I performed experiments on Concrete filled steel tubes. Got the results in the form of load-deflection curves. Now, I want to convert them to moment-curvature curves for the purpose of comparison with previous research. How can I do it as flexure formula is for uniform material and cross-section.
Hi,
The deflections of tested beams if behaved close to the half-sine curve (similar to the deflection diagram in the case of simply supported beam), then, the curvature (φ) at the mid-span can be calculated as follows:
φ=π2.um / L2
where, L is the clear span length of beam, and um is the mid-span deflection.
for further details refer to the attached paper of Han (2004)
regards
Hi.
For every load, a corresponding moment can be calculated at any section. The deflection correspond to the load can be converted into curvature. Your composite beam section can be treated as a uniform material after transferring it.
@kamal
Thanks for your answer. I hope you can tell me any other method to convert the deflection into curvature in my case. As one method is already mentioned by Brother Ahmad
Dear Arbab
I do not think there is another method to convert it. My answer only an explanation how to do it. The equation in the Ahmed's answer sounds fine as the curvature is the change in the angle of a deflected member per a unit length. Um/L is the angle and then divided by the L which becomes um / L2 .
Then you have to obtain the moment which correspond to the specified deflection.
Hope this helps.
can any one please explain how to calculate experimental cracking moment (Mcr) and experimental ultimate moment(Mu) of a beam?
can it be calculated from load deflection diagram?
@sudipta You can easilt calculate Mcr and Mu of beam from load deflection curve. Furthermore, there are some code guidelines for calculating Mcr and Mu.
Regards
How to draw moment-curvature curve of columns when load-deflection curve is given?
Arbab Faisal ... Please check references below.. hope it will be helpful for you…
Regards…
https://hrcak.srce.hr/file/236186
http://digital.lib.lehigh.edu/fritz/pdf/279_7.pdf
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