Investigating Stiffness Property Matching and Homogenization of the Double-Double Family of Laminates

Abstract

The investigation of stiffness property matching and homogenization of the Double-Double (DD) family of laminates is presented. DD laminates are a new layup design approach composed of repeated sub-laminates, comprising two sets of bi-angled plies, [±φ°, ±ψ°]r. The DD laminate approach simplifies the design of composite structures, reduces manufacturing complexity, and allows for rapid thickness tapering, presenting substantial prospects for reducing structural mass. An order-of-magnitude improvement in matching accuracy for both in-plane and bending stiffness properties was observed when extended DD sub-laminates, featuring additional 0°, 90° or ±φ° plies, were incorporated as options in the quad laminate matching process. Additionally, homogenization of laminates comprised of extended DD sub-laminates was examined, concluding that extended DD sub-laminates have no negative implications in terms of laminate homogenization if the correct sub-laminate permutation is selected.