SMS:2D Mesh Elements Menu: Difference between revisions

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The Elements Menu includes the following commands:
The ''Elements'' Menu includes the following commands:


{|border="1" style="text-align:left"
; [[SMS:Mesh Element Options|Options]] : General command – set up the default element options.
|-
; [[SMS:Mesh Node Triangulation|Triangulate]] {{Anchor|Triangulate}} : Generation command – triangulates the selected nodes to form triangle elements.
!align="center"|Command
; [[SMS:Mesh Node Triangulation|Optimize Triangulation]] : Generation command – swaps edges of triangular elements to meet the Dulanay criterion.
!align="center"|Description
; [[SMS:Boundary Triangles|Select Thin Triangles]] {{Anchor|Select Thin Triangles|Select Thin}} : General command – selects all thin triangular element that meet the definition specified in the options command.  
|-
 
|align="center"|[[SMS:Mesh Element Options|Options]]  
:During the process of triangulation, a mesh of triangular elements is created around existing nodes. This usually creates triangular elements outside the desired mesh boundary. Many of these exterior triangles are very skinny, and some are virtually invisible. The '''Select Thin Triangles''' command from the ''Elements'' menu finds and selects skinny triangular elements which are on the mesh boundary.
|General command – set up the default element options.
 
|-
:Thin triangles interior to the mesh will not be selected when this command is  performed, since deletion of interior triangles would result in gaps in the mesh. After the thin triangles have been selected, they can be removed by selecting the [[SMS:Macros|'''Delete''']] [[File:Delete Macro Icon.svg|14 px]] macro.
|align="center"|[[SMS:Select Thin Triangles|Select Thin Triangles]]
; Find {{Anchor|Find|Find Element}} : General command – finds the element with a specified ID or location.
|General command – selects all thin triangular element that meet the definition specified in the options command.  
 
|-
:The '''Find Element''' command from the ''Elements'' Menu is used to locate an element either with a specific ID, or surrounding a specific location. When this command is executed the ''Find Element'' dialog opens.
|align="center"|[[SMS:Find Element|Find]]   
 
|General command – finds the element with a specified ID or location.
:When the ''Find by ID'' option is selected, then the element with the specified ID is highlighted in red. If there is no element with the specified ID, then an error message is given. Conversely, when the Find by nearest (x,y) coordinate option is selected, the element which surrounds to the specified (x, y) location is highlighted in red. With either of these methods, if the current tool is the [[SMS:2D Mesh Module Tools|'''Select Elements''']] [[File:SMS Select Mesh Element Tool.svg|16 px]]  tool, then the found element becomes selected in addition to  being highlighted.
|-
; [[SMS:Convert Elements|Merge Triangles]] {{Anchor|Merge Triangles}} : Conversion command – merges triangle pairs that meet the standard for rectangles defined in the options command. Can operate on selected elements.
|align="center"|[[SMS:Assign Material Type|Assign Material Type]]
; [[SMS:Convert Elements|Split Quadrilaterals]] {{Anchor|Split Quadrilaterals}} : Conversion command – splits quadrilateral elements into two triangular elements. Can operate on selected elements.
|General command – requires a selected element. Sets the material type of the selected elements based on the option defined in the options command.
; [[SMS:Convert Elements#Quad8 ↔ Quad9|QUAD8 ↔ QUAD9]] : Conversion command – converts all QUAD8 to QUAD9 elements and vice versa.  Only applies to the FESWMS model. Can operate on selected elements.
|-
; [[SMS:Convert Elements|Linear ↔ Quadratic]] : Conversion command – converts all elements from linear to quad or vice versa. Only applies to TABS and FESWMS models.
|align="center"|[[SMS:Convert Elements|Merge Triangles]]  
; [[SMS:Convert_Elements#Refine|Refine]] {{Anchor|Refine}} : Generation command – splits all selected elements into four elements.
|Conversion command – merges triangle pairs that meet the standard for rectangles defined in the options command. Can operate on selected elements.
 
|-
:At times, there is not enough definition in a finite element mesh. The '''Refine''' command from the ''Elements'' menu splits each of the selected elements into smaller elements. After the selected elements have been refined, SMS automatically creates transitions, from the refined area of higher density to the unrefined area of lower density, using triangular elements. Refine options are set in the [[SMS:Mesh Element Options|''Element Options'']] dialog.
|align="center"|[[SMS:Convert Elements|Split Quadrilaterals]]  
; [[SMS:Convert_Elements#Relax|Relax]] {{Anchor|Relax}} : Generation command – moves all the nodes on the interior of the selected elements to the centroid of their contributing area.  Iterates based on option set in the options command.
|Conversion command – splits quadrilateral elements into two triangular elements. Can operate on selected elements.
 
|-
:The process of creating and editing a finite element mesh can result in [[SMS:Mesh Quality|poor quality elements]]. These elements may have poor interior angles or may violate the area change guideline for adjacent elements. The '''Relax''' command from the ''Elements'' menu can improve adjacent element areas and interior angles by moving nodes. This command moves nodes to improve the elements shape. Several options are available. Relaxation is an iterative process. The number of iterations performed and other options are specified in the [[SMS:Mesh Element Options|''Element Options'']] dialog. If no elements are selected, then the relaxation is performed on all elements in the mesh.
|align="center"|[[SMS:Convert Elements|QUAD8 ↔ QUAD9]]
 
|Conversion command – converts all QUAD8 to QUAD9 elements and vice versa.  Only applies to the FESWMS model. Can operate on selected elements.
; Fix Bad Area Transitions : Generation command – removes nodes that cause bad area transitions as defined in the element quality control.
|-
 
|align="center"|[[SMS:Convert Elements|Linear ↔ Quadratic]]
:The process of creating and editing a finite element mesh can result in [[SMS:Mesh Quality|poor quality elements]]. These elements may violate the area change guideline for adjacent elements, specifically, the area of the smaller of the adjacent elements divided by the area of the large element may be less than a recommended ratio. This ratio is set in the ''Mesh Quality'' entry of the ''2D Mesh Display Options''.
|Conversion command – converts all elements from linear to quad or vice versa. Only applies to TABS and FESWMS models.
 
|-
:The '''Fix Bad Area Transitions''' command from the  ''Elements'' menu can improve adjacent element areas by removing nodes. The adjacent elements of each node in the mesh are examined for guideline violations. If more that one are found, a calculation is made to determine if the removal of the node and the retriangulation this would cause would maintain compliance for the newly formed elements and their neighbors. If this is the case the node is removed.
|align="center"|[[SMS:Mesh Node Triangulation|Triangulate]]  
; Assign Material Type : General command – requires a selected element. Sets the material type of the selected elements based on the option defined in the options command.
|Generation command – triangulates the selected nodes to form triangle elements.
 
|-
:Each element in the mesh is assigned a material type. The default material ID can be set in the ''Element Options'' dialog. A selected element is assigned a new material type by choosing the '''Assign Material Type''' command from the ''Elements'' menu. If the ''Assign default material'' option is selected in the ''Element Options'' dialog, then the default material is  automatically assigned to the selected element. If the ''Prompt for material when  assigning'' option is selected in the ''Element Options'' dialog, then the ''Materials Data'' dialog opens from which a material type can be chosen.
|align="center"|[[SMS:Optimize_Triangulation_(Data_Menu)|Optimize Triangulation]]
 
|Generation command – swaps edges of triangular elements to meet the Dulanay criterion.
==Obsolete Commands==
|-
The following commands have been removed from the current version of SMS.
|align="center"|[[SMS:Convert Elements|Refine]]
; Rectangular Patch : Patch command – creates elements from four selected node strings. See the article [[SMS:Patches|Patches]] for more information. See also [[SMS:Element Patch Workflow|Element Patch Workflow]].
|Generation command – splits all selected elements into four elements.
; Triangular Patch : Patch command – creates elements from three selected node strings. See the article [[SMS:Patches|Patches]] for more information. See also [[SMS:Element Patch Workflow|Element Patch Workflow]].
|-
|align="center"|[[SMS:Relax Elements|Relax]]
|Generation command – moves all the nodes on the interior of the selected elements to the centroid of their contributing area.  Iterates based on option set in the options command.
|-
|align="center"|[[SMS:Fix Bad Area Transitions|Fix Bad Area Transitions]]
|Generation command – removes nodes that cause bad area transitions as defined in the element quality control.
|-
|align="center"|[[SMS:Rectangular Patch|Rectangular Patch]]
|Patch command – creates elements from four selected node strings.
|-
|align="center"|[[SMS:Triangular Patch|Triangular Patch]]  
|Patch command – creates elements from three selected node strings.
|}






==Related Topics==
==Related Topics==
*[[SMS:Mesh Module|Mesh Module]]
* [[SMS:Mesh Module|Mesh Module]]
* [[SMS:Mesh Element Options|Element Options Dialog]]




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[[Category:SMS 2D Mesh|2]]
[[Category:SMS 2D Mesh|E]]
[[Category:SMS Menus|2]]
[[Category:SMS Menus|2]]

Latest revision as of 20:15, 18 March 2022

The Elements Menu includes the following commands:

Options
General command – set up the default element options.
Triangulate
Generation command – triangulates the selected nodes to form triangle elements.
Optimize Triangulation
Generation command – swaps edges of triangular elements to meet the Dulanay criterion.
Select Thin Triangles
General command – selects all thin triangular element that meet the definition specified in the options command.
During the process of triangulation, a mesh of triangular elements is created around existing nodes. This usually creates triangular elements outside the desired mesh boundary. Many of these exterior triangles are very skinny, and some are virtually invisible. The Select Thin Triangles command from the Elements menu finds and selects skinny triangular elements which are on the mesh boundary.
Thin triangles interior to the mesh will not be selected when this command is performed, since deletion of interior triangles would result in gaps in the mesh. After the thin triangles have been selected, they can be removed by selecting the Delete Delete Macro Icon.svg macro.
Find
General command – finds the element with a specified ID or location.
The Find Element command from the Elements Menu is used to locate an element either with a specific ID, or surrounding a specific location. When this command is executed the Find Element dialog opens.
When the Find by ID option is selected, then the element with the specified ID is highlighted in red. If there is no element with the specified ID, then an error message is given. Conversely, when the Find by nearest (x,y) coordinate option is selected, the element which surrounds to the specified (x, y) location is highlighted in red. With either of these methods, if the current tool is the Select Elements SMS Select Mesh Element Tool.svg tool, then the found element becomes selected in addition to being highlighted.
Merge Triangles
Conversion command – merges triangle pairs that meet the standard for rectangles defined in the options command. Can operate on selected elements.
Split Quadrilaterals
Conversion command – splits quadrilateral elements into two triangular elements. Can operate on selected elements.
QUAD8 ↔ QUAD9
Conversion command – converts all QUAD8 to QUAD9 elements and vice versa. Only applies to the FESWMS model. Can operate on selected elements.
Linear ↔ Quadratic
Conversion command – converts all elements from linear to quad or vice versa. Only applies to TABS and FESWMS models.
Refine
Generation command – splits all selected elements into four elements.
At times, there is not enough definition in a finite element mesh. The Refine command from the Elements menu splits each of the selected elements into smaller elements. After the selected elements have been refined, SMS automatically creates transitions, from the refined area of higher density to the unrefined area of lower density, using triangular elements. Refine options are set in the Element Options dialog.
Relax
Generation command – moves all the nodes on the interior of the selected elements to the centroid of their contributing area. Iterates based on option set in the options command.
The process of creating and editing a finite element mesh can result in poor quality elements. These elements may have poor interior angles or may violate the area change guideline for adjacent elements. The Relax command from the Elements menu can improve adjacent element areas and interior angles by moving nodes. This command moves nodes to improve the elements shape. Several options are available. Relaxation is an iterative process. The number of iterations performed and other options are specified in the Element Options dialog. If no elements are selected, then the relaxation is performed on all elements in the mesh.
Fix Bad Area Transitions
Generation command – removes nodes that cause bad area transitions as defined in the element quality control.
The process of creating and editing a finite element mesh can result in poor quality elements. These elements may violate the area change guideline for adjacent elements, specifically, the area of the smaller of the adjacent elements divided by the area of the large element may be less than a recommended ratio. This ratio is set in the Mesh Quality entry of the 2D Mesh Display Options.
The Fix Bad Area Transitions command from the Elements menu can improve adjacent element areas by removing nodes. The adjacent elements of each node in the mesh are examined for guideline violations. If more that one are found, a calculation is made to determine if the removal of the node and the retriangulation this would cause would maintain compliance for the newly formed elements and their neighbors. If this is the case the node is removed.
Assign Material Type
General command – requires a selected element. Sets the material type of the selected elements based on the option defined in the options command.
Each element in the mesh is assigned a material type. The default material ID can be set in the Element Options dialog. A selected element is assigned a new material type by choosing the Assign Material Type command from the Elements menu. If the Assign default material option is selected in the Element Options dialog, then the default material is automatically assigned to the selected element. If the Prompt for material when assigning option is selected in the Element Options dialog, then the Materials Data dialog opens from which a material type can be chosen.

Obsolete Commands

The following commands have been removed from the current version of SMS.

Rectangular Patch
Patch command – creates elements from four selected node strings. See the article Patches for more information. See also Element Patch Workflow.
Triangular Patch
Patch command – creates elements from three selected node strings. See the article Patches for more information. See also Element Patch Workflow.


Related Topics