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Aug
31
comment Error with ND Solve
Is this "simple harmonic motion"? I'm trying to figure out what the differential equations are solving.
Aug
17
comment Boundary value problem: complicated functionals
@SayaniMajumdar As late as this may be, out of curiosity, this looks like the Euler-Lagrange equation. May I ask what you are trying to minimize via this Euler-Lagrange equation? What physics are you trying to capture? A Lennard-Jones 6-12 potential?
Aug
16
comment Equal flow boundary conditions
Can you give us an idea as to what these two equations are trying to solve? Are they meant to be coupled somehow? The significance of the equation itself may allow for clues to help you.
Aug
12
comment FEM Solution desired for “Plate with orifice” deflection: Application of Boundary Conditions and use of Regions
If I were to modify this problem to have a point load, would I (just have to) use DirichletCondition`` for the load p0/De` at x=L && Y=h?
Aug
12
comment FEM Solution desired for “Plate with orifice” deflection: Application of Boundary Conditions and use of Regions
Let us continue this discussion in chat.
Aug
12
comment FEM Solution desired for “Plate with orifice” deflection: Application of Boundary Conditions and use of Regions
I would gladly share with you (and other mathematica developers) what I am using Mathematica+FEM for if you wish. I am a faculty in a technological university and one of my wishes is to have people use Mathematica for more than just as "scrap paper"
Aug
12
comment FEM Solution desired for “Plate with orifice” deflection: Application of Boundary Conditions and use of Regions
Thank you for confirming my deduction of XY plane.
Aug
12
comment FEM Solution desired for “Plate with orifice” deflection: Application of Boundary Conditions and use of Regions
I doubt that a 3D model would provide a different solution given the axisymmetric nature of the plate and the load applied. But this is definitely food for thought. It is interesting (and perhaps) to note that this FEM model in Mathematica surpasses in computation speed what is obtained through Hyperworks. Hyperworks doesn't allow the application of boundary conditions as derivatives and one is required to choose loose terms such as "free boundary" or "fixed boundary". My hope is to get mathematica significant recognition in my university's mechanical engineering dept.
Aug
12
comment FEM Solution desired for “Plate with orifice” deflection: Application of Boundary Conditions and use of Regions
This is interesting. However, the XZ plane in your method is the plane of the screen (deducing from deflection direction)?
Aug
10
comment FEM Solution desired for “Plate with orifice” deflection: Application of Boundary Conditions and use of Regions
@user21 Yes, for this problem, the deflection boundary conditions are 4th and 3rd order. I am not entirely sure how I could use the plane stress/strain operator problem to do this. I'll look into it.
Aug
10
comment FEM Solution desired for “Plate with orifice” deflection: Application of Boundary Conditions and use of Regions
@user21 I am thinking this is a plane strain problem. And even then the boundary conditions may need to be beyond second order. Maybe in wrong about the latter and I will check.
Aug
8
comment FEM Solution desired for “Plate with orifice” deflection: Application of Boundary Conditions and use of Regions
Yes, you are correct. Initializing my parameters allowed it to run correctly. However, I am still curious as to how I could use Regions and FEM to solve such a problem.
Aug
8
comment Why should the spatial derivative order of the ODE *not* exceed two?
@MichaelE2 The question that this question sprouted from (my question) suggests that the utility of mma be displayed by the use of FEM EVEN if it is a rather trivial problem that needs no complicating through the use of Regions. I understand your point though.
Aug
8
comment FEM Solution desired for “Plate with orifice” deflection: Application of Boundary Conditions and use of Regions
No it doesn't: Encountered non-numerical value for a derivative at r == 0.005., but I suppose I'll amend my question: I would like to use a domain as specified by a region difference. the idea is to plot the deflections on the domain to show the utility of FEM to solve such problems. I hope that makes sense. The link you provide is relevant.
Aug
8
comment FEM Solution desired for “Plate with orifice” deflection: Application of Boundary Conditions and use of Regions
@chris Likely you are correct. I probably haven't used this correctly. However, I am also concerned about the other double and triple derivative conditions. Is there some way I can appoint these boundary conditions on the domain $\Omega$ without needing to resort to the (seemingly cryptic ;)') DirichletCondition` and NeumannValue types.
Jul
29
comment Potential flow over cylinder with FEM: Pressure field is flipped
Is there some way I could choose the range of data represented by the PlotLegend? Thank you for your answer; I'll try this very soon.
Jul
29
comment Specifying NeumannValue for Axial load instead of transverse load (Plane Stress situation)
@user21 You make a good point. I'll try this with MeshOrder
Jul
28
comment Potential flow over cylinder with FEM: Pressure field is flipped
@marcob yikes my mistake. The code I commented out may be treated as "old version". Sorry about that.
Jul
10
comment Specifying NeumannValue for Axial load instead of transverse load (Plane Stress situation)
Yes, I just realized that. Now I am on the hunt for a generalized Hookes law that describes a cantilever with transverse load (original mma example). Would you mind putting the final statement in your answer "The results are unchanged from those produced by the code in the question but differ from that of the test case, because the differential equations are different." in bold? This is vital. I was under the impression that the plane stress operator in full would still solve the linear deflection situation while it solves only the transverse load condition.
Jul
10
comment Specifying NeumannValue for Axial load instead of transverse load (Plane Stress situation)
I suppose I am unable to understand what the x and y directions are. Is x along the thickness of this bar element and y along its span? If so, should the load be an +xload? (of course the difference between - and + loads would be the sign of the deflection alone)