2D Frames and Beams
Internal forces (bending moment, shear force, normal force), bearing reactions and the state of displacement for planar and statically indeterminate supporting structures are calculated.
The finite element method (FEM) is used for this.
To the model data
A model to be examined is specified by:
- All points at which the structure is supported, where loads are introduced and where there are cross-sectional jumps.
When entering the point coordinates, one can access the coordinates of other points via x1,y1,x2,y2 etc.
The mouse can be used: double click to create new nodes, click drag to move existing nodes.
- A list of the elements of the structure. For each element its 2 endpoints must be specified.
Its material index is also required (e.g. 1 if you only use one material).
The last entry (type) determines whether it is a beam (type 0), a truss (type 3) or a beam with a hinge at the front (type 1) or at the back (type 2).
You can also create elements by clicking and dragging with the mouse.
- Material information. These are the cross-sectional area A, the moment of inertia I and the modulus of elasticity.
- Load information. The load on the respective nodes can be specified here.
- Support information. Here you can tie point-related both in x- and y-direction as well as against rotation.
The program is actually primarily designed for the investigation of frame structures.
Frame structures usually only consist of "type 0" beam elements that are connected to each other in a rigid manner.
However, with the help of "type 3" you can also use truss bars for the elements.
Furthermore, with the help of "type 4" you can also use spring elements.
For springs, a material must be assigned that has the corresponding spring rate instead of the elastic modulus E.
Furthermore the cross section A and the sectional areas moment I must be set to 0.
There are no units when entering data. The user is responsible for providing data on compatible units,
e.g. point coordinates in m, loads in N, cross-sections in m² and the modulus of elasticity in N/m².
Displacements then arise in m, bar forces in N.
To the results
The signs of the output displacements and support reactions also refer to a global xy coordinate system, which is aligned by default.
The normal force N, the shear force V and the bending moment M are determined and output as internal forces for beam elements.
In addition to the tabular output of the internal forces, you can also click on the individual elements and the associated internal forces are then displayed.
Since the normal force and the shear force are constant in each element (the program does not recognize line loads), only one value is given for each element.
The bending moment is different. It generally changes linearly from node to node, so 2 values are output here.
In order to be able to assign them correctly, they are indexed with the global node number.
For truss elements, the shear force and the bending moment are always 0.
For this reason, these internal forces are not output for truss elements.
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