Interaction Curves for RC column

N-M Interaction curves of axial(N) and bending(M) are generated for RC column with round or square section.

e32d.m
Purpose
The program intends to find characteristic values and draw graphs for inelastic
deformation at plastic hinge for cantilever column with rec or round section.
Suppose the column deforms by external horizontal load at column top, the
column experience horizontal deformation. Column top deforms horizontally,
so P-delta curve is drawn with characteristic points shown below,
(dy,Py): (yield deformation, yield load)
(dmax,Pmax): (maximum deformation, maximum load)
At the base of the column, M-fei curve is drawn with,
(feiy, My): (yield deformation curvature, yield M),
(feim, Mmax) (maximum fei, maximum M)
When plastic hinge zone is taken into consideration,
(thetay, My): (yield deformation rotation, yield M),
(thetam, Mmax) (maximum rotation, maximum M)
When it is intended for definition of plastic hinge, deformation
contributed by elastic performance is removed from the deformation. So,
(thetay2, My) (modified yield, yield My), and
(thetam2, Mmax): (modified maximum deformation, maximum M)
are shown.
Collapse node deformation can be defined as 2*thetam2 till further notice.
M-N interaction curve for the section is shown.
As for unit, [mm, N] are used.

upgraded 2020/11/15
Intended more to cantilever column and M-fei relation, (fei,m) points
at plastic hinge.
datafiles, e32dControl.txt and *.txt, are detached from program.
M-N curves are obtained, but more empasize was placed for yield and max
points.
See ref for model data parameter.

Attached
Program: e32d.m
control file: e32Control.txt
Data files: e32Rec.txt. e32Rnd.txt etc.