Dynamic vs Quasi-static Crack propagation problem
Dynamic vs Quasi-static Crack propagation problem
(OP)
I'm trying to formulate the crack propagation problem for metal components of rotating machinery. Being an Electrical engineer, I started off learning fem and then fracture mechanics recently. Hence, forgive me for my ignorance.
I'm trying to find a guideline, or some sort of reasoning, as to when to use a quasi-static (iterative methods) for crack propagation vs a full-blown dynamic problem for crack propagation.
Many thanks in advance for your responses.
I'm trying to find a guideline, or some sort of reasoning, as to when to use a quasi-static (iterative methods) for crack propagation vs a full-blown dynamic problem for crack propagation.
Many thanks in advance for your responses.





RE: Dynamic vs Quasi-static Crack propagation problem
for stable crack growth (LEFM), it's enough to know the material toughness and to approach it in small enough increments (iterative ?). but i wouldn't "fuss" the very small crack life available as the crack appraoches critical (heck, fatigue ignores the stable crack growth all together !).
any help ?
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RE: Dynamic vs Quasi-static Crack propagation problem
I read that quasi-static is accurate enough unless the crack growth is 'brutal'. Is that so? Does the natural modes of the component in any way effect the actual growth?
Thanks once again.
RE: Dynamic vs Quasi-static Crack propagation problem
"natural modes" ... means vibration induced stresses ?
Quando Omni Flunkus Moritati
RE: Dynamic vs Quasi-static Crack propagation problem
By quasi-static I mean a XFEM problem to be solved with time update via level set methods. So that, I take time updates, without doing the dynamic problem (only using [K]{u}={R}). Yes, by "natural modes" I mean vibration induced stresses. I'm not going to depend on "factors" because I want this model to be time sensitive for factors like changes in loads, speed, lubrication, temperature etc.
Thanks.
RE: Dynamic vs Quasi-static Crack propagation problem
I also think that something known as cepstrum analysis has something to do with condition monitoring. Personally from what little you have written here I think this is really what you are looking for.
RE: Dynamic vs Quasi-static Crack propagation problem
RE: Dynamic vs Quasi-static Crack propagation problem