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--- doc:user:elements:shells:shell [2013/07/10 13:45] – [Lois] joris
+++ doc:user:elements:shells:shell [2015/01/26 10:23] – joris
@@ Line 1: / Line 1: @@
+====== Shells======
+===== Materials =====
+The definition of shell finite elements follows the same logic as volume elements. First, a material is defined:
+  materialno = materialset.define (number, type)
+  materialno = materialset(number)
+  materialno.put(param, value)
+  materialno.depend(param, fct, Key(Lock)))
+  ...
+|''number'' | material number (must be unique with respect to all elements in ''materialset'', not to shells) |
+|''type'' | shell type (for example ''LinearShellMaterial'') |
+|''param'' | name of the shell parameter (for example ''ELASTIC_MODULUS'') |
+|''value'' | value of the corresponding parameter ''param''|
+|''fct'' | function which characterizes the dependency of the property (optional: no fct if no dependency) |
+|''Lock'' | [[doc:user:general:locks|Lock]] which defines the dependency variable of the property (compulsory if there is a dependency) |
+====  LinearShellMaterial ====
+=== Description ===
+Simple linear elastic law (small strains and displacements).
+=== Parameters ===
+^   Name                                          ^     Metafor Code     ^  Dependency ^
+| Density                                         |   ''MASS_DENSITY''    |              |
+| Young modulus                                   |  ''ELASTIC_MODULUS''  |              |
+| Poisson ratio                                   |   ''POISSON_RATIO''   |              |
+===== Elements =====
+After defining the [[#Materials|material]], it must be associated to an ''[[doc:user:elements:general:def_element_properties|ElementProperties]]'':
+  prp = ElementProperties(typeEl)
+  prp.put(param1, value1)
+  prp.depend(param1, fct1, Lock1)) #facultatif
+  ...
+where
+|''typeEl'' | desired element (for example ''LinearShellFirstDegreeElement'')|
+|''param1''| name of the property associated to the element (for example ''MATERIAL'' to associate the desired material)|
+|''value1''| value of the corresponding property |
+|''fct1''| function which characterizes the dependency of the property (optional: no fct if no dependency) |
+|''Lock1''| [[doc:user:general:locks|Lock]] which defines the dependency variable of the property (compulsory if there is a dependency) |
+====  LinearShellFirstDegreeElement ====
+Linear shell elements (small strains small displacements). 4-nodes linear quadrangles.
+By default, stresses are integrated of ''dim*2'' integration points.
+A thickness must be defined, see table below.
+====  LinearShellSecondDegreeElement ====
+Same as ''LinearShellFirstDegreeElement'' but based on a second order mesh ([[doc:user:geometry:mesh:2d]]).
+The membrane part can be integrated over ''dim*3'' integration points, considering EAS modes, see table below.
+The bending part can be integrated over ''dim*3'' integration points, considering EAS modes, see table below.
+====  LinearShellNineNodeSecondDegreeElement ====
+Same as ''LinearShellSecondDegreeElement'' but based on a 9-nodes second order mesh ([[doc:user:geometry:mesh:2d]]).
+The membrane part can be integrated over ''dim*3'' integration points, considering EAS modes, see table below.
+The bending part can be integrated over ''dim*3'' integration points, considering EAS modes, see table below.
+====  LinearShellSixteenNodeThirdDegreeElement ====
+Same as ''LinearShellNineNodeSecondDegreeElement'' but based on a 16-nodes third order mesh ([[doc:user:geometry:mesh:2d]]).
+The membrane part can be integrated over ''dim*4'' integration points, without EAS modes (no locking), see table below.
+The bending part can be integrated over ''dim*4'' integration points, without EAS modes (no locking), see table below.
+=== Parameters ===
+^   Name                                             ^     Metafor Code     ^  Dependency ^
+| ''MATERIAL''    | Number of the shell material to consider             |  -  |
+| ''STIFFMETHOD'' | Method used to compute the stiffness matrix \\ = ''STIFF_ANALYTIC'' : analytic matrix (default) \\ = ''STIFF_NUMERIC''  : numerical matrix           |  -  |
+| ''GRAVITY_X'' / ''GRAVITY_Y'' / ''GRAVITY_Z'' | gravity  |  time |
+| ''THICKNESS'' | initial thickness  |  -  |
+| ''MEMBRANE_NPG'' | Number of integration points along one direction for membrane solving \\ = 2 classical solving  (second order)\\ = 3 EAS solving with 11 or 13 added modes (8 or 9-nodes second order)\\ = 4 solving without EAS (16-nodes third order)  |  -  |
+| ''BENDING_NPG''  | Number of integration points along one direction for membrane solving \\ = 2 classical solving  (second order)\\ = 3 EAS solving with 22 or 7 added modes (8 or 9-nodes second order)\\ = 4 solving without EAS (16-nodes third order)  |  -  |
+===== Interactions =====
+Shell elements are then generated as [[doc:user:elements:volumes:volumeelement|volume elements]], using a ''FieldApplicator'' interaction. Then, they must be completed with a [[doc:user:elements:shells:interface|DG interface element]] to be consistent.
+  app = FieldApplicator(no)
+  app.push(gObject1)
+  app.push(gObject2)
+  ...
+  app.addProperty(prp)        # association of an ElementProperties
+  interactionset.add(app)     #  the interaction is added in InteractionSet
+or
+  app = interactionset.add(FieldApplicator(no)) #add returns a reference
+  app.push(gObject1)
+  app.push(gObject2)
+  ...
+  app.addProperty(prp)        # association of an ElementProperties
+where
+| ''no''  | number of the ''Interaction'' (which is to say the ''FieldApplicator'') |
+|''gObject1''  | mesh geometric entity where the finite elements are applied |
+| ''prp'' | [[doc:user:elements:general:def_element_properties|Properties]] of shell elements to generate.|