The Experts below are selected from a list of 43404 Experts worldwide ranked by ideXlab platform
Adrian P. Mouritz - One of the best experts on this subject based on the ideXlab platform.
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Stochastic factors controlling the failure of carbon/epoxy composites
Journal of Materials Science, 2015Co-Authors: H.y. Chou, Adrian P. Mouritz, Alain Thionnet, Anthony R. BunsellAbstract:The intrinsic scatter in tensile properties of unidirectional (UD) carbon/epoxy composites is due to several factors, including variability in Fibre Strength and Fibre volume fraction at the local microscopic level. A model included in a multiscale finite element process, previously developed to simulate Fibre failure in composite laminates but having little variation in Fibre Strength and local Fibre volume fraction, has been extended to cover the effects of such material variations. The present study investigates the effects of the variability in material properties which can occur in real UD composite materials subjected to monotonic increasing and sustained loadings. This latter case is one of the originalities of this study. In the interval of variation studied for the Weibull parameters of Fibre Strength and Fibre volume fraction, the mean and standard deviation of the failure stress are never strongly affected. Concerning the time-to-failure, its mean and its standard deviation increase strongly if the mean of Fibre volume fraction increases and if the standard deviation of the Fibre Strength decreases. The standard deviation of local Fibre volume fraction was found to have only a secondary effect on failure stress and time-to-failure. Another original and important result concerns the scatter in the time-to-failure of composites due to the level of applied sustained loading.
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Mechanical properties of thermally-treated and recycled glass Fibres
Composites Part B: Engineering, 2011Co-Authors: Stefanie Feih, E. Boiocchi, G. Mathys, Z. Mathys, A.g. Gibson, Adrian P. MouritzAbstract:This paper investigates the effects of temperature, heating time and atmosphere on the tensile modulus and Strength of thermally-treated E-glass Fibres. The heating conditions that were investigated are identical to those used in thermal recycling of waste polymer matrix composite materials, and therefore this study determines the effects of the recycling process conditions on the properties of reclaimed Fibreglass. The loss in Fibre Strength is dependent on the temperature and time of the thermal process, and large Strength loss occurs under the heating conditions used for high temperature incineration of polymer composites. A phenomenological model is presented for the residual Fibre Strength for the temperatures and heating time of the thermal recycling process. The reduction in Fibre Strength is dependent on the thermal recycling atmosphere under low temperature or short heating time conditions, but at high temperatures the Strength loss is the same, regardless of furnace atmosphere (ambient air, dry air or inert gas). Quantitative fractographic analysis of the Fibres shows that fracture for all heat treatments is caused by surface flaws. The Strength loss is most probably due to structural relaxation during thermal annealing and a secondary effect of adsorbed surface water attacking the glass by thermally-activated stress-corrosion. It is shown that large reductions in Fibre Strength due to thermal recycling are not recovered during composite manufacture, therefore resulting in composite materials with significantly lower Strength. The reduced Strength of the composite matches the reduced Fibre Strength following thermal recycling.
James Thomason - One of the best experts on this subject based on the ideXlab platform.
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Glass Fibre Strength—A Review with Relation to Composite Recycling
Fibers, 2016Co-Authors: James Thomason, Peter Jenkins, Liu YangAbstract:The recovery and reuse of glass Fibres from manufacturing waste and end-of-life composites in an environmentally-friendly, cost-effective manner is one of the most important challenges facing the thermosetting polymer composites industry. A number of processes for recycling Fibres from such materials are available or under development. However, nearly all options deliver recycled glass Fibres that are not cost-performance competitive due to the huge drop in Strength of recycled glass Fibre compared to its original state. A breakthrough in the regeneration of recycled glass Fibre performance has the potential to totally transform the economics of recycling such composites. This paper reviews the available knowledge of the thermally-induced Strength loss in glass Fibres, discusses some of the phenomena that are potentially related and presents the status of research into processes to regenerate the Strength and value of such weak recycled glass Fibres
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Glass Fibre Strength : a review with relation to composite recycling
Fibers, 2016Co-Authors: James Thomason, Peter Jenkins, Liu YangAbstract:The recovery and reuse of glass Fibres from manufacturing waste and end-of-life composites in an environmentally-friendly, cost-effective manner is one of the most important challenges facing the thermosetting polymer composites industry. A number of processes for recycling Fibres from such materials are available or under development. However, nearly all options deliver recycled glass Fibres that are not cost-performance competitive due to the huge drop in Strength of recycled glass Fibre compared to its original state. A breakthrough in the regeneration of recycled glass Fibre performance has the potential to totally transform the economics of recycling such composites. This paper reviews the available knowledge of the thermally-induced Strength loss in glass Fibres, discusses some of the phenomena that are potentially related and presents the status of research into processes to regenerate the Strength and value of such weak recycled glass Fibres.
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Recover : Regenerating the Strength of glass Fibres thermally recycled from end-of-life
2015Co-Authors: James Thomason, Eduardo Saez Rodriguez, Chih-chuan Kao, Ulf Nagel, Liu YangAbstract:Global production of composite materials in 2015 will significantly exceed 10 million tons. Glass Fibre reinforced composites account for more than 90% of all the Fibre-reinforced composites currently produced. Development of economically viable processes for recycling end-of-life glass Fibre composites would have major beneficial economic and environmental impacts for the glass Fibre composites industry. This paper reports a study on regenerating the performance of thermally recycled glass Fibres. The effectiveness of the ReCoVeR treatments on the single Fibre Strength of glass Fibres thermally treated to imitate the conditions of composite recycling technology is presented. The regenerated Strength levels of these ReCoVeRed Fibres must be further protected and maintained by the use of Fibre sizing technology similar to standard glass Fibre products. Consequently the effect on Fibre Strength of the combination of the ReCoVeR treatment with a standard silane coating was also studied. Significant increase of Fibre Strength was obtained through the regeneration treatments, achieving greater than triple the Fibre Strength in comparison with the thermally treated glass Fibre. Furthermore the same treatments have also been applied to glass Fibres recovered from model composites using laboratory thermal recycling. Fibre Strengths have been achieved which makes reusing these Fibres as a composite reinforcement a viable option. Results on the mechanical performance of composites containing ReCoVeRed glass Fibres are presented and discussed in support of this assertion.
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Regeneration of thermally recycled glass Fibre for cost-effective composite recycling: Increasing the Strength of thermally conditioned glass Fibres by HF treatment
2014Co-Authors: Liu Yang, James ThomasonAbstract:In this paper the results of an extensive study will be presented of regenerating performance of thermally conditioned glass Fibre using hydrofluoric acid (HF). The effectiveness of HF was investigated on Strength recovery of glass Fibres thermally conditioned in a typical temperature range for glass Fibre recycling. The chemical treatment was also applied to glass Fibres directly recycled from epoxy composites using a fluidised bed technique. The effect of treatment time on Fibre Strength was studied. A significant increase of Fibre Strength was obtained through the HF treatment and apparent reduction of Fibre diameter suggested that Strengthening mechanism was associated with HF etching. SEM/EDX was used to examine the surface alteration caused by the HF treatment.
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On the application of Weibull analysis to experimentally determined single Fibre Strength distributions
Composites Science and Technology, 2013Co-Authors: James ThomasonAbstract:The application of Weibull theory to the analysis of experimental data obtained from the tensile testing of reinforcement Fibres is widespread in composites research and development. One basic assumption implicit in the use of Weibull analysis is that all values of Fibre Strength described by any set of unimodal or multimodal Weibull parameters are accessible experimentally. However, this is not the case, as a minimum level of Fibre Strength is necessary in order to be able to isolate, prepare and test any Fibre. In this paper the consequences of this experimental limitation are explored in terms of the commonly applied Weibull graphical analysis method. It is demonstrated that this can result in significant curvature in a standard Weibull plot at the low Strength end of the data. Furthermore, at low sampling numbers this effect can be misinterpreted as evidence of multiple defect populations. The phenomenon significantly affects the values of the Weibull parameters obtained from the graphical analysis and also from the average Strength versus gauge length analysis. The presence of this lower limit presents a serious challenge to those wishing to support conclusions on the physics and mechanics of Fibre fracture from Weibull analysis of single Fibre tensile data.
Lucien Laiarinandrasana - One of the best experts on this subject based on the ideXlab platform.
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Propagation of uncertainty from constituents to structural assessments in composite Strength modelling
2020Co-Authors: Faisal Islam, Sébastien Joannès, Lucien LaiarinandrasanaAbstract:In-service safety and reliable lifetime assessments are key challenges for high performance load bearing applications and require great care to be taken during their design. The design of composite material structures can be assisted by computational models. Many complex computational models have been developed for predicting the failure and lifetime analysis of structures. Critical structures such as high pressure composite cylinders require very accurate computational models, to understand the stochastic nature of the predicted structural response. The following issues limit the use of composite Strength models for making reliable structural predictions: -The complex interaction between the Fibres and matrix which governs the failure mechanism has not been accurately incorporated in composite Strength models. -Lack of reliable constituent properties which are used as input for the models. There are several studies aimed at improving the state-of-the-art models. However, accurate constituent properties to be used as input for these models are rarely available. Authors usually do not comment on the uncertainty of the constituent properties reported, which is of major importance for stochastic simulations. Since Fibres are the principal load bearing constituents of unidirectional composites, Islam et al. have quantified the uncertainty in the parameters of the Fibre Strength Weibull distribution arising during to the characterisation process, using a Monte-Carlo approach to capture the stochastic nature of the Fibre Strength behaviour. Strength of T700 carbon Fibres, popularly used in composite pressure vessels, is used as reference. In this study, the influence of uncertainty in input Fibre Strength on model predictions has been evaluated. A composite Strength model developed at Mines ParisTech was used. This model considers physical processes such as Fibre failure and its interactions with the surrounding matrix. It was first developed in 2005 and has been improved over the years to simulate different loading conditions during service of composite structures such as pressure vessels. The Strength and lifetime of a composite structure (coupon) is simulated under two different practical loading conditions (monotonically increasing and sustained loading) to elucidate the sensitivity of different structural responses to the input Fibre Strength distribution. The calculated uncertainties in the shape (m) and scale (sigma_0) parameters of the Fibre Strength Weibull distribution were used as input for the models. The results are listed as follows: 1) Monotonic loading: -The failure stress is seen to be significantly dependent on the scale parameter. The observed variation in the predicted failure stress is about 10% from the mean case, for an uncertainty of 10% in scale parameter. -The sensitivity of the model predictions to the shape parameter was insignificant. 2) Sustained loading: -The time to failure of the composite specimen was also found to be strongly affected by uncertainties in the scale parameter. The calculated uncertainty of 10% in the input scale parameter resulted in a variation in the predicted lifetime of about 15-30%. -The calculated uncertainty of 25% in the shape parameter resulted in a variation of about 16% in the predicted lifetime of the specimen. The structural behaviour predicted by the model is found to be highly sensitive to the uncertainties in the input Fibre Strength distribution which arise during characterisation. The understanding of the constituent properties and their characterisation process needs to be improved, in order to improve the reliability of computational model predictions, so that the predictions can be used with confidence in industrial applications.
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Uncertainty in Fibre Strength Characterisation Due to Uncertainty in Measurement and Sampling Randomness
Applied Composite Materials, 2020Co-Authors: Sébastien Joannès, Faisal Islam, Lucien LaiarinandrasanaAbstract:Carbon Fibres have exceptional mechanical properties and are used for critical structural applications such as composite pressure vessels and aerospace components. For such high performance applications, reliability-based designs and lifetime assessments require very accurate Strength models. Accuracy of the predictions made by composite Strength models depend on realistic material properties of constituents, which are used as input. In practice however, Fibre Strength properties reported by different sources show significant variations. The work described here aims at understanding the influence of measurement uncertainty and sampling randomness on the uncertainty in calculated tensile Strength distribution parameters. Tensile Strength data for T700 carbon Fibres obtained from single Fibre testing process has been analysed for uncertainties. A parametric bootstrap method has been used for the evaluation. It has been shown that although both the causes studied of uncertainty are critical, the sampling randomness has a larger influence on the uncertainty of Fibre Strength, as compared to the uncertainty due to measurement. Choosing an insufficient sample size for analysis can thus result in uncertain or even inaccurate Fibre Strength properties, which would limit the reliability of composite Strength models. The knowledge of the causes and effects of these uncertainties can help in taking appropriate measures for improving the accuracy of results. This would thereby enhance the capability of composite Strength models to estimate the behaviour of different composite structures more accurately.
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Investigation of tensile Strength and dimensional variation of T700 carbon Fibres using an improved experimental setup
Journal of Reinforced Plastics and Composites, 2019Co-Authors: Faisal Islam, Sébastien Joannès, Anthony R. Bunsell, Steve Bucknell, Yann Leray, Lucien LaiarinandrasanaAbstract:Knowledge of Fibre Strength is crucial for understanding the failure behaviour of Fibre-reinforced composite materials and structures. Measuring the properties of technical Fibres has been known to...
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Evaluation of Critical Parameters in Tensile Strength Measurement of Single Fibres
Journal of Composites Science, 2019Co-Authors: Faisal Islam, Sébastien Joannès, Lucien LaiarinandrasanaAbstract:Mechanical properties of Fibre reinforced composites are primarily dependent on those of Fibres. Fibre properties are used for estimating the damage and Strength behaviour of composite materials and structures. Tensile Strength of Fibres is commonly determined by single Fibre tensile tests, which is challenging and is prone to measurement errors. In this study, different possible sources of errors due to experimental limitations in the Fibre testing process were identified. Their effect on Fibre tensile Strength was analytically modelled. This model was used to evaluate the uncertainty in experimentally determined Fibre Strength. A sensitivity analysis was conducted to rank the relative significance of input quantities on the calculated Fibre Strength. Since composite models require Fibre properties determined at very small gauge lengths, the results of the sensitivity analysis were extrapolated to determine critical parameters for tests done at those small gauge lengths of a few millimetres. It was shown that, for sufficiently long Fibres, their Strength depends mainly on the diameter and failure force; however, for shorter gauge lengths, the effects of misalignment become very significant. The knowledge of uncertainty would be useful in estimating the reliability of the predictions made by composite Strength models on the damage and failure behaviour of composite materials and structures. Minimising the influence of critical parameters on Fibre Strength would help in designing improved single Fibre testing systems capable of determining Fibre Strength more accurately.
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Adaptation of Weibull analysis to represent Strength behaviour of brittle Fibres
2019Co-Authors: Faisal Islam, Sébastien Joannès, Anthony R. Bunsell, Lucien LaiarinandrasanaAbstract:Fibre properties are used for estimating the damage and Strength behaviour of composite materials and structures, as the mechanical properties of Fibre reinforced composites are primarily dependent on those of Fibres. Fibre reinforced composites owe their outstanding properties to their constituents, mainly the Fibres which reinforce matrices in composites. The accuracy of the predictions made by composite Strength models would be highly dependent on the accuracy of the Fibre Strength distribution which is used as input. Any error in input Fibre Strength properties would lead to inaccurate model predictions. It has however been highlighted by many studies that there is discrepancy in experimental data even for the same type of Fibres. The Fibre Strength data used to determine Fibre Strength distributions may be inaccurate. Due to the Fibre preselection effect, experimental data is usually incomplete and does not appropriately represent the true Fibre Strength variation. An adaptation to the Weibull analysis has been presented to predict a more accurate statistical distribution for the representation of the Strength behaviour of Fibres inside composites. This analysis considers the preselection effect, which is used in modelling the Fibre Strength behaviour. The described analysis has the potential to significantly improve the accuracy of Fibre Strength distribution determined using experimentally generated Fibre Strength data.
Liu Yang - One of the best experts on this subject based on the ideXlab platform.
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Glass Fibre Strength—A Review with Relation to Composite Recycling
Fibers, 2016Co-Authors: James Thomason, Peter Jenkins, Liu YangAbstract:The recovery and reuse of glass Fibres from manufacturing waste and end-of-life composites in an environmentally-friendly, cost-effective manner is one of the most important challenges facing the thermosetting polymer composites industry. A number of processes for recycling Fibres from such materials are available or under development. However, nearly all options deliver recycled glass Fibres that are not cost-performance competitive due to the huge drop in Strength of recycled glass Fibre compared to its original state. A breakthrough in the regeneration of recycled glass Fibre performance has the potential to totally transform the economics of recycling such composites. This paper reviews the available knowledge of the thermally-induced Strength loss in glass Fibres, discusses some of the phenomena that are potentially related and presents the status of research into processes to regenerate the Strength and value of such weak recycled glass Fibres
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Glass Fibre Strength : a review with relation to composite recycling
Fibers, 2016Co-Authors: James Thomason, Peter Jenkins, Liu YangAbstract:The recovery and reuse of glass Fibres from manufacturing waste and end-of-life composites in an environmentally-friendly, cost-effective manner is one of the most important challenges facing the thermosetting polymer composites industry. A number of processes for recycling Fibres from such materials are available or under development. However, nearly all options deliver recycled glass Fibres that are not cost-performance competitive due to the huge drop in Strength of recycled glass Fibre compared to its original state. A breakthrough in the regeneration of recycled glass Fibre performance has the potential to totally transform the economics of recycling such composites. This paper reviews the available knowledge of the thermally-induced Strength loss in glass Fibres, discusses some of the phenomena that are potentially related and presents the status of research into processes to regenerate the Strength and value of such weak recycled glass Fibres.
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Recover : Regenerating the Strength of glass Fibres thermally recycled from end-of-life
2015Co-Authors: James Thomason, Eduardo Saez Rodriguez, Chih-chuan Kao, Ulf Nagel, Liu YangAbstract:Global production of composite materials in 2015 will significantly exceed 10 million tons. Glass Fibre reinforced composites account for more than 90% of all the Fibre-reinforced composites currently produced. Development of economically viable processes for recycling end-of-life glass Fibre composites would have major beneficial economic and environmental impacts for the glass Fibre composites industry. This paper reports a study on regenerating the performance of thermally recycled glass Fibres. The effectiveness of the ReCoVeR treatments on the single Fibre Strength of glass Fibres thermally treated to imitate the conditions of composite recycling technology is presented. The regenerated Strength levels of these ReCoVeRed Fibres must be further protected and maintained by the use of Fibre sizing technology similar to standard glass Fibre products. Consequently the effect on Fibre Strength of the combination of the ReCoVeR treatment with a standard silane coating was also studied. Significant increase of Fibre Strength was obtained through the regeneration treatments, achieving greater than triple the Fibre Strength in comparison with the thermally treated glass Fibre. Furthermore the same treatments have also been applied to glass Fibres recovered from model composites using laboratory thermal recycling. Fibre Strengths have been achieved which makes reusing these Fibres as a composite reinforcement a viable option. Results on the mechanical performance of composites containing ReCoVeRed glass Fibres are presented and discussed in support of this assertion.
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regeneration of thermally recycled glass Fibre for cost effective composite recycling increasing the Strength of thermally conditioned glass Fibres using cost effective recover treatments
16th European Conference on Composite Materials, 2014Co-Authors: Eduardo Saez Rodriguez, Liu Yang, J L ThomasonAbstract:The paper reports an extensive study on the regenerating performance of thermally treated glass Fibres using two different chemically based treatments routes. The effectiveness of these two different treatments was investigated on Strength recovery of glass Fibres thermally treated with the conditions imitating composite recycling technology. The regenerated Strength levels of these ReCoVeRed Fibres must also be further protected and maintained by the use of standard Fibre sizing technology similar to standard glass Fibre products. Consequently, the effect on Fibre Strength of the combination of our ReCoVeR treatments with the standard silane coatings was also studied. Significant increase of Fibre Strength was obtained through the ReCoVeR and coatings treatments, achieving up to 200% increase in Fibre Strength in comparison with the glass Fibre thermally treated.
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Regeneration of thermally recycled glass Fibre for cost-effective composite recycling: Increasing the Strength of thermally conditioned glass Fibres by HF treatment
2014Co-Authors: Liu Yang, James ThomasonAbstract:In this paper the results of an extensive study will be presented of regenerating performance of thermally conditioned glass Fibre using hydrofluoric acid (HF). The effectiveness of HF was investigated on Strength recovery of glass Fibres thermally conditioned in a typical temperature range for glass Fibre recycling. The chemical treatment was also applied to glass Fibres directly recycled from epoxy composites using a fluidised bed technique. The effect of treatment time on Fibre Strength was studied. A significant increase of Fibre Strength was obtained through the HF treatment and apparent reduction of Fibre diameter suggested that Strengthening mechanism was associated with HF etching. SEM/EDX was used to examine the surface alteration caused by the HF treatment.
Faisal Islam - One of the best experts on this subject based on the ideXlab platform.
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Propagation of uncertainty from constituents to structural assessments in composite Strength modelling
2020Co-Authors: Faisal Islam, Sébastien Joannès, Lucien LaiarinandrasanaAbstract:In-service safety and reliable lifetime assessments are key challenges for high performance load bearing applications and require great care to be taken during their design. The design of composite material structures can be assisted by computational models. Many complex computational models have been developed for predicting the failure and lifetime analysis of structures. Critical structures such as high pressure composite cylinders require very accurate computational models, to understand the stochastic nature of the predicted structural response. The following issues limit the use of composite Strength models for making reliable structural predictions: -The complex interaction between the Fibres and matrix which governs the failure mechanism has not been accurately incorporated in composite Strength models. -Lack of reliable constituent properties which are used as input for the models. There are several studies aimed at improving the state-of-the-art models. However, accurate constituent properties to be used as input for these models are rarely available. Authors usually do not comment on the uncertainty of the constituent properties reported, which is of major importance for stochastic simulations. Since Fibres are the principal load bearing constituents of unidirectional composites, Islam et al. have quantified the uncertainty in the parameters of the Fibre Strength Weibull distribution arising during to the characterisation process, using a Monte-Carlo approach to capture the stochastic nature of the Fibre Strength behaviour. Strength of T700 carbon Fibres, popularly used in composite pressure vessels, is used as reference. In this study, the influence of uncertainty in input Fibre Strength on model predictions has been evaluated. A composite Strength model developed at Mines ParisTech was used. This model considers physical processes such as Fibre failure and its interactions with the surrounding matrix. It was first developed in 2005 and has been improved over the years to simulate different loading conditions during service of composite structures such as pressure vessels. The Strength and lifetime of a composite structure (coupon) is simulated under two different practical loading conditions (monotonically increasing and sustained loading) to elucidate the sensitivity of different structural responses to the input Fibre Strength distribution. The calculated uncertainties in the shape (m) and scale (sigma_0) parameters of the Fibre Strength Weibull distribution were used as input for the models. The results are listed as follows: 1) Monotonic loading: -The failure stress is seen to be significantly dependent on the scale parameter. The observed variation in the predicted failure stress is about 10% from the mean case, for an uncertainty of 10% in scale parameter. -The sensitivity of the model predictions to the shape parameter was insignificant. 2) Sustained loading: -The time to failure of the composite specimen was also found to be strongly affected by uncertainties in the scale parameter. The calculated uncertainty of 10% in the input scale parameter resulted in a variation in the predicted lifetime of about 15-30%. -The calculated uncertainty of 25% in the shape parameter resulted in a variation of about 16% in the predicted lifetime of the specimen. The structural behaviour predicted by the model is found to be highly sensitive to the uncertainties in the input Fibre Strength distribution which arise during characterisation. The understanding of the constituent properties and their characterisation process needs to be improved, in order to improve the reliability of computational model predictions, so that the predictions can be used with confidence in industrial applications.
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Uncertainty in Fibre Strength Characterisation Due to Uncertainty in Measurement and Sampling Randomness
Applied Composite Materials, 2020Co-Authors: Sébastien Joannès, Faisal Islam, Lucien LaiarinandrasanaAbstract:Carbon Fibres have exceptional mechanical properties and are used for critical structural applications such as composite pressure vessels and aerospace components. For such high performance applications, reliability-based designs and lifetime assessments require very accurate Strength models. Accuracy of the predictions made by composite Strength models depend on realistic material properties of constituents, which are used as input. In practice however, Fibre Strength properties reported by different sources show significant variations. The work described here aims at understanding the influence of measurement uncertainty and sampling randomness on the uncertainty in calculated tensile Strength distribution parameters. Tensile Strength data for T700 carbon Fibres obtained from single Fibre testing process has been analysed for uncertainties. A parametric bootstrap method has been used for the evaluation. It has been shown that although both the causes studied of uncertainty are critical, the sampling randomness has a larger influence on the uncertainty of Fibre Strength, as compared to the uncertainty due to measurement. Choosing an insufficient sample size for analysis can thus result in uncertain or even inaccurate Fibre Strength properties, which would limit the reliability of composite Strength models. The knowledge of the causes and effects of these uncertainties can help in taking appropriate measures for improving the accuracy of results. This would thereby enhance the capability of composite Strength models to estimate the behaviour of different composite structures more accurately.
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Effect of input properties on the predicted failure of a composite pressure vessel using a multiscale model
2019Co-Authors: Martinus Widjaja, Sébastien Joannès, Faisal Islam, Anthony Bunsell, G. Mair, Alain ThionnetAbstract:A multiscale Fibre break model (FBM) developed at Mines ParisTech has shown relatively good comparison to the experimental observations by computed tomography (CT) technique, however, it was mentioned that a better description of T700 Fibre properties is necessary as it may affect the accumulation process of the Fibre breaks. Therefore, further study on Fibre Strength characterisation can provide insights on the actual Fibre Strength variation and thereby also improve the quality of the failure predictions of the FBM. In this paper, an attempt has been made to understand the variability in the predicted failure of CPVs using the FBM, as a result of the expected variability in the input Fibre properties.
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Investigation of tensile Strength and dimensional variation of T700 carbon Fibres using an improved experimental setup
Journal of Reinforced Plastics and Composites, 2019Co-Authors: Faisal Islam, Sébastien Joannès, Anthony R. Bunsell, Steve Bucknell, Yann Leray, Lucien LaiarinandrasanaAbstract:Knowledge of Fibre Strength is crucial for understanding the failure behaviour of Fibre-reinforced composite materials and structures. Measuring the properties of technical Fibres has been known to...
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Evaluation of Critical Parameters in Tensile Strength Measurement of Single Fibres
Journal of Composites Science, 2019Co-Authors: Faisal Islam, Sébastien Joannès, Lucien LaiarinandrasanaAbstract:Mechanical properties of Fibre reinforced composites are primarily dependent on those of Fibres. Fibre properties are used for estimating the damage and Strength behaviour of composite materials and structures. Tensile Strength of Fibres is commonly determined by single Fibre tensile tests, which is challenging and is prone to measurement errors. In this study, different possible sources of errors due to experimental limitations in the Fibre testing process were identified. Their effect on Fibre tensile Strength was analytically modelled. This model was used to evaluate the uncertainty in experimentally determined Fibre Strength. A sensitivity analysis was conducted to rank the relative significance of input quantities on the calculated Fibre Strength. Since composite models require Fibre properties determined at very small gauge lengths, the results of the sensitivity analysis were extrapolated to determine critical parameters for tests done at those small gauge lengths of a few millimetres. It was shown that, for sufficiently long Fibres, their Strength depends mainly on the diameter and failure force; however, for shorter gauge lengths, the effects of misalignment become very significant. The knowledge of uncertainty would be useful in estimating the reliability of the predictions made by composite Strength models on the damage and failure behaviour of composite materials and structures. Minimising the influence of critical parameters on Fibre Strength would help in designing improved single Fibre testing systems capable of determining Fibre Strength more accurately.