Minimum Mass Design And Transient Heat Transfer Analysis Of Composite Structure With Multi-layer

Advanced structures, such as ultralight structure and thermal protection structure, are playing more and more important role in aeronautical & astronautical industries. Based on finite element method, efforts are focused on global optimization design of composite laminated plate and numerical technique of transient heat transfer for passive metallic thermal protection system, respectively.Reducing structural weight and increasing payload are the goal which is being pursued all along. Structures of aircraft mainly consist of metallic and composite structure presently;therefore, design of composite structure for minimum weight is significant to improve the performance of aircraft. Making use of designable characteristics of composite sufficiently, quantitative relation between macroscopic performance of each layer and microscopic parameters is established by using composite micro-theory combined with finite element analysis. A novel method for optimal design of composite laminated plate based on structure and material parameters is presented. According to loading type and structure type, multilevel optimization strategy and improved genetic algorithm are proposed, respectively. The computing examples show that the method developed can exploit load carrying capacity of structure further to obtain the globally optimal composite structure.Besides, advanced thermal protection structure is urgently required for developing highly ultrasonic aircraft. Numerical simulation is an effective approach to research the heat transfer of thermal protection system. Multi-layer metallic thermal protection system [Blosser M L.2000] taken as analyzed example, its 3D parametric finite element models with or without assistant structures including racket and circumambient wall are established. It is found that solution efficiency is acutely reduced by fine finite element mesh of honeycomb structure with large area, so calculating equivalent thermal properties of honeycomb core is conducted numerically and theoretically. As a result, the equivalent thermal model of thermal protection structure is set up by simplifying the honeycomb core layer as uniform material plate, which is solved easily. Both of numerical examples with uniform and non-uniform distributed loading indicate that good agreement in temperature response is found between original and equivalent models of thermal protection structure under the same conditions. Undoubtedly, the accuracy of the equivalent model is verified. It is possible to accomplish quickly thermal computation of thermal protection structure with large area to obtain the 3Dtemperature response based on micro-computer by using this equivalent model proposed.The work done can provide valuable design guidance for seeking the reasonable scheme for structures used in the rigorous working conditions.