On estimates of durability of FRP based on accelerated tests

Chastre, Carlos; Fonseca, B. Sena da

doi:10.1016/j.compstruct.2014.05.022

Cited by 90 publications

(53 citation statements)

References 26 publications

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“…To be able to have a better understanding of long term performance, lab based accelerated aging protocol was developed by other researchers (Compos et al, 2016;Silva et al 2014;Chen, 2007) and refined by the author. Such a protocol is described in-depth as: (Lorenzo et al, 2018).…”

Section: Accelerated Aging Methodologymentioning

confidence: 99%

“…The Arrhenius equation describes the temperature dependence of reaction rates and helps in determining the rate of chemical reaction and the activation energies. The relationship is seen as an empirical relationship, and it can be used to model thermally-induced processes (Compos et al, 2006;Silva et al, 2014;Shilpa et al, 2010;Wang et al, 2015). Analyses of accelerated aged data at different temperatures reveals that an Arrhenius relationship seemed to be the best method to analyze the ILSS data.…”

Section: Arrhenius Relationshipmentioning

confidence: 99%

“…Interpreting the degradation rate k as the inverse of the time required for a material property to reach a given value, the logarithm of 1/k shows that the time for a property to degrade to a chosen value is a linear function of 1/T with the slope Ea/R (Silva et al, 2014).…”

Section: Arrhenius Relationshipmentioning

confidence: 99%

“…Once an Arrhenius relationship is developed and proven, an extrapolation of long-term behavior can be used assuming that the Arrhenius relationship is valid. The concept of time shift factors, TSF, is defined as the ratio between the times required for a certain decrease in a mechanical property at two different temperatures (Silva et al, 2014), (Eqn. 2-2).…”

Section: Time Shift Factors (Tsf)mentioning

confidence: 99%

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Short Beam Shear Strength Evaluations of GFRP Composites: Correlations Through Accelerated and Natural Aging

Barker¹

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Short Beam Shear Strength Evaluations of GFRP Composites: Correlations Through Accelerated and Natural Aging William Barker Fiber Reinforced Polymers (FRP) composites have been materials of interest in replacing or reinforcing steel, wood, and concrete, but lack of understanding of degradation under physical and chemical aging is a main concern. Through many years of research, the understanding of aging or durability of GFRPs has improved. To be able to evaluate aging related degradation rates, an accelerated aging methodology under varying environments is introduced. Accelerated aging is a concept used to age composites in a lab controlled environment under varying pH conditions (2 to 13) and temperatures (~-20° to +160°F). Once acceleratedly aged testing is completed, Arrhenius relationships and Time-Temperature Superposition principles can be used to correlate the accelerated data with the naturally aged data to create strength reduction (knock-down) factors for 100-year service life. In this work, accelerated and natural aged data for glass fiber reinforced vinyl-ester composites was collected through in-lab testing and literature data. Knowing that interlaminar shear strength (ILSS) is the most detrimental mechanical property, this work was solely focused on the degradation of ILSS of glass fiber reinforced vinyl-ester under varying pH environments and temperatures. The degradation of ILSS in composites has been found to follow two aging trends. Most of the ILSS degradation occurs within the first 3-10 years of service followed by a more gradual trend. The focus of this report is to understand the reason behind a large amount of strength loss in the initial service life. Accelerated testing was also performed on vinyl ester composites with different thicknesses, as well as pure vinyl ester samples. Examining how degradation occurs with varying thicknesses and the resin system apart from the composite is very crucial in understanding the reasons behind aging.

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Section: Accelerated Aging Methodologymentioning

confidence: 99%

Section: Arrhenius Relationshipmentioning

confidence: 99%

Section: Arrhenius Relationshipmentioning

confidence: 99%

Section: Time Shift Factors (Tsf)mentioning

confidence: 99%

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Short Beam Shear Strength Evaluations of GFRP Composites: Correlations Through Accelerated and Natural Aging

Barker¹

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“…Hygrothermal stresses are known to be the cause for crack initiation and cause the material to become brittle or to deform [2,3]. They can approach or exceed the design load and acceptable material limits [4].A number of works on the modelling of environmental stress effect on FRP material have been reported [5][6][7][8][9][10][11][12]. These reports deal mostly with the characterisation of the effect of temperature and humidity on the stress state of composite laminates.…”

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confidence: 99%

Prediction of thermal strains in fibre reinforced plastic matrix by discretisation of the temperature exposure history

Ngoy

2016

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. Prediction of environmental effects on fibre reinforced plastics habitually is made difficult due to the complex variability of the natural service environment. This paper suggests a method to predict thermal strain distribution over the material lifetime by discretisation of the exposure history. Laboratory results show a high correlation between predicted and experimentally measured strain distribution IntroductionDue to the need for energy efficient materials, there has been a considerable increase of interest in light and green materials such as fibre reinforced plastics (FRP) in the aerospace industry. However, environmental effects have shown to be a hindrance to extensive use of FRP. A reliable method to quantify and predict environmental effects on FRP is required for safe and efficient use of these materials.Stresses resulting from environmental factors such as cycling temperature and humidity have been recognised as one of the most deleterious effect on FRP materials [1]. Hygrothermal stresses are known to be the cause for crack initiation and cause the material to become brittle or to deform [2,3]. They can approach or exceed the design load and acceptable material limits [4].A number of works on the modelling of environmental stress effect on FRP material have been reported [5][6][7][8][9][10][11][12]. These reports deal mostly with the characterisation of the effect of temperature and humidity on the stress state of composite laminates. In this regard, models and computation algorithms of various performance levels have been made available. However, most of the time complication results from the material heterogeneity and the complex variability of the environment. In addition, only the effect of the physical degradation is taken into account explicitly, while the material undergoes a chemical degradation also.This analysis focuses on the determination of environmental stresses without involving the resulting modification on the stress state of the material. Attention is on the prediction of a long-term effect, comprehensively taking into account the physical and the chemical degradation, as well as the viscoelastic, time-dependent effect. In the present paper, the thermal strain history is predicted based on the knowledge of temperature exposure. In a subsequent paper, strains will be used to compute stresses taking into account the time dependent relaxation and environmental degradation.For the purpose of this paper, only a one-dimensional problem in plate laminate is considered. This is because it is demonstrated experimentally that the degradation of the mechanical strength of materials used in aviation varies in a layered way after exposure to a natural environment [13]. The degradation process can be considered as a progressing damaged front that moves from the outer

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Durability of basalt fibers, glass fibers, and their reinforced polymer composites in artificial seawater

Jiang

Pan

et al. 2022

Polymer Composites

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This study focused on the durability of basalt fibers, glass fibers, basalt‐fiber‐reinforced polymer (BFRP) bars, and glass‐fiber‐reinforced polymer (GFRP) bars in an artificial seawater. The specimens were immersed in the artificial seawater at 20, 40, and 60°C; the specimen immersed in distilled water at a temperature of 60°C was also used as a reference. The tensile strength of the monofilament basalt fibers and glass fibers immersed in the seawater for 90 days at a temperature of 60°C decreases by 61% and 59% respectively, showing the most significant degradation; the brittleness of the fibers also increases due to the decomposition of their sizing agent. The chloride ions in the seawater are beneficial to enhancing the resistance of the composites to moisture absorption. In addition, the tensile strength retention of the fiber‐reinforced polymer (FRP) bars is higher than that of the fibers due to the protection by the epoxy resin. The mechanical properties of the FRP bars immersed in the seawater improve after removing their moisture. The mechanical performance of the BFRP bars is inferior to that of the GFRP bars due to their higher water absorption and weak bonding between the basalt fibers and the polymer matrix.

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On estimates of durability of FRP based on accelerated tests

Cited by 90 publications

References 26 publications

Short Beam Shear Strength Evaluations of GFRP Composites: Correlations Through Accelerated and Natural Aging

Short Beam Shear Strength Evaluations of GFRP Composites: Correlations Through Accelerated and Natural Aging

Prediction of thermal strains in fibre reinforced plastic matrix by discretisation of the temperature exposure history

Durability of basalt fibers, glass fibers, and their reinforced polymer composites in artificial seawater

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