Get fiber stress-strain at specific cross-section (IP)

[sanaclet]

Hi,
I am modeling an RC beam that I tested in the lab. I am using a force-based element and fiber cross-sections.
I want to output local responses (steel reinforcement stress-strain) at the exact location where we had strain gauges installed.

Could you please help me find the best approach to do this?

In general, the cross-sections where the strain gauges were installed do not coincide with the integration points (IPs) of any quadrature rule. I have the option to use a user-defined integration rule, but calculating adequate weights does not seem straightforward and I am concerned about the accuracy of the results if I do that. Alternatively, I could increase the number of elements and make the element end nodes (or midpoint) coincide with the desired locations.

What is the best approach to record local responses at specific cross-sections? Can I do that using one force-based element only and one of the predefined quadrature rules?

Thanks

[fmk]

the only options are to figure out the integration weights (you might trying using the default ones and addinng other ones at points wanted with a 0 weight .. check if it works by doing it and comparing results .. they should not change) .. other option is to use disp based elements and put nodes at points wanted & use gauss lobatto.