Evolution of failure pattern by laser induced shockwave within an adhesive bond

This work reveals that the dynamic response of a spherical cap bubble in contact with a rigid wall depends on the effective contact angle at the instant prior to collapse. This parameter allows us to discriminate between two regimes in which the mechanisms of interaction between the collapsing bubble and its surrounding medium differ significantly: when the contact angle is smaller than $90^{\circ }$ , a classical jet directed towards the wall is observed, whereas if the initial contact angle is larger than $90^{\circ }$ , an annular re-entrant jet parallel to the wall appears. We show that this change of behaviour can be explained using the impulse potential flow theory for small times, which shows the presence of a singularity on the initial acceleration of the contact line when the contact angle is larger than $90^{\circ }$ . Direct numerical simulations show that although viscosity regularises the solution at $t > 0$ , the solution remains singular at $t=0$ . In these circumstances, numerical and experimental results show that the collapse of flat bubbles can eventually lead to the formation of a vortex ring that unexpectedly induces long-range effects. The role of the bubble geometry at the instant of maximum expansion on the overall collapse process is shown to be well captured by the impulse potential flow theory, which can be generalised easily to other bubble shapes. These results may find direct application in the interpretation of geophysical flows as well as the control and design of biomedical, naval, manufacturing and sonochemistry applications.

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“…(2017) and Tahan et al. (2020). The laser is focused at the bottom of a liquid tank where a water drop is attached.…”

Section: Long-time Dynamicsmentioning

confidence: 95%

“…α > π/2). The generation of bubbles with α > π/2 can be investigated using the set-up described briefly in Appendix B, and Bourguille et al (2017) and Tahan et al (2020). The laser is focused at the bottom of a liquid tank where a water drop is attached.…”

Section: Viscous Correctionmentioning

confidence: 99%

On the dynamics of a collapsing bubble in contact with a rigid wall

et al. 2022

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“…Indeed, dynamics effects have already been used for the measurement of the bond strength of composite structures, for which various testing methods were developed in the past years. [1][2][3][4][5] The purpose of these methods is mostly to create a mechanical wave inside a structure to test the mechanical strength of the interface. [6][7][8][9][10] Among these methods, the ARCAN test can be mentioned.…”

Section: Introductionmentioning

confidence: 99%

“…[1,5,16] Some of them are contactless like the LAser Shock Adhesion Testing (LASAT), which consists of a rapid diagnostic process based on laser Doppler velocimetry. [2,4] The LASAT method can also be used as a composite delaminator on a variety of composite materials. [17,18] However, the short duration of the pulse and its sensitivity to spot size, which makes the technique dependent on edge effects, limit its application to composites and assemblies with a thickness lying between 0.8 and 3 mm.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of Cross‐Sectional Effects During the Magnetic Pulse Disassembly of Laminate Structures

et al. 2023

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To improve performances of engineered systems, laminate composite structures are widely used as they offer the best strength‐to‐weight ratio. However, maintenance and recycling of these structures still remain a challenge. One solution could be to disassemble the layers, without damaging them, so that they can be repaired, re‐used or recycled. To do so, impulsive source such as high pulsed powers are considered. In the present work, the influence of transverse or cross‐sectional effects on the wave propagation within the laminate and on its disassembly conditions is studied by the means of two‐dimensional numerical simulations performed on a model assembly using the finite element method. The specimen considered is an aluminium/steel assembly joined along a stripe. Two different modelings of the loading applied to the laminate of increasing complexity are successively considered. First, linear elastodynamic simulations show that transverse effects reduce by around 12% the maximum achievable interfacial tensile stress ratio compared with that predicted by the 1D reference model. Then, weakly coupled eddy current‐linear elastodynamic numerical analyses clarify the latter result with an estimation of about 16% with respect to the 1D analytical solution. These results permit the design of experiments serving as a proof of concept of the proposed process.This article is protected by copyright. All rights reserved.

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“…16,17 Tahan studied the positive correlation between laser energy and the damage threshold of aluminum plates by combining experimental and numerical simulation methods. 18 Arai conducted numerous laser shock experiments on T700 S/2592 material, and the results indicate that the laser power density is directly correlated with the interlayer cracking phenomenon of the material. 19 Ghrib, in his findings, showed that an increase in laser energy will expand the extent of delamination damage in composites.…”

mentioning

confidence: 99%

Effect of nanosecond laser pulse width and energy on damage characteristics in carbon fibre reinforced plastic (CFRP) laminates

Qu,

Song,

Wen

et al. 2024

Polymer Composites

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This study explores the effects of laser pulse width and energy on CFRP laminates damage in laser bond inspection technology. Three testing programs were used, including varying laser energy while keeping pulse width constant, altering pulse width while maintaining constant power density, and modifying pulse width while keeping energy constant. The results show that when the pulse width remains constant, increased laser energy has a minimal effect on the initial damage location but leads to gradual interlayer delamination and fiber fracture propagation toward the impact surface. With constant laser energy, a specific threshold for pulse width is observed. When the laser pulse width is below this threshold, it exhibits a positive correlation with the damage characteristics of CFRP laminates, whereas when it exceeds this threshold, it shows a negative correlation. Power density correlates with damage when pulse width is constant, but there is no direct correlation when pulse width varies.Highlights CFRP laminates underwent laser shock tests with varying pulse widths. Power density is positively correlated with damage under specific conditions. There exists a specific threshold for laser pulse width. In single‐sided laser shock, initial damage spreads within a specified range.

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Evolution of failure pattern by laser induced shockwave within an adhesive bond

Cited by 11 publications

References 13 publications

On the dynamics of a collapsing bubble in contact with a rigid wall

On the dynamics of a collapsing bubble in contact with a rigid wall

Numerical Analysis of Cross‐Sectional Effects During the Magnetic Pulse Disassembly of Laminate Structures

Effect of nanosecond laser pulse width and energy on damage characteristics in carbon fibre reinforced plastic (CFRP) laminates

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