Research On The Influence Of Ambient Temperature On Shock Wave Test

The overpressure peak,positive pressure time and specific impulse of explosion shock wave are the main reference basis for evaluating the damage performance of ammunition.The accurate acquisition of shock wave parameters is of great significance to weapon development and damage assessment.The calibration of the test system is done at normal temperature in the laboratory.The actual ambient temperature during the explosion test is-40°C to 50°C.The environment during the explosion test differs greatly from the system calibration environment.Changes in system sensitivity and dynamic characteristics result in Test uncertainty increases.And the same ammunition produces different shock wave signals at different ambient temperatures.In view of this situation,it is necessary to study the influence of ambient temperature on the explosion shock wave test.Aiming at the impact of ambient temperature on the shock wave signal source,several overpressure empirical formulas were introduced and analyzed.The LS-DYNA simulation software was used to perform finite element analysis on the same ammunition at different ambient temperatures.Overpressure-time curves at different distances at different temperatures.It is concluded that when the temperature changes,the peak value of the shock wave overpressure will change with the temperature,and the error between the overpressure peak result obtained under different temperature conditions and the calculated overpressure peak result at 15°C varies from 2%to 14%.For the change of environmental temperature will make the test system of simulation fit step signal circuit and pressure sensor,dynamic characteristics of the shock wave overpressure test system are analyzed.And using the simulation software of ABAQUS to pressure sensor are analyzed in steady state thermodynamics,get the conclusion that the temperature changes,the pressure sensor by stress,heat flux and temperature have obvious change.It is improved on the existing dynamic calibration device of the shock tube in the laboratory.Crawler heating bands are wound on the high and low pressure chambers of the shock tube and the sensor seat to simulate the change of the ambient temperature.The experimental results obtained are consistent with the change trend of the peak value of shock wave overpressure calculated and simulated with the ambient temperature.Using BP neural network to compensate the temperature of piezoelectric pressure sensor,the error after temperature compensation is small.The RBF neural network is used to identify and dynamically compensate the shock wave test system.The results show that the output data of the RBF neural network and the output data of the ideal model of the test system have good consistency,and the average residual value is 0.6×10^-8,and the curve of the amplitude-frequency characteristic of the test system with dynamic compensation after optimization has been greatly improved.