Ivana Partridge - Academia.edu (original) (raw)
Papers by Ivana Partridge
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British Polymer Journal, 1983
... Clive B. Bucknall and Ivana K. Partridge ... The tetrafunctional resin Epoxy IV (Ciba-Geigy M... more ... Clive B. Bucknall and Ivana K. Partridge ... The tetrafunctional resin Epoxy IV (Ciba-Geigy MY720) has a much higher viscosity at room temperature, an epoxy equivalent weight of about 130g/g mole, and a molecular weight of approximately 520. ...
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The paper presents recent developments in the area of impedance cure and flow monitoring of therm... more The paper presents recent developments in the area of impedance cure and flow monitoring of thermosetting matrix/continuous reinforcement composites. Impedance cure monitoring is a variation of dielectric cure monitoring which follows the progress of the curing reaction and the accompanying structural phenomena by means of the impedance spectrum response of the curing material. Currently, a good correlation between specific features of the imaginary impedance spectrum and the progress of the reaction has been found to hold under isothermal conditions. In this paper the correlation between the impedance and the progress of the reaction is extended to dynamic cure conditions. Impedance flow monitoring of the filling stage of liquid moulding of glass composites, based on lineal sensors, has been developed and reported recently. Here, this technique is extended to the case of conductive reinforcements with the development of a new sensing system. The system performance is tested against...
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: The development, analysis and experimental validation of a novel dielectric flow and cure senso... more : The development, analysis and experimental validation of a novel dielectric flow and cure sensor for the resin-transfer-moulding of composites are presented. A linear relationship is established between the flow front position and electrical admittance measurements, allowing accurate flow front location. The sensor performance as an indicator of flow front position is evaluated using visual verification of the flow front position. Its efficiency for monitoring of the curing stage is assessed by comparison of the measurements with conventional microdielectrometry data. Experimental results demonstrate that the sensor can locate the flow front accurately. The measurement output is in the form of a complex number; this appears to offer a potential for a qualitative self-assessment. The monitoring of the cure process shows performance similar to that of the established microdielectrometric techniques.
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Experimental studies have demonstrated the existence of significant thermal gradients during the ... more Experimental studies have demonstrated the existence of significant thermal gradients during the cure stage of Resin Transfer Moulding (RTM). Presence of such thermal gradients can affect the final degree-of-cure distribution and cause the development of residual stresses, leading to a deterioration of the final composite component properties. Therefore the incorporation of heat transfer modelling in the general context of RTM modelling and monitoring of the process is necessary. The present work focuses on the application of combined monitoring and heat transfer modelling to the process. A finite element heat transfer model incorporating resin cure kinetics has been developed and tested. An inverse solution of the heat diffusion model has been implemented in order to extend the local measurements given by in-situ monitoring to global information about the temperature distribution and the degree-of- cure distribution during the cure. Modelling and monitoring of thermoset composites ...
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The development of a heat transfer model for the curing stage of the RTM process is presented. De... more The development of a heat transfer model for the curing stage of the RTM process is presented. Despite the intense interest in the modelling and simulation of this process the relevant work is currently limited to development of flow models of the filling stage. The principles of heat transfer modelling of composites cure have already been reported and applied to the autoclave process by many investigators. In the present investigation, the same concept is used for the implementation of Galerkin finite element approach to RTM curing. The mathematical basis of the resulting semidiscrete model is presented here and the temporal algorithm is described. The experimental mould, which will be used to evaluate and validate the model is also described. 1. BACKGROUND Resin Transfer Moulding process involves the placement of a dry fibre preform in a cavity, the impregnation of resin into the preform and the heating of the component. Although the technique has been employed for composite produ...
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European Structural Integrity Society
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Bookmarks Related papers MentionsView impact
Very short manufacture cycle times are required if continuous carbon fibre and epoxy composite co... more Very short manufacture cycle times are required if continuous carbon fibre and epoxy composite components are to be economically viable material choices for high production volumes in the automotive industry. Manufacturing process variants of resin transfer moulding (RTM) target a reduction of in-mould manufacture time by reducing the time to infuse and cure components using fast curing resin systems with time to cure completion of about 5 minutes at processing temperature. The present study involves a new three part epoxy system supplied by Hexion designed for use with short cycle time RTM processes. Following the establishment of a cure kinetics model for this resin, the potential of dielectric cure monitoring for characterising the flow and cure of the resin in the mould was investigated and is reported here.
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Bookmarks Related papers MentionsView impact
Sample manufacture : -An omega-stiffener/skin joint configuration was selected as a suitable stru... more Sample manufacture : -An omega-stiffener/skin joint configuration was selected as a suitable structural element to evaluate the effects of tufting on the damage resistance of carbon fibre/epoxy composites made via the resin-transfer-moulding route. Tufting is a form of one-sided stitching, whereby a single thread in a hollow needle is passed through a dry fibre preform, exiting through the same position as the insertion point but leaving a loop of the thread held either outside of or within the preform. The dry preform was constructed from several layers of carbon non-crimped fabric, in a quasi-isotropic configuration, and shaped over a specially prepared metal tool to arrive at the so called Ω-stiffener configuration. Commercial twisted glass or carbon thread was used to tuft across the skin-stringer joint (see Fig.1a), using tuft-to-tuft spacing of 5.6 mm. The tufted preform was injected with ACG's MVR444 resin in metal resin-transfer-moulding tool and cured. The cured 300x800...
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Bookmarks Related papers MentionsView impact
A pseudo-UD fabric and a biaxial non-crimped carbon fibre fabric were layered and tufted with Ten... more A pseudo-UD fabric and a biaxial non-crimped carbon fibre fabric were layered and tufted with Tenax twisted carbon sewing thread (3x68 g/km), using tuft spacings of 2.8, 3.9 and 5.6 mm in a square and in a triangular pattern. The selected spacings correspond to areal densities of Z-direction reinforcement of 0.5%, 1% and 2% respectively. A full description of the tufting procedure can be found in [1]. The tufted preforms were infused with ACG's MVR444 resin in a resin transfer moulding (RTM) machine and cured in its rectangular closed mould with adjustable thickness. For a given fabric type the mould thickness determines the fibre volume fraction of the "equivalent" 2D (i.e.tuftless) laminate [2]. In-and out-of-plane 2D micrographs (Fig.1) were used to determine the size and distribution of resin-rich pockets around the perimeter of the (infused and cured) tufts, along with fabric fibre deviation and local fibre volume fraction.
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49th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference <br> 16th AIAA/ASME/AHS Adaptive Structures Conference<br> 10t, 2008
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Robotics and Computer-Integrated Manufacturing, 2015
ABSTRACT The paper aims at providing practical guidelines for the manufacture of composite parts ... more ABSTRACT The paper aims at providing practical guidelines for the manufacture of composite parts reinforced by tufting. The need for through-thickness reinforcement of high performance carbon fibre composite structures is reviewed and various options are presented. The tufting process is described in detail and relevant aspects of the technology are analysed such as: equipment configuration and setup, latest advances in tooling, thread selection, preform supporting systems and choice of ancillary materials. Effects of the process parameters on the preform fibre architecture and on the meso-structure of the reinforced component are discussed. Special emphasis is given to the different options available in terms of tuft insertion and loops management.
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Toughening Mechanisms in Composite Materials, 2015
ABSTRACT his chapter presents a focused update and the addition of new information to published r... more ABSTRACT his chapter presents a focused update and the addition of new information to published reviews of the manufacture and performance of Z-pinned composite structures, concentrating on the mechanisms of enhancement of delamination damage resistance. Special emphasis is placed on the effect of manufacturing routes in terms of generation of the mesostructure of the composite. Effects of manufacturing defects, such as Z-pin misalignment, on the apparent toughness of the composite are explored in experimental and modeling terms, detailing the use of single Z-pin coupons to generate data and to validate models. The strong relationship between the mesostructure of the Z-pinned composite and its performance in both in-plane and out-of-plane properties is highlighted in relation to the differences in dominant failure mechanisms between control and Z-pinned structural elements. The chapter concludes with an update on recent advances in modeling of the effects of load mixity on the apparent toughness of Z-pinned composites.
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Smart Sensor Phenomena, Technology, Networks, and Systems Integration 2013, 2013
ABSTRACT The infusion, flow and cure of RTM6 resin in a carbon fibre reinforced composite preform... more ABSTRACT The infusion, flow and cure of RTM6 resin in a carbon fibre reinforced composite preform have been monitored using a variety of multiplexed fibre optic sensors. Optical fibre Fresnel sensors and tilted fibre Bragg grating (TFBG) sensors were configured to monitor resin infusion/flow in-plane of the component. The results obtained from the different sensors were in good agreement with visual observations. The degree of cure was monitored by Fresnel sensors via a measurement of the refractive index of the resin which was converted to degree of cure using a calibration determined from Differential Scanning Calorimetry. Fibre Bragg grating sensors fabricated in highly linearly birefringent fibre were used to monitor the development of transverse strain during the cure process, revealing through-thickness material shrinkage of about 712 με and residual strain of 223 με. An alternative approach to infusion monitoring, based on an array of multiplexed tapered optical fibre sensors interrogated using optical frequency domain reflectometry, was also investigated in a separate carbon fibre preform that was infused with RTM6 resin.
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European Structural Integrity Society, 2000
The paper presents the results of Mode I and Mode II delamination fracture testing carried out on... more The paper presents the results of Mode I and Mode II delamination fracture testing carried out on 'Z-fibre' reinforced unidirectional beams of IMS/924 laminates. The presence of this new type of through-the-thickness reinforcement is shown to result in dramatic increases in the ...
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European Structural Integrity Society, 2003
Abstract Standard Mode I Double Cantilever Beam specimens for delamination testing of a unidirect... more Abstract Standard Mode I Double Cantilever Beam specimens for delamination testing of a unidirectional (UD) IM7/977-2 composite were Z-pinned with two separate blocks of Z-fiber® reinforcement. The reinforced beam configuration was such as to provoke an unstable ...
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
British Polymer Journal, 1983
... Clive B. Bucknall and Ivana K. Partridge ... The tetrafunctional resin Epoxy IV (Ciba-Geigy M... more ... Clive B. Bucknall and Ivana K. Partridge ... The tetrafunctional resin Epoxy IV (Ciba-Geigy MY720) has a much higher viscosity at room temperature, an epoxy equivalent weight of about 130g/g mole, and a molecular weight of approximately 520. ...
Bookmarks Related papers MentionsView impact
The paper presents recent developments in the area of impedance cure and flow monitoring of therm... more The paper presents recent developments in the area of impedance cure and flow monitoring of thermosetting matrix/continuous reinforcement composites. Impedance cure monitoring is a variation of dielectric cure monitoring which follows the progress of the curing reaction and the accompanying structural phenomena by means of the impedance spectrum response of the curing material. Currently, a good correlation between specific features of the imaginary impedance spectrum and the progress of the reaction has been found to hold under isothermal conditions. In this paper the correlation between the impedance and the progress of the reaction is extended to dynamic cure conditions. Impedance flow monitoring of the filling stage of liquid moulding of glass composites, based on lineal sensors, has been developed and reported recently. Here, this technique is extended to the case of conductive reinforcements with the development of a new sensing system. The system performance is tested against...
Bookmarks Related papers MentionsView impact
: The development, analysis and experimental validation of a novel dielectric flow and cure senso... more : The development, analysis and experimental validation of a novel dielectric flow and cure sensor for the resin-transfer-moulding of composites are presented. A linear relationship is established between the flow front position and electrical admittance measurements, allowing accurate flow front location. The sensor performance as an indicator of flow front position is evaluated using visual verification of the flow front position. Its efficiency for monitoring of the curing stage is assessed by comparison of the measurements with conventional microdielectrometry data. Experimental results demonstrate that the sensor can locate the flow front accurately. The measurement output is in the form of a complex number; this appears to offer a potential for a qualitative self-assessment. The monitoring of the cure process shows performance similar to that of the established microdielectrometric techniques.
Bookmarks Related papers MentionsView impact
Experimental studies have demonstrated the existence of significant thermal gradients during the ... more Experimental studies have demonstrated the existence of significant thermal gradients during the cure stage of Resin Transfer Moulding (RTM). Presence of such thermal gradients can affect the final degree-of-cure distribution and cause the development of residual stresses, leading to a deterioration of the final composite component properties. Therefore the incorporation of heat transfer modelling in the general context of RTM modelling and monitoring of the process is necessary. The present work focuses on the application of combined monitoring and heat transfer modelling to the process. A finite element heat transfer model incorporating resin cure kinetics has been developed and tested. An inverse solution of the heat diffusion model has been implemented in order to extend the local measurements given by in-situ monitoring to global information about the temperature distribution and the degree-of- cure distribution during the cure. Modelling and monitoring of thermoset composites ...
Bookmarks Related papers MentionsView impact
The development of a heat transfer model for the curing stage of the RTM process is presented. De... more The development of a heat transfer model for the curing stage of the RTM process is presented. Despite the intense interest in the modelling and simulation of this process the relevant work is currently limited to development of flow models of the filling stage. The principles of heat transfer modelling of composites cure have already been reported and applied to the autoclave process by many investigators. In the present investigation, the same concept is used for the implementation of Galerkin finite element approach to RTM curing. The mathematical basis of the resulting semidiscrete model is presented here and the temporal algorithm is described. The experimental mould, which will be used to evaluate and validate the model is also described. 1. BACKGROUND Resin Transfer Moulding process involves the placement of a dry fibre preform in a cavity, the impregnation of resin into the preform and the heating of the component. Although the technique has been employed for composite produ...
Bookmarks Related papers MentionsView impact
European Structural Integrity Society
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Very short manufacture cycle times are required if continuous carbon fibre and epoxy composite co... more Very short manufacture cycle times are required if continuous carbon fibre and epoxy composite components are to be economically viable material choices for high production volumes in the automotive industry. Manufacturing process variants of resin transfer moulding (RTM) target a reduction of in-mould manufacture time by reducing the time to infuse and cure components using fast curing resin systems with time to cure completion of about 5 minutes at processing temperature. The present study involves a new three part epoxy system supplied by Hexion designed for use with short cycle time RTM processes. Following the establishment of a cure kinetics model for this resin, the potential of dielectric cure monitoring for characterising the flow and cure of the resin in the mould was investigated and is reported here.
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Sample manufacture : -An omega-stiffener/skin joint configuration was selected as a suitable stru... more Sample manufacture : -An omega-stiffener/skin joint configuration was selected as a suitable structural element to evaluate the effects of tufting on the damage resistance of carbon fibre/epoxy composites made via the resin-transfer-moulding route. Tufting is a form of one-sided stitching, whereby a single thread in a hollow needle is passed through a dry fibre preform, exiting through the same position as the insertion point but leaving a loop of the thread held either outside of or within the preform. The dry preform was constructed from several layers of carbon non-crimped fabric, in a quasi-isotropic configuration, and shaped over a specially prepared metal tool to arrive at the so called Ω-stiffener configuration. Commercial twisted glass or carbon thread was used to tuft across the skin-stringer joint (see Fig.1a), using tuft-to-tuft spacing of 5.6 mm. The tufted preform was injected with ACG's MVR444 resin in metal resin-transfer-moulding tool and cured. The cured 300x800...
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
A pseudo-UD fabric and a biaxial non-crimped carbon fibre fabric were layered and tufted with Ten... more A pseudo-UD fabric and a biaxial non-crimped carbon fibre fabric were layered and tufted with Tenax twisted carbon sewing thread (3x68 g/km), using tuft spacings of 2.8, 3.9 and 5.6 mm in a square and in a triangular pattern. The selected spacings correspond to areal densities of Z-direction reinforcement of 0.5%, 1% and 2% respectively. A full description of the tufting procedure can be found in [1]. The tufted preforms were infused with ACG's MVR444 resin in a resin transfer moulding (RTM) machine and cured in its rectangular closed mould with adjustable thickness. For a given fabric type the mould thickness determines the fibre volume fraction of the "equivalent" 2D (i.e.tuftless) laminate [2]. In-and out-of-plane 2D micrographs (Fig.1) were used to determine the size and distribution of resin-rich pockets around the perimeter of the (infused and cured) tufts, along with fabric fibre deviation and local fibre volume fraction.
Bookmarks Related papers MentionsView impact
49th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference <br> 16th AIAA/ASME/AHS Adaptive Structures Conference<br> 10t, 2008
Bookmarks Related papers MentionsView impact
Robotics and Computer-Integrated Manufacturing, 2015
ABSTRACT The paper aims at providing practical guidelines for the manufacture of composite parts ... more ABSTRACT The paper aims at providing practical guidelines for the manufacture of composite parts reinforced by tufting. The need for through-thickness reinforcement of high performance carbon fibre composite structures is reviewed and various options are presented. The tufting process is described in detail and relevant aspects of the technology are analysed such as: equipment configuration and setup, latest advances in tooling, thread selection, preform supporting systems and choice of ancillary materials. Effects of the process parameters on the preform fibre architecture and on the meso-structure of the reinforced component are discussed. Special emphasis is given to the different options available in terms of tuft insertion and loops management.
Bookmarks Related papers MentionsView impact
Toughening Mechanisms in Composite Materials, 2015
ABSTRACT his chapter presents a focused update and the addition of new information to published r... more ABSTRACT his chapter presents a focused update and the addition of new information to published reviews of the manufacture and performance of Z-pinned composite structures, concentrating on the mechanisms of enhancement of delamination damage resistance. Special emphasis is placed on the effect of manufacturing routes in terms of generation of the mesostructure of the composite. Effects of manufacturing defects, such as Z-pin misalignment, on the apparent toughness of the composite are explored in experimental and modeling terms, detailing the use of single Z-pin coupons to generate data and to validate models. The strong relationship between the mesostructure of the Z-pinned composite and its performance in both in-plane and out-of-plane properties is highlighted in relation to the differences in dominant failure mechanisms between control and Z-pinned structural elements. The chapter concludes with an update on recent advances in modeling of the effects of load mixity on the apparent toughness of Z-pinned composites.
Bookmarks Related papers MentionsView impact
Smart Sensor Phenomena, Technology, Networks, and Systems Integration 2013, 2013
ABSTRACT The infusion, flow and cure of RTM6 resin in a carbon fibre reinforced composite preform... more ABSTRACT The infusion, flow and cure of RTM6 resin in a carbon fibre reinforced composite preform have been monitored using a variety of multiplexed fibre optic sensors. Optical fibre Fresnel sensors and tilted fibre Bragg grating (TFBG) sensors were configured to monitor resin infusion/flow in-plane of the component. The results obtained from the different sensors were in good agreement with visual observations. The degree of cure was monitored by Fresnel sensors via a measurement of the refractive index of the resin which was converted to degree of cure using a calibration determined from Differential Scanning Calorimetry. Fibre Bragg grating sensors fabricated in highly linearly birefringent fibre were used to monitor the development of transverse strain during the cure process, revealing through-thickness material shrinkage of about 712 με and residual strain of 223 με. An alternative approach to infusion monitoring, based on an array of multiplexed tapered optical fibre sensors interrogated using optical frequency domain reflectometry, was also investigated in a separate carbon fibre preform that was infused with RTM6 resin.
Bookmarks Related papers MentionsView impact
European Structural Integrity Society, 2000
The paper presents the results of Mode I and Mode II delamination fracture testing carried out on... more The paper presents the results of Mode I and Mode II delamination fracture testing carried out on 'Z-fibre' reinforced unidirectional beams of IMS/924 laminates. The presence of this new type of through-the-thickness reinforcement is shown to result in dramatic increases in the ...
Bookmarks Related papers MentionsView impact
European Structural Integrity Society, 2003
Abstract Standard Mode I Double Cantilever Beam specimens for delamination testing of a unidirect... more Abstract Standard Mode I Double Cantilever Beam specimens for delamination testing of a unidirectional (UD) IM7/977-2 composite were Z-pinned with two separate blocks of Z-fiber® reinforcement. The reinforced beam configuration was such as to provoke an unstable ...
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact