Manufacturing theory for advanced grid stiffened structures

Lattices of rigidly connected ribs, known as advanced grid stiffened (AGS) structures, have many advantages over traditional construction methods, which use panels, sandwich cores and/or expensive frameworks. The technology behind these structures has progressed significantly during the past five years to the point where these structures are being integrated into operational systems. Two tooling methods for fabricating these structures using composite materials have proven to be highly effective at achieving high quality, low cost AGS structures: the hybrid tooling method and the expansion block method, Both methods rely on a precise understanding of tooling behavior during cure to achieve proper consolidation, often determined through trial and error. This paper proposes a theory governing the behavior of both tooling types during the cure cycle in order to minimize the trial and error required to understand tooling expansion during cure. The theory is validated by experimental data. Published by Elsevier Science Ltd.