Experimental and numerical fracture behaviour of CNC-manufactured OSB beams

The WikiHouse Skylark system is an open-source, CNC-manufactured interlocking-plate structural system without metal connectors with strong prospects for sustainable prefabricated housing. We present the first experimental and numerical study of full-scale Skylark beams manufactured from OSB (oriented strand board); a material of greater circularity potential than the plywood for which the system was originally developed. Nine large-scale specimens across three cross-sections, heights, and spans were tested under monotonic four-point bending to failure. Failure is consistently governed by the castellated joints at the bottom flange, identifying this as the critical design region for the updated Skylark geometry. Analytical and finite element models are developed and show good agreement with the observed responses. Collectively, the results provide the first full-scale validation of the structural performance of OSB Skylark beams and establish a quantitative basis for their use in sustainable prefabricated housing.