Time-of-flight diffraction ultrasonics

About: Time-of-flight diffraction ultrasonics is a research topic. Over the lifetime, 544 publications have been published within this topic receiving 3189 citations.

A non-destructive ultrasonic testing

Abstract: The present invention relates to a non-destructive ultrasonic testing device comprising at least one pair of translators consists of a phased array transmitter (100) and a single-element receiver (200) strongly damped bandwidth. It also relates to a method as phased array transmitter (100) emits an ultrasonic beam having a wavefront with constant power across its section, electronically moved in sector mode and the single-element receiver (200) receives the ultrasonic waves from the area of ​​interest to be analyzed and the resulting ultrasonic beam emitted by the transmitter phased array (100), and optionally a step of receiving by the phased array transmitter (100) corresponding to a mode of operation in a pulsed mode echo and a step in which the phased array transmitter (100) works by emitting combined beams equivalent to a TOFD wide field (120).

Simulation of Ultrasonic Detection of Natural Defects in Weld with Finite Element Analysis

Abstract: With the continuous development of the ultrasonic detection technology, ultrasonic time of flight diffraction (TOFD) method has been widely applied. The paper investigated the TOFD technique in the detection of natural defects. TOFD detection experiment is established in Lab. The finite element analysis simulation of A-scan signal and ultrasonic TOFD technique in the detection of the longitudinal arrangement of pores defects within the weld specimen transmission are studied. The feasibility and correctness of the finite element analysis model are verified by comparing the experimental signals with the simulation signals.

Improved Hilbert transform to process the ultrasonic TOFD signal

Abstract: The difficulty in the TOFD is to identify the arrival time of every echo in the overlap waves, an improved Hilbert transform is proposed in this paper. Firstly, calculating the energy of the noise in the original signal, then processing the original signal and the pure noise that have the same energy as original signal with the EMD method. Comparing every IMF's energy of the two signal, we can decide which IMF to reserve and which to eliminate, filtering partial noisy of the original signal. After that, the threshold denoising is made to the selective IMFs to minimize the noise's impact. Finally, we can perform Hilbert transform. The simulation testified the effectiveness and accuracy of this technique and it can identify the TOFD signal with lower signal-to-noise ratio than perform Hilbert transform directly. In the experiment, the minimum time interval which can identify with this technique is 0.2us, the average error in identify some kinds of typical defects is 0.13mm.

Non-destructive inspection of girth welds by phased array and tofd methods

Abstract: In pipeline steels, which are generally made of low-carbon and low alloy high strength steels to meet the requirements, girth welds are used to join the pipes Submerged arc welding (SAW), semi-automatic or fully automatic welding system, is used to obtain better welding quality The parameters and used equipment changes with regards to the desired properties, ie pipe diameter and wall thickness Ultrasonic phased array and combined inspection systems, ie TOFD, have many significant advantages over conventional methods for pipeline inspection The ad-vantages can be better interpretation, higher detection rates, no chemical wastes, no safety hazards and no requirement the specific area for inspection Trend in the inspection system is decreasing the inspection time and increasing the detection sensitivity Automatic systems, ie PipeWizard, become popular with increasing demands