There is a need, then, for air-coupled ultrasound testing, which is now feasible because of low impedance focused narrow band transducers and sensitive electronics, both of which improve the signal-to-noise ratio. We present results obtained on fibre-reinforced plastics, water sensitive materials ...
or otherwise be destroyed. Additionally, air-coupled ultrasound offers the benefit of low, highly penetrating frequency ultrasound combined with the short wavelength in air. This allows the nondestructive inspection of previously untestable composits like thick, multilayer honeycombs, foam cores or green...
We experimentally demonstrate and theoretically analyze high Q-factor (~107) capillary-based optical ring resonators for non-contact detection of air-coupled ultrasound. Noise equivalent pressures in air as low as 215 mPa/√Hz and 41 mPa/√Hz at 50
Conventional ultrasound inspection has been a standard non-destructive testing method for a long time. In most cases, though, a liquid coupling medium, such as water or gel, is required because of the huge impedance mismatch at a solid-air boundary. The physical contact with a liquid medium ...
Passive focusing devices for Air-Coupled Ultrasound (ACU) transducers provide simple methods to concentrate the sound beam into a focus. This helps to improve lateral resolution and increase sensitivity. This work analyzed both theoretical and experimentally the behavior of three passive focusing devices...
non-destructive testingultrasoundtomographynon-contactair-coupledUltrasonic tomography is a powerful tool for identHallUniv IllinoisKerry S... Hall,S Kerry,Popovics,... - 《Smart Structures & Systems》 被引量: 1发表: 2016年 加载更多研究点推荐 Air-Coupled Ultrasonic Non-destructive Test structural...
aIt is therefore apparent that minimization of loss at every stage is key to achieving an acceptable signal to noise ratio for the inspection if air-coupled ultrasound is the chosen method of inspection 因此它是明显的损失的低估在每个阶段是关键的到达到一个可接受的针对噪音的信号比率为检查,如果空气...
Micromachined capacitance transducers have been investigated in practical situations where air-coupled ultrasound has current application. Their /spl sim/2... DW Schindel,DA Hutchins - 《IEEE Transactions on Ultrasonics Ferroelectrics & Frequency Control》 被引量: 161发表: 1995年 Through-thickness charact...
Air-coupled ultrasound is a non-contact technique for many manufacturing inspections including detection of voids, cracks in woods [1], electronic packaging materials, art work [2], and aerospace carbon fiber reinforced polymer and sandwich laminates [3]. More recently, human-computer interaction, ...
The situation is also pertains when ultrasound in air is transmitted to the interfaces between air and the object materials under inspection. (2) Attenuation of ultrasonic energy in air is about three orders of magnitude larger than in water at 1 MHz [1]. Despite such difficulties, Khuri-...