【正文】 angle during the rearwardsretraction sequence to allow the main wheel to rest flat above the lower end of the main gear strut, or flush within the wing, when fully retracted. Examples are the Curtiss P40, Vought F4U Corsair, Grumman F6F Hellcat, Messerschmitt Me 210 and Junkers Ju 88. The Aero Commander family of twinengined business aircraft also shares this feature on the main gears, which retract aft into the ends of the engine nacelles. The rearwardretracting nosewheel strut on the Heinkel He 219 and the forwardretracting nose gear strut on the later Cessna Skymaster similarly rotated 90 degrees as they retracted.On most World War II singleengined fighter aircraft (and even one German heavy bomber design) with sideways retracting main gear, the main gear that retracted into the wings was meant to be raked forward, towards the aircraft39。下一步對(duì)組裝好的部件進(jìn)行接合，進(jìn)行數(shù)字樣機(jī)收放演示。在本文的最后，總結(jié)各種不足和待改進(jìn)之處，并且對(duì)CATIA建模的優(yōu)缺點(diǎn)進(jìn)行總結(jié)及展望。s nose in the down position for better ground handling, with a retracted position that placed the main wheels at some angle behind the main gear39。 the aircraft then relies on titanium skids on the wingtips for landingFigure 26 Takeoff dollyFigure 27 Aircraft U2Some main gear struts on World War II aircraft, in order to allow a singleleg main gear to more efficiently store the wheel within either the wing or an engine nacelle, rotated the single gear strut through a 90176。然后將各個(gè)部件導(dǎo)入裝配設(shè)計(jì)工作臺(tái)，進(jìn)行組裝，添加結(jié)構(gòu)約束。關(guān)鍵詞：起落架，CATIA，結(jié)構(gòu)設(shè)計(jì)，數(shù)字樣機(jī)中國(guó)民航飛行學(xué)院航空工程學(xué)院畢業(yè)論文ABSTRACT The development history of the landing gear and all kinds of structure form and retraction system are summarized. And some accident cause by landing gear are listed. Then the basic knowledge of CATIA V5 as covered, from the application characteristics to its user interface and all kinds of workbench. Before 3D modeling, first of all, some official data to determine the type of landing gear is collected, and some basic data is also collected. Then Hubcap, Cylinder, Drag brace, Torque arm, Collar and tire are modeled by simplified. The data of each part of the concrete, connecting forms, and lootion are be corrected. Then from the sketch of the various parts of the parts are modeled. The next step is martialing each parts and DMU. At the last, all kinds of deficiency and stay for improvement are summarized, and the advantages of CATIA modeling are prospected.Key Words: Landing gear, CATIA, structural design, DMU中國(guó)民航飛行學(xué)院航空工程學(xué)院畢業(yè)論文ContentChapter 1 Reviews 1 The meaning of this research 1 The history of CATIA 1Chapter2 Overview the landing gear 4 Definition of landing gear 4 Different types of gear 7 Tricycle gear 7 Taildragger 8 Unusual types of gear 9 Landing gear and accidents 12Chapter 3 Introduction about CATIA 14 CATIA’s Interface 14 Mechanical design workbenches 15 The Specification Tree 15 The Sketcher Workbench 16 Part design 18 Assembly Design 18 Generative Part Structural Analysis 19 Parameters and Formulas 20Chapter 4 Modeling process of landing gear 21 Basic structure modeling 21 Main supporting pole 21 Airplane Wheel design 25 Upper Drag Brace 28 Lower Drag Brace 29 Lock assembly 30 Hydraulic shafts 31 Centering Unit steering collar and torque 31 Assembly 33Chapter 5 Digital MockUp 38 Preparation for Digital MockUp 38 Frame Animation 41Chapter 6 Summary 43Reference 44III中國(guó)民航飛行學(xué)院航空工程學(xué)院畢業(yè)論文Chapter 1 ReviewsLanding gear is an important part of the plane. It’s the main ponent for the plane on ground parking, rollout, takeoff, and landing. It can load the weight of the plane and absorb impact energy. The plane landing gear major functions for aircraft in the stationary state under the gravity and the impact of the takeoff and landing, controlling the plane on the ground motion. There is a wide range of plane landing gear model, so these cause the landing gear design difficult, processing document plicated, and maintainability low maintenance rate. It cost a long time from modeling to processing cycle, these lead to the descending of the production efficiency. To lifting the plane landing gear parts production efficiency, the project has put forward fast of parameterized modeling and of parameterized modeling can also be used in other parts. CATIA (Computer Aided TriDimensional Interface Application) is the modeling software to build up a threedimensional model of the platform The meaning of this researchThe reliability of the landing gear plays an important role to the safety of the aircraft, the structure and appearance of the landing gear also decides the economy of the aircraft. And the reliability of the landing gear is by its original design program of the science and engineering analysis. So it is a great significance to research the modeling of the landing gear. This report start at civil aviation maintenance engineering professional characteristics, and bining with 3D technology through to the landing gear of the modeling and finite element analysis, simulation the stress of the landing gear in the real situation, estimated the failure, loading of the important parts such as hydraulic ponents. It plays a vital significance to fault prediction of aircraft structure. The history of CATIACATIA started as an inhouse development in 1977 by French aircraft manufacturer Avions Marcel Dassault, at that time customer of the CAD/CAM CAD software to develop Dassault39。s attachment point to the airframe this led to a plex geometry for setting up the angles for the retraction mechanism39。s centre of gravity due to the deviation), and usually require special pilot training. Sometimes a small tail wheel or skid is added to aircraft with tricycle undercarriage, in case of tail strikes during takeoff. The Concorde, for instance, had a retractable tail bumper wheel, as delta winged aircraft need a high angle when taking off. The Boeing 727 also had a retractable