Non-uniform distributed loads on line elements

[Luciano Jacinto]

I’m trying NextFEM to use it on a regular basis on my academic life as professor of Structural Concrete. Thanks for the free, basic version of your program, which is not so basic. The possibility to use it with API is very powerful.
In this trial, I was faced with some problems. In this post I’ll describe the first one. The method addBeamLoad() doesn’t seem to work properly when using non-uniform distributed loads on a beam. For example, for a simple supported beam with a span of 5 m, subjected to a uniform load of 12 kN/m, the program gives the true result (37.5 kNm). But when we apply the same load on a partial length of the beam, the program gives the same result, as if the beam was loaded in the full length.
Applying the load via GUI doesn’t seem to work properly either.
Attached is the python file with illustrating the problem.
Thank you in advance for your support.
Luciano Jacinto

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[NextFEM Admin]

Dear prof. Luciano,
thanks for writing to us, we immediately released a patch for this. Please re-download version 2.2.0.3 from now on (https://www.nextfem.it/it/download/) and re-install it over the existing copy.

ps.
you can rewrite the Python code as attached, wihtout hard-coding the API path.

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[Luciano Jacinto]

Many thanks for your quick reply. The problem is solved. I will continue to test NextFEM, which seems to be a very interesting program: simple and powerful.

[NextFEM Admin]

Thanks for your appreciation.
Also, we can issue academic licenses for some of the modules for free – if needed, let us know by using the contact page: https://www.nextfem.it/it/request-a-quote/

[Luciano Jacinto]

Sorry, but the problem with non-uniform loads on beams persists. For a simple supported beam with a span of 5 m and a triangular load, 0 at the beginning and 12 kN/m at the end, the moment at the mid-span is 18.75 kNm, but the program gives a strange result (a negative value!). Please verify this. Thanks.

[NextFEM Admin]

Hello, the previous minor patch brake something, a new patch will be released today and then please update again to 2.2.0.4.
We get the correct results by using the attached script.

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[Luciano Jacinto]

Thak you very much. I will look forward for the new release.

[Luciano Jacinto]

Congratulations for the 2.2.0.5 release. I made some tests, and everything seems work perfectly. I also notice that it was made an improvement in API for Python. Now we can specify several load values and the corresponding positions:

nf.addBeamLoad(
elem = e1,
values = [0, -12, -12, 0],
positions = [0.0, 1.0, 4.0, 5.0],
direction = 2,
loadcase = ‘lc4’,
local = True,
)

Is there a change log so that we can look for the improvements in each release?
Thanks for this very nice program.

[NextFEM Admin]

Hello,
thanks for your interest. Yes, the new command for beam loading allows to insert values and positions as arrays. We don’t have a change log for minor releases.

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