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楼主 |
发表于 2015-5-20 09:30:25
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3D新版本发布
Most important to know right now:
** You define a solid region by it's boundary surfaces (like you define
a surface by a closed boundary loop of curves).
** 3D permeability is defined as follows:
- The vector [r3x,r3y,r3z] is used to define the k33 direction, which is
normal to the plane in which the reinforcement lies, e.g. it is the
thickness direction. When this plane has been established, vector
[r1x,r1y,r1z] is projected on it for the k11 direction. The direction of
k22 is perpendicular to k11 in the plane defined by [r3x,r3y,r3z].
** When you define a region, a 3D tetrahedral mesh is automatically
generated, but *not* optimized. The mesh parameter 'e/R' defines the
edge/radius ratio of tets that will be split by inserting an additional
vertex. Use e/R = 0 for no internal vertices (e.g. the tetrahedral mesh
uses only vertices on the boundary surfaces) and e/R = 1 for an
isotropic mesh. Sometimes the mesh generator fails. You can try to fix
this by playing with the Min and Max parameters, and using the [Bounding
box] option. In general, the mesh generator will always succeed to
generate a mesh unless there is a huge difference between the edge size
in your wireframe and/or very small angles.
** Before you run the simulation, optimize the mesh using the [Clean]
button in the mesh generator panel. If you do not do this, the solver
will run much slower and may even terminate before filling is completed.
In any case, expect trouble when the mesh contains slivers: elements
with 0% quality (use the shaded plot 'Element quality' option and shrink
tets to see them). A sliver typically looks like a flat rectangle and
has very small (almost zero) volume but no short edges. On such
elements, the pressure gradient can not be accurately calculated by
linear interpolation in sliver thickness direction.
You have the following parameters and options:
- cN = maximum number of iterations the optimizer will run
- qMin = worst acceptable element (100% is perfect, 0% is extremely bad)
- qEps = measure for improvement of the mesh, independent of the worst
element. This defines what the optimizer will consider an improvement,
even if the worst tet can not be improved.
- [Add points] button: controls whether the optimizer is allowed to add
more points in the region. You can turn this off if you want to have a
coarse tetrahedral mesh combined with a fine(r) surface mesh. However,
it reduces the possibilities for the optimizer to eliminate bad tets.
** Combining runners and shell elements with 3D tets is possible, but
you have to be careful: combination of a single runner with tets (e.g.
using a curve that is an edge of a region) may not produce the results
you want, similar to using an injection point on a surface. Make sure
you define dimensions properly, by also using boundary surfaces to
define injection channels. Tip: you can model the mesh using the top
surface of a region, you don't need to define separate regions. |
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