On 8 April 2010 09:46, Bruno Chareyre <[email protected]> wrote:
> > I need the incremental formulation for the normal force in the contact >>> law. Could you tell me how to do that? >>> >> What is the problem exactly? You have the equation but you don't know how > to implement it, or you have no equation? > Why do you need the incremental formulation? Do you have irreversible > non-linearities? Hi Bruno, I would need the incremental formulation because I need to make distinction between loading and unloading stage. Do you see other ways to do that? Anyway not sure that the incremental formulation is the solution of my problem.. > > > Should I simply used the >>> normalVelocity component computed at contact as we do for the shear >>> force? What about the sign convention? Should it remain the same, >>> right? >>> >>> >> Yes and yes. > > > Or if you want to go more precise, you could store previous normal >> deformation, then compute the current one (total formulation), divide by >> Δt to get increment and add it to previous incremental normal >> deformation... >> > Mmmmh... It is not so complicated but wouldn't it be exactly the same? > Un(t+dt)=Un(t) + dt[(Un(t+dt)-Un(t))/dt]? > Or the rotation of the normal makes the difference? In that case I'd store > the previous Un and use the increment dUn=U(t+dt)-U(t) as you suggest. > > Perhaps this would be actually the easiest method, not the most complicated. Thanks for suggestions. > > Bruno > > > _______________________________________________ > Mailing list: > https://launchpad.net/~yade-dev<https://launchpad.net/%7Eyade-dev> > Post to : [email protected] > Unsubscribe : > https://launchpad.net/~yade-dev<https://launchpad.net/%7Eyade-dev> > More help : https://help.launchpad.net/ListHelp >
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