Timeline for Does Finite Element Method use direct stiffness method?
Current License: CC BY-SA 4.0
10 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Oct 26, 2020 at 1:48 | comment | added | alephzero | Part of my problem is that I've never actually come across the term "direct stiffness method" (maybe I learned FEM before people invented it?) For continuum mechanics you are always going to end up with an equation that represents (some sort of generalized stiffness) x (some sort of generalized displacements) = (some sort of generalized forces). What academics and textbook writers want to call it (or some a subset of the possibilities) doesn't really interest me. If you are using FEM for say heat transfer or electromagnetics, there will still be an analogous equation that needs to be solved.. | |
| Oct 25, 2020 at 14:33 | comment | added | upstream | thanks a lot and the alternatives you mention, also ultimately depend on direct stiffness method? in other words, the direct stiffness method is the main fundamental thing? or, even if there was no direct stiffness method (for the sake of example), the other methods could still exist and work? | |
| Oct 23, 2020 at 16:03 | history | edited | NMech | CC BY-SA 4.0 |
added 719 characters in body
|
| Oct 23, 2020 at 15:17 | comment | added | alephzero | Historically the "weak formulation" of FEM for structural mechanics was derived by minimizing the strain energy for an assumed displacement field within each element. But there are alternative weak formulations which have different physical interpretations. In other applications of FEM the weak formulation may not have any "obvious" physical interpretation at all. | |
| Oct 23, 2020 at 15:12 | comment | added | alephzero | The simplest formulation of FEM uses the direct stiffness method but there are alternatives. For example to model incompressible materials there may be variables representing the hydrostatic pressure in the element, which don't belong to physical "nodes" or "grid points" and don't represent "forces" or "displacements." Also FEM can be used for completely different applications, e.g. electromagnetism, where there are no "displacements" of the structure at all. | |
| Oct 23, 2020 at 13:57 | comment | added | upstream | Please see this link: wiki.csiamerica.com/display/kb/Discretization it talks about a direct stiffness method for node-element model, and then it taalks about a finite element model as if two separate things. I thought FEM used direct stiffness method but then when I saw this I was confused. So the methods you talk about above, do not depend on Direct Stiffness at all? | |
| Oct 23, 2020 at 11:15 | history | edited | Algo | CC BY-SA 4.0 |
Fixed some typos and some reformatting.
|
| Oct 23, 2020 at 9:29 | history | edited | NMech | CC BY-SA 4.0 |
added 848 characters in body
|
| Oct 23, 2020 at 9:13 | comment | added | upstream | So then what does FEM use? and what it uses has nothing to do with direct stiffness method or is it still ultimately based on it? | |
| Oct 23, 2020 at 8:24 | history | answered | NMech | CC BY-SA 4.0 |