Navigation
Navigate Navigate Navigate Navigate Navigate Navigate Navigate Navigate

IfcMechanicalSteelMaterialProperties

Definition from IAI: This is a collection of mechanical properties related to steel (or other metallic and isotropic) materials.

NOTE: In certain dimensioning calculations a secant modulus is used instead of the Young´s modulus. Essentially, this is the same measure, but with a slightly different physical meaning. In such cases, i. e. when a secant modulus is needed, the value of the inherited attribute YoungModulus should be applied.

HISTORY: New entity in Release IFC2x Edition 2.

Illustration:


Figure 1: Material without yield range


Figure 2: Material with pronounced long yield range

EXPRESS specification:

ENTITY IfcMechanicalSteelMaterialProperties
SUBTYPE OF ( IfcMechanicalMaterialProperties);
YieldStress  :  OPTIONAL IfcPressureMeasure;
UltimateStress  :  OPTIONAL IfcPressureMeasure;
UltimateStrain  :  OPTIONAL IfcPositiveRatioMeasure;
HardeningModule  :  OPTIONAL IfcModulusOfElasticityMeasure;
ProportionalStress  :  OPTIONAL IfcPressureMeasure;
PlasticStrain  :  OPTIONAL IfcPositiveRatioMeasure;
Relaxations  :  OPTIONAL SET [1:?] OF IfcRelaxation;
WHERE
WR31  :  NOT(EXISTS(YieldStress)) OR (YieldStress >= 0.);
WR32  :  NOT(EXISTS(UltimateStress)) OR (UltimateStress >= 0.);
WR33  :  NOT(EXISTS(HardeningModule)) OR (HardeningModule >= 0.);
WR34  :  NOT(EXISTS(ProportionalStress)) OR (ProportionalStress >= 0.);
END_ENTITY;

Attribute definitions:

YieldStress  :  A measure of the yield stress (or characteristic 0.2 percent proof stress) of the material.
UltimateStress  :  A measure of the ultimate stress of the material.
UltimateStrain  :  A measure of the (engineering) strain at the state of ultimate stress of the material.
HardeningModule  :  A measure of the hardening module of the material (slope of stress versus strain curve after yield range).
ProportionalStress  :  A measure of the proportional stress of the material. It describes the stress before the first plastic deformation occurs and is commonly measured at a deformation of 0.01%.
PlasticStrain  :  A measure of the permanent displacement, as in slip or twinning, which remains after the stress has been removed. Currently applied to a strain of 0.2% proportional stress of the material.
Relaxations  :  Measures of decrease in stress over long time intervals resulting from plastic flow. Different relaxation values for different initial stress levels for a material may be given.

Formal Propositions:

WR31  :  Yield stress, if given, shall be non-negative.
WR32  :  Ultimate stress, if given, shall be non-negative.
WR33  :  Hardening module, if given, shall be non-negative.
WR34  :  Proportional stress, if given, shall be non-negative.

Inheritance graph

ENTITY IfcMechanicalSteelMaterialProperties;
ENTITY IfcMaterialProperties;
Material  :  IfcMaterial;
ENTITY IfcMechanicalMaterialProperties;
DynamicViscosity  :  OPTIONAL IfcDynamicViscosityMeasure;
YoungModulus  :  OPTIONAL IfcModulusOfElasticityMeasure;
ShearModulus  :  OPTIONAL IfcModulusOfElasticityMeasure;
PoissonRatio  :  OPTIONAL IfcPositiveRatioMeasure;
ThermalExpansionCoefficient  :  OPTIONAL IfcThermalExpansionCoefficientMeasure;
ENTITY IfcMechanicalSteelMaterialProperties;
YieldStress  :  OPTIONAL IfcPressureMeasure;
UltimateStress  :  OPTIONAL IfcPressureMeasure;
UltimateStrain  :  OPTIONAL IfcPositiveRatioMeasure;
HardeningModule  :  OPTIONAL IfcModulusOfElasticityMeasure;
ProportionalStress  :  OPTIONAL IfcPressureMeasure;
PlasticStrain  :  OPTIONAL IfcPositiveRatioMeasure;
Relaxations  :  OPTIONAL SET [1:?] OF IfcRelaxation;
END_ENTITY;