Optimization of stacking
sequence would enable the designer to efficiently exploit tailoring abilities
of such filament wound cylinders. Hence, the main aim of the paper was to
perform optimization of stacking sequence using a genetic algorithm for two representative
models with the first model having a length of 1650 mm and diameter 350 mm and
second model with length 238 mm and diameter 184 mm. MATLAB
programs for calculating critical buckling pressure (CBP), stiffness matrix and
fitness evaluation function were developed using Sander’s type analytical model. Then, the parametric study was performed to investigate the effect of
geometrical dimensions on CBP, determine optimum settings for MATLAB Genetic
Algorithm (GA) toolbox and a number of elements for performing Eigen buckling
analysis in ANSYS. Considering the optimal parameters, optimization of stacking
sequence using MATLAB GA tool for increasing depth of operation of both the
models and decreasing weight of the first representative model was performed. The
parametric study indicated that CBP is inversely proportional to (5/2)th power
of D/t ratio and first power of L/D ratio. The CBP was maximized for a stacking
sequence that leads to the dimensionless bending stiffness ratio nearly equal
to 0.1. Thicknesses of the full-scale models of first representative cylinders
were 13.2 mm and 18 mm of carbon/epoxy
and glass/epoxy respectively for a depth of operation of 1000 m. CBP of the second model with a thickness of 5 mm was 16
MPa and 7.8 MPa for carbon/epoxy and glass/epoxy respectively. For the first
model, substantial improvements of over 85 % and 44 % in depth of operation for
carbon/epoxy and glass/epoxy were achieved, weight reductions of 13 % to 23.4 %
for an operating depth of 1000 m were achieved. For the second representative
model, improvements of 52.36 % and 19 % in depth of operation for carbon/epoxy
and glass/epoxy respectively were achieved. A deviation of 5 – 25 % and 10 – 40
% was observed for glass/epoxy and carbon/epoxy respectively when compared with
results obtained from Eigen buckling analysis using ANSYS.
