Pulse Peak Delay-Total Focusing Method for Ultrasonic Tomography on Concrete Structure

Abstract

An ultrasonic array device like the A1040 MIRA is used to non-destructively visualize the inside of concrete structures. A data set acquired by the ultrasonic array device is so unfocused that an image reconstruction algorithm is required to transform the data set into an understandable image. The image reconstruction algorithm like total focusing method exploits the time-of-flight of an ultrasonic pulse when focusing the image. While a high frequency ultrasonic pulse barely affects the accuracy of results, a low frequency ultrasonic pulse with a long wavelength causes an overall sagging of the resulting image around half wavelength of the pulse, which results in a poor quality of results. In this research, a modified total focusing method called pulse peak delay-total focusing method is proposed to calibrate the sagging in the resulting images due to the long wavelength of the pulse. The simulation of an ultrasonic array signal is implemented to validate the proposed method. The experimental results are compared with the simulation results to validate the proposed method. The simulation using the proposed method shows good agreement with experimental results. Analysis of results using potential damage curve and array performance indicator shows that the proposed method allows the higher accuracy, as well as the increased resolution of resulting images.

A New Prototype for Automatic Identification of Stone Block Internal Structure

“…This test uses the UPV (Ultrasonic Pulse Velocity) method, which is based on the propagation of high-frequency waves inside the sample material; the velocity of such waves varies according to the density and composition of the material. The presence of different amounts of water in the pores, among other factors, allows the evaluation of the homogeneity of the sample and simultaneously to infer the presence of fractures and veins [7][8][9]. Knowing the distance between testing transducers, it is possible to determine the average velocity of the wave.…”

“…The direct arrangement ensures the highest transmission rate. different amounts of water in the pores, among other factors, allows the evaluation of the homogeneity of the sample and simultaneously to infer the presence of fractures and veins [7][8][9]. Knowing the distance between testing transducers, it is possible to determine the average velocity of the wave.…”

Effect of frequency on the evaluation of the concrete defects by ultrasonic shear wave tomography

“…Frekans değişiminin beton elemanların UKDT sonuçları üzerindeki etkileri konusunda birkaç bilimsel çalışmaya rastlanmıştır [10], [22]- [24]. Dawood ve diğ.…”

“…Kwon ve diğ. [24] yaptıkları çalışmada ise ultrasonik sinyalleri üç farklı görüntüleme tekniği ve üç farklı frekansta değerlendirerek yeni bir görüntüleme tekniği önermişlerdir. Çalışmada tek bir demir bulunduran numune üzerinde ölçümler yapılmış ve görüntüleme teknikleri kıyaslanmıştır.…”

3D Internal Visualization of Concrete Structure Using Multifaceted Data for Ultrasonic Array Pulse-Echo Tomography

“…A beam pattern of the transducer in the MIRA device is considered by applying a weighting factor called the apodization factor [ 28 , 29 , 30 ]. A reflection sagging as a result of long ultrasonic pulse duration is complemented by the pulse peak delay calculation [ 31 ]. In the last step, trivial reflections like back-wall reflections are eliminated to emphasize the internal reflections.…”