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ID Date Authorup Type Category Subject Text Attachments
  72   Thu Jul 25 15:54:58 2013 Deep ChatterjeeOpticsGeneralTR results for different dimensions

    

       
            
 Jul_25_1.pdfJul_25_2.pdfrelative_plot.pdf 
  73   Mon Jul 29 22:42:57 2013 Deep ChatterjeeOpticsGeneralAvoiding transient solutions in the Computation of TE/TR noiseAn error was being encountered in the computation
of the TR noise lately. It was observed that
while running the simulations in the case
 Jul29_2.pdf 
  74   Wed Jul 31 15:39:11 2013 Deep ChatterjeeOpticsGeneralFirst try with paramter optimization for TE and TR noise profilesAfter the simulations have been found to
match to a fair extent with the analytic
results by Heinert and Liu and Thorne, the
 Jul31_param_opt.pdf 
  75   Thu Aug 8 17:17:19 2013 Deep ChatterjeeOpticsGeneralSomething like cancellationFor the material parameters of Sapphire
at 300K, the TE and TR Noise profiles, though
not very close, lie close to within an order
 suspected_cance_AUg8l.pdf 
  100   Sat Sep 5 15:04:43 2015 Dennis CoyneMechanicsConfigurationsummary of FEA modal model to State Space model At the 2014 commissioning  FEM2SS_summary.docx 
  2   Tue Feb 5 13:15:13 2013 DmassGeneralGeneralCOMSOL: who's using up all the licenses?

    

       
            
  
  3   Tue Apr 2 19:24:07 2013 Emory BrownOptics First steps producing a Finite Element Model to find the internal Brownian noise of a LIGO test mass 
Motivation:
Reduction
  
  5   Mon Jun 3 21:01:46 2013 Emory BrownOpticsGeneralAnalytic Calculation of Thermal Noise due to Brownian Motion using Levin and Thorne's MethodsMotivation:
Reduction of Brownian thermal noise
in future gravitational wave detectors is
 ComparisonPowerSpectralDensitySurfaceFluctuationsVsFrequency.pngDifferencePlot.pngThorneComparisonPowerSpectralDensitySurfaceFluctuationsVsFrequency.nb 
  6   Tue Jun 4 17:25:11 2013 Emory BrownOpticsGeneralComparison 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,
 ComsolComparisonPowerSpectralDensitySurfaceFluctuationsVsFrequency.png 
  20   Mon Jun 17 11:06:17 2013 Emory BrownGeneralGeneralPlans for the week of 6-17-13 through 6-22-13This week I will update my previous eLog
entry with a nicely labeled plot showing
both lines on the same plot, then I intend
  
  21   Mon Jun 17 14:59:20 2013 Emory BrownOpticsGeneralImproved Meshing in a COMSOL ModelIn order to make computations more efficient
and possibly allow the set of boundary conditions
based on Liu and Thorne's suggestion of a
 COMSOLMeshing.png 
  22   Tue Jun 18 15:26:50 2013 Emory BrownOpticsGeneralAttempting to Implement Liu and Thorne's Boundary ConditionsLiu and Thorne demonstrated in their paper
that the optimal set of boundary conditions
for a problem like the one I am working on
  
  23   Wed Jun 19 14:59:13 2013 Emory BrownGeneralGeneralThe Relative Residual Convergence Error We have been encountering an error
in COMSOL for a while of the form "Failed
to find a solution.; The relative residual
  
  26   Thu Jun 20 12:51:44 2013 Emory BrownGeneralGeneralThe Relative Residual Convergence ErrorI used the same integrator that we had
setup for use with the stationary solver.
 I had expected it to either fail or
  
  28   Sun Jun 23 14:00:05 2013 Emory BrownGeneralGeneralManipulating the Relative Tolerance  We have been seeing an error when
attempting to use a stationary solver in
conjunction with a set of boundary conditions
  
  30   Mon Jun 24 16:02:43 2013 Emory BrownOpticsGeneralRebuilding 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.
  
  33   Tue Jun 25 15:18:41 2013 Emory BrownOpticsGeneralA 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
  
  36   Wed Jun 26 16:46:32 2013 Emory BrownOpticsGeneralA convergent stationary solution By adding additional constraints
as described in the previous eLog to the
model I was able to get a convergent solution
 ConvergingModelMinimal-6-26-13.mph 
  37   Thu Jun 27 11:26:18 2013 Emory BrownOpticsGeneralMissing factor of 4 and a comparison of analytic and simulated Brownian noise    
  40   Fri Jun 28 11:54:10 2013 Emory BrownOpticsGeneralMaintaining 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
  
  44   Tue Jul 2 13:32:30 2013 Emory BrownOpticsGeneralUsing 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
 model_7_1_13.mlooper.m 
  48   Mon Jul 8 15:47:23 2013 Emory BrownOpticsGeneralMeshing 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
  
  51   Tue Jul 9 14:45:04 2013 Emory BrownOpticsGeneralMeshing error when varying geometryI tried removing the constraints and applied
force and was able to get close to the same
frequencies for the butterfly modes as the
 Eigenfrequency.png 
  52   Wed Jul 10 14:15:20 2013 Emory BrownOpticsGeneralComparison 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
 UmaxValuesVsRatioR.pngFrequencyLowestEigenmodes.pngdata.tar.gz 
  55   Fri Jul 12 00:09:17 2013 Emory BrownOpticsGeneralAnalysis of substrate Brownian noise in a silicon test mass with changing ratioR value I performed the same analysis we
previously did on a test mass made of silicon
(using the built-in silicon within COMSOL)
 SiliconEigenfrequencyPlot.pngUmaxPlotSilicon.pngSilicon.tar.gz 
  56   Fri Jul 12 00:31:11 2013 Emory BrownOpticsGeneralReversed face mirror design We had noticed that when we ran an
eigenfrequency analysis, there was often
a node (see attached screenshot) on the face
 node.png 
  59   Mon Jul 15 13:14:30 2013 Emory BrownOpticsGeneralUmax curves for varying height test masses I ran sweeps over the ratioR range
from 0.5 to 0.9 for test masses with modified
height, and thus mass, which were otherwise
 MassComparison.png 
  76   Mon Sep 16 10:07:32 2013 EvanGeneralConfigurationCOMSOL 4.3 on the OS X command lineIf you're running Matlab scripts that iterate
over simulation parameters (à la Tara),
  
  82   Thu Apr 17 16:52:09 2014 EvanGeneralCharacterizationInterpreting logfiles and picking a solverHere are two entries by Walter Frei on
the Comsol blog that I've found useful.
Solving
  
  105   Tue Jun 28 15:50:45 2016 Joy WestlandMechanicsAnalysisA Simple Model of the Modal Analysis of a Cantilever Circular/Cylinder Cross Section in ANSYS tutorialHere is a tutorial to implement a simple
Modal Analysis of a Cantilever Cylinder

1. Open the ANSYS workbench
 Simple_Cantilever_200_mm_Long_Geometry.PNGSimple_Cantilever_200_mm_Long.PNGComparison_between_ANSYS_and_Calculations_Fused_Silica_200_mm_L.PNG 
  107   Wed Jun 29 14:14:44 2016 Joy WestlandMechanicsAnalysisANSYS Tutorials with Basic MeshingHere are a series of tutorials for basic
meshing principles from ANSYS Meshing Basics:


ANSYS Meshing Fine Mesh
  
  108   Fri Jul 29 14:33:41 2016 Joy WestlandMechanicsGeneralA Tutorial in Importing SolidWorks Files and Applying a Gaussian Force in ANSYS for a LIGO Test MassHere is a tutorial in importing SolidWorks
into ANSYS and the steps needed to apply
a Gaussian Force to the LIGO test mass that’s
 Bottom_Test_Mass_With_Ears.PNGApplying_Parameters.PNGApplying_Gaussian_Force.PNG 
  4   Thu May 2 14:00:36 2013 KojiGeneralConfigurationtest mass TR with Levin's approachThermo-refractive noise in a finite
cylindrical/infinite test mass with Levin's
approach
 thermo_refractive_1D_axisym_result.pdf 
  29   Sun Jun 23 14:29:04 2013 KojiOpticsGeneralDifferences on using a coarser mesh in calculating TR noiseWhat about the dependence on the size of
the time slice?
It is unclear what the unit fo the
  
  45   Wed Jul 3 00:04:46 2013 KojiOpticsGeneralUsing Matlab to run our COMSOL simulationsPlease use zipped files instead of uploading
extremely long text files on the elog. 
Or use wiki or svn instead of elog
  
  53   Wed Jul 10 17:52:18 2013 KojiGeneralGeneralHow to force time steps for a time dependent simulationA common trap in COMSOL:
When you run a time series simulation,
COMSOL tries to be "clever" by
  
  90   Sun Jun 29 20:25:44 2014 KojiOpticsGeneralDifficulty with the COMSOL stationary module; Test CasesWhat about this example? The result is
easier to understand intuitively.
Consider a bar with the length of
  
  92   Mon Jul 7 19:47:00 2014 KojiOptics Heinert Model TR Noise VerificationHow close are these FEA calculations with
the analytical values? 
Can you plot residual too? (Put analytical
  
  111   Mon Jul 24 15:54:26 2017 KojiGeneralConfigurationRunning Comsol to Matlab The number of licenses already used by
whom / still remains can be confirmed by
running the following command on a comsol-installed
  
  138   Tue May 12 14:16:28 2020 KojiGeneralGeneralFEA tutorial resourcescf. Forwarded email from Stephen

1) Tuesday Demo - Basics of FEA
Meshing G2000696
  
  110   Mon Jul 24 15:35:34 2017 MariiaGeneralConfigurationRunning Comsol to Matlab WIth Gautam's help, I have created
a user directory in 40 meter Lab and
copied Rana's documents (MATLAB
  
  113   Fri Jul 28 15:48:58 2017 MariiaGeneralConfigurationComsol batch for windowsUsing the written path from elog by
ericq: Computer
Scripts/Programs, Comsol can be run from
  
  7   Wed Jun 5 13:31:41 2013 Matt AOpticsGeneralAnalytic Calculation of Thermal Noise due to Brownian Motion using Levin and Thorne's MethodsNice Work Emory,
Can you make a plot with both of
the lines on the same plot, with a legend,
  
  9   Wed Jun 5 16:56:53 2013 Matt A.OpticsGeneralDifference in the Levin and Liu & Thorne results for thermal noiseGood Work Deep,
Can you include the equations that
you used to calculated these expressions?
  
  10   Wed Jun 5 16:59:51 2013 Matt A.OpticsGeneralMatlab 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.
 besselzero.m 
  13   Thu Jun 6 12:40:07 2013 Matt A.OpticsGeneralConventional Thermal noise (Sec V) from Liu & ThorneGood work Deep,
Can you write more on what this is
and why you're doing it? We want our elog
 Thorne_thermal_noise.pngPercentage_difference.png 
  16   Mon Jun 10 18:37:09 2013 Matt A.GeneralGeneralResponse to question in: Disscussion of the code of a 'comsol with matlab' model file (partially complete). 
trange = ['range(0,' num2str(dt)
',' num2str(t_end) ')'];
  
  24   Thu Jun 20 10:26:38 2013 Matt A.GeneralGeneralThe Relative Residual Convergence ErrorEmory:
I don't understand how you're getting
the strain energy from the eigenvalue solver.
  
  49   Mon Jul 8 18:39:31 2013 Matt A.OpticsGeneralMeshing error when varying geometry

    

       
            
  
  50   Mon Jul 8 19:04:35 2013 Matt A.OpticsGeneralMeshing error when varying geometry

    

       
            
 SimpleCylinder.mph 
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