In the event of an aircraft crash over the ocean,the potential risk of the Flight Data Recorder(FDR)system sinking to the ocean in conjunction with the aircraft debris is substantial,which would significantly complica...In the event of an aircraft crash over the ocean,the potential risk of the Flight Data Recorder(FDR)system sinking to the ocean in conjunction with the aircraft debris is substantial,which would significantly complicate search and rescue operations.To mitigate this challenge,a separable flight data recorder has been developed by our team which called Emergency Flight Data Recorder(EFDR)system.Encapsulated within a cushioning airbag,the recorder is ejected from the aircraft and decelerates to the sea surface via a deceleration parachute,enhancing both the efficiency of search and recovery operations and the feasibility of flight data analysis.This paper presents an experimental study on the ejection velocity of the ejection system in the EFDR framework,focusing on three critical parameters:airbag material,deceleration parachute placement,and flight data recorder weight.The experimental results indicate that encapsulating the device in an airbag reduces ejection velocity,with fabric airbags inducing a smaller velocity decrement compared to rubber counterparts.Additionally,the deployment of a deceleration parachute further decreases ejection velocity,with a more pronounced reduction observed when the parachute is positioned in front of the projectile than when placed at rear.However,this velocity penalty is deemed acceptable due to the enhanced reliability of parachute deployment in the anterior configuration.Within the counterweight weight range of 2–6 kg,ejection velocity exhibits a marginal decrease with increasing weight,suggesting that variable payloads have a negligible influence on ejection performance.These findings provide empirical insights for the subsequent design optimization of the EFDR system.展开更多
This paper focuses on the design of an impact-resistant protective structure for an ejection flight data recording and emergency tracking system.To ensure that the protective structure possesses excellent impact resis...This paper focuses on the design of an impact-resistant protective structure for an ejection flight data recording and emergency tracking system.To ensure that the protective structure possesses excellent impact resistance and energy absorption performance under the design constraints of light weight and miniaturization,a preliminary design of the impact-resistant protective structure is achieved by adopting a thin-walled shell with a periodic perforation pattern based on the analysis of protective theory and design principles.A parametric study of the structure through axial compression simulations indicate that the structure exhibits superior energy absorption when subjected to lower impact velocities,larger wall thicknesses,and moderate hole diameters.A multi-objective optimization for structural dimensions is conducted to maximize specific energy absorption and minimize peak crushing force.The performance of the impact-resistant structure is validated with a numerical model by analyzing the stress distribution and acceleration of the circuit board.The results show that the optimized structure reduces the peak stress by 15%and the maximum acceleration by 44%.展开更多
基金support of Shanghai Central Guide Local Science and Technology Development Funds(YDZX20233100004008)the Fundamental Research Funds for the Central Universities:Key Laboratory of Civil Aviation Emergency Science and Technology CAAC(Grant No.XCA2402202).
文摘In the event of an aircraft crash over the ocean,the potential risk of the Flight Data Recorder(FDR)system sinking to the ocean in conjunction with the aircraft debris is substantial,which would significantly complicate search and rescue operations.To mitigate this challenge,a separable flight data recorder has been developed by our team which called Emergency Flight Data Recorder(EFDR)system.Encapsulated within a cushioning airbag,the recorder is ejected from the aircraft and decelerates to the sea surface via a deceleration parachute,enhancing both the efficiency of search and recovery operations and the feasibility of flight data analysis.This paper presents an experimental study on the ejection velocity of the ejection system in the EFDR framework,focusing on three critical parameters:airbag material,deceleration parachute placement,and flight data recorder weight.The experimental results indicate that encapsulating the device in an airbag reduces ejection velocity,with fabric airbags inducing a smaller velocity decrement compared to rubber counterparts.Additionally,the deployment of a deceleration parachute further decreases ejection velocity,with a more pronounced reduction observed when the parachute is positioned in front of the projectile than when placed at rear.However,this velocity penalty is deemed acceptable due to the enhanced reliability of parachute deployment in the anterior configuration.Within the counterweight weight range of 2–6 kg,ejection velocity exhibits a marginal decrease with increasing weight,suggesting that variable payloads have a negligible influence on ejection performance.These findings provide empirical insights for the subsequent design optimization of the EFDR system.
基金supported by the Shanghai Central Guidance Science and Technology Development Fund[YDZX20233100004008].
文摘This paper focuses on the design of an impact-resistant protective structure for an ejection flight data recording and emergency tracking system.To ensure that the protective structure possesses excellent impact resistance and energy absorption performance under the design constraints of light weight and miniaturization,a preliminary design of the impact-resistant protective structure is achieved by adopting a thin-walled shell with a periodic perforation pattern based on the analysis of protective theory and design principles.A parametric study of the structure through axial compression simulations indicate that the structure exhibits superior energy absorption when subjected to lower impact velocities,larger wall thicknesses,and moderate hole diameters.A multi-objective optimization for structural dimensions is conducted to maximize specific energy absorption and minimize peak crushing force.The performance of the impact-resistant structure is validated with a numerical model by analyzing the stress distribution and acceleration of the circuit board.The results show that the optimized structure reduces the peak stress by 15%and the maximum acceleration by 44%.
