Differences

This shows you the differences between two versions of the page.

--- doc:user:geometry:mesh:1d [2015/01/07 17:53] – [1D mesh elements : CellLineMesher] boman
+++ doc:user:geometry:mesh:1d [2016/03/30 15:23] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
-====== 1D Meshers ======
+====== 1D Meshers (Curves) ======
-===== MeshedPoints =====
+FIXME __Mesh Elements versus Finite Elements__: these two notions are different and should not be misunderstood. A mesh is made of geometric cells, the mesh elements. A finite element is a physical entity, which is supported by a mesh element. In Metafor, this is a two-steps method: first, the mesh is created, then the finite elements are applied to the mesh (this second step is done once the integration is started and programmed in the ''InteractionSet'').
-==== Simple mesher - SimpleMesher1D ====
+Automatic meshers create nodes and mesh cells from the geometry. Metafor meshers are quite basic but still useful to mesh simple geometries, to avoid using external software.
-Automatic meshers create mesh elements from the geometry. Metafor meshers are quite basic but still useful to mesh simple geometries, to avoid using external softwares.
+===== Generating nodes (& cells) =====
-:!: __Mesh Elements versus Finite Elements__: these two notions are different and should not be misunderstood. A mesh is made of geometric cells, the mesh elements. A finite element is a physical entity, which is supported by a mesh element. In Metafor, this is a two-steps method: first, the mesh is created, then the finite elements are applied to the mesh (this second step is done once the integration is started and programmed in the ''InteractionSet'').
+==== SimpleMesher1D ====
-Meshing lines is done with the command:
+{{:doc:user:ico-beginner.png?40 |Beginner}}
+Basic meshing of ''Curves'' can be done with the following command:
-   SimpleMesher1D(curveset(number)).execute(ne, d, cells)
+   SimpleMesher1D(curve).execute(ne, d=1.0, gencells=False)
-|''number'' | number of the line to be meshed |
+with
-|''ne''	| number of segments |
+|''curve''    | [''Curve''] | the curve to be meshed |
-|''d'' 	| distribution (ratio between the length of the last and first segments) -  [default=1.0] |
+|''ne''	      | [''int'']   | number of segments |
-|''cells'' | Boolean which governs whether 1D meshed elements should be generated [default=False] |
+|''d'' 	      | [''float''] | distribution (ratio between the length of the last and first segments) |
+|''gencells'' {{:doc:user:ico-advanced.png?18|Advanced}} | [''bool'']  | generate mesh cells (e.g. for 1D springs)  |
+{{:doc:user:ico-advanced.png?40 |Advanced}}
 Likewise, meshing at a higher degree (second or third):
    HighDegreeSimpleMesher1D(curveset(number), degree).execute(ne, d, cells)
-Note : The ''d'' parameters is used to create segments ''d'' times smaller at the beginning of the curve than at its end. Therefore, the curve orientation matters.
+Note : The ''d'' parameter is used to create segments ''d'' times smaller at the beginning of the curve than at its end. Therefore, the curve orientation matters.
 ==== Density mesher - DensityMesher1D ====
+{{:doc:user:ico-advanced.png?40 |Advanced}}
 The density mesher is used to mesh a line while specifying the length of the desired segment as a function of the curvilinear abscissa. This is done in two steps:
@@ Line 46: / Line 50: @@
 The parameter ''False'', passed to ''execute'', is used to generate only nodes, and not segments. This is important to be consistent with 2D meshing and for defo-defo contact.
-=== HybridDensityMesher1D ===
+==== HybridDensityMesher1D ====
+{{:doc:user:ico-advanced.png?40 |Advanced}}
 The way to create a grid of $n$ intervals on a curve starts with specifying the distribution of points on this curve. This is done by specifying the distribution of the curve parameter ${u(\xi) \; 0 \leq \xi \leq n+1}$ in the parametric domain, corresponding to the points of the curve ${\boldsymbol{x}(u) \; 0 \leq u \leq 1}$ in the physical domain. The final task is to specify ${u(\xi) \; 0 \leq \xi \leq n+1}$ such as ${\boldsymbol{x}(u(\xi)) \; 0 \leq \xi \leq n+1}$ is a good parametrization of the curve $\boldsymbol{x}(u)$.
@@ Line 99: / Line 103: @@
 |''kJ''	|attraction factor|
-===== 1D Mesh elements =====
+===== Generating cells alone =====
+Generating cells is only useful if you plan to define 1D elements (such as springs) in your model.
-==== 1D mesh elements : manually ====
+==== Manual definition ====
 {{:doc:user:ico-advanced.png?40 |Advanced}}
-To manually create a 1D mesh element based on two mesh points,
+To manually create a 1D cell based on two mesh points,
   mesh.define(no, CELL_LINE, grp, no1, no2)
-| ''no'' | number of the 1D mesh element |
+| ''no''  | number of the 1D cell |
 | ''grp'' | entity which will contain the mesh element (for example a ''[[doc:user:geometry:user:selections|Group]]'') |
-| ''no1'' | number of the first mesh point |
+| ''pt1'' | first mesh point |
-| ''no2'' | number of the second mesh point |
+| ''pt2'' | second mesh point |
-==== 1D mesh elements : CellLineMesher ====
+==== CellLineMesher ====
 {{:doc:user:ico-advanced.png?40 |Advanced}}
-The ''CellLineMesher'' can also generate a 1D mesh element based on two sets of mesh points.
+The ''CellLineMesher'' is used to generate a series of 1D cells linking two sets of mesh points.
-The ''CellLineMesher'' is a mesher which, based on two meshed geometric entities, generates objects of ''CELL_LINE'' type in the topology. Every ''MeshPoint'' of the first entity will be linked by a ''CELL_LINE'' to every ''MeshPoint'' of the second entity.
+The ''CellLineMesher'' is a mesher which, based on two meshed geometric entities, generates objects of ''CELL_LINE'' type. Every mesh point of the first entity will be linked by a ''CELL_LINE'' to every ''MeshPoint'' of the second entity.
 The ''interaction'' generated on these ''CELL_LINE'' will be defined by the first geometric entity passed to the ''CellLineMesher''.