LIGO-G030555-00 LIGO Scientific Collaboration1 VIBRATION REDUCTION IN ISC PERISCOPE Peter Fritschel,...
-
Upload
thomasina-bradford -
Category
Documents
-
view
216 -
download
0
Transcript of LIGO-G030555-00 LIGO Scientific Collaboration1 VIBRATION REDUCTION IN ISC PERISCOPE Peter Fritschel,...
![Page 1: LIGO-G030555-00 LIGO Scientific Collaboration1 VIBRATION REDUCTION IN ISC PERISCOPE Peter Fritschel, Ken Mason, Richard Mittleman, Robert Schofield, Akiteru.](https://reader031.fdocuments.in/reader031/viewer/2022032205/56649e885503460f94b8c223/html5/thumbnails/1.jpg)
LIGO Scientific Collaboration 1LIGO-G030555-00
VIBRATION REDUCTION IN ISC PERISCOPE
Peter Fritschel, Ken Mason, Richard Mittleman, Robert Schofield, Akiteru Takamori
![Page 2: LIGO-G030555-00 LIGO Scientific Collaboration1 VIBRATION REDUCTION IN ISC PERISCOPE Peter Fritschel, Ken Mason, Richard Mittleman, Robert Schofield, Akiteru.](https://reader031.fdocuments.in/reader031/viewer/2022032205/56649e885503460f94b8c223/html5/thumbnails/2.jpg)
LIGO Scientific Collaboration 2LIGO-G030555-00
Goals
Increase first mode by a factor of 3 (140 to 420 hz)
Reduce acoustic coupling by a factor of 10
Eliminate dog clamps used to hold periscope to ISC table
Reduce table skin rocking which is amplified by the lever arm of the periscopes
![Page 3: LIGO-G030555-00 LIGO Scientific Collaboration1 VIBRATION REDUCTION IN ISC PERISCOPE Peter Fritschel, Ken Mason, Richard Mittleman, Robert Schofield, Akiteru.](https://reader031.fdocuments.in/reader031/viewer/2022032205/56649e885503460f94b8c223/html5/thumbnails/3.jpg)
LIGO Scientific Collaboration 3LIGO-G030555-00
Design Process
• Start with simple structural shape -Allows easy calculation of attainable natural
frequencies -Inexpensive, easy to obtain and modify• Make modifications to basic shape which have
minimal effect on first modal frequency -Each modification checked with FEA• Consult the experts - Professor Samir Nayfer MIT Department of
Mechanical Eng. consulted on acoustic damping
![Page 4: LIGO-G030555-00 LIGO Scientific Collaboration1 VIBRATION REDUCTION IN ISC PERISCOPE Peter Fritschel, Ken Mason, Richard Mittleman, Robert Schofield, Akiteru.](https://reader031.fdocuments.in/reader031/viewer/2022032205/56649e885503460f94b8c223/html5/thumbnails/4.jpg)
LIGO Scientific Collaboration 4LIGO-G030555-00
Analysis of Basic Shape
Added mirror, mount, and top plate
Removed mass in upper 1/3 of tube to compensate for added weight
Added access holes Added welded base
to tube and ability to rotate assembly
8.0”dia. x .322 wall pipe
![Page 5: LIGO-G030555-00 LIGO Scientific Collaboration1 VIBRATION REDUCTION IN ISC PERISCOPE Peter Fritschel, Ken Mason, Richard Mittleman, Robert Schofield, Akiteru.](https://reader031.fdocuments.in/reader031/viewer/2022032205/56649e885503460f94b8c223/html5/thumbnails/5.jpg)
LIGO Scientific Collaboration 5LIGO-G030555-00
Periscope Design
![Page 6: LIGO-G030555-00 LIGO Scientific Collaboration1 VIBRATION REDUCTION IN ISC PERISCOPE Peter Fritschel, Ken Mason, Richard Mittleman, Robert Schofield, Akiteru.](https://reader031.fdocuments.in/reader031/viewer/2022032205/56649e885503460f94b8c223/html5/thumbnails/6.jpg)
LIGO Scientific Collaboration 6LIGO-G030555-00
Acoustic Damping
Recent work by Professor Samir and Graduate student Kripa Varanesi at MIT saw a 10 X reduction in noise above 400 hz
Optimum damping occurred using Isodamp acoustic foam EAR C3201-25 with .05 mm stainless steel jacket
K.K. Varanasi and S.A. Nayfeh, 2003, "Vibration Damping by Coupling to Lossy Low-Wave-Speed Media". In Smart Structures and Materials 2003: Damping and Isolation, SPIE 03, Agnes and Wang Eds.
![Page 7: LIGO-G030555-00 LIGO Scientific Collaboration1 VIBRATION REDUCTION IN ISC PERISCOPE Peter Fritschel, Ken Mason, Richard Mittleman, Robert Schofield, Akiteru.](https://reader031.fdocuments.in/reader031/viewer/2022032205/56649e885503460f94b8c223/html5/thumbnails/7.jpg)
LIGO Scientific Collaboration 7LIGO-G030555-00
Acoustic Damping
![Page 8: LIGO-G030555-00 LIGO Scientific Collaboration1 VIBRATION REDUCTION IN ISC PERISCOPE Peter Fritschel, Ken Mason, Richard Mittleman, Robert Schofield, Akiteru.](https://reader031.fdocuments.in/reader031/viewer/2022032205/56649e885503460f94b8c223/html5/thumbnails/8.jpg)
LIGO Scientific Collaboration 8LIGO-G030555-00
Before and After
![Page 9: LIGO-G030555-00 LIGO Scientific Collaboration1 VIBRATION REDUCTION IN ISC PERISCOPE Peter Fritschel, Ken Mason, Richard Mittleman, Robert Schofield, Akiteru.](https://reader031.fdocuments.in/reader031/viewer/2022032205/56649e885503460f94b8c223/html5/thumbnails/9.jpg)
LIGO Scientific Collaboration 9LIGO-G030555-00
Acoustic Foam on Older Style Periscope
![Page 10: LIGO-G030555-00 LIGO Scientific Collaboration1 VIBRATION REDUCTION IN ISC PERISCOPE Peter Fritschel, Ken Mason, Richard Mittleman, Robert Schofield, Akiteru.](https://reader031.fdocuments.in/reader031/viewer/2022032205/56649e885503460f94b8c223/html5/thumbnails/10.jpg)
LIGO Scientific Collaboration 10LIGO-G030555-00
Acoustic Foam on Older Style Periscope
No Damper Damper 1: 5mm steel plate / ½” foam Damper 2: 1mm steel plate / ¼” foam with additional clips
![Page 11: LIGO-G030555-00 LIGO Scientific Collaboration1 VIBRATION REDUCTION IN ISC PERISCOPE Peter Fritschel, Ken Mason, Richard Mittleman, Robert Schofield, Akiteru.](https://reader031.fdocuments.in/reader031/viewer/2022032205/56649e885503460f94b8c223/html5/thumbnails/11.jpg)
LIGO Scientific Collaboration 11LIGO-G030555-00
Acoustic Foam on Older Style Periscope