New method for determining P‐S‐N curves in terms of equivalent fatigue lives

Bai, Xin; Peng, Zhaohua; Zhang, Zhenjun; Li, Rui; Zhang, Zhe‐Feng

doi:10.1111/ffe.13075

Cited by 21 publications

(3 citation statements)

References 28 publications

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“…Besides, Xie et al 17 proposed a backward statistical inference method and accurately estimated the life distribution of small samples and the P-S-N equation based on the mechanism called the consistency of sample percentiles and the linear relationship between life standard deviation and stress. Bai et al 18 and Li et al 19 improved this method respectively. And Liu and Pan et al 20,21 applied the bootstrap method to expand the fatigue data under the highest load level into large samples and applied the backward statistical inference method to curve fitting.…”

Section: Introductionmentioning

confidence: 99%

P–S–N curves fitting method of small samples obeying Weibull distribution

Song,

Zhao,

Xie

et al. 2024

Fatigue Fract Eng Mat Struct

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A three‐parameter Weibull small sample aggregation method is proposed to address the problem of small sample fatigue data in practical engineering. First, based on the empirical assumption that the shape parameter is a constant and data equivalent conversion and aggregation, the small sample fatigue life data are converted into “equivalent large samples.” Second, through the linear relationship between logarithmic scale parameter and stress, an iterative procedure is established to estimate the scale parameters of small sample data. At the same time, the moment and rank estimation methods are used to solve the location parameters quickly. Finally, P–S–N curves with different survival rates are given, and a 7‐series aluminum alloy is selected to verify the correctness and reliability of the method proposed in this study. The results show that the predicted life obtained by the method still has high accuracy under a high survival rate, which can provide a theoretical basis for solving practical engineering problems.

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Section: Introductionmentioning

confidence: 99%

P–S–N curves fitting method of small samples obeying Weibull distribution

Song,

Zhao,

Xie

et al. 2024

Fatigue Fract Eng Mat Struct

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“…Another noteworthy article which provides a critical review of the P-S-N approach is [32]. Several other authors have indicated the significance of the P-S-N approach as a means of evaluating this relationship [33][34][35][36][37].…”

Section: Introductionmentioning

confidence: 99%

Statistically Modeling the Fatigue Life of Copper and Aluminum Wires Using Archival Data

Harlow

2023

Metals

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It has been known for at least 150 years that fatigue life data exhibits a considerable amount of variability. Furthermore, statistically modeling fatigue life adequately is challenging. Different empirical approaches have been used, each of which has merit; however, none is appropriate universally. Even when a sufficiently robust database exists, the scatter in the fatigue lives may be extremely large and difficult to characterize. The purpose of this work is to review traditional and more modern empirically based methodologies for estimating the statistical behavior of fatigue data. The analyses are performed on two historic sets of data for annealed aluminum wire and annealed electrolytic copper wire tested in reverse torsion fatigue. These data are readily available In publications. Specifically, the review considers a traditional method for stress-cycle (S-N) analysis which includes linear regression through load dependent medians and mean square error (MSE) confidence bounds. Another approach that is used is Weibull distribution estimation for each loading condition, from which estimations for the median behavior and confidence bounds are determined. The preferred technique is the development of a cumulative distribution functions for fatigue life, which contains aspects of traditional reliability, classical S-N, and applied loading modeling. Again, confidence bounds are estimated for this technique. Even though it is an empirical technique, there are mechanistic aspects that underlie the empiricism. This approach is suggested because the method is very robust, and the estimation is more accurate than the other methods.

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“…In fact, each P-S-N curve is fitted with one of methods listed above or a combination of these methods 9,[11][12][13] .According to sampling theory, the larger the sample, the higher the accuracy of the tests conducted on the sample. However, owing to high costs and long fatigue testing times, it is difficult to achieve sample sizes that satisfy sampling theory requirements, especially in the case of large-sized structural parts or expensive parts [14][15][16] . The maximum likelihood method can fit the P-S-N curve with a small sample 17,18 , but the life means and standard deviations under each stress level must have been measured with high accuracy to achieve good results.…”

mentioning

confidence: 99%

Improved maximum likelihood method for P-S-N curve fitting method with small number specimens and application in T-welded joint

Liu,

Zhang,

et al. 2023

Sci Rep

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In fatigue data analysis, fitting accurate P-S-N curve is problematic if only a small number of specimen is available, especially to evaluate the relationship between the stress level and the standard deviation. This paper proposes a sample information reconstruction method that can effectively solve this problem. Based on this method and the life equivalent principle, a new maximum likelihood method (which is abbreviated to improved maximum likelihood method) is proposed for P-S-N curve fitting. T-joint specimens of Q450NQR1 steel were fabricated and tested, then the P-S-N curves was fitted by the improved maximum likelihood method, least square method, maximum likelihood method, standard BS7608 and standard IIW. Finally, P-S-N curves by three methods and two standards are compared and analyzed. The results show that the relevant parameters of the P-S-N curve with 99.9% survival probability fitted by the improved maximum likelihood method are similar to those in the two standards, and it is indicated that the improved maximum likelihood method is a better way for P-S-N curve fitting with the small number of fatigue test specimens.

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New method for determining P‐S‐N curves in terms of equivalent fatigue lives

Cited by 21 publications

References 28 publications

P–S–N curves fitting method of small samples obeying Weibull distribution

P–S–N curves fitting method of small samples obeying Weibull distribution

Statistically Modeling the Fatigue Life of Copper and Aluminum Wires Using Archival Data

Improved maximum likelihood method for P-S-N curve fitting method with small number specimens and application in T-welded joint

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