- Raghu V Prakash

###### Options

# Raghu V Prakash

Loading...

Preferred name

Raghu V Prakash

Official Name

Raghu V Prakash

Alternative Name

Prakash, Raghu

Prakash, R.

Prakash, R. V.

Prakash, Raghu V.

Main Affiliation

Scopus Author ID

Google Scholar ID

6 results Back to results

### Filters

##### Date

##### Author

##### Organization

##### Subject

##### Has files

##### Type

### Settings

Sort By

Results per page

Now showing 1 - 6 of 6

- PublicationCorrosion fatigue crack growth studies in Ni-Cr-Mn steel(01-12-2010)
;Madduri, ChinnaiahShow more This paper presents the results of corrosion fatigue crack growth behaviour of a Ni-Cr-Mn steel commonly used in marine applications. The effect of mechanical variables such as frequency and load ratio on fatigue crack growth rate at various stages has been studied using compact tension (C(T)) specimens along the rolling direction of steel plate under 3.5% saturated NaCl aqueous environment. The significance of crack closure on corrosion fatigue, and the validity of Elber's empirical linear crack closure model with the ASTM compliance offset method have been examined. Fatigue crack growth rate is higher and threshold stress intensities are lower in aqueous environment compared to the lab air conditions. It is also observed that the crack growth rate increases at lower frequencies. The higher stress ratio promotes the crack growth. The effect of oxidization and corrosion pit formation is very less as the stress ratio is increased. It is observed that as stress ratios are increased, the Elber's crack closure model agrees well with the crack closure estimated by the ASTM compliance offset method for tests conducted at 5Hz frequency compared to tests conducted at 1Hz in corrosive environment.Show more - PublicationEffect of low cyclic frequency on fatigue crack growth behavior of a Mn-Ni-Cr steel in air and 3.5% NaCl solution(15-07-2014)
;Dhinakaran, S.Show more Corrosion fatigue phenomenon involves the time dependent corrosion and cycle dependent fatigue loading. The intention of this study is to develop a test method to evaluate the crack growth rate of a material in a corrosive environment at low frequencies. The effect of cyclic frequency on crack growth rate of a Mn-Ni-Cr steel in lab air and 3.5% NaCl solution is evaluated using frequency shedding method where the cyclic frequency is decreased exponentially as a function of crack length at a constant stress intensity factor range. A Zn sacrificial anode coupled to the specimen slows down the rate of crack growth. © 2014 Elsevier B.V.Show more - PublicationUnderstanding fatigue crack growth behavior at low frequencies for a Mn-Ni-Cr steel in 3.5 % NaCl solution under controlled cathodic potential(01-01-2015)
; Dhinakaran, SampathShow more Fatigue crack growth behavior at low loading frequencies for a Mn-Ni-Cr steel immersed in 3.5 % NaCl solution, with and without cathodic polarization, is investigated and presented in this paper. Frequency shedding method is used to estimate fatigue crack growth rate over a range of frequencies between 0.01 and 5 Hz at a constant stress intensity factor range of 15MPa Hm. The effectiveness of cathodic potential of - 900 mV SCE in containing corrosion contribution to crack growth is estimated by comparing with published data on fatigue crack growth rate in lab air and 3.5 % NaCl solution without cathodic polarization. It is noted that there are three regions of crack growth rate as a function of applied frequencies when the data is plotted in log-log scale: linear crack growth rate, plateau crack growth rate, and high crack growth rate. The crack growth rate of steel in 3.5 % NaCl solution at 15MPa Hm is scanned for different cathodic potentials between - 760 mV SCE and 1150 mV SCE at 0.01 and 0.1 Hz. The potentials at which the crack growth rates are the maximum and the minimum are found to be - 760 and - 950 mV, respectively. The optimum cathodic protection potential for the minimum corrosion fatigue crack growth rate ranges between - 900 and - 950 mV. This optimum potential for the minimum corrosion crack growth rate is more negative than the cathodic potential required for restraining the corrosion effects on fatigue strength of steel to normal ambient air behavior.Show more - PublicationEstimation of corrosion fatigue-crack growth through frequency shedding method(01-01-2012)
; Dhinakaran, SampathShow more Corrosion fatigue-crack growth characteristics are important for the design of marine and off-shore structures. Design of critical components requires data on fatigue-crack growth rate at very low frequencies of the order of 10 -2 to 10-3 Hz. Experiments at low frequencies pose practical difficulties of enormous test duration. To address this, it is proposed to estimate corrosion crack growth characteristics using a frequency shedding method where the frequency is shed with crack advance using an exponential law. Fatigue-crack growth rate tests have been conducted on Ni-Mn-Cr steel at a constant ΔK range of 18 MPa√m (lower Paris regime) under lab air conditions as well as 3.5% NaCl solution. Crack growth rate data plotted as a function of test frequency presents a straight-line trend in log-log scale for a frequency range of 1-0.1 Hz; however, there is a change in trend when the frequencies are dropped further, which could be due to domination of corrosion mechanism. To understand the role of crack closure, crack closure estimates were obtained at periodic intervals of crack length and the effective stress intensity graphs suggest acceleration in crack growth rate due to corrosion as the frequency is reduced. Copyright © 2012 by ASTM International.Show more - PublicationEstimation of corrosion fatigue-crack growth through frequency shedding method(01-05-2012)
; Dhinakaran, SampathShow more Corrosion fatigue-crack growth characteristics are important for the design of marine and off-shore structures. Design of critical components requires data on fatigue-crack growth rate at very low frequencies of the order of 10 -2 to 10 -3 Hz. Experiments at low frequencies pose practical difficulties of enormous test duration. To address this, it is proposed to estimate corrosion crack growth characteristics using a frequency shedding method where the frequency is shed with crack advance using an exponential law. Fatigue-crack growth rate tests have been conducted on Ni-Mn-Cr steel at a constant δK range of 18 MPa√m (lower Paris regime) under lab air conditions as well as 3.5 % NaCl solution. Crack growth rate data plotted as a function of test frequency presents a straight-line trend in log-log scale for a frequency range of 1-0.1 Hz; however, there is a change in trend when the frequencies are dropped further, which could be due to domination of corrosion mechanism. To understand the role of crack closure, crack closure estimates were obtained at periodic intervals of crack length and the effective stress intensity graphs suggest acceleration in crack growth rate due to corrosion as the frequency is reduced. Copyright © 2012 by ASTM International.Show more - PublicationFatigue crack growth behavior of a Mn-Ni-Cr Steel in 3.5 % NaCl medium and its modeling(01-01-2019)
;Sampath, DhinakaranShow more Understanding the fatigue crack growth behavior of marine steel at low frequencies in a corrosive environment under cathodic protection is essential for the design and prognosis of offshore structures. Experimental results demonstrate that the corrosion fatigue crack growth rate increases with a decrease in frequency, and this behavior can be mitigated by reducing the corrosion rates with the application of a cathodic potential. Knowledge of an optimum cathodic protection potential for corrosion fatigue crack growth without entering the domain of hydrogen-assisted cracking potentials is vital. To that end, the corrosion processes within the enclave of a stationary crack and a pulsating fatigue crack under different crack mouth potentials are elucidated through modeling of mass transport of electrolytic species and electrode reactions. Effect of crack tip strain enhanced electrochemical reaction rates on electrochemical parameters such as pH, potential, and corrosion current density at the crack tip is evaluated. The corrosion current density at the crack tip is reduced significantly when the applied crack mouth potential is changed from -550 to -1,050 mV SCE for both stationary and pulsating cracks. In the case of strain-enhanced corrosion processes, the corrosion current density is increased significantly when compared with the equivalent model without considering the straining effects. However, the corrosion current density is the same for the applied crack mouth potential below -900 mV SCE. The crack solution becomes alkaline as the crack tip pH increases with a decrease in cathodic potential. This result agrees with the experimental observation of the minimum corrosion fatigue crack growth rate of a steel in sodium chloride solution at around -900 and -950 mV SCE.Show more