Textile structures owe their structural stability to the double-curvature geometry of the membranes. By applying this principle to any point across its surface, the membrane is tensioned in two opposing directions making the structure resistant to loading, be it wind or snow and ensures the stability of the entire structural unit. Thus, during severe weather conditions, the membrane can be left in place and noise caused by flapping is avoided. Because they’re structurally stable, premature ageing through wear and tear of the membranes is prevented and the comfort of the end user is assured.
Illustration of the principle of double curvature
Fig. 1. A ball held by four ropes in a plane is easily deflected vertically.
Fig. 2. Lifting two opposing ropes and lowering the others leaves the ball is stabilized in all directions.
This process, when applied to a membrane, creates an anticlastic (saddle-shaped) curvature, a hyperbolic paraboloid, more commonly known as the hypar.
Anticlastic – the two axes are of opposing curvature
The most common forms are the hypar, the cone and the arch. The design of most lightweight textile structures is usually based on one or a combination of these forms.
Inflatable fabric structures are synclastic forms where the constant air pressure forms them into dome-shaped structures.
Synclastic – the two axes are curved in the same direction