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Reliability-Based Multidisciplinary Design Optimization Under Uncertainty for Reusable Flexible Launch Vehicle Using Genetic Algorithm

Mojibi, Motahareh | 2022

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 55550 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Fathi Jegarkandi, Mohsen
  7. Abstract:
  8. In this research, a Reusable Flexible Launch Vehicle (RFLV) design problem is presented by Multi-Disciplinary Design Optimization (MDO) approach in primary design phase. Trajectory, structure, aerodynamic, aeroelasticity and thermal protection system are considered as involved disciplines in design problem. The study purpose will be to obtain an optimal trajectory which meets all the control and structure limitation while the estimating body skin and thermal protection thicknesses base on structural evaluating in re-entry trajectory is in process. The flexible launch vehicle body is considered as a free-free Bernoulli-Euler beam and D’alembert’s principle addresses inertia force in static model to compute structural design factors. The 3DOF longitudinal dynamic equations plus the first bending mode are considered. By Chebyshev polynomial interpolation, the trajectory optimization problem is transformed to a discreted nonlinear programming problem (NLP), through the angle of attack scope and numerical integration of state equation to aim of satisfying all path constraints. The design problem formulation has developed by single level MDO framework which optimization has implemented by Non-Dominated Sorting Genetic Algorithm (NSGA-II). Finally, epistemic and aleatory uncertainties has applied through Probability Theory to estimate reliability of constraints those have affected by uncertainties. Result shows a significant effect of utilizing evolutionary multi-objective technique against gradient-based algorithm in design space optimization. The other conclusion is that sequential reliability analysis modeling efficiency is much better compare to parallel construction
  9. Keywords:
  10. Uncertainty ; Aeroelasticity ; Reliability Analysis ; Multi-Disciplinary Design Optimization ; Flexible Launch Vehicle ; Reliability Based Design ; Uncertainty Modeling ; Reusable Flexible Launch Vehicle (RFLV)

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