The FlectoLine module: Transferring glass fiber-reinforced polymer/elastomer hybrid composites to responsive architectural outdoor applications

• Hingeless, pneumatically actuated shading system based on fiber-reinforced composites • Material meets requirements profile for building envelopes and outdoor usage • 101 modules operate autonomously based on target parameter-based control logic Previous studies have shown that responsive façades are essential for improving building energy efficiency and occupant comfort. It is also known that implementing hingeless, compliant deformation mechanisms can significantly reduce the maintenance required for such systems. However, previous studies have been limited to the technical implementation of laboratory demonstrators. Up to now, there is a lack of results on the actual feasibility of hingeless adaptive systems in the built environment. This study presents the development of FlectoLine, a pneumatically actuated façade module composed of a glass fiber-reinforced polymer/elastomer hybrid laminate, functionalized with organic photovoltaic sheets. The development is based on the initial validation of the materials-system in terms of outdoor and building requirements: weathering stability and flammability (class B2/E); followed by a functional validation proving energy-efficient compliance for full shading (deflection 90 ∘ ) at a moderate actuation pressure of approx. 0.45 bar. Building up on this, a performance validation of scaled functional FlectoLine element is conducted with regard to usage requirements: fatigue testing (35,000 cycles, corresponding to 30 years lifetime) and wind load resistance. FlectoLine is a full-scale outdoor façade demonstrator with 101 modules at the Botanical Garden in Freiburg (Germany) and thereby proves robustness and scalability of pneumatically actuated compliant mechanisms under real climatic conditions. This study thereby presents an example of how material innovations can be translated into building envelopes for dynamic solar shading that are responsive, low-maintenance, and energy-active.