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Research Publications (Engineering and Built Environment)

Permanent URI for this collectionhttp://ir-dev.dut.ac.za/handle/10321/215

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    Optimal design of fibre-reinforced laminated plates accounting for manufacturing uncertainty
    (Springer, 2005) Walker, Mark
    A procedure to design symmetrically laminated plates under buckling loads for minimum weight with manufacturing uncertainty (tolerance) in the ply angle and plate thickness, which are the design variables, is described. A minimum buckling load capacity is the design constraint implemented. It is assumed that the probability of any tolerance value occurring within the tolerance band, compared with any other, is equal, and thus the approach is a worst case scenario approach. The effects of bending–twisting coupling are neglected in implementing the procedure, and the Downhill Simplex method is used as the search technique, but the methodology is flexible and allows any appropriate problem formulation and search algorithm to be substituted. Two different tolerance scenarios are used for the purposes of illustrating the methodology, and plates with varying aspect ratios and loading ratios are optimally designed and compared. The results demonstrate the importance of carrying out design optimisation of composite structures with the effects of manufacturing tolerances included.
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    Optimal design of symmetric laminates with cut-outs for maximum buckling load
    (Elsevier, 1999) Walker, Mark
    Finite element solutions are presented for the optimal design of symmetrically laminated rectangular plates with central circular cut-outs subject to a combination of simply supported, clamped and free boundary conditions. The design objective is the maximisation of the biaxial buckling load by determining the fibre orientations optimally with the effects of bending–twisting coupling taken into account. The finite element method coupled with an optimisation routine is employed in analysing and optimising the laminated plate designs. The effect of plate size and boundary conditions on the optimal ply angles and the buckling load are numerically studied, and these results are compared to those from an article which appeared in this journal in 1996; viz. plates without cut-outs (Walker M, Adali S, Verijenko VE. Optimisation of symmetric laminates for maximum buckling load including the effects of bending–twisting coupling.