CN-121980743-A - Helicopter floating system air opening safety analysis and verification method

CN121980743ACN 121980743 ACN121980743 ACN 121980743ACN-121980743-A

Abstract

The invention belongs to the field of helicopter flight mechanics design, and particularly relates to an analysis and verification method for the safety of an aerial opening of a helicopter floating system. The method comprises the steps of firstly determining a safety analysis frame, constructing a multi-dimensional safety analysis frame for flight state change analysis, package cover track analysis and buoy deformation analysis based on the unfolding process of a helicopter emergency floating system, secondly determining a test verification scheme, verifying the result of theoretical analysis through wind tunnel tests, collision damage verification and ground simulation tests, thirdly developing a flight test and testing the unfolding process of the emergency floating system in actual flight.

Inventors

CHEN BIN
HUANG LEI
WANG HUAJI
KONG BO
MAO XU
HAN CHONG
ZHU XIYANG
DONG SHENGHUA

Assignees

中国直升机设计研究所

Dates

Publication Date: 20260505
Application Date: 20251209

Claims (10)

1. An analysis and verification method for the safety of a helicopter floating system in the air, which is characterized by comprising the following steps: The method comprises the steps of determining a safety analysis frame, constructing a multi-dimensional safety analysis frame for flight state change analysis, encapsulation flap track analysis and pontoon deformation analysis based on the unfolding process of a helicopter emergency floating system; determining a test verification scheme, and verifying a theoretical analysis result through a wind tunnel test, collision damage verification and a ground simulation test; and thirdly, carrying out a flight test, and testing the unfolding process of the emergency floating system in actual flight.
2. The method for analyzing and verifying the safety of the airborne opening of the helicopter floating system according to claim 1, wherein in the first step, the flight state change analysis comprises gesture response analysis; (1) Fitting the aerodynamic characteristic data in different unfolding states into a function related to the unfolding angle of the pontoon as an aerodynamic drag coefficient expression of the helicopter; (2) According to the aerodynamic drag coefficient expression of the helicopter when the pontoon is not opened, constructing a helicopter flight mechanics analysis model; (3) In the helicopter flight mechanics model, balancing the helicopter in different flight states to obtain the flight attitude in the balancing state, setting aerodynamic force variation as excitation of the helicopter flight mechanics analysis model, and obtaining the attitude response and the speed response in different unfolding states through simulation calculation. (4) The attitude response is determined whether it is within the pilot's operable range, and the velocity response is determined whether it can cause dangerous position, altitude drift.
3. The method for analyzing and verifying the safety of the helicopter floating system in the air, according to claim 2, wherein in the first step, the flight state change analysis further comprises load analysis; balancing the helicopter in different flight states in a helicopter flight mechanics analysis model to obtain load in the balancing state; Applying maneuvering excitation and gust disturbance to the helicopter flight mechanics analysis model in the trim state, setting aerodynamic force variation as excitation of the helicopter flight mechanics analysis model, and obtaining the maximum load when opening the pontoon in the maneuvering flight state through simulation calculation; By means of the structural strength analysis tool, it is confirmed whether or not stress concentration may cause a flight safety problem.
4. The method for analyzing and verifying the safety of the aerial opening of a helicopter floating system according to claim 2, wherein in the first step, the analysis of the track of the encapsulation flap comprises: Firstly, establishing a three-dimensional geometric model according to the actual structure of a helicopter and the installation position of an emergency floating system, wherein the three-dimensional geometric model comprises a fuselage, a rotor wing and a tail rotor; then, simulating a real flight environment comprising flight speed, altitude, atmospheric pressure and temperature, pitch angle and roll angle of the helicopter; Setting the rotor pitch as a pitch value in a balancing state, and obtaining a fuselage surrounding flow field after rotor downward washing interference through simulation; When the packaging flap swings out of the rotor disk in the horizontal direction, a swing track of the corresponding packaging flap in the current flight state is obtained.
5. The method for analyzing and verifying the safety of the aerial opening of the helicopter floating system according to claim 4, wherein in the first step, the track analysis of the encapsulation flap further comprises the steps of collision damage analysis; judging collision possibility: Firstly, acquiring a movement track of an encapsulation cover, acquiring movement track data of the encapsulation cover in different flight states, and determining the three-dimensional space position and orientation of the encapsulation cover at any moment; then analyzing the spatial layout of key parts of the helicopter, wherein the key parts comprise the positions of the external and internal weak parts of the helicopter, the length and position arrangement of a main rotor wing and a tail rotor, the positions and heights of landing gear struts, a supporting structure and the positions of cockpit glass; judging whether a space overlapping area exists between the motion track data of the packaging flap and the space layout information of the key components by using the geometric intersection inspection; calculation of intensity margin: If the possibility of collision is judged initially, impact loads are generated between the packaging flap and the key components in the collision process, the sizes, directions and acting time of the loads need to be analyzed, then strength margin calculation is carried out, the safety and reliability of the structure are evaluated through calculation of the strength margin, if the strength margin is positive, the structure can safely bear the expected load, otherwise, corresponding optimization design needs to be carried out, finally, damage form prediction is carried out, and the possible damage form is predicted according to the result of collision damage analysis.
6. The method for analyzing and verifying the air opening safety of a helicopter floatation system according to claim 5, wherein the analyzing of the track of the encapsulation flap further comprises the following steps: Based on the collision damage analysis, the method evaluates the influence of the collision event on the flight state of the helicopter, and specifically comprises the following steps: (1) The collision gesture response analysis is to set the impact force received by the machine body in the collision process as excitation of a helicopter flight mechanics analysis model, obtain gesture response and speed response under different unfolding states through simulation calculation, and analyze the influence of the impact force on the operability of the helicopter. (2) And analyzing the flight capacity after damage, namely simulating the aerodynamic performance and the operating characteristic of the helicopter after the structure is damaged, and judging whether the helicopter can maintain a stable flight state or finish the water forced landing operation.
7. The method for analyzing and verifying the safety of the open air of the helicopter floating system according to claim 6, wherein the deformation analysis of the pontoon is specifically as follows: If the situation that the pontoon can block the pilot's sight is found, the influence of the pontoon deformation on the pilot's sight is evaluated through a man-machine efficiency modeling tool, and the method specifically comprises (1) analyzing the flight control capability of the pilot to judge whether the pontoon blocking can affect the control precision and the response speed of the pilot, (2) analyzing the track judging and the water forced landing capability to evaluate whether the pontoon blocking can cause the erroneous judgment of the pilot on the position, the height or the forced landing track of the helicopter so as to affect the forced landing success rate.
8. The method for analyzing and verifying the safety of the helicopter floating system in the air, according to claim 1, is characterized in that the second step is as follows: the test model selects a section of the helicopter body provided with a pontoon, and an equal proportion test piece is manufactured, and a half of the test piece is cut and arranged on an open wind tunnel; installing an equal-ratio test piece on a high-speed open wind tunnel, and simulating a scene of a helicopter for expanding an emergency floating system in the air; after the wind speed is stable, triggering an inflation ignition switch of the emergency floating system, and opening a pontoon, wherein after the pontoon is opened, a packaging flap pops up and track change occurs under the influence of wind tunnel airflow, and a high-speed camera is used for capturing the track and analyzing the track; If the possibility that the packaging flap collides with the helicopter structure exists, an impact strength test is carried out, and the bearing capacity and damage tolerance of the structure are verified by simulating the impact speed and force of the packaging flap on the interference component.
9. The method for analyzing and verifying the safety of the aerial opening of the helicopter floating system according to claim 8, wherein the second step further comprises a pontoon deformation related test comprising a deformation interference test and a driver visual field test; in the deformation interference test, in a wind tunnel or ground simulation environment, the curling, bending and flexible swinging conditions of the pontoon in the unfolding process are tested, and theoretical analysis results are verified by measuring the deformation amplitude of the pontoon and the distance between the pontoon and key parts of the helicopter; The driver visual field test is to simulate the situation that the pontoon is unfolded to block the sight of the pilot, evaluate the influence on the flight control, reproduce the pontoon to block the scene in the simulator, and test the pilot's ability to finish the flight mission under different blocking conditions.
10. The method for analyzing and verifying the safety of the helicopter floating system in the air, according to claim 1, is characterized in that the third step is as follows: Triggering the unfolding function of the emergency floating system in the flight process of the helicopter, and monitoring the unfolding speed, attitude change and aerodynamic performance of the pontoon in real time; under different flight states, verifying whether the unfolding process of the emergency floating system can cause the helicopter to lose stability and controllability, recording the unfolding state of the pontoon, the attitude change of the helicopter and the operation reaction of a pilot in real time through an onboard sensor and a camera device, comparing a test result with a theoretical analysis and numerical simulation result, and further optimizing the system design; the pilot's ability to operate and judge the precision after the flotation pontoon is expanded is tested through the scene of simulating water forced landing.

Description

Helicopter floating system air opening safety analysis and verification method Technical Field The invention belongs to the field of helicopter flight mechanics design, and particularly relates to an analysis and verification method for the safety of an aerial opening of a helicopter floating system. Background With the rapid development of aviation technology, helicopters are widely applied in the fields of water rescue, traffic, offshore oil and gas detection and the like due to the unique flight capacity of the helicopters. However, the safety problem of helicopters when forced on water is always a serious challenge. In case of an emergency situation, such as an engine failure or an operational error, causing the helicopter to approach the water surface, the emergency floating system will become the last barrier for the life safety of the crew and passengers. Before forced landing to the water surface, the emergency floating system is firstly ensured to be opened safely and controllably. Existing helicopter emergency floating systems are generally of inflatable design, which can expand rapidly and provide support for the helicopter after being opened in the air. However, such systems still have a number of safety hazards and disadvantages in practical applications. The present invention sets forth in detail the background of the prior art and products in order to fully analyze these safety issues and to present an effective solution. Verification of current helicopter emergency floatation systems is typically accomplished through experimentation and pilot flight. Firstly, the strength, reliability and other functions and performances of the floating system are usually verified through laboratory tests, but the method cannot verify the influence of the floating system on the whole helicopter, particularly on the flight safety after being integrated in the helicopter. The method is characterized in that firstly, the space of a laboratory is limited, the size of a helicopter is larger, and an equal-proportion complete machine model cannot be arranged in the laboratory environment due to space and size limitation, and secondly, the laboratory does not have the condition of simulating the flying state of the complete machine of the helicopter in the air, in particular to the speed. Secondly, the verification of the system function performance by trial flight is a main means adopted in the current industry, but the method is also beneficial and disadvantageous in that firstly, the problem of trial flight cost is solved, a large number of ground service, airforce, operation and maintenance equipment, fuel oil, airport guarantee and the like are involved in simulation by trial flight, the cost is too high for system development, secondly, the problem of risk control is solved, various risks existing in development are transferred to the trial flight by taking the trial flight as a main verification means, and once an emergency or design problem occurs, serious flight accidents are easily caused. Disclosure of Invention The invention aims to provide an analysis and verification method for the safety of the helicopter emergency floating system in the air, which aims to ensure that the unfolding process of the emergency floating system does not threaten the flight safety under the condition of forced landing or water emergency of the helicopter through the safety evaluation flow of the system. The method combines theoretical analysis, numerical modeling, experimental verification and actual flight test to form a complete safety evaluation system. An analysis and verification method for the safety of a helicopter floating system in an open air, the method comprising: The method comprises the steps of determining a safety analysis frame, constructing a multi-dimensional safety analysis frame for flight state change analysis, encapsulation flap track analysis and pontoon deformation analysis based on the unfolding process of a helicopter emergency floating system; determining a test verification scheme, and verifying a theoretical analysis result through a wind tunnel test, collision damage verification and a ground simulation test; and thirdly, carrying out a flight test, and testing the unfolding process of the emergency floating system in actual flight. The beneficial effects of the invention are as follows: the helicopter emergency floating system safety assessment method provided by the invention has wide application prospect: and the flight safety is improved. Through comprehensive safety evaluation, the emergency floating system can be ensured not to threat flight safety in the unfolding process of the emergency floating system under emergency conditions, and the accident risk is reduced. Optimizing the system design. Based on theoretical analysis and experimental verification results, the structural design and unfolding logic of the emergency floating system are further optimized, and the reliability and the p