Surface mechanics design by cavitation peening

Soyama, Hitoshi

doi:10.1049/joe.2015.0055

Cited by 9 publications

(9 citation statements)

References 25 publications

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“…up to a few microseconds before the bubble collapse – similar bubble shapes are observed independently of the viscosity, a general scaling over a wide range of maximum radii and viscosities seems difficult, as the substantial viscous dissipation is associated with the entirety of the complex, non-spherical flow field. These experimentally confirmed data could be useful for the validation of numerical simulations of single bubble dynamics, for evaluation of the distance of bubbles for surface treatment and particle generation (Soyama 2015; Barcikowski et al. 2019), and to test advanced analytical models of the collapse at small stand-off distances.…”

Section: Discussionmentioning

confidence: 75%

The Rayleigh prolongation factor at small bubble to wall stand-off distances

2022

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The Rayleigh collapse time is the time it would take to shrink an empty spherical bubble in an infinite liquid domain to zero size, which is a function of ambient pressure and initial bubble radius. If a solid boundary is located in the vicinity of the shrinking or collapsing bubble, then liquid flow is hindered, such that the collapse time is prolonged. This can be quantified with the Rayleigh prolongation factor $k$ . Here, we provide $k$ for intermediate to smallest bubble to wall stand-off distances. It is measured with single laser-induced cavitation bubbles in water close to a solid boundary. Maximum bubble radii are determined from microscopic high-speed imaging at one million frames per second. Collapse times are measured acoustically via the acoustic transients emitted during bubble seeding and collapse. The experimental findings are compared, with good agreement, to numerical simulations based on a volume of fluid method. As a result, a polynomial fit of $k$ versus stand-off distance is given for the near-wall bubble collapse in water. Then the influence of the viscosity on $k$ is studied numerically in the near-wall regime.

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Section: Discussionmentioning

confidence: 75%

The Rayleigh prolongation factor at small bubble to wall stand-off distances

2022

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“…It has been believed that the peening effect is due to laser ablation, as the amplitude of the shock wave induced by laser ablation is larger than that due to laser cavitation; however, when the impact through the target was measured using a Polyvinylidene Fluoride (PVDF) sensor [15,16], the impact due to laser cavitation collapse was found to be larger than that due to laser ablation [3,17]. Soyama proposed a technique for cavitation peening using a pulsed laser without laser ablation by focusing the laser in the water [18].…”

Section: Introductionmentioning

confidence: 99%

Comparison between Shot Peening, Cavitation Peening, and Laser Peening by Observation of Crack Initiation and Crack Growth in Stainless Steel

Soyama

2019

Metals

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The traditional technique used to modify the surface of a metallic material is shot peening; however, cavitation peening, a more recent technique in which shot is not used, was developed, and improvements in the fatigue strength of metallic materials were demonstrated. In order to compare the fatigue properties introduced by shot peening with those introduced by cavitation peening, crack initiation and crack growth in specimens of austenitic stainless steel (Japanese Industrial Standards JIS SUS316L) treated using these techniques were investigated. With conventional cavitation peening, cavitation is produced by injecting a high speed water jet into water. In the case of submerged laser peening, bubbles are generated using a pulsed laser after laser ablation, and the impact produced when the bubbles collapse is larger than that due to laser ablation. Thus, in this study, cavitation peening using a water jet and submerged laser peening were investigated. To clarify the mechanisms whereby the fatigue strength is improved by these peening techniques, crack initiation and crack growth in specimens with and without treatment were examined by means of a K-decreasing test, where K is the stress intensity factor, and using a constant applied stress test using a load controlled plane bending fatigue tester. It was found that the improvement in crack initiation and the reduction in crack growth were roughly in a linear relationship, even though the specimens were treated using different peening methods. The results presented here show that the fatigue strength of SUS316L treated by these peening techniques is closely related to the reduction in crack growth, rather than crack initiation.

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“…The amplitude of the signal from the submerged shockwave sensor with LA was larger than that of LC. Thus, when the focus point of the pulse laser was set in the water, LC can peen the surface without LA [91]. As shown in Figure 11b, the impact induced by secondary collapse was detected at t = 1.54 ms by the PVDF sensor, although the secondary collapse could not be observed by the submerged shockwave sensor (Figure 11c).…”

Section: Laser Cavitationmentioning

confidence: 95%

Cavitation Peening: A Review

Soyama

2020

Metals

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The most popular surface modification technology used to enhance the mechanical properties of metallic materials is shot peening. Shot peening improves fatigue life and strength by introducing local plastic deformation pits. However, the pits increase surface roughness, which is a disadvantage for fatigue properties. Recently, cavitation peening, in which cavitation bubble collapse impacts are used, has been developed as an advanced surface modification technology. The advantage of cavitation peening is the lesser increase in surface roughness compared with shot peening, as no solid collisions occur in cavitation peening. In conventional cavitation peening, cavitation is generated by injecting a high-speed water jet into water. However, cavitation peening is different from water jet peening, in which water column impacts are used. In the present review, to avoid confusing cavitation peening and water jet peening, fundamentals and mechanisms of cavitation peening are described in comparison to water jet peening, and the effects and applications of cavitation peening are reviewed compared with the other peening methods.

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Surface mechanics design by cavitation peening

Cited by 9 publications

References 25 publications

The Rayleigh prolongation factor at small bubble to wall stand-off distances

The Rayleigh prolongation factor at small bubble to wall stand-off distances

Comparison between Shot Peening, Cavitation Peening, and Laser Peening by Observation of Crack Initiation and Crack Growth in Stainless Steel

Cavitation Peening: A Review

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