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;