Biomechanics Simulation and Damage Analysis of Head and Neck on Extraction Aircrew Escape System

Currently, aviation lifesaving methods are mostly divided into ejection escape and traction rescue. Compared with ejection lifesaving, traction lifesaving technology is an active lifesaving method, and its advantages are simple structure, light weight, small space occupation, good stability, more suitable for low-speed light aircraft lifesaving. It uses the rocket to pull the crew out of the aircraft in an accident. The rocket first exits the cockpit, and then pulls out a rope to pull the crew out of the aircraft, and after a delay of a certain time, the parachute automatically opens, so that the crew can safely land on the ground. In order to avoid serious injury in the process of traction, it is necessary to study the stress of human head and neck joints which are most vulnerable to injury in the process of traction. In this study, CT image scans of the head and neck were performed on 2 volunteers who fit the body standards of pilots. MIMICS software was used to process the scanned image data and reconstruct the prototype of the human head and neck model. The model was further processed by geomagic software to obtain a complete and smooth head and neck geometric model. A complete head and neck finite element model was obtained by dividing the grid of the geometric model, setting the element format and material parameters of the body structure. The finite element model of head and neck was verified by axial impact test of cadaver from 0° and 15°. The results showed that the finite element model established in this paper has high accuracy. After processing the test data, the initial loading conditions of the traction rescue simulation were obtained, and the stress of the head and neck joints during the helicopter rescue was simulated. The LS-PrePost module in ANSYS software was used to obtain the data needed for dynamic response and damage analysis. Based on the HIC and NIC criteria, the head and neck injury during the life-saving process was determined. The results showed that the neck of the human body may be damaged during the positive traction, and the analysis of the obtained stress curve showed that the vertebrae may fracture at the maximum stress, and the intervertebral disc may be caused by overextension. In order to reduce the deformation of the cervical vertebra during the life-saving process of traction, a set of effective restraint system should be designed to restrain the human body and reduce the relative movement between various vertebrae in the neck, so as to better protect the cervical vertebra.