The Research Of Metal Magnetic Memory Detector

Metal magnetic memory testing(MMMT) is by far a new effective non-destructive method for early diagnosis of the ferromagnetic internal damage, it can be used to detect the stress concentration areas in ferromagnetic metallic component so as to accomplish inchoate exploration and diagnose of structural damage and evaluate security of equipment accurately.So MMMT technology is very important to the prevention of sudden accident. Although MMMT has good application prospect,its deficiency of theory research has been become one bottleneck of restricting its application and development.Present theory study indicates that the tangential orientation of the stress concentration region magnetic field component Hp (x) has a maximum value, while the normal component Hp (y) changes direction and has zero value.We define the normal component Hp (y) changes direction and has zero value as the basis to determine the stress concentration areas.This paper introduces the MMM theory as well as the hardware and software design of the detection system. The system hardware consists of the DSP-TMS320F28335, CPLD-EPM570, The HMC1052type magnetoresistive sensor, signal conditioning circuitry and peripherals. The system software includes DSP software, CPLD software and host computer Lab VIEW software design.The system workflow is:the signal, which is detected by the sensor and processed by the conditioning circuit, is collected by the A/D acquisition module of the DSP, after DSP processes the signal then communication with CPLD, CPLD display the signal on the LCD, meanwhile,by using a serial port DSP sent the signals to PC,and then PC use Lab VIEW software to save the signals.After the actual debugging and verification, the testing equipment has the advantages of simple structure, high control speed, reliable performance, and has good application prospects.