The future development trend of nondestructive testing

1. Ultrasonic phased array technology Ultrasonic testing is the most widely used non-destructive testing technology, with many advantages, but the couplant and transducer need to be close to the material being inspected, therefore, ultrasonic transducer, electromagnetic ultrasound, ultrasonic phased array technology Rapid development. Among them, ultrasonic phased array technology is a new hotspot in ultrasonic detection in recent years.

Ultrasonic phased array technology uses different shapes of multi-element transducers to generate and receive ultrasonic beams, and to control the arrival (or arrival) of sound waves by controlling the time delay of transmitting (or receiving) pulses from each array element in the transducer array. The phase relationship at a certain point in the body realizes the change of the focus point and the sound beam direction, and then uses a combination of mechanical scanning and electronic scanning to realize image imaging. Compared with traditional ultrasonic testing, ultrasonic phased array technology can detect complicated structural components, blind spot position defects, and high detection frequency due to controllable beam angles and dynamic focusing. It can achieve high speed, all-round and multiple Angle detection. For some of the tested objects, such as tubular welds, plates, and tubes, ultrasonic phased array technology can improve detection efficiency, simplify design, and reduce technology costs. Especially in the weld seam detection, using a reasonable phased array inspection technology, only the transducer can be scanned in the direction of the weld to achieve coverage scan detection of the weld.

2. Microwave non-destructive testing The microwave non-destructive testing technology will irradiate electromagnetic waves at a certain frequency from 330 to 3300 MHz to the measured object. The measured amplitude and phase changes of the reflected and transmitted waves as well as the mode changes of the waves are used to understand the measured values. Defects such as cracks, cracks, and pores in the sample were determined to determine the location and size of de-bonding, inclusions, etc. of the layered media, and the degree of unevenness of the internal density of the composite was examined.

The microwave has a short wavelength, a wide frequency band, good directivity, and a strong ability to penetrate the dielectric material, similar to ultrasound. Microwaves can also be used in both transmissive or reflective modes, but microwaves do not require a coupling agent to avoid contamination of the material by the coupling agent. Because microwaves penetrate non-metallic materials that attenuate sound waves, the most significant feature of this technique is that the most effective non-destructive scanning can be performed. The polar characteristics of microwaves make it possible to determine the direction of the fiber bundles of the material and monitor the non-linearity of the production process. It also provides accurate data to accurately determine the size and extent of defect areas. In addition, there is no need for special analysis processing, and three-dimensional real-time images of defective areas can be obtained at any time using this technology. Microwave non-destructive testing equipment is simple, low cost, easy to operate, and easy to carry. However, since microwaves cannot penetrate composite materials with good metal and electrical conductivity, they cannot detect defects in such composite structures and can only detect metal surface crack defects and Roughness.

In recent years, with the application of various high-performance composite materials and ceramic materials in military industry and aerospace industry, the theory, technology, and hardware system of microwave non-destructive testing have made great progress, which greatly promoted the microwave nondestructive testing technology. development of.