Nowadays fiber reinforced plastics (composites) are increasingly used for thick-walled, tubular components.
For dimensioning of such tubes typically either relatively complex finite element calculations are performed or the classical laminate theory is used without checking, whether its assumption of a thin wall is permissible for the geometry at hand.
This toolbox enables the accurate calculation of stresses in thick-walled composite tubes under axisymmetric loading conditions (internal pressure, external pressure, axial force and twisting moment)
A consideration of isotropic materials shows that, in dependence of the load situation 20% difference between the thick- and thin-walled calculation results for a radius ratio (outer radius / inside radius) of R = 1.2. This radius ratio is often regarded in the literature as permissible limit for a thin-walled approximate calculation.
In anisotropic materials, differences between thin and thick-walled calculation of up to 60% are possible for R = 1.2 Basically, the larger the radius ratio and the larger the anisotropy of the material, the greater the differences in the stresses and strains of the two calculation methods.
Jakobi, R.: Zur Spannungs-, Verformungs- und Bruchanalyse an dickwandigen rohrförmigen Bauteilen aus Faser-Kunststoff-Verbunden, Fortschrittsberichte VDI, Reihe 5: Grund- und Werstoffe Nr. 126, 1987