Defect Detection via Instrumented Impact in Thick-Sectioned Laminate Composites

Esola, Shane; Bartoli, Ivan; Horner, Suzanne; Zheng, James; Kontsos, Antonios

doi:10.1007/s10921-017-0422-8

Cited by 4 publications

(3 citation statements)

References 27 publications

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“…Existing studies have shown that the physical phenomenon behind the coin-tap test can be explained by the principle of membrane resonance [16][17][18][19]. When the composite laminate is delaminated or the skin of the honeycomb sandwich structure is debonded from the core, the material layer above the defective area can be imagined as a thin plate bound by its edge [20]. Assuming that the radius of the defective area is R, when the lateral concentrated force F acts on the defective area, the force analysis of the section is shown in Figure 3.…”

Section: Shock and Vibrationmentioning

confidence: 99%

Research on the Distribution Rule of Percussion Response Pulse Width in Coin‐Tap Test

et al. 2021

Shock and Vibration

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The coin-tap method performs nondestructive testing by measuring the width of the tapping response pulse on the surface of the material. Existing studies have shown that defects in the material will cause the width of the tapping response pulse to increase. However, experiments have confirmed that different detection positions in the defective area will show different values of the width of the tapping response pulse, and the physical laws behind it have not been studied yet. To discuss its physical meaning, a mathematical model of the defective area is established, a method for calculating the width of the tapping response pulse is proposed, and a composite honeycomb structure with preset defects is used for data testing. Both the test results and the calculation results show that the pulse width of the tapping response will decrease with the increase of the defect depth and the deviation of the tapping position from the defect center. The consistency between the calculated results and the experimental results shows that the established defect model and pulse width calculation method can better explain the distribution law of the pulse width of the tapping response in the defective area.

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Section: Shock and Vibrationmentioning

confidence: 99%

Research on the Distribution Rule of Percussion Response Pulse Width in Coin‐Tap Test

et al. 2021

Shock and Vibration

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“…Modelling for steel structures has demonstrated that defects' local resonance does dominate the signal [10]. Despite this, the key study of TT sonic/force analysis methods applied to thick composites by [11] shows that the vibrational modes of the surface locally and globally need to be considered in order to build an accurate defect map for thick composites. The additional outcome of this study is the determination that force and sound combined can provide more information than either on their own, though without a suitable fusion method.…”

Section: Introductionmentioning

confidence: 99%

Force and Sound Data Fusion for Enhanced Tap Testing Scanning of Composites

Poole

Hartley

2023

IEEE Access

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Coin or hammer tap testing is one of the oldest methods of NDT inspection. Inspection techniques originated with human operators observing the tonal change of the audible sound produced by striking were later automated with use of mechanical instruments that measured surface stiffness from the contact time of the striker. Numerous applications have evolved from this technique, from predicting rock falls to defect detection and identification in composite structures. Since operator applied tap testing requires extensive training and knowledge of the part's structure to accurately locate defects, it is widely regarded as a subjective method and does not allow for digitised recording of results or validation against reference standards. In addition, this type of tap testing is generally confined to simple structural materials such as thin skin composites with foam or honeycomb cores, where defects can easily be identified. More complex structures with varying thicknesses present a much greater challenge for this method, as defects may have a similar response signal to thinner, non-defective regions, so neither force nor sonic data can differentiate between the two. This article seeks to introduce a novel analysis technique, applying the principle of resonant membranes to global and local frequency perspectives to generate two functions. The first sharpens tap testing images from the sonic and force responses returning greater clarity when observing the underlying structure, the second creating a local ranking of defect positions allowing an automatic highlighting of regions of high depth flux. The outcome is a process that enables operators to identify disbonds within an unknown composite structure with greater precision than either force or sound approaches on their own in lieu of prior information of defect, surface, or global resonance modes. The developed technique is suitable for application with a robotic platform to unknown curved composites surfaces since future developments will aim to achieve robotised TT deployment. The algorithm is validated within a laboratory environment on a physical reference sample, representative of an RNLI Severn class lifeboat hull, imitating a dry-dock inspection scenario.INDEX TERMS Tap testing, force/sound data fusion, thick composite inspection.

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“…The coin-tap test has also been applied in the damage inspection of composite laminates. 46 A tapping system was proposed by Lyu et al 47 to detect different types of defects, including delamination and voids. With their advantages of wide bandwidth along with dual-sensing and actuating functions, 48–50 Lead zirconium titanate (PZT)-based transducers are used to detect the typical defects, including the debonds, 51,52 voids, 53 and cracks.…”

Section: Introductionmentioning

confidence: 99%

Detection of near-surface defects using a coin-tap approach based on the equivalent impact stiffness of Hertzian contact theory

Chen

Huo

Song

et al. 2022

Structural Health Monitoring

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In this paper, a novel method to analyze the mechanical behavior of the coin-tap test using the principle of pounding mechanics is proposed. Based on the Hertzian contact theory, the linearized contact law is applied to simplify the mathematical model of the coin-tap test. By modeling the stiffness of the defect as an equivalent spring in a serial connection with the contact stiffness, the impact force and impact time can be theoretically derived. The derived expressions show that, the closer the defect is to the surface of the structure, the longer the impact duration time and the smaller the impact force will be. In addition, with the increase of defect radii, the peak force and duration of the impact will decrease and increase, respectively. Another innovation of this paper is that an equivalent impact stiffness (EIS)-based damage index (DI) is proposed to reveal the severity and location of the near-surface damages. Two validation experiments were carried out to validate the influences of the damage’s radii and under-surface depths. In the first experiment, the impact force and time of the central point for eight plates are measured to validate the accuracy of the proposed model. In the second experiment, 18 points on the horizontal centerline of eight specimens were tapped at an interval of 1 cm. The recorded pounding force and time were processed by EIS-based DI. Experimental results show that the EIS-based DI can effectively predict the position and severity of the defects and it holds the potential for practical application.

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Defect Detection via Instrumented Impact in Thick-Sectioned Laminate Composites

Cited by 4 publications

References 27 publications

Research on the Distribution Rule of Percussion Response Pulse Width in Coin‐Tap Test

Research on the Distribution Rule of Percussion Response Pulse Width in Coin‐Tap Test

Force and Sound Data Fusion for Enhanced Tap Testing Scanning of Composites

Detection of near-surface defects using a coin-tap approach based on the equivalent impact stiffness of Hertzian contact theory

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