Karamba3D

1116 members

Description

Karamba3D is a parametric structural engineering tool which provides accurate analysis of spatial trusses, frames and shells.

Current Version: 1.3.2 (July 9 2019)

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Shell ForceFlow resultant computation (vs PrincStress)

by Alessio Lombardi

Nov 23, 2016

In the following image, A, B and C are the Sources and ForceDirs in the ShellLineResults component.

Quoting Karamba manual, "If there are two ForceFlow (FF) lines, the resultant force between those in a predefined direction stays constant". This is what makes FF different from the PrincStress Lines.

It is then clear that:

 resultant force between A–B = resultant force between B–C

1) If I had only one Source point, therefore only one FF line, how would the resultant force be computed for that line? What would be the boundary for computing the resultant force? Would Karamba take all the length of the beam, measured orthogonally from the SourceDir input?

2) Consequently, what is the correct way to compute the resultant force associated with each FF line in Karamba?

  • up

    Karamba3D

    Dear Alessio,

    the condition of constant resultant force holds for two flow force lines each. Therefore it is not the case that 'resultant force between A–B = resultant force between B–C'.

    In order to calculate the force flow lines it is not necessary to determine the resultant force. If you want to determine for example the flow line in a liquid you can simply follow the path of one of its particles.

    You could calculate the resultant force by integrating the stresses in the section perpendicular to the direction supplied for calculating the force flow lines.

    Best,

    Clemens

    2

    Nov 28, 2016