A form finding method for post formed timber grid shell structures.

D'Amico, Bernardino; Kermani, Abdy; Zhang, Hexin

Abstract

Timber grid shells provide efficient ways of covering large openings with relatively small amount of materials. With three-dimensional CAD software, it is now possible to model a free-form surface and discretize it in smaller straight elements, thus postponing the design of the node-connections geometry to the manufacturing process (i.e. by Computer-Aided-Manufacturing). A "low-tech" method for building free-form timber grid shell structures with standardized connections is that of assembling an initially flat grid of continuous rods and then, post-forming (bending) it in a double curved shape. Accordingly, the latter method doesn't require high-tech manufacturing processes. However, being the final shape influenced by equilibrium of the internal forces, a form-finding procedure is required. A novel "facilitating" numerical framework is introduced in this paper: For a given continuous reference shape, a geometrically similar discrete model is found by implementation of the Dynamic Relaxation method. Numerical methods to the finding of grid cutting pattern, as well as, a Newton-Raphson method to assess the allowable timber cross-section, are illustrated.

Citation

D'Amico, B., Kermani, A., & Zhang, H. (2014, July). A form finding method for post formed timber grid shell structures. Presented at World Conference Timber Engineering

• Conference Name: World Conference Timber Engineering
• Start Date: Jul 10, 2014
• End Date: Aug 14, 2014
• Publication Date: 2014
• Deposit Date: Jan 20, 2015
• Publicly Available Date: Jan 20, 2015
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.13140/2.1.3949.8888
• Keywords: Free-form structures; grid shell; solid wood; form-finding; parametric design; dynamic relaxation; Newton-Raphson
• Public URL: http://researchrepository.napier.ac.uk/id/eprint/7496
• Contract Date: Jan 20, 2015