The Experts below are selected from a list of 39 Experts worldwide ranked by ideXlab platform

Xiao Ling Zhao - One of the best experts on this subject based on the ideXlab platform.

  • failure of cfrp to steel Double Strap Joint bonded using carbon nanotubes modified epoxy adhesive at moderately elevated temperatures
    Composites Part B-engineering, 2016
    Co-Authors: Asghar Habibnejad Korayem, Shu Jian Chen, Qianhui Zhang, Xiao Ling Zhao, Wenhui Duan
    Abstract:

    Abstract The bond characteristics of Double Strap Joints between carbon fibre reinforced polymer (CFRP) laminates and steel with carbon nanotubes (CNTs) modified epoxy, under moderately elevated temperature (23–70 °C) were studied. The effect of CNTs on the failure modes, bond interface, and bond strength were presented. Results show that increasing test temperature causes transition of failure from epoxy-CFRP interface to steel–epoxy interface and to cohesive layer in the Joints with neat epoxy. The cohesive failure could be avoided in the Joints with CNT-epoxy. The observations from scanning electron microscopy revealed that CNTs bridge the cracks in epoxy matrix indicating a reinforcing effect. Moreover, CNT-epoxy can provide a significant increase (about two fold) of bond strengths at moderately elevated temperatures when compared with neat epoxy. It demonstrated that the incorporation of CNTs into the bond adhesive could allow better exploiting the potential of CFRP system in strengthening of steel structures at moderately elevated temperature.

  • experimental and finite element analysis of a Double Strap Joint between steel plates and normal modulus cfrp
    Composite Structures, 2006
    Co-Authors: Sabrina Fawzia, Riadh Almahaidi, Xiao Ling Zhao
    Abstract:

    Strengthening of steel structures using externally-bonded carbon fibre reinforced polymers ‘CFRP’ is a rapidly developing technique. This paper describes the behaviour of axially loaded flat steel plates strengthened using carbon fibre reinforced polymer sheets. Two steel plates were joined together with adhesive and followed by the application of carbon fibre sheet Double Strap Joint with different bond lengths. The behaviour of the specimens was further investigated by using nonlinear finite element analysis to predict the failure modes and load capacity. In this study, bond failure is the dominant failure mode for normal modulus (240 GPa) CFRP bonding which closely matched the results of finite elements. The predicted ultimate loads from the FE analysis are found to be in good agreement with experimental values.

  • Double Strap Joint tests to determine the bond characteristics between cfrp and steel plates
    Fourth International Conference on Advances in Steel Structures#R##N#Proceedings of the Fourth International Conference on Advances in Steel Structure, 2005
    Co-Authors: Sabrina Fawzia, Xiao Ling Zhao, Riadh Almahaidi, Sami H Rizkalla
    Abstract:

    Advanced composite materials offer remarkable potential in the upgrade of civil engineering structures. The evolution of CFRP (carbon fibre reinforced polymer) technologies and their versatility for applications in civil constructions require comprehensive and reliable codes of practice. Guidelines are available on the rehabilitation and retrofit of concrete structures with advanced composite materials. However, there is a need to develop appropriate design guidelines for CFRP strengthened steel structures. It is important to understand the bond characteristics between CFRP and steel plates. This paper describes a series of Double Strap shear tests loaded in tension to investigate the bond between CFRP sheets and steel plates. Both normal modulus (240 GPa) and high modulus (640 GPa) CFRPs were used in the test program. Strain gauges were mounted to capture the strain distribution along the CFRP length. Different failure modes were observed for Joints with normal modulus CFRP and those with high modulus CFRP. The strain distribution along the CFRP length is similar for the two cases. A shorter effective bond length was obtained for Joints with high modulus CFRP whereas larger ultimate load carrying capacity can be achieved for Joints with normal modulus CFRP when the bond length is long enough.

Castro-fresno Daniel - One of the best experts on this subject based on the ideXlab platform.

  • Fatigue behaviour of adhesive bonds in tensile CFRP-metal Double-Strap Joints with puddle iron plates taken from a 19th century bridge
    'Elsevier BV', 2022
    Co-Authors: Jiménez Vicaria, José David, Castro-fresno Daniel, Pulido, Dolores M. G
    Abstract:

    ABSTRACT: The use of adhesively-bonded CFRP crack-patching in old metallic bridges seems to be a promising fatigue strengthening technique, but the internal laminar structure of puddle iron could influence its efficiency, resulting in premature interlaminar failure within the metal before CFRP debonding. To investigate the fatigue behaviour of this retrofitting system, six Double-Strap Joints with CFRP laminates adhesively-bonded to puddle iron plates taken from a 19th century bridge were tested. Three specimens were statically loaded until failure as control specimens, and other three were tested under tensile-tensile fatigue loading up to 2 million cycles at a frequency of 10 Hz, with stress ranges in the metal of 60, 75 and 90 MPa. An analytical model is used to compute the maximum principal stress range in the adhesive during fatigue loading, which is assumed as the governing fatigue strength parameter in the Double-Strap Joint. Based on the experimental results of the present work, together with a database for Joints with modern steel collected from literature, an S-N fatigue curve is obtained for CFRP-metal Double-Strap specimens, and a fatigue limit in terms of maximum principal stress range in the adhesive layer is proposed to be used in design guidelines.The research leading to these results has received partial funding from the European Union's Horizon 519 2020 Programme in the framework of the research project IN2TRACK under grant agreement n° 730841. The authors also wish to thank the laboratory technicians of ACCIONA Construction Technological Centre, where all the tests were carried out

  • Influence of carbon fibre stiffness and adhesive ductility on CFRP-steel adhesive Joints with short bond lengths
    'Elsevier BV', 2022
    Co-Authors: Jiménez Vicaria, José David, Pulido, Dolores M. G, Castro-fresno Daniel
    Abstract:

    The use of adhesively-bonded CFRP laminates is a promising technique to strengthen steel structures that have been deteriorated due to corrosion, ageing or increasing loads, as in the case of old metallic riveted bridges. But the relatively short available space between rivets requires the use of adhesively-bonded CFRP laminates with short bond lengths, which needs to be deeply studied as most previous research works have focused on large bond lengths. To study the bond behaviour between CFRP laminates and steel plates in such strengthened structures, a series of tests has been carried out in Double-Strap Joints under tensile loading, evaluating the influence of CFRP stiffness and adhesive ductility on the strength and failure mode of short bond length adhesive Joints. Based on the experimental results of the present work, together with a large database collected from literature, a fracture-mechanics model based on interfacial fracture energy in shear GII is calibrated, and a simple expression is developed to be used in design for the strength prediction of such adhesive Joints. Finally, Double-Strap Joint specimens are simulated using cohesive zone models (CZM) for the adhesive layers, and the results are compared to the analytical model and experimental tests.The research leading to these results has received partial funding from the European Union's Horizon 519 2020 Programme in the framework of the research project IN2TRACK under grant agreement n° 730841. The authors also wish to thank the laboratory technicians of ACCIONA Construction Technological Centre, where all the tests were carried out

  • Influence of carbon fibre stiffness and adhesive ductility on CFRP-steel adhesive Joints with short bond lengths
    'Elsevier BV', 2020
    Co-Authors: Jimenez-vicaria J. David, Gómez Pulido, María Dolores, Castro-fresno Daniel
    Abstract:

    The use of adhesively-bonded CFRP laminates is a promising technique to strengthen steel structures that have been deteriorated due to corrosion, ageing or increasing loads, as in the case of old metallic riveted bridges. But the relatively short available space between rivets requires the use of adhesively-bonded CFRP laminates with short bond lengths, which needs to be deeply studied as most previous research works have focused on large bond lengths. To study the bond behaviour between CFRP laminates and steel plates in such strengthened structures, a series of tests has been carried out in Double-Strap Joints under tensile loading, evaluating the influence of CFRP stiffness and adhesive ductility on the strength and failure mode of short bond length adhesive Joints. Based on the experimental results of the present work, together with a large database collected from literature, a fracture-mechanics model based on interfacial fracture energy in shear GII is calibrated, and a simple expression is developed to be used in design for the strength prediction of such adhesive Joints. Finally, Double-Strap Joint specimens are simulated using cohesive zone models (CZM) for the adhesive layers, and the results are compared to the analytical model and experimental tests.The research leading to these results has received partial funding from the European Union's Horizon 2020 Programme in the framework of the research project IN2TRACK under grant agreement n° 730841.Peer reviewe

  • Fatigue behaviour of adhesive bonds in tensile CFRP-metal Double-Strap Joints with puddle iron plates taken from a 19th century bridge
    'Elsevier BV', 2020
    Co-Authors: Jimenez-vicaria J. David, Castro-fresno Daniel, Gómez Pulido, María Dolores
    Abstract:

    The use of adhesively-bonded CFRP crack-patching in old metallic bridges seems to be a promising fatigue strengthening technique, but the internal laminar structure of puddle iron could influence its efficiency, resulting in premature interlaminar failure within the metal before CFRP debonding. To investigate the fatigue behaviour of this retrofitting system, six Double-Strap Joints with CFRP laminates adhesively-bonded to puddle iron plates taken from a 19th century bridge were tested. Three specimens were statically loaded until failure as control specimens, and other three were tested under tensile-tensile fatigue loading up to 2 million cycles at a frequency of 10 Hz, with stress ranges in the metal of 60, 75 and 90 MPa. An analytical model is used to compute the maximum principal stress range in the adhesive during fatigue loading, which is assumed as the governing fatigue strength parameter in the Double-Strap Joint. Based on the experimental results of the present work, together with a database for Joints with modern steel collected from literature, an S-N fatigue curve is obtained for CFRP-metal Double-Strap specimens, and a fatigue limit in terms of maximum principal stress range in the adhesive layer is proposed to be used in design guidelines.The research leading to these results has received partial funding from the European Union's Horizon 2020 Programme in the framework of the research project IN2TRACK under grant agreement n° 730841.Peer reviewe

Sabrina Fawzia - One of the best experts on this subject based on the ideXlab platform.

  • experimental and finite element analysis of a Double Strap Joint between steel plates and normal modulus cfrp
    Composite Structures, 2006
    Co-Authors: Sabrina Fawzia, Riadh Almahaidi, Xiao Ling Zhao
    Abstract:

    Strengthening of steel structures using externally-bonded carbon fibre reinforced polymers ‘CFRP’ is a rapidly developing technique. This paper describes the behaviour of axially loaded flat steel plates strengthened using carbon fibre reinforced polymer sheets. Two steel plates were joined together with adhesive and followed by the application of carbon fibre sheet Double Strap Joint with different bond lengths. The behaviour of the specimens was further investigated by using nonlinear finite element analysis to predict the failure modes and load capacity. In this study, bond failure is the dominant failure mode for normal modulus (240 GPa) CFRP bonding which closely matched the results of finite elements. The predicted ultimate loads from the FE analysis are found to be in good agreement with experimental values.

  • Double Strap Joint tests to determine the bond characteristics between cfrp and steel plates
    Fourth International Conference on Advances in Steel Structures#R##N#Proceedings of the Fourth International Conference on Advances in Steel Structure, 2005
    Co-Authors: Sabrina Fawzia, Xiao Ling Zhao, Riadh Almahaidi, Sami H Rizkalla
    Abstract:

    Advanced composite materials offer remarkable potential in the upgrade of civil engineering structures. The evolution of CFRP (carbon fibre reinforced polymer) technologies and their versatility for applications in civil constructions require comprehensive and reliable codes of practice. Guidelines are available on the rehabilitation and retrofit of concrete structures with advanced composite materials. However, there is a need to develop appropriate design guidelines for CFRP strengthened steel structures. It is important to understand the bond characteristics between CFRP and steel plates. This paper describes a series of Double Strap shear tests loaded in tension to investigate the bond between CFRP sheets and steel plates. Both normal modulus (240 GPa) and high modulus (640 GPa) CFRPs were used in the test program. Strain gauges were mounted to capture the strain distribution along the CFRP length. Different failure modes were observed for Joints with normal modulus CFRP and those with high modulus CFRP. The strain distribution along the CFRP length is similar for the two cases. A shorter effective bond length was obtained for Joints with high modulus CFRP whereas larger ultimate load carrying capacity can be achieved for Joints with normal modulus CFRP when the bond length is long enough.

Asghar Habibnejad Korayem - One of the best experts on this subject based on the ideXlab platform.

  • failure of cfrp to steel Double Strap Joint bonded using carbon nanotubes modified epoxy adhesive at moderately elevated temperatures
    Composites Part B-engineering, 2016
    Co-Authors: Asghar Habibnejad Korayem, Shu Jian Chen, Qianhui Zhang, Xiao Ling Zhao, Wenhui Duan
    Abstract:

    Abstract The bond characteristics of Double Strap Joints between carbon fibre reinforced polymer (CFRP) laminates and steel with carbon nanotubes (CNTs) modified epoxy, under moderately elevated temperature (23–70 °C) were studied. The effect of CNTs on the failure modes, bond interface, and bond strength were presented. Results show that increasing test temperature causes transition of failure from epoxy-CFRP interface to steel–epoxy interface and to cohesive layer in the Joints with neat epoxy. The cohesive failure could be avoided in the Joints with CNT-epoxy. The observations from scanning electron microscopy revealed that CNTs bridge the cracks in epoxy matrix indicating a reinforcing effect. Moreover, CNT-epoxy can provide a significant increase (about two fold) of bond strengths at moderately elevated temperatures when compared with neat epoxy. It demonstrated that the incorporation of CNTs into the bond adhesive could allow better exploiting the potential of CFRP system in strengthening of steel structures at moderately elevated temperature.

Gómez Pulido, María Dolores - One of the best experts on this subject based on the ideXlab platform.

  • Influence of carbon fibre stiffness and adhesive ductility on CFRP-steel adhesive Joints with short bond lengths
    'Elsevier BV', 2020
    Co-Authors: Jimenez-vicaria J. David, Gómez Pulido, María Dolores, Castro-fresno Daniel
    Abstract:

    The use of adhesively-bonded CFRP laminates is a promising technique to strengthen steel structures that have been deteriorated due to corrosion, ageing or increasing loads, as in the case of old metallic riveted bridges. But the relatively short available space between rivets requires the use of adhesively-bonded CFRP laminates with short bond lengths, which needs to be deeply studied as most previous research works have focused on large bond lengths. To study the bond behaviour between CFRP laminates and steel plates in such strengthened structures, a series of tests has been carried out in Double-Strap Joints under tensile loading, evaluating the influence of CFRP stiffness and adhesive ductility on the strength and failure mode of short bond length adhesive Joints. Based on the experimental results of the present work, together with a large database collected from literature, a fracture-mechanics model based on interfacial fracture energy in shear GII is calibrated, and a simple expression is developed to be used in design for the strength prediction of such adhesive Joints. Finally, Double-Strap Joint specimens are simulated using cohesive zone models (CZM) for the adhesive layers, and the results are compared to the analytical model and experimental tests.The research leading to these results has received partial funding from the European Union's Horizon 2020 Programme in the framework of the research project IN2TRACK under grant agreement n° 730841.Peer reviewe

  • Fatigue behaviour of adhesive bonds in tensile CFRP-metal Double-Strap Joints with puddle iron plates taken from a 19th century bridge
    'Elsevier BV', 2020
    Co-Authors: Jimenez-vicaria J. David, Castro-fresno Daniel, Gómez Pulido, María Dolores
    Abstract:

    The use of adhesively-bonded CFRP crack-patching in old metallic bridges seems to be a promising fatigue strengthening technique, but the internal laminar structure of puddle iron could influence its efficiency, resulting in premature interlaminar failure within the metal before CFRP debonding. To investigate the fatigue behaviour of this retrofitting system, six Double-Strap Joints with CFRP laminates adhesively-bonded to puddle iron plates taken from a 19th century bridge were tested. Three specimens were statically loaded until failure as control specimens, and other three were tested under tensile-tensile fatigue loading up to 2 million cycles at a frequency of 10 Hz, with stress ranges in the metal of 60, 75 and 90 MPa. An analytical model is used to compute the maximum principal stress range in the adhesive during fatigue loading, which is assumed as the governing fatigue strength parameter in the Double-Strap Joint. Based on the experimental results of the present work, together with a database for Joints with modern steel collected from literature, an S-N fatigue curve is obtained for CFRP-metal Double-Strap specimens, and a fatigue limit in terms of maximum principal stress range in the adhesive layer is proposed to be used in design guidelines.The research leading to these results has received partial funding from the European Union's Horizon 2020 Programme in the framework of the research project IN2TRACK under grant agreement n° 730841.Peer reviewe