Using Aggregate Mass in ADAMS to Check NREL CS_Monopile.bmi

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Lingling.Yin
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Organization: University of Houston
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Using Aggregate Mass in ADAMS to Check NREL CS_Monopile.bmi

Postby Lingling.Yin » Wed Jun 05, 2013 10:24 pm

Dear Jason,

I first used Aggregate Mass in ADAMS to calculate SNL 13.2MW mass moment of inertia and I used the outputs into .bmi file. The results of N.F are quite off from what I got from ADAMS (with only Twr DoFs on).

I then downloaded http://wind.nrel.gov/public/jjonkman/BModes/
and http://wind.nrel.gov/public/jjonkman/NR ... Bsline5MW/
offshore part to run the Aggregate Mass in ADAMS.

I specified a rigid NRELOffshrBsline5MW_Monopile_RF with all DoFs turning off since I only want to see the mass moment of inertia.
I used FAST 2012Feb edition I believe and thus I delete the line added in the new FAST this year.
I generated ADAMS model and get the mass inertia properties as following:


The aggregate mass in the global reference frame is:
Mass : 3.500003109E+005 kg
Center of Mass :
Location : -0.4106407744, -2.3123880885E-009, 109.5667156223 (meter, meter, meter)
Orientation : 89.9989498566, 5.3861985327, 270.0010456486 (deg)
Mass Inertia Tensor :
IXX : 4.2454591844E+009 kg-meter**2
IYY : 4.2253361673E+009 kg-meter**2
IZZ : 2.5520945258E+007 kg-meter**2
IXY : 0.2290994561 kg-meter**2
IZX : -1.4007405804E+007 kg-meter**2
IYZ : 2.8746322068 kg-meter**2


which I updated your .bmi, the results are quite off again.

Please help me to check I am doing the right thing.

Thanks,

Regards.
Attachments
Check NREL.zip
I can't update FAST.exe since not be allowed. The edition is released on 2012/02/22 I believe.
(108.27 KiB) Downloaded 2253 times
BModesJJ.zip
(421 KiB) Downloaded 2205 times
Lingling Yin, Research Assistant
University of Houston
5000 Gulf Freeway Bldg. 3, Rm. 152-B
Houston, TX 77204-0931
United States of America

Jason.Jonkman
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Re: Using Aggregate Mass in ADAMS to Check NREL CS_Monopile.

Postby Jason.Jonkman » Fri Jun 07, 2013 7:42 am

Dear Lingling,

Here are the data I get (calculated by ADAMS) regarding the mass & inertia of the rigid rotor-nacelle assembly (RNA) for the NREL 5-MW turbine:

Mass : 3.500003109E+005 kg
Center of Mass :
Location : -0.4137754432, -8.3126516178E-009, 1.9669893542 (meter, meter, meter)
Orientation : 359.9999911963, 90.0000955298, 354.6136364306 (deg)
Mass Inertia Tensor :
IXX : 4.5050443961E+007 kg-meter**2
IYY : 2.4940615741E+007 kg-meter**2
IZZ : 2.5477667652E+007 kg-meter**2
IXY : 0.2010825213 kg-meter**2
IZX : 1.4540376371E+006 kg-meter**2
IYZ : 2.8803379356 kg-meter**2

The center-of-mass (CM) location, orientation, and inertias above are all relative to FAST's nacelle coordinate system, which originates at the yaw bearing (i.e., tower top) with "X" pointing downwind, "Y" pointing to the left when looking downwind, and "Z" pointing vertically upwards.

Some of the values you report are close to these; others (especially the Z-coordinate of the CM and the IXX and IYY inertias) are quite a bit different because you've output yours relative to the global reference frame.

However, what BModes needs as input is the inertias of the RNA specified relative ot the CM of the RNA. Here are the inertias I report above translated to the CM of the RNA:

Ixx = 4.370E7 kg*m^2
Iyy = 2.353E7 kg*m^2
Izz = 2.542E7 kg*m^2
Izx = 1.169E6 kg*m^2

See my Nov 23, 2009 post in the forum topic found here for more information: viewtopic.php?f=4&t=289.

I hope that helps!

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

Lingling.Yin
Posts: 57
Joined: Wed Jan 23, 2013 12:47 pm
Organization: University of Houston
Location: Houston

Re: Using Aggregate Mass in ADAMS to Check NREL CS_Monopile.

Postby Lingling.Yin » Fri Jun 07, 2013 9:36 pm

Dear Jason,

That is great!

Thanks,

Regards
Lingling Yin, Research Assistant
University of Houston
5000 Gulf Freeway Bldg. 3, Rm. 152-B
Houston, TX 77204-0931
United States of America

Lingling.Yin
Posts: 57
Joined: Wed Jan 23, 2013 12:47 pm
Organization: University of Houston
Location: Houston

Re: Using Aggregate Mass in ADAMS to Check NREL CS_Monopile.

Postby Lingling.Yin » Sat Jun 08, 2013 11:30 am

Dear Jason,

Did you use my uploaded .adm file in ADAMS to get these number? I tried it again and I had these number:


The aggregate mass relative to .NRELOffshrBsline5MW_Monopile_RF_ADAMS.Nacelle_P.NacelleCS_M is:
Mass : 3.500003109E+005 kg
Center of Mass :
Location : -0.4106407744, -2.3123880885E-009, 1.9667156223 (meter, meter, meter)
Orientation : 89.9989498566, 5.3861985327, 270.0010456486 (deg)
Mass Inertia Tensor :
IXX : 4.5106432675E+007 kg-meter**2
IYY : 2.4983415493E+007 kg-meter**2
IZZ : 2.5520945258E+007 kg-meter**2
IXY : 0.2290994561 kg-meter**2
IZX : 1.4573394965E+006 kg-meter**2
IYZ : 2.9617168196 kg-meter**2


And there is an error info showing that "ERROR: The inertia tensor is ill formed. Both the CM/IM orientation and IP will be incorrect."


Does this mean I have some problem with my model or I did a wrong thing with ADAMS? How can we interpret the orientation of outputs?

Really appreciate,

Regards.
Lingling Yin, Research Assistant
University of Houston
5000 Gulf Freeway Bldg. 3, Rm. 152-B
Houston, TX 77204-0931
United States of America

Jason.Jonkman
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Joined: Thu Nov 03, 2005 4:38 pm
Location: Boulder, CO
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Re: Using Aggregate Mass in ADAMS to Check NREL CS_Monopile.

Postby Jason.Jonkman » Mon Jun 17, 2013 2:18 pm

Dear Lingling,

No, I didn't use your version of the *.adm file. I posted values from an analysis I had run a while ago. However, the results I posted in my Jun 07 post are nearly identical to your results from Jun 08; I suspect that there are only very small differences between our models.

I recall getting that same error about the inertia tensor being ill formed, but don't remember what caused it. I suggest you ask MSC Technical Support if you are concerned. The results look reasonable to me.

The "Orientation" specifies the 3-1-3 rotational sequence needed to orient the principle axes relative to the inertia frame coordinate system.

I hope that helps.

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

Jing.Li
Posts: 12
Joined: Thu Aug 29, 2019 2:42 pm
Organization: GE Research
Location: US - New York

Re: Using Aggregate Mass in ADAMS to Check NREL CS_Monopile.

Postby Jing.Li » Sun Jun 21, 2020 2:11 pm

Dear Jason,

According to the BModes User Manual (authored by Gunjit S. Bir and dated Sept 2007), for example, ixx_tip is "the side-to-side moment of inertia of the tip mass about the tip section x_T reference axis" (Table 2, pp.12) . My interpretation therefore is that the RNA inertia parameters are specified relative to the tower top central point.

However, I came across your June 7th, 2013 post which contradicts the above:

Jason.Jonkman wrote:However, what BModes needs as input is the inertias of the RNA specified relative to the CM of the RNA.



Could you confirm that this is true, in particular for the BModes version which allows a hub_conn=2 boundary condition (downloadable from https://drive.google.com/drive/folders/ ... zksGRnrqxJ)?

Thank you,
Jing

Jason.Jonkman
Posts: 5763
Joined: Thu Nov 03, 2005 4:38 pm
Location: Boulder, CO
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Re: Using Aggregate Mass in ADAMS to Check NREL CS_Monopile.bmi

Postby Jason.Jonkman » Mon Jun 22, 2020 7:00 am

Dear Jing.Li,

I confirm that ixx_tip is the side-to-side inertia about the x axis passing through the center of mass of the rotor-nacelle assembly.

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

Jing.Li
Posts: 12
Joined: Thu Aug 29, 2019 2:42 pm
Organization: GE Research
Location: US - New York

Re: Using Aggregate Mass in ADAMS to Check NREL CS_Monopile.bmi

Postby Jing.Li » Mon Jun 22, 2020 8:07 am

Hi Jason,

Thank you very much for your response!

Best regards,
Jing


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