Analysis and design optimization of laminated composite structures using symbolic computation.

UKZN ResearchSpace

Show simple item record

dc.contributor.advisor Adali, Sarp.
dc.contributor.advisor Verijenko, Viktor.
dc.creator Summers, Evan.
dc.date.accessioned 2012-10-14T12:23:42Z
dc.date.available 2012-10-14T12:23:42Z
dc.date.created 1994
dc.date.issued 1994
dc.identifier.uri http://hdl.handle.net/10413/6877
dc.description Thesis (Ph.D.)-University of Natal, Durban, 1994. en
dc.description.abstract The present study involves the analysis and design optimization of thin and thick laminated composite structures using symbolic computation. The fibre angle and wall thickness of balanced and unbalanced thin composite pressure vessels are optimized subject to a strength criterion in order to maximise internal pressure or minimise weight, and the effects of axial and torsional forces on the optimum design are investigated. Special purpose symbolic computation routines are developed in the C programming language for the transformation of coordinate axes, failure analysis and the calculation of design sensitivities. In the study of thin-walled laminated structures, the analytical expression for the thickness of a laminate under in-plane loading and its sensitivity with respect to the fibre orientation are determined in terms of the fibre orientation using symbolic computation. In the design optimization of thin composite pressure vessels, the computational efficiency of the optimization algorithm is improved via symbolic computation. A new higher-order theory which includes the effects of transverse shear and normal deformation is developed for the analysis of laminated composite plates and shells with transversely isotropic layers. The Mathematica symbolic computation package is employed for obtaining analytical and numerical results on the basis of the higher-order theory. It is observed that these numerical results are in excellent agreement with exact three-dimensional elasticity solutions. The computational efficiency of optimization algorithms is important and therefore special purpose symbolic computation routines are developed in the C programming language for the design optimization of thick laminated structures based on the higher-order theory. Three optimal design problems for thick laminated sandwich plates are considered, namely, the minimum weight, minimum deflection and minimum stress design. In the minimum weight problem, the core thickness and the fibre content of the surface layers are optimally determined by using equations of micromechanics to express the elastic constants. In the minimum deflection problem, the thicknesses of the surface layers are chosen as the design variables. In the minimum stress problem, the relative thicknesses of the layers are computed such that the maximum normal stress will be minimized. It is shown that this design analysis cannot be performed using a classical or shear-deformable theory for the thick panels under consideration due to the substantial effect of normal deformation on the design variables. en
dc.language.iso en en
dc.subject Composite materials--Testing. en
dc.subject Composite materials--Mechanical properties. en
dc.subject Laminated materials--Mechanical properties. en
dc.subject Strength of materials. en
dc.subject Theses--Mechanical engineering. en
dc.title Analysis and design optimization of laminated composite structures using symbolic computation. en
dc.type Thesis en

Files in this item

This item appears in the following Collection(s)

Show simple item record

Search UKZN ResearchSpace


Advanced Search

Browse

My Account