Displacement controlled static analysis

[msuhairil]

Hi there,

I am working with dog bone specimen (3D solid) and have elastic and plastic properties given to the model. But, i dont know how to apply displacement controlled (as load)..using 1mm/min in ABAQUS..Anybody can help me?..

or should i use velocity BC or displement/rotation BC's?..please guide me..urgent..(bottom part fixed, only top side will pulled upward 1mm/min..

 

[rb1957]

i don't know abaqus (so wtf are you answering, eh?) but i'd be looking under loading (enforced displacement) rather than boundary conditions

Quando Omni Flunkus Moritati

 

[rickfischer51]

I dont know Abacus either, but usually you apply the load the same way, by defining a displacement and stepping it over time. If your material model is rate dependent, then rate effects are included. If the material is not rate dependent, then time is irrelevant and you get the same result fot 1 second, 1 fortnight, etc.

Rick Fischer
Principal Engineer
Argonne National Laboratory

 

[rb1957]

if you're applying a loading rate, is it really a static analysis ? i guess it's a time-domain static ... there's no dynamic inertia load, just a continuously changing applied load

Quando Omni Flunkus Moritati

 

[bkal]

Why do you call it 'static analysis' in the subject field?

If inertial or time dependent effects are important you need to use dynamic analysis, and it is easy to aplly time dependent load.

If, on the other hand, time dependent effects are not important, you just apply total (final) displacement and the program will sort it out. You can apply it in the Load -> BC -> Displacement/Rotation, which also allows you to define how is it ramped (but I doubt it that it can be time dependent).

 

[msuhairil]

Thanks for the comment..i thought the static model suit to this problem..i should move to dynamics,probably can get it..in which part i can put displacemnt rate in dynamics analysis?

 

[rickfischer51]

At a loading rate of 1 mm/min, I seriously doubt that there are any dynamic effects, and this does not need to be run as a transient dynamic. Again, the effects of loading rate are determined by the material model you use. If you use a rate dependent model, like Anand, then the loading rate will have an effect. A simple model like a bilinear kinematic hardening, von Mises yield crterion, Prandtl Reuss flow rule, is rate independent, and the predicted plastic strains will be the same regardless of the loading rate.

Rick Fischer
Principal Engineer
Argonne National Laboratory