Structural modelling of deformable screens for large door openings

Abstract

The mathematical modelling of deformable, permeable screen doors was explored to assess their behaviour under wind loading. A load-response model was proposed whereby the wind load was modelled using a simplified approach that allowed it to be approximated as a uniformly distributed pressure load with empirical modification factors applied to relate it to the real case of a door on a building. Several approaches were adopted to model the mechanical behaviour of the door system in response to load, including discrete models based on mass-spring systems, continuum models based on the membrane equations (including tension modulation in some cases), and computational models using finite element packages. The primary aim of the work was to determine the distribution of wind load to the door's supporting `tabs' and estimate a failure wind speed. The mass-spring model and the membrane models without tension modulation both generated unrealistic deflection magnitudes in response to wind load, but could be calibrated in future work, and then used to obtain an estimate of the total force on the tabs. A tension-modulated version of the membrane model performed better with regards to deflected shape and magnitude, but time constraints meant that the load on the tabs was not calculated. Preliminary validation experiments were undertaken and deflected shape and magnitude were successfully measured in response to given wind speeds.