Effect of single-pulse laser irradiation energy on healing fatigue damage for copper film

Ren, Chong-Gang; Shang, De‐Guang; Wang, Lu; Guo, Y. B.

doi:10.1007/s12206-013-1206-4

Cited by 4 publications

(7 citation statements)

References 21 publications

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“…pointed out that the major residual stress relaxation took place during the early stage, and the rate of residual stress relaxation was drastic in the early stages of fatigue cycling, which is consistent with Ref. []. Kodama found the residual stress relaxation of annealed mild steel varied linearly with the logarithm of the fatigue cycles while the relaxation rate was proportional to the stress amplitude.…”

Section: Resultssupporting

confidence: 86%

“…Under the optimal laser irradiation parameters, the surface microscope structure of the treated specimen had been observed in Ref. [] (surface roughness R a : 379.01 nm, R q : 468.20 nm, and R t : 3.6 um). By contrasting the surface states of the original specimen surface roughness ( R a : 401.85 nm, R q : 490.00 nm, and R t : 4.42 um), it is found that a good surface state can be obtained by laser surface irradiation treatment for copper film, as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The S–N curve for the original notched specimens can be obtained by fitting the fatigue experimental data in previous work, as shown in Fig. .…”

Section: Resultsmentioning

confidence: 99%

“…The single pulse energy and the laser spot width and pulse number are controllable. Details of laser surface irradiation treatment mode can be found in Refs []. The optimal laser irradiation parameters were obtained in the previous work, which is the energy density of 7 × 10 3 J/m 2 and the pulse number of 1.…”

Section: Methodsmentioning

confidence: 99%

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Fatigue life prediction of damaged copper film by laser irradiation repairing

Ren

Shang

Sun

et al. 2014

Fatigue Fract Eng Mat Struct

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A B S T R A C T The mechanism of fatigue life improvement for damaged and undamaged copper film specimens with thickness of 25 um was investigated by laser surface irradiation under optimal parameters of laser irradiation at different loading levels. The results showed that the degree of improvement in fatigue life for the damaged specimens is more evident when the applied nominal stress was larger. The hardening induced by laser irradiation and a smooth surface feature can be obtained after the laser irradiation treatment, which results in fatigue life to be extended. A fatigue life prediction method was proposed by the view of equivalent stress. The predicted lives by the proposed prediction method were in good agreement with the experimental results.Keywords healing fatigue damage; laser surface irradiation; copper film; fatigue life prediction. N O M E N C L A T U R ED = damage amount e = nominal strain of notched specimens. h D = hardening coefficient K′ = cyclic strength coefficient K 0 ′ = cyclic strength coefficient for original specimens K 1 ′ = cyclic strength coefficient for the undamaged specimens (D = 0) after LSI K 2 ′ = cyclic strength coefficient for the damaged specimens (D = 0.5) after LSI K σ = effective stress concentration factor LSI = laser surface irradiation n′ = cyclic strain hardening exponent n 0 ′ = cyclic strain hardening exponent for original specimens n 1 ′ = cyclic strain hardening exponent for the undamaged specimens (D = 0) after LSI n 2 ′ = cyclic strain hardening exponent for the damaged specimens (D = 0.5) after LSI N c = fatigue life of specimens corresponding to the conversion stress N r = residual life of specimens healed by laser irradiation treatment R a = arithmetical average roughness R q = root-mean-squared roughness R t = peak-to-valley difference s = nominal stress of notched specimens α σ = theoretical stress concentration factor Δe = nominal strain range of notched specimens Δe 0 = nominal strain range of specimens before laser irradiation treatment Δe t = nominal strain range of specimens after laser irradiation treatment Δs = nominal stress range of notched specimens Δε = strain range Δε e = elastic strain range Δε p = plastic strain range

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Section: Resultssupporting

confidence: 86%

Section: Resultsmentioning

confidence: 99%

“…The S–N curve for the original notched specimens can be obtained by fitting the fatigue experimental data in previous work, as shown in Fig. .…”

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Fatigue life prediction of damaged copper film by laser irradiation repairing

Ren

Shang

Sun

et al. 2014

Fatigue Fract Eng Mat Struct

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“…It is significantly important to heal the damage before fatigue failure for the engineering application. In the field of material strength, some methods for healing damage of materials have been investigated by some researchers, including conventional heat treatment (Du et al, 2004;Wagner et al, 2008), surface removal (Sharp et al, 2002), high-density electric current pulses (Qiao et al, 2009;Zhou et al, 2004), plasma nitriding (Alsaran et al, 2004), laser surface treatment (Choi1 et al, 2012;Ren et al, 2014;Shang et al, 2013), self-healing repairing for composite materials (White et al, 2001), and so on. These methods can effectively improve the fatigue property of materials.…”

Section: Introductionmentioning

confidence: 99%

Life prediction method of copper thin film repaired by laser irradiation based on healing variable

Ren

Shang

2016

International Journal of Damage Mechanics

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The cyclic stress–strain constitutive relationships for copper film smooth specimens with different damage degrees before and after laser irradiation treatment were investigated. Compared with the changes of the constitutive relationships under different damage degrees, a healing variable for the repaired copper film by laser irradiation was defined. Based on the analysis of the healing variable, a fatigue life prediction method was proposed. The experimental lives of the damaged notched specimens after laser irradiation treatment were used to verify the proposed life prediction method. The results showed that the predicted lives are in good agreement with the experimental results.

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