FAQ 002840 EN 9 April 2019

Andreas Niemeier General RFEM RF-FORM-FINDING

Why does not RFEM find an equilibrium for an upward load on a downwardly curved membrane roof?


The downwardly curved, synclastic roof geometry is numerically stable for downward loads. Loads in the direction of the arch ultimately increase the tensile load in the membrane and thus stabilize the system.

Loads against the curved shape of the roof reduce the tensile load in the membrane. If in this case the membrane tensile load approaches zero, numerical difficulties arise due to the sole, membrane tensile strength of the element used. In this case, the solution process reacts with poor convergence, instability reports, or positive definite Jacobian matrix messages.   


Unstable Jacobite Membrane -removing


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RFEM Main Program
RFEM 5.xx

Main Program

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

Price of First License
3,540.00 USD
RFEM Tensile Membrane Structures

Add-on Module

Form-finding of tensile membrane and cable structures

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1,750.00 USD