Composite amalgam: development of joining approaches for additively manufactured fibre composites in complex geometry in architecture

Abstract This paper presents an iterative, research-through-design methodology for advancing joint design in multi-material additively manufactured fibre composite systems. The research responds to a condition inherent to large-scale additive manufacturing and composite lamination, where robotic reach envelopes, print-bed dimensions and curing protocols impose mandatory divisions on continuous geometries, producing tectonic seams that become structurally critical in multi-material systems where materials are deposited and cured in sequential stages. The methodology combines robotic additive manufacturing of polymer shells with carbon fibre reinforcement through sequential cycles of prototyping, mechanical testing and full-scale application. Seven joint iterations were developed across two experimental stages, the first establishing an embedded spine and plate configuration and the second responding to fabrication and performance observations from Ghost Tectonics, the full-scale architectural demonstrator. Three-point flexural mechanical testing established that configurations with a continuous internal carbon fibre spine substantially outperformed those omitting or interrupting the spine, with the embedded spine and plate configuration achieving the highest flexural performance in the series. The research demonstrates that joint performance is governed by the interaction of reinforcement continuity, fastener integration and interface control. The joint is therefore treated as a tested architectural detail, where structural behaviour and tectonic expression are developed through the same assembly logic. Thus, the research advances frameworks for materially integrated joints that operate across the scales of digital design, composite fabrication, and architectural tectonics.