Author

Bin Su

Advisor

Rais-Rohani, Masoud

Committee Member

Newman, James C. III

Committee Member

Eamon, Christopher D.

Date of Degree

1-1-2001

Document Type

Graduate Thesis - Open Access

Major

Engineering Mechanics

Degree Name

Master of Science

College

College of Engineering

Department

Department of Aerospace Engineering

Abstract

The reliability analysis and reliability-based optimization of laminated circular cylinders under axial buckling instability are studied. Structural reliability is measured in terms of Hasofer-Lind reliability index. The response surface models are used in both the calculation of the reliability index and the reliability-based optimization. In reliability analysis, both deterministic and probabilistic sensitivity factors are investigated; the results show that the reliability index is most sensitive to the applied load and Young's modulus of the material. Two cases are considered in the optimization study. In the first case, the cylinder weight is minimized subject to a reliability constraint whereas in the second case, cylinder reliability is maximized subject to a weight constraint. In addition, two different optimization techniques are studied. In the first technique, a global response surface model of the buckling response based on 3000 Monte Carlo simulations is used for the design optimization whereas in the second technique, multiple local regression models, with each based on approximately 20 simulations, are used in sequential search of an optimum design. An optimum design is found. The results based on sequential application of multiple local regression models are close to those from global optimization while the former is much more efficient in terms of computational cost.

URI

https://hdl.handle.net/11668/19193

Comments

reliability-based optimization||response surface||reliability analysis

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