Stacking sequence listings are presented for fully orthotropic angle-ply laminates, with up to 21 plies, together with rules for mixing these sequences to form laminates containing any number of plies. The mixing rules are demonstrated through an abridged set of sequences, which are characterized in terms of angle-and cross-ply sub-sequence symmetries. The abridged set of sequences is derived from a new definitive list that supersedes previously published listings. Stacking sequences are presented together with dimensionless parameters from which the bending stiffness terms are readily calculated and an assessment of the bending stiffness efficiency made for angle-and cross-ply subsequences. Expressions relating the dimensionless parameters to the well-known lamination parameters are also given, together with graphical representations of feasible domains for all sub-sequence symmetries contained in the definitive list. Feasible domains for extensionally isotropic and fully isotropic laminates are also presented as important sub-sets of fully orthotropic laminates. Finally, examples are given for tapered laminates with fully orthotropic properties, derived from compatible sequences in the definite list.
PurposeThe purpose of this paper is to demonstrate new design concepts for 24 classes of laminate, which have been derived as part of an ongoing study on the development of a unified approach to the characterization of coupled laminates. The paper presents a description of each class of coupled laminate.Design/methodology/approachThe paper gives an overview of the desired performance and requirements of a smart leading edge device, its aerodynamic design for the wind tunnel tests and the structural pre‐design and sizing of the full‐scale leading edge section which will be tested in the wind tunnel.FindingsCoupled laminates have potential applications in the design of aero‐elastic compliant rotor blades or aircraft wing structures, by introducing tailored extension‐twist and/or shear‐extension coupling at the laminate level; or in the design of thermally activated morphing structures, by exploiting more complex coupling behaviour.Practical implicationsThese laminates contain standard cross‐ply and/or angle‐ply combinations, although double angle‐ply laminates are also considered, and correspond to any standard fibre/matrix system with a constant ply thickness throughout.Originality/valueThe vast majority of the laminate described possess coupling behaviour not previously identified in the literature.
The definitive list of stacking sequences is presented for Bending-Twisting coupled (ASB0DF) laminates, with up to 21 plies. This class of laminate arises from the ubiquitous balanced and symmetric design rule, but symmetry is shown to be a sufficient rather than a necessary constraint. Each stacking sequence configuration is derived in symbolic form together with dimensionless parameters from which the extensional and bending stiffness terms are readily calculated for any fibre/matrix system and angle-ply orientation. Expressions for ply orientation dependent lamination parameters are also given, together with graphical representations, which demonstrate the extent of the design space. Pseudo Quasi-Homogeneous (ASB0DF) laminates are introduced as an important laminate sub-set, since such laminates have concomitant orthotropic properties, i.e. matching orthotropic or isotropic stiffnesses in extension and bending, from which the isolated effects of Bending-Twisting coupling can be studied.
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