# Section properties

### Material properties

 Emod Modulus of elasticity in tension or compression (Young's modulus) N/mm2 Poisson Poisson's ratio (ν) is a measure of the Poisson effect, the deformation (expansion or contraction) of a material in directions perpendicular to the specific direction of loading Unitless G Shear modulus or modulus of rigidity as G = Emod / (2 · (1+Poisson)) N/mm2 Rho Density or the volumetric mass density or specific mass of material (ρ) kN/m3 LinExp Coefficient of linear thermal expansion C°m

### Section properties

#### General properties

Area Cross-sectional area (A) of mono-material cross section mm2
n · Area Cross-sectional area (n · A) of multi-material cross section  mm2
lyz Product of inertia. Product of inertia is a feature of a cross section that describes an imbalance relative to a defined set of coordinate axes. Product of inertia is equal to zero for the axis symmetrical cross section mm4

Qy, Qz,
Qu, Qv

Maximal first moment of area with respect to the global and principal axis of the cross section. Calculation of the Additional-advanced property may be restricted by technical module mm3
p External perimeter of a cross section mm
pint Inner perimeter of a cross section, i.e. perimeter of the holes of the hollow core cross section  mm
g Weight per length unit of the cross section bar N/mm
EA Axial stiffness as the ratio of the axial load to axial deflection N

Ycg, Zcg,
Ucg, Vcg

Coordinate of the axis system origin point is placed in the center of gravity of the cross section. Coordinate is calculated from the left bottom corner of the cross section mm

Y+, Y-, Z+, Z-,
U+, U-, V+, V-

Core distances from the neutral axis system origin point defined in the global (Y-Z) or principal (U-V) axis system to the most top (-), bottom (+), left (-) or right (+) corner of the cross-section core. Axial loading is placed on the section core, doesn’t affect appearance of the bending actions mm

#### Flexural (bending) properties

Yac, Zac,
Uac, Vac

Coordinate of the neutral axis system origin point. Coordinate is calculated from the left bottom corner of the cross section mm

Iy, Iz,
Iu,Iv

Second moment of area with respect to the global and principal axis of the cross section mm4
ryy, rzz,
ruu, rvv
Radius of gyration with respect to the global and principal axis of the cross section. Radius of gyration is valuable in calculating buckling load of a beam/column under compression mm

ey+, ey-, ez+, ez-,
eu+, eu-, ev+, ev-

Distances from the neutral axis system origin point in the global (Y-Z) or principal (U-V) axis system to the most top (-), bottom(+), left(-) or right (+) corner of the cross section mm

Wy+, Wy-,
Wz+, Wz-,
Wu+, Wu-,
Wv+, Wv-

Elastic section modulus with respect to neutral axis in the global (Y-Z) or principal (U-V) axis system for the most top (-), bottom(+), left(-) or right (+) corner of the cross section mm3
EIyy, EIzz,
EIuu, EIvv
Bending stiffness as the resistance of a member against bending deformation with respect to the global and principal axis of the cross section N·mm2
Alpha Rotation angle of the principal axis system deg
Ycg, Zcg,
Ucg, Vcg
Coordinate of the axis system origin point is placed in the center of gravity of the cross section. Coordinate is calculated from the left bottom corner of the cross section mm
QQy, QQz,
QQu,QQv
Value of      with respect to the global or principal axis of the cross section. Value is used for the Mcr calculation (prEN 1993-1-1#C.2.1). Calculation of the Additional-advanced property may be restricted by technical module mm

#### Plastic properties

Ypl, Zpl,
Upl, Vpl
Distance to plastic neutral axis with respect to centroid based global (Y-Z) or principal (U-V) neutral axis mm
Wy,pl, Wz,pl,
Wu,pl, Wv,pl
Plastic section modulus mm3

#### Shear properties

Avy, Avz Shear area with respect to the global axis of the cross section. Shear area is represented for the mono-material cross section only. Calculation of the Additional-advanced property may be restricted by technical module mm2
ys, zs Shear center coordinate with respect to centroid of the cross section. Calculation of the Additional-advanced property may be restricted by technical module, takes more computer resources and is performed on press of "Additional" button mm

#### Torsion properties

Ip Polar moment of inertia mm4
It Torsional constant. Calculation of the Additional-advanced property may be restricted by technical module, takes more computer resources and is performed on press of "Additional" button mm4
GIp Torsional stiffness N·mm2
Iw Warping section modulus with respect to shear center. Calculation of the Additional-advanced property may be restricted by technical module, takes more computer resources and is performed on press of "Additional" button mm6

By using the multi-material cross section, some section properties are reduced to the single (base) material,  based on specific reduction formulas: see Bi-material reduction.