Bug in member strains with trapezoidal temperature load

[cohen]

I have a strange bug in RFEM 5.23.01.
For beams that only have temperature loads, and of wich at least one loadcase includes a trapezoidal temperature load, the strains of the first node are shown incorrect (usually as 0)

Steps to reproduce:
Create a new model in 3D.
Draw a new single member. make it a EN - IPE80 steel beam, make 1 node a rigid support.
Add one loadcase, disable selfweight. Give it a member load: Temperature, uniform Tc = +10 degC
Calculate.
Now look at table 4.8: Member strains.
For member 1, Both node 1 and node2 show a strain (ex,max and ex,min) of approx 0.12 mm/m. This is correct. See picture 1.


Now add a second loadcase. (don't touch the first one!)
In the second loadcase, assign a member load: Temperature, trapezoidal Tc1=+10, Tc2=+9
Calculate.
Now look at table 4.8: Member strains for the first loadcase
For member 1, node1 now has a strain (ex,max and ex,min)of 0. This is obviously incorrect. See picture 2.

In the result diagram it is clear that node 1 has 2 strains at the same point. 0 and 0.12mm/m. See picture 3


While this may not hurt the global results, if you export table 4.8 to excel and use those values, it results in big errors.

[cohen]

And to continue on this:
Delete the uniform load from loadcase1.
Add a new trapezoidal temperature load in loadcase1: Tc1=Tc2=+10.
The result now looks like this: (see picture)

Node 1 now has 2 lines, that show different stresses at the same position.....

[Frank Faulstich]

Hello cohen, thank you very much for the hint and the good documentation. We will correct the problem in the next RFEM version.

Frank Faulstich

[cohen]

Hello cohen, thank you very much for the hint and the good documentation. We will correct the problem in the next RFEM version.

Frank Faulstich

Thank you for the swift response.

[Frank Faulstich]

Last Friday we released a new version which fixes this problem. You can download the version in your Dlubal account.

Frank Faulstich