Moment of inertia
The symbol for this is I and the unit in SI is mm 4 , cm 4 , m 4 (i.e. L 4 ).
There are 3 types of moments of area:
- Axial second moment of area:
The axial moments of area Iy and Iz describe the stiffnesses against bending about the local axes y and z. The deflection as well as the occurring stresses are smaller as soon as the moment of inertia increases with a constant load. The y-axis is often referred to as the "strong" axis because the moment of inertia Iy is greater here.
Iy Second moment of area about the y-axis z Vertical distance of the y-axis to the element dA Iz Second moment of area about the z-axis y Vertical distance of the z-axis to the element dA
- Biaxial moment of area
The biaxial moment of area is often referred to as the surface centrifugal moment, the moment of deviation, the moment of surface deviation or simply as the centrifugal moment. It is used to calculate deformations on asymmetrical sections and to determine non -symmetrical loads on any sections.
- Polar second moment of area
A second moment of area, which describes the resistance of a closed circular ring cross -section or of circular cross -sections against torsion, is referred to as a polar moment of inertia. The polar moment of area Ip is composed of the two moments of area Iy and Iz . It is also to be equated with the torsional moment of inertia IT for circular and circular ring cross-sections, which describes the stiffness against rotation about the longitudinal axis.
For asymmetrical sections, the moments of inertia are displayed around the cross-section's principal axes u and v.
In RFEM, it is possible to modify stiffnesses for materials, cross -sections, members, load cases, and load combinations in many places.
SHAPE-THIN Table "6.2 Classification of the Cross-Section According to EN 1993-1" and Stress Diagram
The material model Orthotropic Masonry 2D is an elastoplastic model that additionally allows softening of the material, which can be different in the local x- and y-direction of a surface. The material model is suitable for (unreinforced) masonry walls with in-plane loads.
- Why do I get large differences for the design of a longitudinally stiffened buckling panel in comparison with the German and Austrian National Annex?
- How are the signs for the release results of a line release and line hinges interpreted?
- How can I create a curved or arched section?
- How can I perform the stability analysis in RF‑/STEEL EC3 for a flat bar supported on edges, such as 100/5? Although the cross-section is rotated by 90° in RFEM/RSTAB, it is displayed as lying flat in RF‑/STEEL EC3.
- How are hot-dip galvanized components considered for fire resistance in the RF‑/STEEL EC3 add-on module?
- How is the rotational stiffness of a buckling stiffener determined in PLATE‑BUCKLING?
- Is it possible to manually specify a longitudinal reinforcement for design in RF‑PUNCH Pro?
- Is it possible to design the support pressure or the compression perpendicular to the grain in RX‑TIMBER?
- After the design with RF‑/TIMBER Pro, I optimized a cross-section. Why is the utilization of the optimized cross-section exceeded now?
- Can I simulate the cracked state of a concrete cross-section for a bending beam with the "Isotropic Nonlinear Elastic 1D" material model?
The structural engineering software for design of frame, beam and truss structures, performing linear and nonlinear calculations of internal forces, deformations, and support reactions
Structural engineering software for finite element analysis (FEA) of planar and spatial structural systems consisting of plates, walls, shells, members (beams), solids and contact elements