Simulated design of experiments for detection of explosive cutting impulse noise in aircraft escape system
Objective To accomplish simulated design of experiments for detection of impulse noise from explosive cutting during aircraft escape in order to protect against hearing damage.Methods The relationship between the proportional distance of the overpressure estimation of the impulse noise from explosion cutting during aircraft escape and the point of measurement of bombing in the cockpit of the aircraft was analyzed according to the overpressure evaluation standard stipulated in the safety threshold of auditory damage by impulse noise.Then,simulated design was initiated based on the spatial and temporal characteristics of the instantaneous ejection of the pilot and on the ejection design of the aircraft cockpit and seat.The instantaneous scenario of explosion cutting during aircraft escape was analyzed and simulated.An experimental platform was built with adjustable points of explosion and measurement that were accurately simulated in each posture of the seat.Finally,ground experiments for detection of explosion cutting were carried out and data was collected and analyzed.Results The simulated design was completed based on the cockpit scenario of explosive cutting during aircraft escape.The values of impulse noise overpressure calculated by the two experiments were 165.9 dB and 165.2 dB,respectively.The results of simulated experiments were consistent with the peak value of impulse noise of the measurement curve.In the experiment,the sound insulation value of the helmet was 21.8 dB and the actual value of sound insulation of the helmet was 22 dB.Conclusion The simulated design of experiments for detection of impulse noise from explosion cutting during aircraft escape can provide data for pilots'protection against hearing damage and other research.