FUSELAGE STRUCTURAL OPTIMIZATION WITH MSC／MOD PRE－PROCESSING AND MSC／PAL2 POST－PROCESSING

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FUSELAGE STRUCTURAL OPTIMIZATION WITH MSC/MOD PRE-PROCESSING AND MSC/PAL2 POST-PROCESSING

Based on the finite element method,a structural optimization design is studied on thin-walled fuselage structures for multiple load conditions,and subjected to ,tress, displacement and gauge constraints.The thickness of plates and cross sectional area of beams and bars are chosen as design variables. The Kuhn-Tucker necessary condition is used to obtain the minimum weight design. In order to speed up the iteration process of the multiple displacement constraint problem, we simplify it to a single most critical displacement constraint, which eliminates the need of calculating a large set of Lagrange multipliers for all the active constraints. An optimization criterion is derived. A recursion formula for stress and displacement constraints is derived and implemented into the design optimization algorithm named FOPT, which approaches to the optimum design along the most active constraint boundary. Design variable linking technique is used to reduce the number of independent design variables to several design groups.A program using finite element analysis for optimization of large scale structures is developed; the program is running on IBM-3081 computer.APplication of the program to a number of structures demonstrates the efficiency and accuracy of the method.Using the MSC/MOD and MSC/PAL2 which are linked to an HP PRINTERJET,a set of coloured printings are obtained and the results of this study are shown.