Design Of Temperature And Pressure Control Ultrasonic Testing System Base On Virtual Instrument

The charactertistics of the sediments can be obtained fastly by the non-destructive techniquesof acoustic detection.So we can indirectly get the physical properties of the sediments.Thesediment acoustic testing is an important part of marine research.In-situ testing is the improtent areas because it have high-precision. But sailing is needed andthe equipment should be large and complex for in-situ testing.It is unrealistic for frequentlytesting of sediments.For the need of acoustic research,the Design of Temperature and Pressureand Pressure Control Ultrasonic Testing System base on Virtual Instrument was borned.Achievedtesting sediment and simulation of environment of the sediment in laboratory,to solve theproplem of frequently and a large number of experiments for obtain the characteristics ofacoustic of sediments.So, if the system is completely correct,it can replace the existing system ofin-situ testing.First,reviewed the research of sediment acoustic,and summarizes the sediments acoustictesting development and the in-situ testing situation in the national and domestic. Then introducethe theoretical basis of the system,Biot model and BISQ model,then analysis of the acoustictransducer and the transducer impedance.And then,introduce the framework of the systemhardware,consists of four parts:(1) Build a platform for small-scale temperature and pressurecontrol.(2)Power supply design,to provide a stable and reliable high voltage and low voltage DCpower.(3) Transducer drive circuitry to achieve a pulse excitation and continuousexcitation.(4)Automatic frequency tracking circuit.Started by the signal samling,through thephase circuit,then input to LabVIEW,to complete automatic tracking for the transducer.Then thehost computer was designed,to control the sampling and receiving enviromental data and thesignals of acoustic. Virtual instrument can be realize the automatically judge the time of the firstwave of the acoustic pulse excitation,and phase method test velocity and measurementattenuation of sound by the acoustic amplitude method.In the sediment chatacteristics testing experiments,have two experiments.One is comparative experiments to testing the systemreliability,another is practical experiments to test samples from HangZhou bay.Finally,make asummary and outlook about the research.In this thesis,for marine sediments.Temperature and Pressure and Pressure Control UltrasonicTesting System based on Virtual Instrument has been designed.The theories of sedimentsacoustic has been analyzed,and a test system hardware architecturehas has been developed threemethods of testing characteristics of sediment acoustic has been proposed,the main test problemwhich acoustic characteristics of sediment velocity and acoustic attenuation has been solved.