| The objective of this thesis was to optimize the structure of a space vehicle (sustainer) for minimum weight under a given critical loading condition, by optimizing the wall thicknesses of its structural components. In addition, a sensitivity analysis was performed on the optimum design to further highlight the critical design variables influencing the structure the most.; Besides optimizing the detailed sustainer structure, which contained 7 design variables (DVs), a simplified sustainer FE model was built and optimized. The results obtained from both approaches were compared to estimate the accuracy of the results obtained from the simplified model against the ones obtained from the detailed FE model.; In this thesis, the idealized approach was proven to have some great advantages; and the results obtained from the idealized structure were inline with the ones obtained from the detailed structure in general. By lowering the number of DVs and DOFs (degrees of freedom) in the structure, a significant time and cost savings can be achieved, especially in the bigger and more complex systems. Idealizing the structure should be handled with caution though, and assumptions made to simplify the structure should be validated.; Sensitivity analysis was also proven to be a great tool for design engineers. It relates the system's design variables to its responses, which not only gives the designer a better perspective, it also saves time and cost by eliminating the need for reanalysis every time the value of a particular design variable is changed.; The theory behind the optimization and sensitivity analysis was briefly introduced in the second and third chapters of this thesis. |
