topic Re: Thermal Load in Robot Structural Analysis Forum

Thermal Load

Anonymous — Sat, 16 Mar 2013 15:31:07 GMT

I am trying to apply an 80 degree thermal load to the upper surface of an RC Shell but it won't let me specify a temperature in the "surface > thermal loads" window. I can assign a gradient and apply it to the shell but no temperature.

Re: Thermal Load

Rafal.Gaweda — Mon, 18 Mar 2013 07:44:25 GMT

Example: http://screencast.com/t/c08lYme4Ku

Example: http://screencast.com/t/AyyDhU54OJW

Re: Thermal Load

Anonymous — Thu, 28 Mar 2013 12:22:55 GMT

Sorry for the late reply, I've tried these already... I'm designing a flat RC slab and the option to input a temperature is not available.

I do "load definition", trying both "live" and "temperature" but within both of these the program does not allow me to input a temperature, only a gradient as seen in the image attached.

I wish to apply a temperature of 80 degrees C to the top surface of the slab, I'm designing it within "Plate Design".

Re: Thermal Load

Rafal.Gaweda — Thu, 11 Apr 2013 07:06:38 GMT

temperature gradient along an element's thickness , along local Z.

Convention:

gradient value -> on top = +half of gradient value , on bottom = -half of gradient value.

Re: Thermal Load

Anonymous — Thu, 28 Mar 2013 14:47:04 GMT

So for a slab thickness 650mm where it is desired to have 80 degrees at the upper surface and 20 at the base.... I would specify a gradient of -60/0.65 = -92.31 oC/m and this will simulate the desired affect?

Re: Thermal Load

Rafal.Gaweda — Wed, 03 Apr 2013 10:53:18 GMT

No,

In such case you have to change structure type on Shell then:

if you consider assembling temperature as 0 deg then:

if you consider assembling temperature as 20 deg then (elements have already temp 20 deg):

Re: Thermal Load

Rafal.Gaweda — Wed, 03 Apr 2013 10:55:45 GMT

Important : message 6 updated \ corrected!

Re: Thermal Load

Anonymous — Wed, 03 Apr 2013 14:22:53 GMT

Thanks a lot for the help!

My slab is 650mm deep does this affect the gradient in any way?

Re: Thermal Load

Rafal.Gaweda — Wed, 03 Apr 2013 14:52:38 GMT

My slab is 650mm deep does this affect the gradient in any way?

No ; gradient between top and bottom layers whatever slab thicness is.

Re: Thermal Load

Refaat — Thu, 04 Apr 2013 07:40:19 GMT

Dear Rafal

What is the meaning of "assembling temperature" and what is the difference between assembling temperature and the value of "dT1" in the "thermal load 3p window" ?

Thanks

Refaat

Re: Thermal Load

Rafal.Gaweda — Thu, 04 Apr 2013 07:58:51 GMT

What is the meaning of "assembling temperature" and what is the difference between assembling temperature and the value of "dT1" in the "thermal load 3p window" ?

This is written just above second screen shot in message 6:

"if you consider assembling temperature as 20 deg then (elements have already temp 20 deg):" - it means starting temp is already 20 so you need to "heat it' +30 and gradient 60.

Re: Thermal Load

Refaat — Thu, 04 Apr 2013 09:05:52 GMT

Dear Rafal

What about this situation , how can I calculate the " temperature and gradient values" in the thermal load window definition ?

Initial temp. = 20 c

(Maximum temperature )Summer temp. = + 45 c

(Minimum temperature )Winter temp. = - 5 c

Minimum thermal gradient ,ΔT= (-5-20) = -25 c

Maximum thermal gradient ,ΔT=(45-20) = + 25 c

Thanks in advance

Refaat

Re: Thermal Load

Rafal.Gaweda — Thu, 04 Apr 2013 09:48:40 GMT

Initial temp. = 20 c

(Maximum temperature )Summer temp. = + 45 c

(Minimum temperature )Winter temp. = - 5 c

Minimum thermal gradient ,ΔT= (-5-20) = -25 c

Maximum thermal gradient ,ΔT=(45-20) = + 25 c

The meaning of "gradient" in robot temp panel load is the temp difference between top and bottom layers of panel (difference along panel thickness)

so in your case(s) (I understood the whole panel has the temp +45 or -5 along thickness)

1. Summer : load window setings : Temperature = +25, Gradient = 0.

1. Winter : load window setings : Temperature = -25, Gradient = 0.

Re: Thermal Load

Refaat — Thu, 04 Apr 2013 11:10:11 GMT

Dear Rafal

Thanks a lot for your advise

Refaat

Re: Thermal Load

Anonymous — Tue, 17 Nov 2015 14:16:41 GMT

how should i apply a thermal load with gradiient

external temperature in winter = -15 c

in summer = 40c

internal tempreature = 20 C

i have concrete wall of 20 cm thickness with internal insolation

kindly show me how to calculate the DT and the gradient to use in a Robot model

Re: Thermal Load

Rafal.Gaweda — Tue, 17 Nov 2015 14:38:22 GMT

considering initial temp = 0:
summer: Temperature = 30, Gradient = 20
winter: Temperature = 2,5, Gradient = -35

Re: Thermal Load

Anonymous — Tue, 17 Nov 2015 15:00:13 GMT

can u plz send how u calculated the temperature ?

Re: Thermal Load

Rafal.Gaweda — Tue, 17 Nov 2015 15:01:42 GMT

http://forums.autodesk.com/t5/robot-structural-analysis/thermal-load/m-p/3817573#M12030 -> top screen shot

Re: Thermal Load

Anonymous — Mon, 06 Jun 2016 14:54:54 GMT

If i undserstand your post :
I have only one case of temperature (dT1) for summer and winter : 50 if assembling temperature is 0° C and 30 if assembling temperature is 20° C.
Can you explain how you have 50° C ??

And there is a mistake in your post if i consedering 20° C assembling temperature
:
30 + 30 = 60 (not 80° C)
30-30 = 0 (not 20° C)

So we have gradient = 60 - 0 = 60.

Re: Thermal Load

Rafal.Gaweda — Tue, 07 Jun 2016 07:08:29 GMT

I assume you are refering to second screen shot in post 6

Assembling temperature is the temparature which "already has the panel" so to reach 80 deg on outer fibers you need to add uniform temp of 30 + gradient 60 (which will give 30 on top fibers) so finally on top: 20(assembling ; see text above 80 on screen shot) + 30 uniform + 30 (coming from gradient) gives 80

similar way on bottom