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*STIFFENER
Data format:
One line with up to an arbitrary number of values
NGR IMAT IPRO1 NEL IEL(1)..IEL(NEL)
Status :
Optional
Purpose :
To efine stiffener elements in the mesh
Restriction :
The elements must have been previously defined and must have physical properties.
Details :
| Parameter | Description |
|---|---|
| NGR | user number of the group defining the stiffener |
| IMAT | material number of the stiffener |
| IPRO1 | property number of the stiffener |
| NEL | number of elements of the stiffener |
| IEL(i) | number of the element I |
It is recommended to use binodal beams for a stiffener (see notes).
Note
A stiffener is a varying section beam which is modeled by a series of constant section elements. Each element is given the dimension of the stiffener corresponding to the middle point of this element.
For the binodal beams, the internal loads are integrated according to the Gauss method with a single point located in the middle. The bending stiffness is therefore the exact stiffness at that point.
The trinodal beams require two Gauss points. These points are located near both beam ends. Their contribution is then integrated with the same bending stiffness which is not the real stiffness at those points.
This is why it is better to use binodal beams for a stiffener.
