Research On OPCM Transducer Of Stress Wave Pre-stack Migration Imaging Technology In Structural Damage Detection

With the development of the new non-destructive testing technology,using Stack migration imaging technology of seismic wave in structural damage detection can overcome many shortcomings and limitations of traditional non-destructive testing We will come across a series of new problems because of the difference between engineering structures and geology structures.How to reduce the interference of lateral reflection wave,obtain the reflection wave signal of wide bandwidth, waveform sharp,and further improve signal to noise ratio,become a urgent problem which need to be solved.The transducer is one of the key devices for this technology, choosing ideal transducer is very helpful for solving the problem mentioned before and improve signal to noise ratio.Therefore,it becomes the keystone of the selection and development of ideal transducer in this study.In this paper,firstly,the propagation characteristics of ultrasonic wave in the medium and the basic theory of the transducer are theoretically analyzed,which lay a foundation for searching and developing the ideal transducer.It's is given by theoretic analysis expounded the Orthotropic Piezoelectric Composite Material(abbr.OPCM) actuator can drive signals of high-energy along the special direction as low-voltage driving,and obtained the orthotropic characteristics of OPCM sensor through formula derivation.Then,the basic theories and general steps of the finite element method in analysis of piezoelectric transducers,and the selection and input of units type and materials parameter in detail are introduced.It's obtained the difference between signals of two directions excited by OPCM actuator,and also obtained orthotropic characteristics of OPCM sensor,the sensitivity and bandwidth of the sensor is obtained by simulation.We obtained the acoustic field of the focused transducer and general transducer by simulation,the characteristic of the focused transducer is obtained by comparing with general transducer.Finally,we search out a kind of high frequency and short aftershock transducer is suitable for stress wave pre-stack migration imaging technology in the field of structural damage detection,and compared with general low frequency transducer through test,the results showed that the high frequency transducer is more suitable for stress wave pre-stack migration imaging technology than ordinary transducers in the field of structural damage detection.According to the theory,the OPCM actuator and the OPCM sensor were developed,by design experiment program and data processing, the difference between the signal attenuation of the two directions driven by the OPCM actuator was test and verified.We also obtain the relationship between the actuator output and the number of piezoelectric phase under the same voltage.It is provides protection for obtaining high energy reflected wave signal,weakening the impact of lateral interference.By test the orthotropic characteristics of OPCM sensor was obtained,which may provide references and support for reducing the impact of lateral interference and improving signal to noise ratio used in stress wave pre-stack migration imaging technology in the field of structural damage detection.