Research On Ground Simulation Test Method For Recoil Of Certain Type Of Gun

Aerogun recoil is an important fact while analyzing the structural strength, dynamic designing and evaluating, and fault diagnosing of aircraft. Besides, aerogun recoil also affects the safety of aircrafts. Thus, this paper carried out study on recoil measuring method on ground of a certain type of aerogun.The transmission characteristics of aerogun recoil were studied, and dynamical model of install interface system was built. By analyzing the experimental data and theoretical derivation, it is clear of aerogun recoil parameters that the amplitude of recoil is less than 20KN and the first order natural frequency of recoil is less than 100Hz. According to the installation of the aerogun and its recoil characteristics, the ground simulation test method of aerogun recoil was determined. Based on the ground simulated test principle, the calculating models of the aerogun recoil parameters and eccentricity parameters were set up. Moreover, the influence of recoil eccentricity on the test results was analyzed, and the influences of machining errors and installation errors, etc. on recoil test results were analyzed as well.Based on the characteristics of aerogun recoil, the design index and requirements of test bench were determined. Software ANSYS was used to build the finite element model of the existing test bench and the influence of stiffness of test bench on recoil test result was analyzed. It is clear that increasing the stiffness of the recoil test bench is conductive to improve the measurement precision of recoil, and the stiffness of the existing test bench is lower than need. Thus, two improved design method was proposed, and each new test bench was built by software SolidWorks and analyzed by ANSYS workbench. The simulation analysis results show that the first natural frequency of modified test bench increases from 10.116 HZ to 421.34 HZ, beneficial to improving the test accuracy of recoil.According to the aircraft gun recoil characteristic parameters and test bench structure, the in-situ calibration method was determined. Besides, an in-situ calibration device was designed based on the principle of the calibration, which can be used for both in-situ static calibration and dynamic calibration. Based on the theory of negative step signal produce in in-situ dynamic calibration device, the property of negative step signal was studied. The influences of different brittle material on amplitude and fall time of negative step signal were studied in detail. The experimental results showed that 8 mm thick High-Speed-Steel fracture moment can produce negative step signal with amplitude about 12 KN and falling time less than 50 us.