## PLOT OF LOAD AND DEFLECTION

## PLOT OF LOAD AND DEFLECTION

(OP)

HELLO,

I HAVE DONE THE NON LINEAR BUCKLING ANALYSIS OF A BEAM. WHEN I PLOT LOAD - DEFLECTION CURVE ITS SHOWING A LINEAR GRAPH WHICH SHOULD NOT BE SO.

PLEASE SUGGEST ME HOW CAN I GET THE NON LINEAR PLOT.

I HAVE DONE THE NON LINEAR BUCKLING ANALYSIS OF A BEAM. WHEN I PLOT LOAD - DEFLECTION CURVE ITS SHOWING A LINEAR GRAPH WHICH SHOULD NOT BE SO.

PLEASE SUGGEST ME HOW CAN I GET THE NON LINEAR PLOT.

## RE: PLOT OF LOAD AND DEFLECTION

## RE: PLOT OF LOAD AND DEFLECTION

As per previous use stabilisation (STABILIZE is the command can be set up also from /SOLU in Ansys) in ansys it is much better than ARCLEN.

Finally make sure you push past its limit load to see instability/collapse and make sure that you included BISO for plasticity for say steel.

Obviously the results are greatly influenced by the imperfection which say in steel design of buildings is given by the code (e.g., EC3). So make sure which imperfection to use and why it needs to be applied (say due to manufacturing)

## RE: PLOT OF LOAD AND DEFLECTION

THE CURVE IS ATTACHED BELOW

## RE: PLOT OF LOAD AND DEFLECTION

This horizontal part of the curve means that displacements increase without change in load (neutral equilibrium path). For me it indicates that even though this approach shows correct buckling load, it can’t predict postbuckling behavior correctly. To obtain better results I advise you to follow Erik’s suggestions. Especially in terms of the use of displacement instead of load control and adding plasticity and stabilization.

## RE: PLOT OF LOAD AND DEFLECTION

## RE: PLOT OF LOAD AND DEFLECTION

What code are you using ? ANSYS ??

another day in paradise, or is paradise one day closer ?

## RE: PLOT OF LOAD AND DEFLECTION

I am using ANSYS APDL, From post-processing I have the options of plotting the curve between node displacement and time. But I need a curve between displacement and load.

By the way who told u I was shouting at you.

## RE: PLOT OF LOAD AND DEFLECTION

if you can only get displacement vs time, do you have a fixed relationship between load vs time ? then you can plot displacement vs load.

but then that may be a different interpretation of your graph. if your loading is a step function (100% load applied at time = 0), then the graph shows that the deflection increases to some steady state ?

another day in paradise, or is paradise one day closer ?

## RE: PLOT OF LOAD AND DEFLECTION

## RE: PLOT OF LOAD AND DEFLECTION

your advice will be highly appreciated.

thank you

## RE: PLOT OF LOAD AND DEFLECTION

"I have the load vs time relation I want to plot the graph between the two." … sorry, what do you mean ?

you have load vs time, and displacement vs time, and you want load vs displacement ? … at some time, what is the load and the displacement ?

"which node to select" … can you plot the deformed shape ? then see which nodes look most interesting … the one with the largest displacement, the one with the largest change in displacement (per unit time), ...

another day in paradise, or is paradise one day closer ?

## RE: PLOT OF LOAD AND DEFLECTION

I am using time history plot for the load deflection curve

## RE: PLOT OF LOAD AND DEFLECTION

If you're saying that you're using load vs time instead of load vs deflection,

then you can find the deflection at whatever time from the model output (yes?, do you understand this)

then you have the load and the deflection at whatever time (time from zero to the end, yes?).

Then decide which node to plot.

another day in paradise, or is paradise one day closer ?

## RE: PLOT OF LOAD AND DEFLECTION