Finite Element Model

Overview

The Model class is designed to provide a convenient encapsulation of all objects which define an entire finite element model. This includes such information as element connectivity, node coordinates in Mesh, element and material properties in ElementProperty and MaterialProperty, load in LoadCase, restraint and initial condition cases in RestraintCase and InitialConditionCase, etc. It provides a single container for all other core objects required to describe a finite element model.

The functions associated with a Model object are the following.

Set objects
- setMesh() - Register the Mesh object.
- setUnits() - Register the Units object
- setGlobalProperties() - Register the GlobalProperty object
- setCoordinateSystems() - Register the HashTable container of CoordinateSystem objects
- setRestraintCases() - Register the HashTable container of RestraintCase objects
- setMultipointConstraintCases() - Register the HashTable container of MultipointConstraintCase objects
- setLoadCases() - Register the HashTable container of LoadCase objects
- setInitialConditionCases() - Register the HashTable container of InitialConditionCase objects
- setMaterialProperties() - Register the HashTable container of MaterialProperty objects
- setElementProperties() - Register the HashTable container of ElementProperty objects
- setTableFunctions() - Register the HashTable container of TableFunction objects
- setElementData() - Register the HashTable container of ElementData objects
- setNodeSets() - Register the HashTable container of IdTranslator nodes sets
- setElementSets() - Register the HashTable container of IdTranslator elements sets
- setElementEntitySets() - Register the HashTable container of IdTranslator element entities sets
- setInteractionPairs() - Register the HashTable container of InteractionPair objects
- setRigidBodies() - Register the HashTable container of RigidBody objects
- setAnalyticSurfaces() - Register the HashTable container of AnalyticSurface objects
- setSolutionPropertiesList() - Register the List container of SolutionProperty objects
- setMeshInterface() - Register the MeshInterface object
Get objects
- getMesh() - Get the Mesh object.
- getUnits() - Get the Units object
- getGlobalProperties() - Get the GlobalProperty object
- getCoordinateSystems() - Get the HashTable container of CoordinateSystem objects
- getRestraintCases() - Get the HashTable container of RestraintCase objects
- getMultipointConstraintCases() - Get the HashTable container of MultipointConstraintCase objects
- getLoadCases() - Get the HashTable container of LoadCase objects
- getInitialConditionCases() - Get the HashTable container of InitialConditionCase objects
- getMaterialProperties() - Get the HashTable container of MaterialProperty objects
- getElementProperties() - Get the HashTable container of ElementProperty objects
- getTableFunctions() - Get the HashTable container of TableFunction objects
- getElementData() - Get the HashTable container of ElementData objects
- getNodeSets() - Get the HashTable container of IdTranslator nodes sets
- getElementSets() - Get the HashTable container of IdTranslator elements sets
- getElementEntitySets() - Get the HashTable container of IdTranslator element entities sets
- getInteractionPairs() - Get the HashTable container of InteractionPair objects
- getRigidBodies() - Get the HashTable container of RigidBody objects
- getAnalyticSurfaces() - Get the HashTable container of AnalyticSurface objects
- getSolutionPropertiesList() - Get the List container of SolutionProperty objects
- getMeshInterface() - Get the MeshInterface object
- getElementThickness() - Query for element nodal thickness values
- getElementOffset() - Query for element nodal offsets
Define and query library type
- setSourceType() - Set source library type
- getSourceType() - Get source library type
General functions
- write() - Write the contents of the model object to an input file
- deleteStorage() - Delete all objects set in the model
- print() - Print the object content
- printSummary() - Print a summary of the object content
- getErrorCode() - Get error code

Use setMesh() to register the Mesh and/or setMeshInterface() to register MeshInterface objects which define the element connectivity and associations and node coordinates. If a Mesh object is registered and a MeshInterface object is not registered, Model will internally create and register a MeshInterface object tied to the Mesh object. The Mesh or MeshInterface object currently registered with the Model object can be queried using getMesh() or getMeshInterface() respectively. The GlobalProperty object is used to define global properties. The Units object is used to define the units for physical quantities.

Node sets, element sets, element edge and face sets are entered into series of IdTranslator objects. A name associated with each set may be specified using the setName() function. The node and element indices (not user Id) are entered into the IdTranslator objects. The IdTranslator objects are, in turn, entered into HashTable objects with a user defined integer key. If there is a useful integer associated with the node or element set, this integer should be used as the HashTable key otherwise use keys starting from one. The HashTable objects of node set, element set, element edge and face set are registered in the Model object using setNodeSets(), setElementSets() and setElementEntitySets() respectively.

Element and material properties are entered into one or more ElementProperty and MaterialProperty objects respectively. There should be an ElementProperty object for each element property identifier and a MaterialProperty object for each material property identifier. The ElementProperty objects are then entered into a HashTable object using the element property identifier as a key. The MaterialProperty objects are also entered into a HashTable object using the associated material property identifier as a key. The two HashTable objects containing the ElementProperty and MaterialProperty objects are then registered in the Model object using setElementProperties() and setMaterialProperties().

Certain vector valued functions may be stored in one or more TableFunction objects. These functions may represent relationships such as temperature dependent material properties or load factor time functions. The TableFunction objects are entered into a HashTable object in a manner similar to ElementProperty and MaterialProperty objects using an integer curve identifier as key. The HashTable object containing the TableFunction objects is then registered in the Model object using setTableFunctions().

Analytical surfaces may be stored in one or more AnalyticSurface objects. There should be an AnalyticSurface object for each analytical surface in the model. Each AnalyticSurface object is stored into a HashTable with an integer key. This HashTable, in turn, is stored in the Model object using setAnalyticSurfaces().

Rigid bodies may be stored in one or more RigidBody objects. There should be a RigidBody object for each rigid body in the model. Each RigidBody object is stored into a HashTable with an integer key. This HashTable, in turn, is stored in the Model object using setRigidBodies().

Some element properties, such as shell thickness or offset vectors, may be specified on an element-by-element basis using ElementData objects. Each element property so defined is installed in a HashTable object using the property type as a key. Currently supported property types are as follows:

THICKNESS - Thickness.
OFFSET - Nodal scalar offset.
NORMAL - Normal vector.
FIBER_BOTTOM - Location of shell bottom, usually for output.
FIBER_TOP - Location of shell top, usually for output.
ELEMENT_VECTOR - Element local system orientation vector.
MATERIAL_VECTOR - Material local system orientation vector.
END_A_VECTOR - End point A position or offset vector.
END_B_VECTOR - End point B position or offset vector.
OFFSET_VECTOR - Nodal offset vector.

To obtain the thickness at all nodes of a given element, use the function getElementThickness(). Similarly, to obtain the offset vectors at each node of a given element, use the function getElementOffset().

A similar technique is used for load, restraint and initial condition cases. A LoadCase object is instanced for each load case and entered into a HashTable object using the load case identifier as a key. A RestraintCase object is instanced for each restraint case and entered into a HashTable object using the restraint case identifier as a key. A MultipointConstraintCase object is instanced for each multipoint constraint case and entered into a HashTable object using the multipoint constraint case identifier as a key. An InitialConditionCase object is instanced for each initial condition case and entered into a HashTable object using the initial condition case identifier as a key. Register these HashTable objects with the Model using setLoadCases(), setRestraintCases(), setMultipointConstraintCases() and setInitialConditionCases().

Contact pairs, or more generally interaction pairs, may be entered into sets of InteractionPair objects. The InteractionPair objects are entered into a HashTable object using an integer key. Register this HashTable object with the Model using setInteractionPairs().

The properties of solution steps are entered into a sequence of SolutionProperty objects. The sequence of SolutionProperty objects is entered into a List object in the order in which the solution steps are to be performed. The first solution step is given identifier 1 in the List object, the second step identifier 2, etc. Register this List object with the Model using setSolutionPropertiesList(). Any List object registered with the Model object can be queried using getSolutionPropertiesList().

The function deleteStorage() is provided as a convenient mechanism for deleting all objects set in the Model object. This includes all HashTable objects set and the objects they in turn contain, and all List objects set using getSolutionPropertiesList() and the objects they in turn contain.

The write() function is provided to write the contents of the model object to industry standard file formats. An example of such a format is ABAQUS input file or NASTRAN bulk data format:

Gap element property mapping

Gap element property mapping
Gap element	ABAQUS	NASTRAN
`INITIAL_GAP`		`PGAP U0`
`PRELOAD_FORCE`		`PGAP F0`
`COMPRESSION_STIFFNESS` (> 0)	`*SURFACE BEHAVIOR, PRESSURE-OVERCLOSURE=TABULAR`	`PGAP KA`
`COMPRESSION_STIFFNESS` (= 0)	`*SURFACE BEHAVIOR, PRESSURE-OVERCLOSURE=HARD`
`TENSION_STIFFNESS`		`PGAP KB`
`TRANSVERSE_STIFFNESS`		`PGAP KT`
`STATIC_FRICTION_COEFFICIENT_Y_AXIS`	`*FRICTION, ANISOTROPIC`	`PGAP MU1`
`STATIC_FRICTION_COEFFICIENT_Z_AXIS` (!= 0)		`PGAP MU2 (TMAX = -1.)`
`STATIC_FRICTION_COEFFICIENT_Z_AXIS` (!= 0)		`PGAP MU2 (TMAX = 0.)`
`KINETIC_FRICTION_COEFFICIENT_Y_AXIS`		ignored
`KINETIC_FRICTION_COEFFICIENT_Z_AXIS`		ignored
`NO_SEPARATION`	`*SURFACE BEHAVIOR, NO SEPARATION`	ignored
`NO_SLIP`	`*FRICTION, ROUGH`	ignored

If COMPRESSION_STIFFNESS > 0., then the INITIAL_GAP, PRELOAD_FORCE and TENSION_STIFFNESS properties are used to create a tabular pressure-overclosure definition under the *SURFACE BEHAVIOR keyword.

Note that the MASTER option does not exist for element constraints.

Class Members Descriptions

The currently available Model enumerations and functions are described in detail in this section.

class Model

Finite Element Model.

Public Types

enum class ElementDataType

Model element data properties.

Values:

enumerator THICKNESS: Thickness.

enumerator OFFSET: Nodal scalar offset.

enumerator NORMAL: Normal vector.

enumerator FIBER_BOTTOM: Location of shell bottom, usually for output.

enumerator FIBER_TOP: Location of shell top, usually for output.

enumerator ELEMENT_VECTOR: Element local system orientation vector.

enumerator MATERIAL_VECTOR: Material local system orientation vector.

enumerator END_A_VECTOR: End point A position or offset vector.

enumerator END_B_VECTOR: End point B position or offset vector.

enumerator OFFSET_VECTOR: Nodal offset vector.

Public Functions

ErrorCode getErrorCode()

Return the current ErrorCode of the Model object.

Returns:	`ErrorCode` - The current error code, or `NONE` if no error.

Status setMesh(Mesh *mesh)

Set a pointer to a Mesh attribute object. By default, all finite element topology, connectivity, node coordinate and node and element association queries are made through the Mesh attribute object. If the MeshInterface object is registered, it is used by the write() function for basic finite model queries rather than the Mesh object.

Parameters:	mesh – Pointer to the Mesh object to be registered.
Returns:	Status

Parameters:	mesh – The Mesh object registered.
Returns:	Status

Parameters:	units – Pointer to the Units object to be registered.
Returns:	Status

Parameters:	units – The Units object registered.
Returns:	Status

Finite Element Model

Overview

Class Members Descriptions

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