hi

you can do that by normalizing both load and deflection by their yield values. yo do so for each beam then compare their normalized load-deflection curves

Use the analytical formulas. See attached file.

Hope it can help you.

Franco

@Raafat E S ismail. Thanks for the answer. Will try this method.

@franco Will it be accurate for the deflections after yield?

I fully agreee with Mr. Raafat, Normalization of load and beam length will solve your issue.

Depending on the shape of load ,concentrated load or distributed load

@hamidreza It is two point load. But a/d ratio is same for both the beams

To convert load-deflection of a 2m beam to 3m beam:

divide load by 3/2

multiply deflection by (3/2)^2

@reza wouldn't it be (3/2)^3 for deflection?

Hi,

Can you use the strain instead of deflection? and stress instead of load? 

This will be more logical and convenience for a comparison. 

hi multiply deflection by (3/2)^3

 @hamidreza. .  Thanks for Your answer. . . What about load? Will it be the same? And wouldn't it be only for linear range?

hi  for concentrated load, multiply deflection by (3/2)^3

if you have distributed load, multiply deflection by (3/2)^4

@Arbab

If linear, they would be the same, otherwise no.

It also depends on the type of load, extension and torque scales the same and linearly, bending scales in a cubic fashion. If your beam is relatively short, then you need to consider transverse shear, a simple scale does not exist, as the aspect ratio also affects the results. 

Because the nonlinearity don't use any of deflection formula. Only normalize the results