7.7.3.6 IfcStructuralAnalysisModel

Modèle d'analyse structurelle
Statisches Modell: Idealisierung zur Berechnung der Auflagerreaktionen und des Kräfteverlaufs

The IfcStructuralAnalysisModel is used to assemble all information needed to represent a structural analysis model. It encompasses certain general properties (such as analysis type), references to all contained structural members, structural supports or connections, as well as loads and the respective load results.

Important functionalities for the description of an analysis model are derived from existing IFC entities:

HISTORY  New entity in IFC2x2.
IFC4 CHANGE  Attribute SharedPlacement and informal propositions added, allowing for easy retrieval of the common object placement and for specification of the analysis model's coordiante system before any structural item is instantiated. WHERE rule added.

Informal Propositions:

  1. If one or more structural item (instance of a subtype of IfcStructuralItem) is grouped into an IfcStructuralAnalysisModel, the attribute SharedPlacement shall be provided with a value.
  2. The ObjectPlacements of all structural items which are grouped into the same instance of IfcStructuralAnalysisModel shall refer to the same instance of IfcObjectPlacement as IfcStructuralAnalysisModel.SharedPlacement.
NOTE  This rule is necessary to achieve consistent topology representations. The topology representations of structural items in an analysis model are meant to share vertices and edges und must therefore have the same object placement.
NOTE  A structural item may be grouped into more than one analysis model. In this case, all these models must use the same instance of IfcObjectPlacement.

Common Use Definitions

The following concepts are inherited at supertypes:

 Instance diagram

Object Aggregation

The Object Aggregation concept applies to this entity as shown in Table 624.
PredefinedTypeRelatedObjectsDescription
 IfcStructuralAnalysisModelThis relationship provides the hierarchy between separate (partial) analysis models.

Table 624 — IfcStructuralAnalysisModel Object Aggregation



Group Assignment

The Group Assignment concept applies to this entity as shown in Table 625.
TypeDescription
IfcStructuralItemStructural members and connections assigned to the analysis model.

Table 625 — IfcStructuralAnalysisModel Group Assignment




XSD Specification:

 <xs:element name="IfcStructuralAnalysisModel" type="ifc:IfcStructuralAnalysisModel" substitutionGroup="ifc:IfcSystem" nillable="true"/>
 <xs:complexType name="IfcStructuralAnalysisModel">
  <xs:complexContent>
   <xs:extension base="ifc:IfcSystem">
    <xs:sequence>
     <xs:element name="OrientationOf2DPlane" type="ifc:IfcAxis2Placement3D" nillable="true" minOccurs="0"/>
     <xs:element name="LoadedBy" nillable="true" minOccurs="0">
      <xs:complexType>
       <xs:sequence>
        <xs:element ref="ifc:IfcStructuralLoadGroup" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:attribute ref="ifc:itemType" fixed="ifc:IfcStructuralLoadGroup"/>
       <xs:attribute ref="ifc:cType" fixed="set"/>
       <xs:attribute ref="ifc:arraySize" use="optional"/>
      </xs:complexType>
     </xs:element>
     <xs:element name="HasResults" nillable="true" minOccurs="0">
      <xs:complexType>
       <xs:sequence>
        <xs:element ref="ifc:IfcStructuralResultGroup" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:attribute ref="ifc:itemType" fixed="ifc:IfcStructuralResultGroup"/>
       <xs:attribute ref="ifc:cType" fixed="set"/>
       <xs:attribute ref="ifc:arraySize" use="optional"/>
      </xs:complexType>
     </xs:element>
     <xs:element name="SharedPlacement" type="ifc:IfcObjectPlacement" nillable="true" minOccurs="0"/>
    </xs:sequence>
    <xs:attribute name="PredefinedType" type="ifc:IfcAnalysisModelTypeEnum" use="optional"/>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>

EXPRESS Specification:

ENTITY IfcStructuralAnalysisModel
SUBTYPE OF IfcSystem;
PredefinedType : IfcAnalysisModelTypeEnum;
OrientationOf2DPlane : OPTIONAL IfcAxis2Placement3D;
LoadedBy : OPTIONAL SET [1:?] OF IfcStructuralLoadGroup;
HasResults : OPTIONAL SET [1:?] OF IfcStructuralResultGroup;
SharedPlacement : OPTIONAL IfcObjectPlacement;
WHERE
HasObjectType : (PredefinedType <> IfcAnalysisModelTypeEnum.USERDEFINED) OR EXISTS(SELF\IfcObject.ObjectType);
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

Attribute Definitions:

PredefinedType : Defines the type of the structural analysis model.
OrientationOf2DPlane : If the selected model type (PredefinedType) describes a 2D system, the orientation defines the analysis plane (P[1], P[2]) and the normal to the analysis plane (P[3]). This is needed because structural items and activities are always defined in three-dimensional space even if they are meant to be analysed in a two-dimensional manner.
  • In case of predefined type IN_PLANE_LOADING_2D, the analysis is to be performed within the projection into the P[1], P[2] plane.
  • In case of predefined type OUT_PLANE_LOADING_2D, only the P[3] component of loads and their effects is meant to be analyzed. This is used for beam grids and for typical slab analyses.
  • In case of predefined type LOADING_3D, OrientationOf2DPlane shall be omitted.
LoadedBy : References to all load groups to be analyzed.
HasResults : References to all result groups available for this structural analysis model.
SharedPlacement : Object placement which shall be common to all items and activities which are grouped into this instance of IfcStructuralAnalysisModel. This placement establishes a coordinate system which is referred to as 'global coordinate system' in use definitions of various classes of structural items and activities.
NOTE  Most commonly, but not necessarily, the SharedPlacement is an IfcLocalPlacement whose z axis is parallel with the z axis of the IfcProject's world coordinate system and directed like the WCS z axis (i.e. pointing "upwards") or directed against the WCS z axis (i.e. points "downwards").
NOTE  Per informal proposition, this attribute is not optional as soon as at least one IfcStructuralItem is grouped into the instance of IfcStructuralAnalysisModel.

Formal Propositions:

HasObjectType : The attribute ObjectType shall be given if the predefined type is set to USERDEFINED.

Inheritance Graph:

ENTITY IfcStructuralAnalysisModel
ENTITY IfcRoot
GlobalId : IfcGloballyUniqueId;
OwnerHistory : OPTIONAL IfcOwnerHistory;
Name : OPTIONAL IfcLabel;
Description : OPTIONAL IfcText;
ENTITY IfcObjectDefinition
INVERSE
HasAssignments : SET OF IfcRelAssigns FOR RelatedObjects;
Nests : SET [0:1] OF IfcRelNests FOR RelatedObjects;
IsNestedBy : SET OF IfcRelNests FOR RelatingObject;
HasContext : SET [0:1] OF IfcRelDeclares FOR RelatedDefinitions;
IsDecomposedBy : SET OF IfcRelAggregates FOR RelatingObject;
Decomposes : SET [0:1] OF IfcRelAggregates FOR RelatedObjects;
HasAssociations : SET OF IfcRelAssociates FOR RelatedObjects;
ENTITY IfcObject
ObjectType : OPTIONAL IfcLabel;
INVERSE
IsDeclaredBy : SET [0:1] OF IfcRelDefinesByObject FOR RelatedObjects;
Declares : SET OF IfcRelDefinesByObject FOR RelatingObject;
IsTypedBy : SET [0:1] OF IfcRelDefinesByType FOR RelatedObjects;
IsDefinedBy : SET OF IfcRelDefinesByProperties FOR RelatedObjects;
ENTITY IfcGroup
INVERSE
IsGroupedBy : SET OF IfcRelAssignsToGroup FOR RelatingGroup;
ENTITY IfcSystem
INVERSE
ServicesBuildings : SET [0:1] OF IfcRelServicesBuildings FOR RelatingSystem;
ENTITY IfcStructuralAnalysisModel
PredefinedType : IfcAnalysisModelTypeEnum;
OrientationOf2DPlane : OPTIONAL IfcAxis2Placement3D;
LoadedBy : OPTIONAL SET [1:?] OF IfcStructuralLoadGroup;
HasResults : OPTIONAL SET [1:?] OF IfcStructuralResultGroup;
SharedPlacement : OPTIONAL IfcObjectPlacement;
END_ENTITY;

Examples:

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