scholarly journals The Use of Spectral Method for Fatigue Life Assessment for Non-Gaussian Random Loads

2016 ◽  
Vol 10 (2) ◽  
pp. 100-103 ◽  
Author(s):  
Adam Niesłony ◽  
Michał Böhm ◽  
Tadeusz Łagoda ◽  
Filippo Cianetti
Keyword(s):  
Fatigue Life ◽  
Spectral Method ◽  
Life Assessment ◽  
Frequency Domain Method ◽  
Compression Tests ◽  
Domain Method ◽  
Calculation Results ◽  
Rainflow Cycle Counting ◽  
Gaussian Signal ◽  
Non Gaussian

Abstract The well-known problem with the fatigue lifetime assessment of non-Gaussian loading signals with the use of spectral method has been presented in the paper. A correction factors that transform the non-Gaussian signal into an equivalent Gaussian signal proposed by Bracessi et al. (2009) has been used for the purpose of lifetime calculations together with Palmgren-Miner Hypothesis. The calculations have been performed for the 10HNAP steel under random non-Gaussian load with four dominating frequencies. The signal has been generated on the test stand SHM250 for random tension-compression tests. The results with zero and non-zero mean stresses have been used to calculate the fatigue life with the frequency domain method based on Dirlik’s model and with a time domain method with the use of the rainflow cycle counting algorithm. The obtained calculation results have been compared with experimental results.

scholarly journals Influence of the Elastoplastic Strain on Fatigue Durability Determined with the Use of the Spectral Method

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 423 ◽  
Author(s):  
Michał Böhm ◽  
Mateusz Kowalski ◽  
Adam Niesłony
Keyword(s):  
Fatigue Life ◽  
Probability Density ◽  
Spectral Method ◽  
Fatigue Tests ◽  
Life Assessment ◽  
Loading Conditions ◽  
Random Loading ◽  
Elastoplastic Deformations ◽  
Fatigue Life Assessment ◽  
Safe Side

The paper presents experimental static and fatigue tests results under random loading conditions for the bending of 0H18N9 steel. The experimental results were used in performing calculations, according to the theoretical assumptions of the spectral method of fatigue life assessment, including elastoplastic deformations. The presented solution extends the use of the spectral method for material fatigue life assessment, in terms of loading conditions, above Hooke’s law theorem. The work includes computational verification of the proposal to extend the applicability of the spectral method of determining fatigue life for the range of elastoplastic deformations. One of the aims of the proposed modification was to supplement the stress amplitudes used to calculate the probability density function of the power spectral density of the signal with correction, due to the plastic deformation and its use for notched elements. The authors have tested the method using four of the most popular probability density functions used in commercial software. The obtained results of comparisons between the experimental and calculation results show that the proposed algorithm, tested using the Dirlik, Benasciutti–Tovo, Lalanne, and Zhao–Baker models, does not overestimate fatigue life, which means that the calculations are on the safe side. The obtained results prove that the elastoplastic deformations can be applied within the frequency domain for fatigue life calculations.

Fatigue life assessment of a four-rotor swather based on rainflow cycle counting

2014 ◽  
Vol 127 ◽  
pp. 1-10 ◽  
Author(s):  
Dimitris S. Paraforos ◽  
Hans W. Griepentrog ◽  
Stavros G. Vougioukas ◽  
Dietrich Kortenbruck
Keyword(s):  
Fatigue Life ◽  
Life Assessment ◽  
Fatigue Life Assessment ◽  
Rainflow Cycle Counting

scholarly journals Fatigue Life Evaluation under Service Loading by Frequency Domain Method

2008 ◽  
Vol 57 (12) ◽  
pp. 1186-1190 ◽  
Author(s):  
Akito ITO ◽  
Naoya NISHIMURA ◽  
Toshio HATTORI ◽  
Norio TAKEDA ◽  
Yasuki KITA
Keyword(s):  
Fatigue Life ◽  
Frequency Domain ◽  
Frequency Domain Method ◽  
Life Evaluation ◽  
Domain Method ◽  
Fatigue Life Evaluation ◽  
Service Loading

Determination of Fatigue Life with the Use of Spectral Method on the Basis of Fatigue Strain Characteristics

2014 ◽  
Vol 224 ◽  
pp. 112-117 ◽  
Author(s):  
Michał Böhm ◽  
Adam Niesłony
Keyword(s):  
Fatigue Life ◽  
Spectral Method ◽  
Analytical Formula ◽  
Life Assessment ◽  
Engineering Practice ◽  
Strain Characteristic ◽  
Fatigue Life Assessment ◽  
Theoretical Assumptions ◽  
New Formula

The paper presents a new formula for fatigue life determination with the use of the spectral method for fatigue life assessment on the basis of fatigue strain characteristics. The spectral method is widely used together with the stress characteristics, but the literature does not contain a case where it is used together with strain characteristics. The paper shows the theoretical assumptions as well as the derived analytical formula for fatigue life determination. The presented formula is using constants gained from the Manson-Coffin-Basquin strain characteristic. Due to the popularity of strain characteristics, the formula may be widely used in the engineering practice.

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