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Systems Analysis Seminar by Resit Unal |
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Date: April 11, 2006
Time: 2:00pm
Location: NASA Langley, Bldg 1209, Rm 180
Additional Information: Presentation (PDF)
Optimization on Cost Basis and Robust Design Approaches for Reducing Risk
Resit Unal, Old Dominion University
The requirements for affordability and cost effectiveness dictate that future space systems must be designed for both performance and cost. Conceptual design also contains considerable element of uncertainty. A robust design seeks to minimize the variability from the expected performance. However, conducting risk analysis is a challenging process at conceptual design, primarily due to the lack of historical data.
First, a design optimization study on cost basis for a launch vehicle is presented. Different material and technology options were studied to optimize performance and cost. The results suggest that the approach taken facilitate evaluation-on-cost-basis and may provide valuable information to engineers and managers early in the design phase.
Second, the use of dual response surfaces is presented to estimate variability and conduct multidisciplinary optimization to reduce risk for a robust design. The dual response surface approach was applied to a conceptual design study for a wing-body vehicle.
Third, an expert-judgment elicitation methodology to quantify parameter uncertainty in conceptual design is presented. The methodology seeks to obtain expert opinion for quantifying uncertainties as a probability distribution so that multidisciplinary risk analysis studies can be performed. An application exercise is presented. Finally, the current research conducted in enhancing the expert judgment approach and the methodology for quantifying uncertainty is outlined. Use of non-probabilistic approaches such as possibility and evidence theory are being investigated.
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