LIGO Document T1500271-v7

Tuned Mass Damper Simulations for Quad Bounce and Roll Modes

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Document type:
T - Technical notes
Other Versions:
09 Jun 2015, 09:36
This note simulates the damping and thermal noise performance of tuned mass dampers (TMDs) applied to the springs tips in the quad's upper-intermediate-mass (UIM) to damp the high frequency bounce and roll modes. The details of the TMD design are given.

The MATLAB code is on the SVN at:

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Notes and Changes:
-v7 adds the section on direct longitudinal coupling to the UIM; changes the roll to DARM coupling from 5e-5 to 3e-6 m/rad; adds a list of references at the end; and adds this section on the revision history.

-v6 corrects more references to n3 that describe it as the full wire spacing rather than half the wire spacing between the PUM prisms. Also, the Latex source files are added here.

-v5 corrects a typo in the Notation section. n3 was described as the distance between the wire prisms on the PUM, but it is actually half the distance, i.e. it is the distance from the prism tip to the center of mass. In v2 the definition in the Notation section is correct, but the description in section 3.1 still refers to the diameter.

-v4 adds viscous damping thermal noise plots for considering eddy current damping. It also replaces the gwinc curve with a predicted suspension thermal noise curve from Alan Cumming.

-v3 adds a thermal noise curve to Figure 8, to help the design process. Also the gwinc curve in the other figures is updated with the latest Mark Barton thermal noise, and set to 25 W input power rather than 125 W.

-v2 adds some trend plots showing the damping factor and Qs as a function of damper mass ratio.

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