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Applying arbitary loading to a beam

Prithivirajan Veerappan

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say i have a beam of length l with a given B.C. i have the load data for various points along the length of the beam.

like

F(0.1*l)=a;F(0.2*l)=b; and so on....

can i directly import the txt file containing coordinate-load data.


i do not want to create points and apply ;because mine is a complex structure , creating points are very tedious...


can somebody give me a suggestion


prithivi

2 Replies Last Post Apr 28, 2011, 1:00 p.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago Apr 27, 2011, 1:16 a.m. EDT
Hi

you have one way by defining an interpolated function from your text data (see the "definitions functions" node), then you must decide if you know the coordinates or if its along the arc length, and you refer to this function in your BC.

The BC are applied to all mesh elements, using the default x,y,z coordinates of each element to extract the correct value, when referred to this way.

Try it out with a simple equation, lets say a beam along X, with a BC load on the upper surface along -y of Fy = -F0*x where F0 is i.e. a Parameter. Note you must decide on x or X in structural (solid) as one refers to the deformed spatial frame and the upper case to the material frame in v4 (by default, this has changed since v3.5 !)

--
Good luck
Ivar
Hi you have one way by defining an interpolated function from your text data (see the "definitions functions" node), then you must decide if you know the coordinates or if its along the arc length, and you refer to this function in your BC. The BC are applied to all mesh elements, using the default x,y,z coordinates of each element to extract the correct value, when referred to this way. Try it out with a simple equation, lets say a beam along X, with a BC load on the upper surface along -y of Fy = -F0*x where F0 is i.e. a Parameter. Note you must decide on x or X in structural (solid) as one refers to the deformed spatial frame and the upper case to the material frame in v4 (by default, this has changed since v3.5 !) -- Good luck Ivar

Prithivirajan Veerappan

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Posted: 1 decade ago Apr 28, 2011, 1:00 p.m. EDT
i have tried but getting the following error


Error: 9048
Format of data file is not correct.
It should contain grid and data values separated by lines starting with %.

say my data for interpolation is
x=[0 1...]
y=[0 2...]
data=[10 20 ...]


and this is the data format i have given (like in three column format) , for eg.



%x y (data)
0 0 101
1 2 174
....... so on...


could you please tell me the format in which ihave to give.....
i have tried but getting the following error Error: 9048 Format of data file is not correct. It should contain grid and data values separated by lines starting with %. say my data for interpolation is x=[0 1...] y=[0 2...] data=[10 20 ...] and this is the data format i have given (like in three column format) , for eg. %x y (data) 0 0 101 1 2 174 ....... so on... could you please tell me the format in which ihave to give.....

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