Optimum Design of Steered Fibre Composite Cylinders with Arbitrary Cross-sections

Optimum Design of Steered Fibre Composite Cylinders with Arbitrary Cross-sections

Khani, A.

Gurdal, Z. (promotor)

Aerospace Engineering

Aerospace Structures and Computational Mechanics Group

2013-12-10

Automated fibre placement (AFP) machines are able to place simultaneously several bundles of fibres, called tows, on a surface. Using AFP machines, it is also possible to manufacture composite laminates with fibres placed in curvilinear paths. The fibre orientations and stiffness properties of these laminates are spatially varied and hence they are called variable stiffness (VS) laminates in contrast to the traditional laminates with straight fibres which are called constant stiffness (CS) laminates. Past research has shown that the structural performance of laminated composite structures can be improved by spatial tailoring of laminate stiffness. One of the widely used structural components in aerospace industry are cylindrical shells. In this thesis, a computationally efficient framework was developed for circumferential laminate stiffness tailoring of unstiffened and longitudinally stiffened cylindrical shells with arbitrary cross sections to maximise the buckling capacity with consideration of strength constraints. In addition, the AFP manufacturing constraint on the maximum curvature of curvilinear fibre paths was considered. This constraint was applied to avoid wrinkling of the fibres placed inside the turn of a curved tow. The aforementioned framework utilised computationally efficient analysis and optimisation tools.

variable stiffness
cylindrical shells
fibre steering
fibre placement
buckling
strength

https://doi.org/10.4233/uuid:6d9c2f9e-358f-4398-8daa-c37004c816ae

2014-12-10

9789461085627

Institutional Repository

doctoral thesis

(c) 2013 Khani, A.