1. Ultrasound testing, acoustic impedance testing and acoustic fixed distance transmission receiving testing are widely used in aerospace, automobile, chemical industry and other manufacturing industries. Composite materials and bonded structures are commonly used nondestructive testing methods. There are many defects in composite materials and bonded structures. It is difficult to detect all defects with only one testing method.

2. SMART-6000 is a comprehensive composite material testing system, which has ultrasonic, acoustic impedance, acoustic fixed-distance emission and reception detection methods. The instrument is designed with ABC scanning, frequency sweeping, radio frequency, pulse and MIA modes.


Ultrasonic mode

Ultrasonic testing is widely used in the detection of internal defects of metal, nonmetal, composite materials. For thick composite materials, such as multi-layer metal bonded composite plate, ultrasonic Pulse Echo (non-contacting and contacting) or Through Transmission method is commonly used to detect poor bonding, debonding, holes, etc. inside the material.

Sound sweep frequency mode

20KHz~80KHz electronic sweep is used to excite the transmit transducer of acoustical fixed distance transmitting/receiving probe in sound sweep frequency mode. Different frequencies will work on the workpiece being inspected in many times. And the signals acquired will be linked in two-dimensional coordinate mode according to the order and finally form the sweep frequency image.

   

RF(Radio frequency) mode

RF mode uses cw steady-state incentives to measure the change of amplitude and phase, this can be used to detect debonding.

   

Impulse mode

Impulse mode uses short-pulse to excite the transmit transducer. Select the best frequency to make the workpiece generate the biggest bending vibration. When the probe is passed over the poor bonding part, the signal amplitude will be bigger than that on the good bond part.

   

Acoustical impedance detecting

Acoustical impedance detecting (also known as mechanical impedance analysis - MIA) is a method to change the mechanical impedance reflecting the material vibration performance into load impedance of energy transducer. Since there’s a certain relation between the mechanical impedance and the material structure, by measuring the performance of the energy transducer we can estimate the variation of the material mechanical impedance, and achieve the detection purpose. A drive element generates audible sound waves, sound waves are transmitted to the structural parts through a special probe and stimulate the vibration of the structural parts. A receive element detects the effect of composite material bond variations on probe loading. Acoustical impedance method is typically used to detect the quality of bonding in Honeycomb sandwich plate. Acoustical impedance method does not require for couplant.