Form and function: The significance of material properties in the design of tensile fabric structures

Abstract

Coated woven fabrics have been used in state-of-the-art structures for over 40 years yet their design is not codified and relies heavily on experience and precedent. The mechanical behaviour of fabrics is non-linear and time dependent, with assumed or highly simplified material properties commonly used for analysis.The shape of a tensile fabric canopy is fundamental to its ability to resist all applied loads in tension. Increasingly Architects are moving away from conventional fabric forms, utilising lower levels of curvature and new materials. This paper considers the importance of material properties and structural geometry in the design and analysis of tensile fabric structures. Three typical tensile forms are examined: the conic, hyperbolic paraboloid ('hypar') and barrel vault. Whilst the barrel vault demonstrates the expected result that minimally curved structures are inefficient and highly sensitive to changes in materials properties, the hypar exhibits more complex behaviour with the structural action varying dramatically with changes in geometry, material properties and patterning (fabrication) direction. For conic structures the feasible geometries that can be attained using 'soap film' form-finding is established, which combined with checks for ponding provide a range of geometric parameters for the efficient design of conic structures.

Stiffness Parameters for Architectural Fabrics: An Analysis of Two Determination Procedures

“…This wide spectrum of results highlights the importance of getting an accurate determination of stiffness parameters, and it confirms existing results. 11 Design engineers might face these variations, yet they would not know which stress and deformation values to rely upon. As shown in Table 8, the degree of variation does not decrease significantly with increasing curvature.…”

Influence of the membrane structure plan shape on the displacements under point load

“…Najveća opasnost pri ovim deformacijama nisu prevelika izduženja materijala, već mogućnost da dođe do oštećenja membrane zbog kontakta sa drugim površinama. Druga opasnost je moguća pojava mesta sa kojih voda ne bi mogla da otiče zbog nepovoljne zakrivljenosti površine [3,4]. Pri proveri maksimalnih deformacija projektanti konstrukcije se uglavnom oslanjaju na prethodna iskustva iz prakse.…”

Biaxial Testing for Fabrics and Foils

“…The membrane structures field is regarded a continuous and rapid evolution due to the constant interest of the producers in new materials characterised by higher levels of resistance, durability, weld ability, handiness and translucently at a feasible price (Bridgens 2005;Campioli and Zanelli 2009). The development of new products is not facilitated by the scant number of international standards for technical textiles.…”

“…The scientific production of these research groups in the last decade allowed the validation of the effectiveness of the plane biaxial test based on cruciform samples (Reichard et al 1953;Checkland et al 1958;Klein 1959;Freeston et al 1967;Bridgens et al 2004a), the development of a framework of reference for the necessary tests (Blum et al 2004;Bridgens et al 2004b;Galliot and Luchsinger 2010a, b), the analysis of the principal parameters involved in a testing procedure (Bridgens 2005), the investigation of innovative models of calculus and representation Gosling and Bridgens 2007;Galliot and Luchsinger 2009;Galliot and Luchsinger 2010a, b;Uhlemann and Stranghöner 2013) and the reliability of the current procedures and equipment (Uhlemann et al 2011;Bridgens et al 2012).…”