DxfSecProp (Dxf Cross-Section Properties)
Born from the passion for the finite element method and the need for a rigorous method for the characterization of the arbitrary beam cross-sections, this online calculation tool uses a known format for importing section shapes. The input of the shape and the material can be done via DXF.
Dxf file format
The supported format is DXF version 11/12. Any BLOCK that is not anonymous (anonymous block names start with an asterisk *) is read and becomes a section.
The shape of the cross-section must be drawn with: 2d polylines made of lines and circumference arcs; circles. Of these elements are considered the coordinates X and Y.
How to draw the cross-section.
The materials can be assigned to the elements associating them with the layers with appropriate names. For the calculation of the properties it is sufficient to know the parameter ν (Poisson's coefficient), and if the material is not recognized a material is assigned ν=0.3.
Examples: "HE200A-HE220A S235.dxf", "schuco ADS65.dxf".
The properties of the cross-sections are divided into two parts:
Properties determined in an exact manner based on contour integrals, the drawing elements are used directly:
The results refer to two coordinate system:
- elastic modulus;
- plastic modulus;
- moment of inertia;
- centroid with coordinates with respect to the reference system in BLOCK;
- principal axes of inertia;
- radius of rotation;
- coordinates of the most stressed edges with respect to the centroid.
- origin in the centroid and oriented axes in X and Y of the local coordinate system of BLOCK, referring to X and Y in subscripts;
- origin in the centroid and oriented axes with the principal axes of inertia, referring to X0 and Y0 in subscripts.
Properties determined in a approximate manner by FEM method, a mesh of triangular elements with 6 nodes is generated:
The results refer to a coordinate system with origin in the shear center and axes oriented with the principal shear system, reference to XC and YC in the subscripts.
- shear center with coordinates with respect to the coordinate system of BLOCK;
- shear principal system;
- shear areas (stiffness);
- primary and secondary torsion constant;
- warping constant.
Main bibliographic references
- J.Murín, V.Kutiš. An effective finite element for torsion of constant cross-sections including warping with secondary torsion moment deformation effect (Engineering Structures - Volume 30, Issue 10, October 2008, Pages 2716-2723). https://doi.org/10.1016/j.engstruct.2008.03.004
- V.G.Mokos, E.J.Sapountzakis. Secondary torsional moment deformation effect by BEM (International Journal of Mechanical Sciences - Volume 53, Issue 10, October 2011, Pages 897-909). https://doi.org/10.1016/j.ijmecsci.2011.08.001
- M. Ciambrone, A.S. Petrolo, R. Casciaro (Ottobre 2001). Calcolo automatico dei coefficienti elastici per il modello di trave di De Saint-Venant in presenza di interazione taglio-torsione (Labmec, report n.22). Università della Calabria.
- A.S. Petrolo, R. Casciaro. 3D beam element based on Saint Venànt’s rod theory (Computers & Structures - Volume 82, Issues 29–30, November 2004, Pages 2471-2481). https://doi.org/10.1016/j.compstruc.2004.07.004