Abstract
S-N behavior has been a backbone of material fatigue life studies since the 19th century. Numerous S-N curve models have been produced but they have been arbitrarily chosen in numerous research works dominantly for composite materials. In this paper, they were critically reviewed and evaluated for capability using the following criteria: data fitting capability, efficiency of curve fitting, applicability to data sets at various stress ratios (−0.43, −1, −3, 0.1, and 10), representability of fatigue damage at failure, and satisfaction of the initial boundary condition. The S-N curve models were found to be in two categories—one for fatigue data characterization independent of stress ratio, and the other for those designed for predicting the effect of stress ratio. The models proposed by Weibull, Sendeckyj, and Kim and Zhang for fatigue data characterization appeared to have the best capabilities for experimental data obtained from Weibull for R = −1, from Sendeckyj for R = 0.1, and from Kawai and Itoh (for R = −0.43, −3, and 10). The Kim and Zhang model was found to have an advantage over the Weibull and the Sendeckyj models for representing the fatigue damage at failure. The Kohout and Vechet model was also found to have a good fitting capability but with an inherent limitation for shaping the S-N curve at some stress ratios (e.g., R = −0.43). The S-N curve models developed for predicting the effect of stress ratio were found to be relatively inferior in data fitting capability to those developed directly for fatigue data characterization.
Highlights
Fatigue is a phenomenon that causes the progressive damage to materials under cyclic loading
Experimental data obtained at five different stress ratios i.e., R = −1, 0.1, −0.43, −3, and 10, which arEexapveariilmabelnetianl dthaetaliotebrtaatinuered, awt ifillvbeeduifsfeedrefnotrsStr-eNsscurartvioesfiit.eti.n, Rg e=v−al1u,a0t.i1o,n−
S-N curve models with more than two fitting parameters were eliminated from evaluation because its implementation is not economical, involving unnecessary efforts, given that some models available with two parameters are sufficiently accurate for data fitting
Summary
Fatigue is a phenomenon that causes the progressive damage to materials under cyclic loading. Philippidis and Passipoularidi [30] evaluated nine selected damage models involving residual strength degradation in relation to fatigue life They found that no model is consistent in accurately predicting the residual strength degradation behavior of different composite laminates for fatigue life. S-N curve models available since 1910 are critically reviewed and evaluated to identify their capabilities for applications at a wide range of stress ratios when subjected to the uniaxial loading for less than giga load cycles which may be more applicable for composite materials. For evaluation and critical review, the following criteria were adopted: capability of curve fitting, efficiency of curve fitting, applicability to data sets at various stress ratios, representability of fatigue damage at failure, and satisfaction of S-N curve initial boundary condition at the first load cycle
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
