this by exciting the ship structure allowing the dynamic properties to be
measured by an array of accelerometers.
The
Navy submitted a patent application for the AMA1000 on May 6, 2015, and Miesner
completed it July 7, 2015, with the assistance of Signature Measurement
Technologies and Systems Division employee Matthew Willey, who did the detailed
design drawings and oversaw the manufacture and assembly, and his fellow
Acoustic Signatures Technology Division employee Richard Cohen, who did most of
the machining.
“Dr.
Miesner's patent application underscores the Acoustic Signatures Technology
Division's reputation for technical excellence and innovation,” said Marylou
McNamara, division head, Acoustic Signatures Technology Division. “The
development of the AMA100 and the completion of the patent application process
are incentives for my employees and for all potential Carderock inventors.”
The prototype AMA1000 is
currently being tested at the Carderock Division Shaker Lab at up to 1,200
pounds of force output and meets or exceeds design requirements.