Design And Research Of Passenger Door Mechanism Based On The Metamorphic Principle

The overall development direction of large aircraft is to expand transportation space,increase takeoff weight and reduce redundant mechanical structure weight.This paper designs a new kind of passenger door mechanism based on the metamorphic principle,which makes the opening force of cabin door smaller,the overall mass of driving parts smaller and the overall structure lighter.The digital modeling,structural analysis,kinematic analysis and reliability analysis are taken into account to complete the whole design and analysis work,and make a little contribution to improve the manufacturing level of cabin door for our country.In this paper,in view of a certain type of transport aircraft's main structure.The principle of metamorphic mechanism is introduced into the structural design of passenger door by referring to the existing design scheme of passenger door.Based on the top-down design criteria,the digital model of metamorphic passenger door is established.The sealing structure,latch mechanism,driving mechanism and hinge structure are described in detail.The working principle of the mechanism and the design purpose of each mechanism are described.The design scheme of metamorphic passenger door is formed.The metamorphic type of the mechanism is determined by the degree of freedom analysis.Based on the gene modeling theory of metamorphic mechanism,the gene structure of each working configuration of the mechanism is designed,the gene configuration of mechanism source configuration is obtained by gene evolution.Based on topological graph method and adjacency matrix method,the configuration transformation process of the metamorphic mechanism is designed.The metamorphic matrix and equations of the mechanism are derived,the transformation routemap of each configuration state of the mechanism is obtained.The rationality analysis of the structural design of the metamorphic mechanism is completed.The binding force variation characteristics of kinematic pair are analyzed,the kinematic cycle diagram of the mechanism is given,and the full configuration kinematic model of the mechanism is established.The opening force of the metamorphic hatch and the traditional lifting hatch is analyzed and compared,and the numerical solution of the specific example is verified by ADAMS simulation.The simulation results are highly consistent with the established kinematic model,the practicability of kinematic analysis method is proved.The opening force of the traditional hatch mechanism is about twice than the metamorphic hatch.When the thrust is reduced,the weight of the driving components can be reduced,and the energy consumption of the motor can be reduced.This kind of metamorphic mechanism has a strong application value.The self-locking function of the metamorphic passenger door mechanism in the open state depends on the compound movement of the combined metamorphic pair.Therefore,the displacement error calculation model of combined metamorphic pair under the influence of the rod length error and the hinge clearance error is established,and the MATLAB reliability analysis program is compiled to verify the accuracy of the two theoretical models of error calculation.The result showed that the locking mechanism of passenger door has higher reliability,when the push speed of push rod is lower or the cabin door is lighter.The reliability connection equation is established with the displacement reliability of the combined metamorphic pair as the constraint condition.The specific parameters of spring assembly which can meet the design function requirements are analyzed.The MATLAB software is used to compile the sampling algorithm of variable bar length.The resulted show that the displacement reliability of the combined metamorphic pair can be greatly improved by increasing the length of the push rod.When the hinge clearance is in the continuous contact model,the change of rod length is more significant to improve the reliability.However,when the installation offset and installation elevation of push rod increase,the reliability of the combined metamorphic pair displacement is decreased.Therefore,it can improve the reliability of mechanism locking function to select the larger stroke push rod and smaller rigidity spring assembly in practical application.At the same time,the installation offset and elevation of push rod are reduced,which can not only increase the space in the cabin,but also increase the self-locking reliability of the mechanism.The reliability analysis model established in this paper provides a new method for reliability analysis and component parameter design of constrained metamorphic mechanism.Figure [66] table[7] reference [87]...