Linkage Retraction Mechanism Design And Air Tightness Analysis Of Landing Gear Door Of Aircraft

With the development of modern aircraft design, the landing gear retraction-extend mechanism is generally used, which brings that mechanism design of landing gear door and air tightness problems have caught widely attention. In this paper, the retraction mechanism of landing gear door was analyzed firstly. Taking an aircraft nose landing gear door as research object, the parameterized models of door linkage constructions were built, then optimized. Door seal structure was built to analysis the main factors influencing air tightness and improvement scheme was put forward. The whole research provides a meaningful reference for fast high-quality mechanism design and airtight security design of landing gear door linkage retraction mechanism.Several typical configurations of landing gear door linkage retraction mechanism were analyzed and carried on the summary. Three similar types of the linkage mechanism were compared from different aspects. Then, regarding an aircraft as research object, the paper analyzed the movement form, established the key parameters of mechanism, expressed the motion relationship by parameters. The parameterized models of the landing gear door linkage were established by CATIA to make it easy to modify. Using MIGA and RSM as optimizing methods, the landing gear door linkage mechanisms were optimized, by taking the key parameters as design variables and taking optimal hatch of aerodynamic load force as design objectives. Comparing the results, it effectively reduced the negative impact on the emergency produced by the aerodynamic load of landing gear doors.For the landing gear door linkage mechanism, since the impact of structural rigidity of transmission, aerodynamic loads will cause structure deformation and then air-tightness problems. In order to analyze the problems, based on the theory of nonlinearity and incompressible Mooney-Rivlin constitutive equation, a finite element model of sealing structure was established, which was designed for the landing gear door. It conduced to get the hydrostatic curves of the seals at working process. A rigid-flexible coupling prototype of landing gear mechanism was established to figure out the air tightness under different aerodynamic load conditions. The results show that elastic deformation of relevant members caused by aerodynamic loads, is an important cause of seal failure, which leads to P-ring seals without contact or small contact stress. Axial preloads were separately applied to the rods of doors to improve air tightness effectively.