How can i calculate area under the cyclic curve and max ordinate of every curve?

I have an excel scatter curve. in which the horizontal axis shows displacement and vertical one shows base shear.

how can I calculate maximum displacement in every cycle and area under the curve of every cycle

[darova]

But how can i define start and end points of a cycle? Can you please explain?

Answer 1

[RAHUL CHOUHAN]

This Whole Cyclelic curve is composed of a different number of cyclic curves.

the first curve will start from the first value and end at last positive value. the second curve will start at the endpoint of the first curve. this process will continue until the last value of the whole curve.

Please find attached file.

sorry for the delay in response.

[darova]

You broke Star Strider's heart

[Star Strider]

@darova —

:-(

[RAHUL CHOUHAN]

Sorry Sir, :-(

Answer 2

[darova]

Use this to find all start points of curves

ind = find(diff(x > 0));
ind = [1; ind];

Use trapz to calculate area under the curve

[darova]

Can you please show where is area under this curve?

[RAHUL CHOUHAN]

Sorry..area between two lines.

[darova]

like this?

Curve #3 looks complicated. What we gonna do with it?

[RAHUL CHOUHAN]

first Graph shows proper result

[RAHUL CHOUHAN]

we can calculate approximate area for 3rd graph.

[RAHUL CHOUHAN]

Sir, how can i sort number of curve usign matlab function. and how can calculate approxiame area b/w this curves.

[darova]

For simple curve like this you can use polyarea()

For curve that intersects itself i'd divide it into 2 parts (using max and min)

I used polyxpoly() to find intersections

polyxpoly() also returns indices of curves (where they intersect) so you can calculate area each of them apart using polyarea()

This kind of curve remains. Honestly i don't know where is an area here