Research On NDT Technology For Fuel Tank Weld Seam

The research on the ultrasonic testing system of the fuel tank weld seam is of great significance for ensuring the sealing performance and quality reliability of the fuel tank.At present,the ultrasonic detection of the welding seam of the fuel tank cannot meet the needs of the practical application in the country.According to the defects that may appear in the welding process of the annular weld outside the fuel tank,and supported by the ultrasonic testing method,the nondestructive testing system for the weld of the fuel tank is studied and designed in this paper.First of all,according to the characteristics of fuel tank weld,the overall scheme of the detection system is designed.Aiming at the annular weld of fuel tank,a hardware control card based on STM32F103ZET6 single chip microcomputer is designed,and the operation interface of signal processing is designed with Labview upper computer software,and a set of testing mechanism of fuel tank weld is designed.In this system,the ultrasonic signal is transmitted and received by a single probe,and the annular weld of the fuel tank is detected by liquid immersion coupling between the probe and the weld.In the hardware design,the ultrasonic transmitting circuit,the signal receiving and processing circuit and the power module are mainly designed.The ultrasonic transmitting circuit generates a control signal to control the emission of the ultrasonic wave through the STM32;The receiving and processing circuit of the signal designs the limiting,amplifying,filtering and sampling circuits of the received echo signal.The design of the power module includes the selection and design of the high voltage power module and the design of the power supply of each chip in the hardware circuit;The high voltage power supply adopts high voltage power supply module,which provides enough voltage for the generation of high voltage pulse in the transmitting circuit;The supply voltage of the chip is obtained by the design of the converter circuit.The development process of each function module is introduced in the software design.In this paper,the design and development of STM32 main program and Labview upper computer program are completed.And the serial communication between the STM32 and Labview software is designed and completed,and the interface writing of the upper computer system is also completed.Finally,the key circuits are simulated and analyzed,and the weld specimens are tested,which verifies the reliability of the nondestructive testing system for fuel tank weld seams.