Measuring the aero-elastic movement of fabric structures: An experimental approach

The use of fabric structures and the further development of analytical investigations increased a lot during the last decade. However, a high entry threshold regarding the behaviour, application and design process of fabric structures is still present. Advancements in the technology of fabric structures are continuously taking place, trying to obtain one unified code applicable as a general guideline. Wind analysis of fabric structures is currently based on rough approximations referring to flat, mono-, duopitch or spherical shapes of the Eurocode EN 1991-1-4. Wind is a highly dynamic load case in its nature, being difficult to characterize or predict. The global goal is to understand how the wind will affect these lightweight fabric structures, to ensure an improved structural safety over the lifespan of the design. Presently, little experimental work has been done on the response of fabric structures under turbulent wind loads and how structural parameters affect this behaviour. This research enabled, with the support of Digital Image Correlation (DIC), to obtain a method in which precise membrane movements are being detected. It was important to gain knowledge, in the optical background of the system, by understanding the important link between its intrinsic and extrinsic parameters. This ensured a stable base to achieve good measurement conditions and hence, reliable results. The innovative study led to the obtainment of a measuring methodology serving as a framework for future experiments, regarding the displacements on flexible models.