Damping in a dynamic model?
Damping in a dynamic model?
(OP)
In a static analysis we are solving: [K]{x}={F}
In a dynamic analysis we are solving: [M]{x''}+[C]{x'}+[K]{x}={F}
Now by introducing a quasi static problem, the initial acceleration at the beginning of each iteration is 0. so we are left with: [C]{x'}+[K]{x}={F}
As I have not specified damping in my model is this now:[K]{x}={F} or is damping used somehow in the model to counteract the [M]{x''} ?
I'm rather confused about this and struggling to find a clear definition.
In a dynamic analysis we are solving: [M]{x''}+[C]{x'}+[K]{x}={F}
Now by introducing a quasi static problem, the initial acceleration at the beginning of each iteration is 0. so we are left with: [C]{x'}+[K]{x}={F}
As I have not specified damping in my model is this now:[K]{x}={F} or is damping used somehow in the model to counteract the [M]{x''} ?
I'm rather confused about this and struggling to find a clear definition.





RE: Damping in a dynamic model?
RE: Damping in a dynamic model?
Now i may be incorrect on this, because I've just been looking through the Abaqus manual and it says Quasi static applications introduce inertia to stabalise the system. So im guessing it is counteracting inertia with inertia!?
I'm hoping someone can clear this up?
RE: Damping in a dynamic model?
You're using *Dynamic, application=Quasi-Static? There is a lot of numerical damping in this method.
RE: Damping in a dynamic model?
Here is a quote from the Abaqus theory manual, the section in bold is what is confusing me, as you say damping is being introduced, affecting the inertia (increasing it?)
•Quasi-static applications are primarily interested in determining a final static response. These problems typically show monotonic behavior, and inertia effects are introduced primarily to regularize unstable behavior. For example, the statically unstable behavior may be due to temporarily unconstrained rigid body modes or “snap-through” phenomena. Large time increments are taken when possible to obtain the final solution at minimal computational cost. Considerable numerical dissipation may be required to obtain convergence during certain stages of the loading history.
RE: Damping in a dynamic model?
RE: Damping in a dynamic model?
Is the inertia being introduced a product of the numerical damping you speak of?
RE: Damping in a dynamic model?