The Experts below are selected from a list of 99 Experts worldwide ranked by ideXlab platform

Benedictus R. - One of the best experts on this subject based on the ideXlab platform.

  • Fusion-based damage diagnostics for stiffened composite panels
    'SAGE Publications', 2021
    Co-Authors: Broer, Agnes A.r., Benedictus R., Galanopoulos Georgios, Loutas Theodoros, Zarouchas D.
    Abstract:

    Conducting damage diagnostics on stiffened panels is commonly performed using a single SHM technique. However, each SHM technique has both its strengths and limitations. Rather than straining the expansion of single SHM techniques going beyond their intrinsic capacities, these strengths and limitations should instead be considered in their application. In this work, we propose a novel fusion-based methodology between data from two SHM techniques in order to surpass the capabilities of a single SHM technique. The aim is to show that by considering data fusion, a synergy can be obtained, resulting in a comprehensive damage assessment, not possible using a single SHM technique. For this purpose, three single-stiffener carbon–epoxy panels were subjected to fatigue compression after impact tests. Two SHM techniques monitored damage Growth under the applied fatigue loads: acoustic emission and distributed fiber optic strain sensing. Four acoustic emission sensors were placed on each panel, thereby allowing for damage detection, localization, type identification (delamination), and severity assessment. The optical fibers were adhered to the stiffener feet’ surface, and its strain measurements were used for damage detection, Disbond localization, damage type identification (stiffness degradation and Disbond Growth), and severity assessment. Different fusion techniques are presented in order to integrate the acoustic emission and strain data. For damage detection and severity assessment, a hybrid health indicator is obtained by feature-level fusion while a complementary and cooperative fusion of the diagnostic results is developed for damage localization and type identification. We show that damage Growth can be monitored up until final failure, thereby performing a simultaneous damage assessment on all four SHM levels. In this manner, we demonstrate that by proposing a fusion-based approach toward SHM of composite structures, the intrinsic capacity of each SHM technique can be utilized, leading to synergistic effects for damage diagnostics

  • Fusion-based damage diagnostics for stiffened composite panels
    'SAGE Publications', 2021
    Co-Authors: Broer, Agnes A.r., Benedictus R., Galanopoulos Georgios, Loutas Theodoros, Zarouchas D.
    Abstract:

    Conducting damage diagnostics on stiffened panels is commonly performed using a single SHM technique. However, each SHM technique has both its strengths and limitations. Rather than straining the expansion of single SHM techniques going beyond their intrinsic capacities, these strengths and limitations should instead be considered in their application. In this work, we propose a novel fusion-based methodology between data from two SHM techniques in order to surpass the capabilities of a single SHM technique. The aim is to show that by considering data fusion, a synergy can be obtained, resulting in a comprehensive damage assessment, not possible using a single SHM technique. For this purpose, three single-stiffener carbon–epoxy panels were subjected to fatigue compression after impact tests. Two SHM techniques monitored damage Growth under the applied fatigue loads: acoustic emission and distributed fiber optic strain sensing. Four acoustic emission sensors were placed on each panel, thereby allowing for damage detection, localization, type identification (delamination), and severity assessment. The optical fibers were adhered to the stiffener feet’ surface, and its strain measurements were used for damage detection, Disbond localization, damage type identification (stiffness degradation and Disbond Growth), and severity assessment. Different fusion techniques are presented in order to integrate the acoustic emission and strain data. For damage detection and severity assessment, a hybrid health indicator is obtained by feature-level fusion while a complementary and cooperative fusion of the diagnostic results is developed for damage localization and type identification. We show that damage Growth can be monitored up until final failure, thereby performing a simultaneous damage assessment on all four SHM levels. In this manner, we demonstrate that by proposing a fusion-based approach toward SHM of composite structures, the intrinsic capacity of each SHM technique can be utilized, leading to synergistic effects for damage diagnostics.Structural Integrity & Composite

  • Towards Understanding Fatigue Disbond Growth via Cyclic Strain Energy
    Elsevier Ltd., 2014
    Co-Authors: Pascoe J.a., Alderliesten R.c., Benedictus R.
    Abstract:

    AbstractThe concept of relating fatigue Disbond Growth to the strain energy release rate (SERR) is critically examined. It is highlighted that the common practise of using only the maximum SERR or only the SERR range is insufficient to correctly characterize a load cycle. As crack Growth requires energy, it is argued that Growth should be related to the total amount of energy released during a fatigue cycle, and not to the amount of energy that would be released by a crack Growth increment under the instantaneous load conditions at one point in the load cycle. This argument is supported by experimental evidence, showing that the relationship between fatigue Disbond Growth (FDG) rate and either maximum SERR or SERR range is R-ratio dependent, whereas the relationship between FDG rate and the loss of strain energy is not

  • On the relationship between Disbond Growth and the release of strain energy
    Elsevier, 2014
    Co-Authors: Pascoe J.a., Alderliesten R.c., Benedictus R.
    Abstract:

    Current prediction methods for Growth of Disbonds under fatigue loading are generally based on a correlation with either the maximum strain energy release rate (SERR) or the SERR range. This paper highlights some issues with this approach. In particular, it is argued that the maximum SERR or the SERR range alone do not give sufficient information to uniquely characterize the driving force for crack Growth. Furthermore it is argued that the relationship between crack Growth rate and loss of strain energy should be considered on the scale of the entire load cycle. By means of Disbond Growth experiments it is shown that there is indeed a very strong correlation between the crack Growth rate and the strain energy lost during a fatigue cycle. Unlike methods based on the SERR, this correlation is not affected by the R-ratio. Based on the found correlation a possible basis for a new approach to Disbond Growth prediction is suggested

  • Towards Understanding Fatigue Disbond Growth via Cyclic Strain Energy
    'Elsevier BV', 2014
    Co-Authors: Pascoe J.a., Alderliesten R.c., Benedictus R.
    Abstract:

    The concept of relating fatigue Disbond Growth to the strain energy release rate (SERR) is critically examined. It is highlighted that the common practise of using only the maximum SERR or only the SERR range is insufficient to correctly characterize a load cycle. As crack Growth requires energy, it is argued that Growth should be related to the total amount of energy released during a fatigue cycle, and not to the amount of energy that would be released by a crack Growth increment under the instantaneous load conditions at one point in the load cycle. This argument is supported by experimental evidence, showing that the relationship between fatigue Disbond Growth (FDG) rate and either maximum SERR or SERR range is R-ratio dependent, whereas the relationship between FDG rate and the loss of strain energy is not.Aerospace Structures & MaterialsAerospace Engineerin

Rans C.d. - One of the best experts on this subject based on the ideXlab platform.

  • Evaluation of mode II fatigue Disbonding using Central Cut Plies specimen and distributed strain sensing technology
    'Informa UK Limited', 2019
    Co-Authors: Ribeiro, Fabricio N., Martinez M.j., Rans C.d.
    Abstract:

    The lack of a widely-accepted test standard for characterizing the mode II fatigue Disbond Growth behavior of adhesively bonded interfaces is a challenge to the research community in terms of producing consistent and repeatable results. Typically, researchers apply the End Notch Flexure specimen, which is already used for static delamination studies. However, the needs for static and fatigue Disbond Growth characterization are not the same, resulting in some undesirable effects in such specimen. This study looks at a particular mode II test configuration known as the Central Cut Plies (CCP) specimen. A critical evaluation of the suitability of this specimen, including the influence of geometry, Disbond measurement approaches and the stability of the Disbond Growth is carried out through a combination of numerical and experimental investigations. A distributed strain sensing system based on Rayleigh Backscattering provided a surface strain profile from which Disbond Growth rate data was obtained. A finite element model was used to verify the experimental results and determine the Disbond length from the strain profiles. Results of this evaluation have shown that the CCP specimen is a promising specimen configuration for characterizing fatigue Disbond Growth; however, it also presents several challenges that require consideration in its application.Structural Integrity & Composite

  • Evaluation of mode II fatigue Disbonding using Central Cut Plies specimen and distributed strain sensing technology
    2019
    Co-Authors: Ribeiro, Fabricio N., Martinez M.j., Rans C.d.
    Abstract:

    The lack of a widely-accepted test standard for characterizing the mode II fatigue Disbond Growth behavior of adhesively bonded interfaces is a challenge to the research community in terms of producing consistent and repeatable results. Typically, researchers apply the End Notch Flexure specimen, which is already used for static delamination studies. However, the needs for static and fatigue Disbond Growth characterization are not the same, resulting in some undesirable effects in such specimen. This study looks at a particular mode II test configuration known as the Central Cut Plies (CCP) specimen. A critical evaluation of the suitability of this specimen, including the influence of geometry, Disbond measurement approaches and the stability of the Disbond Growth is carried out through a combination of numerical and experimental investigations. A distributed strain sensing system based on Rayleigh Backscattering provided a surface strain profile from which Disbond Growth rate data was obtained. A finite element model was used to verify the experimental results and determine the Disbond length from the strain profiles. Results of this evaluation have shown that the CCP specimen is a promising specimen configuration for characterizing fatigue Disbond Growth; however, it also presents several challenges that require consideration in its application

Steve C Galea - One of the best experts on this subject based on the ideXlab platform.

  • detection of Disbond Growth in a cyclically loaded bonded composite repair patch using surface mounted piezoceramic elements
    Structural Health Monitoring-an International Journal, 2003
    Co-Authors: Y L Koh, Wing Kong Chiu, Nik Rajic, Steve C Galea
    Abstract:

    This paper reports on an experimental study in which an array of surface-mounted lead zirconate titanate elements (PZT) are used for the in situ detection of Disbond Growth in a bonded composite repair patch. Two techniques are used to track the evolution of Disbond Growth: the transfer function method and the electromechanical impedance method. Both techniques were found to provide a reliable and robust basis for the detection of Disbond Growth. The results also demonstrate the importance of transducer placement relative to the Disbond location as a factor in the sensitivity to Disbond Growth.

Chun H. Wang - One of the best experts on this subject based on the ideXlab platform.

  • Plasticity induced crack closure in adhesively bonded joints under fatigue loading
    International Journal of Fatigue, 2015
    Co-Authors: M Donough, Adrian C. Orifici, Andrew J. Gunnion, Chun H. Wang
    Abstract:

    The mean load of a cyclic loading has a large effect on fatigue crack Growth rates in metallic materials and bonded joints. In metallic structures, this effect has been attributed to plasticity-induced crack closure, but little is known about the mechanism responsible for this mean load effect on fatigue crack Growth in adhesively bonded joints. This paper presents a computational investigation of the plasticity-induced crack closure mechanism affecting Disbond Growth in adhesively bonded joints under fatigue loading. The results show that the ratios of crack-opening and crack-closure are approximately independent of the level of plastic constraint, indicated by the ratio between the plastic zone size and the adhesive thickness. An effective strain-energy release rate parameter, which accounts for the crack closure behaviour, has been developed as a new correlating parameter for Disbond Growth. Comparisons with the experimental results pertinent to four different adhesive bonded joints reveal that this new correlating parameter is capable of unifying the fatigue Growth rates by eliminating the effect of mean loads.

Zarouchas D. - One of the best experts on this subject based on the ideXlab platform.

  • Fusion-based damage diagnostics for stiffened composite panels
    'SAGE Publications', 2021
    Co-Authors: Broer, Agnes A.r., Benedictus R., Galanopoulos Georgios, Loutas Theodoros, Zarouchas D.
    Abstract:

    Conducting damage diagnostics on stiffened panels is commonly performed using a single SHM technique. However, each SHM technique has both its strengths and limitations. Rather than straining the expansion of single SHM techniques going beyond their intrinsic capacities, these strengths and limitations should instead be considered in their application. In this work, we propose a novel fusion-based methodology between data from two SHM techniques in order to surpass the capabilities of a single SHM technique. The aim is to show that by considering data fusion, a synergy can be obtained, resulting in a comprehensive damage assessment, not possible using a single SHM technique. For this purpose, three single-stiffener carbon–epoxy panels were subjected to fatigue compression after impact tests. Two SHM techniques monitored damage Growth under the applied fatigue loads: acoustic emission and distributed fiber optic strain sensing. Four acoustic emission sensors were placed on each panel, thereby allowing for damage detection, localization, type identification (delamination), and severity assessment. The optical fibers were adhered to the stiffener feet’ surface, and its strain measurements were used for damage detection, Disbond localization, damage type identification (stiffness degradation and Disbond Growth), and severity assessment. Different fusion techniques are presented in order to integrate the acoustic emission and strain data. For damage detection and severity assessment, a hybrid health indicator is obtained by feature-level fusion while a complementary and cooperative fusion of the diagnostic results is developed for damage localization and type identification. We show that damage Growth can be monitored up until final failure, thereby performing a simultaneous damage assessment on all four SHM levels. In this manner, we demonstrate that by proposing a fusion-based approach toward SHM of composite structures, the intrinsic capacity of each SHM technique can be utilized, leading to synergistic effects for damage diagnostics

  • Fusion-based damage diagnostics for stiffened composite panels
    'SAGE Publications', 2021
    Co-Authors: Broer, Agnes A.r., Benedictus R., Galanopoulos Georgios, Loutas Theodoros, Zarouchas D.
    Abstract:

    Conducting damage diagnostics on stiffened panels is commonly performed using a single SHM technique. However, each SHM technique has both its strengths and limitations. Rather than straining the expansion of single SHM techniques going beyond their intrinsic capacities, these strengths and limitations should instead be considered in their application. In this work, we propose a novel fusion-based methodology between data from two SHM techniques in order to surpass the capabilities of a single SHM technique. The aim is to show that by considering data fusion, a synergy can be obtained, resulting in a comprehensive damage assessment, not possible using a single SHM technique. For this purpose, three single-stiffener carbon–epoxy panels were subjected to fatigue compression after impact tests. Two SHM techniques monitored damage Growth under the applied fatigue loads: acoustic emission and distributed fiber optic strain sensing. Four acoustic emission sensors were placed on each panel, thereby allowing for damage detection, localization, type identification (delamination), and severity assessment. The optical fibers were adhered to the stiffener feet’ surface, and its strain measurements were used for damage detection, Disbond localization, damage type identification (stiffness degradation and Disbond Growth), and severity assessment. Different fusion techniques are presented in order to integrate the acoustic emission and strain data. For damage detection and severity assessment, a hybrid health indicator is obtained by feature-level fusion while a complementary and cooperative fusion of the diagnostic results is developed for damage localization and type identification. We show that damage Growth can be monitored up until final failure, thereby performing a simultaneous damage assessment on all four SHM levels. In this manner, we demonstrate that by proposing a fusion-based approach toward SHM of composite structures, the intrinsic capacity of each SHM technique can be utilized, leading to synergistic effects for damage diagnostics.Structural Integrity & Composite