Tension structures undergo significant deformation in order to carry applied loading, typically due to wind or snow.

This necessitates a geometrically non-linear analysis capability, coupled with the ability to model the effects of cable slackening and membrane wrinkling. These requirements are handled naturally by the inTENS software suite.

The stress defined state of the equilibrium form model is first replaced by its equivalent elastic model with the same distribution of prestress throughout the membrane and cable system. The membrane elastic properties have been previously established by biaxial testing.

The design load cases are defined from appropriate national codes of practice, with wind tunnel tests frequently used to establish the wind loading coefficients for larger and more complex structural forms. Particular surface loading values are associated with the membrane elements. The calculated wind forces are perpendicular to the surface, and are therefore updated during analysis to take account of the deformations of that surface. Slope dependent snow loading is updated in the same way.

The results of the analysis are the element stresses and nodal deflections, which are presented in output files listing all values. These may be post-processed into a more readily used collated form, and examined graphically.