Design Of Ultrasonic Test System For Solid Rocket Motor Combustion Surface Retreating Array

Solid rocket motor has been widely used in military and civilian fields because of its advantages of quick response,short preparation time,large thrust and low cost.It is of great significance to the development,test and production of solid rocket motor to effectively detect the real time change of propellant combustion surface retreat during the working process,which can reflect many combustion phenomena and problems,such as erosion combustion,unstable combustion,etc.However,the structure of solid rocket motors is a multi-layer bonded structure with large thickness and strong material ultrasonic attenuation,which requires low frequency and high pressure ultrasound for penetration detection.At the same time,solid rocket motor propellant combustion process is characterized by wide burning surface,fast changing frequency and long duration.In order to test comprehensiveness and improve detection efficiency,ultrasonic test system is required to be equipped with array,high precision and continuous long time test capabilities.The existing array ultrasonic testing system generally adopts high-frequency ultrasound,which is applied to the nondestructive testing of static defects.Due to the limited transmission and storage rate,the continuous testing time is short,which cannot meet the real-time testing requirements of propellant combustion surface retreat during the thermal test of solid rocket motor.In order to solve the above problems,the ultrasonic test system of solid rocket motor propellant backsliding array was designed based on ZYNQ SOC.Firstly,the propagation law of ultrasonic wave in solid rocket motor is studied,the relevant technical index of test system is proposed and the overall design scheme of the system is completed.Secondly,the system hardware circuits of bipolar high-voltage ultrasonic excitation module,multiplexing module,signal reception and conditioning module,high-speed differential analog to digital conversion module and transmission and storage control module are designed by modules.Thirdly,FPGA high-speed sequential logic circuits such as non-blocking ultrasonic drive,multi-channel cyclic reuse timing sequence and multi-channel synchronous high-speed acquisition drive are designed,as well as ARM embedded software programs such as multi-core heterogeneous high-speed data interaction link and gigabit Ethernet transmission control.Finally,the static test and thermal test of solid rocket motor are carried out to verify the performance of the system.The test results show that the array ultrasonic test system designed in this paper can complete the real-time test of propellant combustion surface retreat during the thermal test of solid rocket motors with a 6-shot,24-receipt array layout.The sampling rate is 10 MSps,the on-chip data link throughput rate is 640 Mbps,the array test repetition frequency is100 Hz,and the test time is not less than 40 s.It has the advantages of good real-time performance and high detection efficiency.