scholarly journals Air-Coupled, Contact, and Immersion Ultrasonic Non-Destructive Testing: Comparison for Bonding Quality Evaluation

2020 ◽  
Vol 10 (19) ◽  
pp. 6757
Author(s):  
Bengisu Yilmaz ◽  
Aadhik Asokkumar ◽  
Elena Jasiūnienė ◽  
Rymantas Jonas Kažys

The objective of this study is to compare the performance of different ultrasonic non-destructive testing (NDT) techniques for bonding quality evaluation. Aluminium-epoxy-aluminium single lap joints containing debonding in the form of release film inclusions have been investigated using three types of ultrasonic NDT methods: contact testing, immersion testing, and air-coupled testing. Apart from the traditional bulk wave ultrasound, guided wave testing was also performed using air coupled and contact transducers for the excitation of guided waves. Guided wave propagation within adhesive bond was numerically simulated. A wide range of inspection frequencies causing different ultrasonic wavelengths has been investigated. Average errors in defect sizing per ultrasonic wavelength have been used as a feature to determine the performance of each ultrasonic NDT technique. The best performance is observed with bulk wave investigations. Particularly, the higher frequencies (10–50 MHz) in the immersion testing performed significantly better than air-coupled testing (300 kHz); however, air coupled investigations have other advantages as contactless inspection. Whereas guided wave inspections show relatively lower accuracy in defect sizing, they are good enough to detect the presence of the debonding and enable to inspect long range. Even though each technique has its advantages and limitations, guided wave techniques can be practical for the preliminary in-situ inspection of adhesively bonded specimens.

Author(s):  
Ju Ding ◽  
Min Zhang ◽  
Shu-hong Liu ◽  
Chen-huai Tang ◽  
Xu-chen Zhu ◽  
...  

Abstract This paper discusses four different ultrasonic guided wave standards. Three of them are China’s national standards or industry standards: GB/T 31211-2014 “Nondestructive Testing Ultrasound Guided Wave Detection”, GB/T 28704-2012“Non-destructive testing—Test method for ultrasonic guided wave testing based on magnetostrictive effects”, and DL/T 1452-2015 “Thermal Power Pipeline Ultrasound Guided Wave Detection”. The another one is ASTM E2929:“Standard Practice for Guided Wave Testing of Above Ground Steel Piping with Magnetostrictive Transfusion”. Through six aspects in this article, including testing application scope, preliminary requirements, standard specimen and comparative specimen, distant amplitude curve and time gain curve, the existing difference between China and America is obvious and diversity. It is necessary to explore the underlying reasons for the connection of Chinese code and international code in the field of Non-destructive testing. During the standardization, anyone of the standard should be actually compared on the presentation of chart, and the verification and comparison of results, and lists the similarities and differences of each part based on GB31211. This paper provides reference for China to integrate with foreign standards in the field of ultrasonic guided wave detection of pressure vessel and pipelines.


Author(s):  
George M. Lloyd ◽  
Gu Hua ◽  
Ming L. Wang

Interdigitated surface and guided-wave transducers have only recently received attention as possible tools for non-destructive testing. This may be due in part to the increasing attention being paid to piezoelectric polymers as practical transduction materials for structural sensing and actuation. However, much remains to be done to produce a rugged, monolithic device oriented toward these sorts of applications, to characterize and optimize its passive and active response, to develop excitation strategies and signal processing algorithms that in tandem can be employed for arrayed structure monitoring applications. In this paper we confine ourselves to the first two topics and report on the development and proof-of-principle testing of a monolithic interdigitated polyvinyldine fluoride (PVDF) transducer. Specifically, we report on the design and response of an interdigitated transducer with relatively large finger spacings. The finger spacing yield measureable responses in the asymptotically slow single-mode region of Lamb wave dispersion behavior for frequency-thickness products which may be useful for nondestructive testing of many mechanical and civil structural systems.


2018 ◽  
Vol 8 (12) ◽  
pp. 2378 ◽  
Author(s):  
Houman Mahal ◽  
Kai Yang ◽  
Asoke Nandi

In the past decade, guided-wave testing has attracted the attention of the non-destructive testing industry for pipeline inspections. This technology enables the long-range assessment of pipelines’ integrity, which significantly reduces the expenditure of testing in terms of cost and time. Guided-wave testing collars consist of several linearly placed arrays of transducers around the circumference of the pipe, which are called rings, and can generate unidirectional axisymmetric elastic waves. The current propagation routine of the device generates a single time-domain signal by doing a phase-delayed summation of each array element. The segments where the energy of the signal is above the local noise region are reported as anomalies by the inspectors. Nonetheless, the main goal of guided-wave inspection is the detection of axisymmetric waves generated by the features within the pipes. In this paper, instead of processing a single signal obtained from the general propagation routine, we propose to process signals that are directly obtained from all of the array elements. We designed an axisymmetric wave detection algorithm, which is validated by laboratory trials on real-pipe data with two defects on different locations with varying cross-sectional area (CSA) sizes of 2% and 3% for the first defect, and 4% and 5% for the second defect. The results enabled the detection of defects with low signal-to-noise ratios (SNR), which were almost buried in the noise level. These results are reported with regard to the three different developed methods with varying excitation frequencies of 30 kHz, 34 kHz, and 37 kHz. The tests demonstrated the advantage of using the information received from all of the elements rather than a single signal.


2015 ◽  
Author(s):  
Umar Amjad ◽  
Susheel K. Yadav ◽  
Chi H. Nguyen ◽  
Mohammad Ehsani ◽  
Tribikram Kundu

2013 ◽  
Vol 834-836 ◽  
pp. 233-236
Author(s):  
Lin Dong Liu ◽  
Xiao Qing Wu

In this paper, an attempt is made to introduce the defect types relevant to ultrasonic non-destructive testing, and then, we explain how these defects generate in fiber-reinforced composites. The common failure modes which occur are described and discussed. The significance of each of the fracture mechanisms, in terms of their effects on the residual load-bearing properties, is considered. The second part describes briefly the main relevant ultrasonic NDT methods used to identify these defects and indicates the sensitivity to the different types of defect.


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