Study On The Dynamic Load Of The Key Components Of A Aircraft In The Process Of Crash

According to the statistics,the aircraft hitting the ground is the main cause of civil aircraft accidents in recent years.A large portion of these accidents is caused by the inactive landing gears.To improve the survival rate of passengers in such accidents,the aircraft airworthiness authorities put forward specific requirements.Aircraft crashworthiness is an important indicator to evaluate its safety performance and the key to obtain airworthiness certification.Aircraft WUL(Wheels-UP landing)analysis is an important component of airworthiness certification requirements.When the plane is in WUL,the body of the aircraft will be impacted strongly at the moment of touching the ground.In order to safeguard the passengers,the body of the airplane must have enough strength to maintain a certain proportion of living space.However,the strength of the airplane should not be very high,because high strength will lead to a great inertia load in the body of the passengers.To address this issue,a detailed study on the dynamic response of the airplane during WUL should be carried.Due to the complex structure and the large scale of the airplane,many scholars only carried on simulation analysis for some key parts of the aircraft separately,such as cabin section,wing boxes and so on.However,the fuselage and wings will affect each other during the process of aircraft crash.In the present study the load response of the whole plane in WUL is examined.The main work of this paper is as follows:1.The initial conditions of the WUL are summarized according to the domestic and international airworthiness certification guidelines,which include: landing weight,landing gear active and inactive combinations,as well as mass distribution and so on;and a suitable calculation process is developed based on the existing analysis method of dynamic response.The developed process covers determining the touchdown location of the simplified model under different landing configuration and the equivalent force for the initial collision and secondary collision;2.A new model simplification method is proposed.First,the detailed model of a typical airliner is established;second,a new model simplification method is proposed according to t equivalent stiffness;third,the simplified method is verified by comparing the calculation results with those of the real model using finite element program.3.Numerical simulation method is used to analyze the dynamic response of aircraft under different conditions of landing.The shear forces,bending and torsional moments in fuselage,left wing and right wing are examined.Main factors influencing the dynamic response during WUL are identified.The findings can be used for the design of aircraft structures.