Study On Equivalent Models Of Aviation Quick-release Honeycomb Sandwich Door

The door is one of the essential components for aircraft, whose disassembly time largely determines the time of refurbishment as well, and the door's quick disassembly performance became a part of the aircraft performance evaluation index. In order to decrease the time used in disassembly process, a quick-release honeycomb sandwich door including two sets of quick-release device and a basic equivalent model for the research of honeycomb sandwich structure are proposed in this text. Combining different theories, 8 macroscopic and microscopic equivalent models can be got. According to these models, random vibration,static analysis and sinusoidal frequency sweep tests were conducted with the honeycomb sandwich test piece. And the optimal model is finally got by comparing the results of tests and simulation. Based on this model, random vibration and static analysis, fast disassembly performance tests are made, so that the door can be exhaustively evaluated. The main research content about the honeycomb sandwich door and its equivalent model is divided as follows:Firstly, the present of quick-released honeycomb sandwich door and its equivalent models are summarized, and the limitation of them is proposed at the same time. Considering the filling, arrangement and other factors of the after buried pieces and the existing limitations, a new quick-release honeycomb sandwich door is designed, including the design of filling style and arrangement of after buried pieces, the design of the whole door, the design of two sets of quick-release device, and finally complete the fabrication of the prototype, which lay the foundation for the next research and tests.Secondly, considering the main shortcomings of the present equivalent model of honeycomb sandwich structure, the new Y model is proposed to equivalent the core of regular hexagon. According to the model, the research on the equivalent parameters of the core is carried on by the mechanical analysis, which can reflect the relationship between the equivalent parameters and geometric parameters of honeycomb sandwich structure from the microscopic.Thirdly, three types of current equivalent models of honeycomb sandwich structure, static theory, dynamic theory and sandwich theory are summarized. According to different theories,7 macroscopic models are proposed. The main shortcomings of current models are modified and a method to deduce the basic equation of the free vibration and the natural frequency is presented the same time,which provide a basis for the validation and comparison of the dynamic characteristics of the equivalent modelFinally, after the simulation of centrifuge, random vibration, sinusoidal frequency sweep in ANSYS Workbench, the tests are conducted with the test piece of honeycomb sandwich structure. Comparing the results of tests and simulation, the optimal model for honeycomb sandwich structure both in static and dynamic properties can be obtained. Then, the dissertation applies the optimal model in the virtual simulation of the quick-released honeycomb sandwich door to show its static and dynamic performance to verify that the door can meet the requirements of strength, and test the prototype in terms of its quick disassembly performance the same time to verify that the door can meet the requirements of quick disassembly performance. While for the problems appearing in simulation and testing process,improvements program are proposed to lay a foundation for subsequent work.