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--- doc:user:elements:specials:spring [2013/07/09 17:09] – joris
+++ doc:user:elements:specials:spring [2023/06/20 19:00] (current) – papeleux
@@ Line 1: / Line 1: @@
+====== Spring ======
+===== Materials  =====
+A spring (linear or not, with or without failure criterion) is defined is the same way as volume materials:
+  materialno = materialset.define (number, type)
+  materialno = materialset(number)
+  materialno.put(param, value)
+  materialno.depend(param, fct, Key(Lock)))
+  ...
+|''number'' | spring number (must be unique for all element in ''materialset'', not just for springs) |
+|''type'' | type of spring (for example ''ConstantSpringMaterial'') |
+|''param'' | name of the spring parameter (for example ''SPRING_FK'') |
+|''value'' | value of the corresponding parameter|
+|''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) |
+==== ConstantSpringMaterial ====
+=== Description ===
+Linear spring
+=== Parameters ===
+^   Name                                          ^     Metafor Code     ^  Dependency ^
+| Stiffness|  ''SPRING_FK''  |  -  |
+| Damping coefficient   |  ''SPRING_FC''  |  -  |
+==== NonLinearSpringMaterial ====
+=== Description ===
+Nonlinear spring.
+=== Parameters ===
+^   Name                                          ^     Metafor Code     ^  Dependency ^
+| Amplitude of the associated **stiffness force** as a function of the elongation. This force is described by the associated ''nf'' function. Careful, this function must also be described for negative elongation (compression)                      |  ''SPRING_FK''  |  ''GD''  |
+| Amplitude of the associated **damping force** as a function of the elongation rate. This force is described by the associated ''nf'' function. Careful, this function must also be described for negative elongation rates         |  ''SPRING_FC''  |  ''GV''  |
+Remarks :
+  * ''SPRING_FK'' et ''SPRING_FC'' are forces and not stiffness/damping coefficient (unlike ConstantSpringMaterial)
+  * the dependency is written as :
+''materialset(no).depend(SPRING_FK,fct1,Field1D(TX,RE))''\\
+''materialset(no).depend(SPRING_FC,fct2,Field1D(TX,GV))''
+==== BreakingSpringMaterial ====
+=== Description ===
+Nonlinear spring with failure criterion.
+=== Parameters ===
+^   Name                                          ^     Metafor Code     ^  Dependency ^
+| Stiffness|  ''SPRING_FK''  |  -  |
+| Damping coefficient   |  ''SPRING_FC''  |  -  |
+| Maximal length of the spring. Above, failure appears and forces are equal to zero. This length can depend on time though ''nf''    |  ''SPRING_LMAX''  |  ''TM''  |
+===== Element=====
+Once the [[#Materials|material]] is defined, 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 ''Spring[2|3]DElement'')|
+|''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) |
+==== Spring[2|3]DElement ===
+Nonlinear spring element. Associates two nodes with a stiffness. No axisymmetric correction is implemented. They must be associated with a ''[[#Interaction|FieldApplicator]]'' interaction.
+=== Parameters ===
+^   Name                                          ^     Metafor Code     ^  Dependency ^
+| ''MATERIAL''    | Number of the spring material to consider             |  -  |
+| ''STIFFMETHOD'' | Method used to compute the stiffness matrix\\ = ''STIFF_ANALYTIC'' : analytic matrix (default)\\ = ''STIFF_NUMERIC''  : numerical matrix \\ <del>Not applicable, only the numerical one exists !</del> |  -  |
+| ''SPRING_LI''   | Defines the spring length "at rest" (relevant or not depending on the value of SPRING_CLI) |  |
+| ''SPRING_CLI''  | Defines the way the "length at rest" (''lengthIni '') will be computed \\ assume L0 is the measured length at the end of the preprocessing (geometrical length)\\ = 0 : lengthIni = L0 (default - do not require SPRING_LI)\\ = 1 : lengthIni = SPRING_LI \\ = 2 : lengthIni = L0 * SPRING_LI \\ = 3 : lengthIni = L0 + SPRING_LI                           |  -  |
+===== Interaction =====
+Finally, once the ''Spring[2|3]DElement'' ''[[#Element|ElementProperties]]'' is defined, the corresponding interaction is generated with the ''FieldApplicator''. To do so, the corresponding geometric mesh element must be generated using [[doc:user:geometry:mesh:1D]]. Once done, the interaction can be defined and included in the ''interactionset'':
+  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 [[#spring_2_3_delement|spring elements]] to generate.|