| ID |
Date |
Author |
Type |
Category |
Subject |
Text |
 |
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121
|
Tue Dec 5 10:50:54 2017 |
aaron | Mechanics | PonderSqueeze | FEA on optimus | I had some trouble running this on optimus.
Optimus has COMSOL 5.1 installed,
but I made these files in 5.3. I downloaded |
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122
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Tue Dec 5 19:50:47 2017 |
aaron | Mechanics | PonderSqueeze | FEA on optimus | Gautam advised me against trying to install
version 5.3, lest it break version 5.1--I
had already gone through the install, but |
|
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123
|
Tue Dec 12 11:50:12 2017 |
aaron | Mechanics | PonderSqueeze | FEA on optimus | Simulation results
First
run
Gautam ran the
COMSOL model on sandbox1 since we were trying |
|
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125
|
Mon Jan 22 21:13:25 2018 |
aaron | Mechanics | PonderSqueeze | tips from Shoaib | I talked with Shoaib about some changes
I could make to the FEA model to improve
convergence and reduce memory usage. Summary: |
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126
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Mon Jan 29 23:02:13 2018 |
aaron | Mechanics | PonderSqueeze | tips from Shoaib | I started implemented some of these changes:
Started the mesh with a
boundary free quad mesh on the interface |
|
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129
|
Sun Aug 26 16:42:54 2018 |
rana | Mechanics | Analysis | Test Mass Thermal Noise: Consistency Checks | For the Voyager test masses, we have been
considering a barrel coating to increase
the IR emissivity to increase the radiative |
|
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131
|
Thu Feb 14 12:38:51 2019 |
Ching Pin | Mechanics | | comsol modelling | So I did a simple comsol model of laser
heating of a silicon disk, with only radiation,
to see the temperature variation at steady |
|
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132
|
Fri Feb 15 21:05:31 2019 |
Ching Pin | Mechanics | | comsol modelling |
So I got the time dependence to
work, but I'm not sure what went wrong |
|
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133
|
Tue Feb 19 19:52:53 2019 |
Ching Pin | Mechanics | | comsol modelling | The time step response to heating via laser
(22.5 mW) is given in the attached picture,
for 2 starting temperatures, 122.5 K and |
|
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134
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Fri Mar 1 19:33:40 2019 |
Ching Pin | Mechanics | | comsol modelling | I've changed the heating to be from
two heat sources, to better model the situation
with a heater and a laser. The heater deposits |
|
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135
|
Mon Mar 4 17:22:07 2019 |
Ching Pin | Mechanics | | comsol modelling | I've updated the material properties
to vary with temperature, mainly in the range
of 90-140 K. Using the parametric sweep function |
|
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136
|
Wed Mar 6 09:51:18 2019 |
Ching Pin | Mechanics | | comsol modelling | So I tried adding the sapphire lens to
the comsol model, and I am having teething
issues. I can't seem to get the solver |
|
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137
|
Thu Mar 7 10:10:37 2019 |
Ching Pin | Mechanics | | comsol modelling | There are no issues with the thermal side
of the modeling, the issue seems to be with
the structural mechanics side. I'm not |
|
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3
|
Tue Apr 2 19:24:07 2013 |
Emory Brown | Optics | | First steps producing a Finite Element Model to find the internal Brownian noise of a LIGO test mass |
Motivation:
Reduction |
|
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5
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Mon Jun 3 21:01:46 2013 |
Emory Brown | Optics | General | Analytic Calculation of Thermal Noise due to Brownian Motion using Levin and Thorne's Methods | Motivation:
Reduction of Brownian thermal noise
in future gravitational wave detectors is |
|
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6
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Tue Jun 4 17:25:11 2013 |
Emory Brown | Optics | General | Comparison of First Results from COMSOL Model to the Analytic Solution | Motivation: Before we can attempt
to modify the mirror designs to reduce the
thermal noise due to Brownian motion in them, |
|
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7
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Wed Jun 5 13:31:41 2013 |
Matt A | Optics | General | Analytic Calculation of Thermal Noise due to Brownian Motion using Levin and Thorne's Methods | Nice Work Emory,
Can you make a plot with both of
the lines on the same plot, with a legend, |
|
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8
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Wed Jun 5 13:49:13 2013 |
Deep Chatterjee | Optics | General | Difference in the Levin and Liu & Thorne results for thermal noise | The analytical expressions for thermal
noise, as calculated by Liu & Thorne
and Levin, was plotted as a function of frequency |
|
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9
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Wed Jun 5 16:56:53 2013 |
Matt A. | Optics | General | Difference in the Levin and Liu & Thorne results for thermal noise | Good Work Deep,
Can you include the equations that
you used to calculated these expressions? |
|
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10
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Wed Jun 5 16:59:51 2013 |
Matt A. | Optics | General | Matlab code for calculating the zeros of Bessel functions from GWINC | For calculating the Liu and Thorn
U_0 + DU, you need to sum over the first
N zeros of the first-order Bessel function. |
|
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11
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Wed Jun 5 20:39:48 2013 |
Deep Chatterjee | Optics | General | Conventional Thermal noise (Sec V) from Liu & Thorne | >The linearized PSD plots are created
for the case of thermal noise in finite test
mass (Sec. V) of Liu and Thorne. |
|
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13
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Thu Jun 6 12:40:07 2013 |
Matt A. | Optics | General | Conventional Thermal noise (Sec V) from Liu & Thorne | Good work Deep,
Can you write more on what this is
and why you're doing it? We want our elog |
|
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14
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Thu Jun 6 17:00:11 2013 |
Deep Chatterjee | Optics | General | Comparison of ITM and FTM geometries (FIG. 3 Liu & Thorne) | In section V of their paper on thermoelastic
and homogenous thermal noise, Liu and Thorne
have corrected the result of power spectral |
|
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19
|
Wed Jun 12 13:52:44 2013 |
Deep Chatterjee | Optics | General | Difference in COMSOL and Analytic solution for TR noise | In this post, I am reporting of the relative
difference between the analytic and COMSOL
results. |
|
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21
|
Mon Jun 17 14:59:20 2013 |
Emory Brown | Optics | General | Improved Meshing in a COMSOL Model | In order to make computations more efficient
and possibly allow the set of boundary conditions
based on Liu and Thorne's suggestion of a |
|
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22
|
Tue Jun 18 15:26:50 2013 |
Emory Brown | Optics | General | Attempting to Implement Liu and Thorne's Boundary Conditions | Liu and Thorne demonstrated in their paper
that the optimal set of boundary conditions
for a problem like the one I am working on |
|
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27
|
Thu Jun 20 16:29:38 2013 |
Deep Chatterjee | Optics | General | Differences on using a coarser mesh in calculating TR noise | In the code for evaluating TR noise, the
parameter for automatic meshing (which can
take values from 1 to 9 - 1 being the |
|
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29
|
Sun Jun 23 14:29:04 2013 |
Koji | Optics | General | Differences on using a coarser mesh in calculating TR noise | What about the dependence on the size of
the time slice?
It is unclear what the unit fo the |
|
|
30
|
Mon Jun 24 16:02:43 2013 |
Emory Brown | Optics | General | Rebuilding a minimal version of our COMSOL model | I rebuilt our COMSOL model in order
to see if I could find any errors in it and
to clean out unnessesary features and parameters. |
|
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31
|
Mon Jun 24 18:00:26 2013 |
Deep Chatterjee | Optics | General | The problem of TE Noise calculation for a beam passing through a cylindrical substrate | In this post, I mention of my immediate
plan for the week and also describe the problem
I am looking at in brief. |
|
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32
|
Tue Jun 25 15:16:59 2013 |
Arnaldo Rodriguez | Optics | General | Setting Up Looped Simulation for PID Controller | After setting up a COMSOL model that includes
the heat flux from the laser and the ring
heater, I've made the model solve over time |
|
|
33
|
Tue Jun 25 15:18:41 2013 |
Emory Brown | Optics | General | A new boundary condition to attempt to avoid the relative residual error | I contacted COMSOL support about
our difficulties with the relative residual
error and was told "Typically for solid |
|
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34
|
Wed Jun 26 13:52:06 2013 |
Arnaldo Rodriguez | Optics | General | Verifying Relative Error in Defocus for Regular and Manual-Loop Simulations | To verify the validity of the solutions
produced by the manual simulation, I've calculated
the relative error between the results from |
|
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35
|
Wed Jun 26 15:23:55 2013 |
Arnaldo Rodriguez | Optics | General | Solving Time per Loop in Manual Dynamic Simulation | I've attempted to determine the solving
time per loop as a function of the simulation
time, in an attempt to identify any trends |
|
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36
|
Wed Jun 26 16:46:32 2013 |
Emory Brown | Optics | General | A convergent stationary solution | By adding additional constraints
as described in the previous eLog to the
model I was able to get a convergent solution |
|
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37
|
Thu Jun 27 11:26:18 2013 |
Emory Brown | Optics | General | Missing factor of 4 and a comparison of analytic and simulated Brownian noise | |
|
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38
|
Thu Jun 27 15:06:13 2013 |
Arnaldo Rodriguez | Optics | General | PID Function in Manual Simulation | I have inserted a rudimentary PID
function into the manual simulation code
as a way to test whether or not the PID function |
|
|
39
|
Thu Jun 27 17:12:33 2013 |
Arnaldo Rodriguez | Optics | General | Defocusing in P-Controlled Manual Simulation | To test the effectiveness of the
PID loop, I've only given a nonzero value
to the K_p constant and varied it over a |
|
|
40
|
Fri Jun 28 11:54:10 2013 |
Emory Brown | Optics | General | Maintaining a constant volume while modifying the radii of the test mass faces | When changing the dimensions of the
mirror, we want to keep a constant volume.
To do so, we must modify the height of the |
|
|
42
|
Mon Jul 1 13:01:58 2013 |
Arnaldo Rodriguez | Optics | General | Brief Parameter Study on P-active Control Loop | The following is a plot of the defocus
as a function of time with only the proportional
gain being nonzero. Only three cases were |
|
|
43
|
Mon Jul 1 17:31:40 2013 |
Arnaldo Rodriguez | Optics | General | Parameter Study on Sampling Time for P-active Loop | The following is a plot of the defocus
as a function of time for a fixed proportionality
gain of 150, and different listed sampling |
|
|
44
|
Tue Jul 2 13:32:30 2013 |
Emory Brown | Optics | General | Using Matlab to run our COMSOL simulations | We want to be able to test a number
of values for the ratio of the radii of the frustum
which will be much easier once we can get |
|
|
45
|
Wed Jul 3 00:04:46 2013 |
Koji | Optics | General | Using Matlab to run our COMSOL simulations | Please use zipped files instead of uploading
extremely long text files on the elog.
Or use wiki or svn instead of elog |
|
|
46
|
Thu Jul 4 15:23:47 2013 |
Deep Chatterjee | Optics | General | Attempt to compute TE noise following Liu and Thorne | Liu and Thorne, in their paper have analytically
solved for the TE noise spectra considering
the test mass to be a half infinite space. |
|
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47
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Fri Jul 5 14:06:24 2013 |
Deep Chatterjee | Optics | General | Attempt to compute TE noise following Liu and Thorne |
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48
|
Mon Jul 8 15:47:23 2013 |
Emory Brown | Optics | General | Meshing error when varying geometry | I attempted to run the Matlab code
built last week, but received an error that
the mesh failed to generate on the inner |
|
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49
|
Mon Jul 8 18:39:31 2013 |
Matt A. | Optics | General | Meshing error when varying geometry |
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50
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Mon Jul 8 19:04:35 2013 |
Matt A. | Optics | General | Meshing error when varying geometry |
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51
|
Tue Jul 9 14:45:04 2013 |
Emory Brown | Optics | General | Meshing error when varying geometry | I tried removing the constraints and applied
force and was able to get close to the same
frequencies for the butterfly modes as the |
|
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52
|
Wed Jul 10 14:15:20 2013 |
Emory Brown | Optics | General | Comparison of Umax and the frequency of the lowest eigenmode against ratioR | I was able to run the looper program
designed last week over the interval ratioR=[0.5,
0.9] with a step size of 0.01 and obtained |
|