Ultrasonic pulse-echo

Due to the outer circumference of the silo, about 25 meters, a non- or rarely destructive testing method was needed for the localization. Because the building was still in use, it was only accessable from the exterior side. We chose the ultrasonic pulse-echo-technique as an appropriate way of doing the testing. 

Hillger, W. Inspection of Concrete by Ultrasonic-Pulse-Echo-Technique, In Proceedings of the European Conference on Non Destructive Testing, Nice 1994, pp. II59-II63... 

The common civil engineering seismic testing techniques work on the principles of ultrasonic through transmission (UPV), transient stress wave propagation and reflection (Impact Echo), Ultrasonic Pulse Echo (UPE) and Spectral Analysis of Surface Waves (SASW). 

Instrumentation for revealing the presence of bulk quantities of concealed drugs will differ from those developed to find evidence of minute quantities on surfaces. Bulk detection is concerned with amounts ranging from grams to kilograms [4], Bulk detection is done by manual inspection, X-ray, CT scans, and acoustic inspection. X-ray or CT scanners used as bulk detectors have sensitivity of 2-10 g, and suspect items are subsequently confirmed by chemical analysis. Hand-held acoustic inspection instruments such as the Acoustic Inspection Device (AID) and the Ultrasonic Pulse Echo (UPE) developed by Pacific Northwest National Laboratories/Battelle, can be used for analysis of cargo liquids in sealed containers of various sizes within seconds [5]. The acoustical velocity and attenuation of multiple echoes returned to the instrument is evaluated by software which compares the data to the shipping manifest. 

Figure 4. Schematic diagram of the experimental configuration for an ultrasonic pulse-echo experiment.

Figure 10. Ultrasonic pulse-echo technique for determining the thickness of layers in multilayer materials.

Povey, M.J.W., Wilkinson, J.M. 1980. Application of ultrasonic pulse-echo techniques to albumen quality testing - a preliminary report. Br. Poult. Sci. 21, 489-495. 

McClements, D.J., and P. Fairley, Ultrasonic Pulse Echo Reflectometer, Ultrasonics 29.-58-62 (1991). 

The acoustic velocity of SiC has been measured using both ultrasonic resonance [1] and ultrasonic pulse echo techniques. The latter has resulted in the appearance of CVD-SiC diaphragms in commercially available speakers [2]. 

Elastic constants (E and v) were determined by ultrasonic pulse-echo method using a 200 MHz ultrasonic pulser-receiver (Panametrics 5900 PR, USA) and bulk density was determined by Archimedes method. Crystalline phases were identified by X-ray diffraction (XRD) analysis and the microstructural and iiactogn hic analyses were perfomied using a scanning electron microscope (SEM) (JMS 6300, Jeol, Japan) coupled with an energy dispersive spectroscope (EDS) (Noram, USA). 

Ultrasonic Pulse Echo Contact Impedance Testing... 

Wong BS, Tui CG, Tan KS, Kwan KW, Evaluation of small defects in carbon fiber reinforced composites using ultrasonic pulse echo amplitude, Insight, 39(4), 257-263, 1997. 

Greiner et al. (1976) also have determined the single crystal elastic constants from 6 to 300 K using the ultrasonic pulse-echo-overlap (10 MHz) method. No thermal expansion corrections for density and acoustic path length were made because no thermal expansion data were available in the experimental temperature range. In addition to the four constants measured by Lenkkeri and Palmer (1977), Greiner et al. measured C13 consequently, polycrystalline elastic... 

In recent years a number of other non-intrusive techniques for determining the contents and status of unopened munitions have been developed. These include neutron interrogation techniques such as neutron-induced prompt photon spectroscopy and hydrogen concentration measurement, and ultrasonic pulse echo and acoustic resonance techniques. Equipment based on the use of neutron-induced prompt photon spectroscopy has been fielded and successfully used by US EOD teams on many occasions over the last two years. This equipment, which is based on the analysis of photons emitted as the result of the interaction of neutrons with the chemical elements present in the munition and its contents, makes it possible to identify the presence or absence of key elements such as phosphorus, sulphur, chlorine, fluorine and arsenic within the munition. Clearly this information not only helps to identify the presence of a chemical fill, but in many circumstances also means that it is possible to identify the fill. 

Figure 15.12 Ultrasonic pulse-echo technique for detection of adhesion flaws.

J. L. Rose, M. J. Avioli, and R. Bilgram, A feasibility study on the nondestructive evaluation of an adhesively bonded metal to metal bond An ultrasonic pulse echo approach, Br. J. Non-Destr. Test, 25, 67 (1983). 

Fig. 12. A tear-strap inspection sample problem showing in the proper time domain gated region the decrease in amplitude and signature change for the poorly bonded tear strap and the loss of signal amplitude for the debonded tear strap, (a) Ultrasonic pulse-echo approach for tear strap inspection, (b) Underside of a tear strap, (c) Ultrasonic signals for the sample tear strap inspection (pulse-echo) / = 1.1 MHz, 6 = 45° (i) good adhesion, (ii) poor adhesion and (iii) bad adhesion (debonded).

The ultrasonic pulse echo (UPE) method is used to measure the wall thickness of vessels. UPE can be adapted to distinguish chemical munitions from conventional types and to determine the filling level of shells. Differentiation between munition types is based on the fact that, besides the normal reflexion signal from the front wall, the detection of a rear-wall or burster-tube echo clearly indicates the presence of a liquid as filling, whereas with conventional munitions the original pulse is reflected only from the front wall. 

Tattersall, A.G., 1973, "The Ultrasonic Pulse-Echo Technique as Apphed to Adhesion Testing", J. Phys. D Appl. Phys, Vol. 6, pp819-832. 

Tattersall, H.G., 1973, The Ultrasonic Pulse-Echo Technique as Applied to Adhesion Testing, J. Appl. Phys.D., 6, 819-832. 

---