On the strengthening effect of increasing cycling frequency on fatigue behavior of some polymers and their composites: Experiments and modeling

Eftekhari, Mohammadreza; Fatemi, Ali

doi:10.1016/j.ijfatigue.2016.01.014

Cited by 87 publications

(61 citation statements)

References 40 publications

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“…However, at higher frequency, fatigue becomes cycle dominated. This behaviour was corroborated by results from Eftekhari and Fatemi [16,22]. The accumulation of fatigue induced creep strains was also reported by Kujawski and Eyllin [23] for [±45] 5s glass-epoxy composites at room temperature.…”

Section: Introductionsupporting

confidence: 84%

“…Finally, Eftekhari and Fatemi [16,22] have used the model by Epaarachchi and Clausen [13] -which is also the basis of the current work -in order to predict the effects of frequency and temperature on several neat, talc filled or short glass fibres reinforced thermoplastics. In these papers, they found that Epaarachchi and Clausen's model provides a good fit on experimental results and used a Larson-Miller type relationship to account for viscoelastic effects that were present at higher temperatures or lower load rates.…”

Section: Discussionmentioning

confidence: 99%

“…An alternative model based on the work of Reifsnider's [12] strength evolution integral concept is also shown to provide better life predictions when accounting for viscoelastic effects at low stresses (long fatigue life). Also, Eftekhari and Fatemi [16,22] used Epaarachchi and Clausen's [13] fatigue model in conjunction with a Larson-Miller type relationship to adequately model the effects of high temperature and high frequencies on neat, talc filled and short glass fibres reinforced thermoplastics.…”

Section: Introductionmentioning

confidence: 99%

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Modelling the effect of temperature on the probabilistic stress–life fatigue diagram of glass fibre–polymer composites loaded in tension along the fibre direction

Cormier

Joncas

2017

Journal of Composite Materials

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Predicting the fatigue performance of composites has proven to be a challenge both conceptually, due to the inherent complexity of the phenomenon, and practically, because of the resource-intensive process of fatigue testing. Moreover, mechanical behaviour of polymer matrix composites exhibits a complicated temperature dependence, making the prediction of fatigue performance under different temperatures even more complex and resource intensive. The objective of this paper is to provide a method for the prediction of fatigue life of glass-polymer composites loaded in the fibre direction at various temperatures with minimal experimental efforts. This is achieved by using a static strength degradation approach to fatigue modelling, where only two parameters (including static strength) are temperature dependent, in conjunction with relationships for these two fatigue model parameters temperature dependence. The method relies on fatigue data at a single temperature and simple static tests at different temperatures to predict the effects of temperature on the material's fatigue behaviour. The model is validated on experimental data for two unidirectional (UD) and one woven glass-epoxy composites and is found to accurately predict the effect of temperature on fatigue life of composites. A method to obtain probabilistic stress-life (P − S − N) fatigue diagrams including temperature effects is also discussed. 1

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Section: Introductionsupporting

confidence: 84%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Modelling the effect of temperature on the probabilistic stress–life fatigue diagram of glass fibre–polymer composites loaded in tension along the fibre direction

Cormier

Joncas

2017

Journal of Composite Materials

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“…A Larson–Miller type parameter was successfully used for these materials to correlate stress amplitude, cycling frequency, test temperature and cycles to failure for each materials at a given R ratio, expressed as:

S_{a} = A' {[\frac{T ((), normallog \frac{N_{f}}{f \times 3600} + C_{L M P})}{1000}]}^{B'}

where T is the test temperature, f is the cycling frequency and C LMP is a material constant. A′ and B′ are material constants and their values were reported in . The Larson–Miller master curves are shown in Fig.…”

Section: Temperature Effectmentioning

confidence: 99%

“…A fatigue life prediction model based on strength degradation of a polymeric material under constant amplitude loading developed by Epaarachchi and Clausen was applied to the experimental fatigue data in this study. This model was used in the study of Eftekhari and Fatemi to consider the strengthening effect of frequency on fatigue behaviour of PP, PP‐T and PP‐G. A variation of this model which does not consider the effect of frequency was also applied to PA6 and PBT fatigue data (materials for which the strengthening effect of frequency is negligible) by Mortazavian and Fatemi to consider the effect of temperature, anisotropy and mean stress.…”

Section: Correlation Of Fatigue Data With a General Modelmentioning

confidence: 99%

Fatigue behaviour and modelling of talc‐filled and short glass fibre reinforced thermoplastics, including temperature and mean stress effects

Eftekhari

Fatemi

2016

Fatigue Fract Eng Mat Struct

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Effects of temperature and mean stress on fatigue behaviour of talc‐filled polypropylene (PP‐T) and short glass fibre reinforced polypropylene (PP‐G), polyamide‐66 (PA66), and a blend of polyphenylene ether and polystyrene (PPE/PS) were investigated. Load‐controlled fatigue tests were conducted under positive stress ratios (R = 0.1 and 0.3) and at several temperatures (T = 23, 85 and 120 °C). Larson–Miller parameter was used and a shift factor of Arrhenius type was developed to correlate fatigue data at various temperatures. Effect of mean stress on fatigue life was significant for some of the studied materials; however, for the PPE/PS blend no effect of mean stress was observed. Modified Goodman and Walker mean stress equations were evaluated for their ability to correlate mean stress data. A general fatigue life prediction model was also used to account for the effects of mean stress, temperature, anisotropy and frequency.

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Study of Fatigue Behavior of Epoxy‐Carbon Composites under Mixed Mode I/II Loading

et al. 2017

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This paper presents an experimental assessment of the initiation and propagation of interlaminar cracks under mixed mode I/II dynamic fracture loading of a composite material with an MTM45-1 epoxy matrix and unidirectional IM7 carbon-fiber reinforcement. The aims of the experimental program developed for this purpose are to determine, on the one hand, the initiation curves of the fatigue delamination process, understood as the number of load cycles needed to generate a fatigue crack, and on the other, the crack growth rate (delamination rate) for different percentages of static Gc, in both cases for two mode mixities (0.2 and 0.4) and for a tensile ratio R ¼ 0.1. All this with the goal of quantifying the influence of the degree of mode mixity on the overall behavior of the laminate under fatigue loading. The results show that the energy release rate increases with increasing loading levels for both degrees of mode mixity and that the fatigue limit is located around the same percentages. However, crack growth rate behavior differs from one degree of mode mixity to the other. This difference in the behavior of the material may be due to the varying influence of mode I loading on the delamination process.

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On the strengthening effect of increasing cycling frequency on fatigue behavior of some polymers and their composites: Experiments and modeling

Cited by 87 publications

References 40 publications

Modelling the effect of temperature on the probabilistic stress–life fatigue diagram of glass fibre–polymer composites loaded in tension along the fibre direction

Modelling the effect of temperature on the probabilistic stress–life fatigue diagram of glass fibre–polymer composites loaded in tension along the fibre direction

Fatigue behaviour and modelling of talc‐filled and short glass fibre reinforced thermoplastics, including temperature and mean stress effects

Study of Fatigue Behavior of Epoxy‐Carbon Composites under Mixed Mode I/II Loading

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