The Experts below are selected from a list of 10095 Experts worldwide ranked by ideXlab platform
Heinz Voggenreiter - One of the best experts on this subject based on the ideXlab platform.
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Simulation and experimental validation of mixed Mode Delamination in multidirectional CF/PEEK laminates under fatigue loading
International Journal of Solids and Structures, 2011Co-Authors: Parya Naghipour, Marion Bartsch, Heinz VoggenreiterAbstract:Cyclic mixed Mode Delamination in multidirectional composite laminates subjected to high cycle fatigue loading has been investigated by numerical simulations and cyclic mixed Mode bending experiments. The numerical Model includes lamina and interface elements. The description of the Delamination crack growth rate is based on the cyclic degradation of bilinear interface elements linking the evolution of the damage variable with the Delamination crack growth rate. The constitutive cyclic damage Model is calibrated by means of mixed Mode fatigue experiments and reproduces the experimental results successfully and with minor error. It is concluded that only with implementing a cyclic damage variable in the cohesive interface element the experimentally observed crack growth and stiffness degradation can be captured properly. Scanning electron microscopy of fracture surfaces after cyclic loading revealed that abrasion of crack bridging surface roughness is the main microscopical cause of weakening and degradation of the interface.
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effect of fiber angle orientation and stacking sequence on mixed Mode fracture toughness of carbon fiber reinforced plastics numerical and experimental investigations
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010Co-Authors: Parya Naghipour, Marion Bartsch, Heinz Voggenreiter, Liudmila Chernova, Joachim HausmannAbstract:Abstract This paper focuses on the effect of fiber orientation and stacking sequence on the progressive mixed Mode Delamination failure in composite laminates using fracture experiments and finite element (FE) simulations. Every laminate is Modelled numerically combining damageable layers with defined fiber orientations and cohesive zone interface elements, subjected to mixed Mode bending. The numerical simulations are then calibrated and validated through experiments, conducted following standardized mixed Mode Delamination tests. The numerical Model is able to successfully capture the experimentally observed effects of fiber angle orientations and variable stacking sequences on the global load–displacement response and mixed Mode inter-laminar fracture toughness of the various laminates. For better understanding of the failure mechanism, fracture surfaces of laminates with different stacking sequences are also studied using scanning electron microscopy (SEM).
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effect of fiber angle orientation and stacking sequence on mixed Mode fracture toughness of carbon fiber reinforced plastics numerical and experimental investigations
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010Co-Authors: Parya Naghipour, Marion Bartsch, Heinz Voggenreiter, Liudmila Chernova, Joachim HausmannAbstract:Abstract This paper focuses on the effect of fiber orientation and stacking sequence on the progressive mixed Mode Delamination failure in composite laminates using fracture experiments and finite element (FE) simulations. Every laminate is Modelled numerically combining damageable layers with defined fiber orientations and cohesive zone interface elements, subjected to mixed Mode bending. The numerical simulations are then calibrated and validated through experiments, conducted following standardized mixed Mode Delamination tests. The numerical Model is able to successfully capture the experimentally observed effects of fiber angle orientations and variable stacking sequences on the global load–displacement response and mixed Mode inter-laminar fracture toughness of the various laminates. For better understanding of the failure mechanism, fracture surfaces of laminates with different stacking sequences are also studied using scanning electron microscopy (SEM).
Parya Naghipour - One of the best experts on this subject based on the ideXlab platform.
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Numerical Simulations and Experimental Investigations on Quasi-Static and Cyclic Mixed Mode Delamination of Multidirectional CFRP Laminates
2011Co-Authors: Parya NaghipourAbstract:The structural applications of Carbon Fibre Reinforced Plastic (CFRP) composites are gradually expanding in aerospace industry as a result of their outstanding mechanical properties such as high stiffness to weight ratio and fatigue resistance. With the increasing application, the need for understanding their mechanical behaviour and failure mechanisms also rises. Interfacial cracking between layers or Delamination is one of the most common failure types in laminated fibre-reinforced composites due to their relatively weak inter-laminar strengths. Typically, Delamination failures initiate and propagate under mixed Mode effect of normal and shear stresses. Therefore, mixed Mode Delamination failure in fibrous composites has been one of the major issues being studied extensively in recent years. In this scope, the development of predictive, reliable and robust numerical and experimental analysis tools for quasi-static or cyclic mixed Mode Delamination of CFRPs is the major focus of this work. Quasi-static and cyclic mixed Mode Delamination failure in multidirectional CFRP laminates are analyzed using fracture experiments and finite element (FE) simulations.
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Simulation and experimental validation of mixed Mode Delamination in multidirectional CF/PEEK laminates under fatigue loading
International Journal of Solids and Structures, 2011Co-Authors: Parya Naghipour, Marion Bartsch, Heinz VoggenreiterAbstract:Cyclic mixed Mode Delamination in multidirectional composite laminates subjected to high cycle fatigue loading has been investigated by numerical simulations and cyclic mixed Mode bending experiments. The numerical Model includes lamina and interface elements. The description of the Delamination crack growth rate is based on the cyclic degradation of bilinear interface elements linking the evolution of the damage variable with the Delamination crack growth rate. The constitutive cyclic damage Model is calibrated by means of mixed Mode fatigue experiments and reproduces the experimental results successfully and with minor error. It is concluded that only with implementing a cyclic damage variable in the cohesive interface element the experimentally observed crack growth and stiffness degradation can be captured properly. Scanning electron microscopy of fracture surfaces after cyclic loading revealed that abrasion of crack bridging surface roughness is the main microscopical cause of weakening and degradation of the interface.
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effect of fiber angle orientation and stacking sequence on mixed Mode fracture toughness of carbon fiber reinforced plastics numerical and experimental investigations
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010Co-Authors: Parya Naghipour, Marion Bartsch, Heinz Voggenreiter, Liudmila Chernova, Joachim HausmannAbstract:Abstract This paper focuses on the effect of fiber orientation and stacking sequence on the progressive mixed Mode Delamination failure in composite laminates using fracture experiments and finite element (FE) simulations. Every laminate is Modelled numerically combining damageable layers with defined fiber orientations and cohesive zone interface elements, subjected to mixed Mode bending. The numerical simulations are then calibrated and validated through experiments, conducted following standardized mixed Mode Delamination tests. The numerical Model is able to successfully capture the experimentally observed effects of fiber angle orientations and variable stacking sequences on the global load–displacement response and mixed Mode inter-laminar fracture toughness of the various laminates. For better understanding of the failure mechanism, fracture surfaces of laminates with different stacking sequences are also studied using scanning electron microscopy (SEM).
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effect of fiber angle orientation and stacking sequence on mixed Mode fracture toughness of carbon fiber reinforced plastics numerical and experimental investigations
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010Co-Authors: Parya Naghipour, Marion Bartsch, Heinz Voggenreiter, Liudmila Chernova, Joachim HausmannAbstract:Abstract This paper focuses on the effect of fiber orientation and stacking sequence on the progressive mixed Mode Delamination failure in composite laminates using fracture experiments and finite element (FE) simulations. Every laminate is Modelled numerically combining damageable layers with defined fiber orientations and cohesive zone interface elements, subjected to mixed Mode bending. The numerical simulations are then calibrated and validated through experiments, conducted following standardized mixed Mode Delamination tests. The numerical Model is able to successfully capture the experimentally observed effects of fiber angle orientations and variable stacking sequences on the global load–displacement response and mixed Mode inter-laminar fracture toughness of the various laminates. For better understanding of the failure mechanism, fracture surfaces of laminates with different stacking sequences are also studied using scanning electron microscopy (SEM).
Hao Cui - One of the best experts on this subject based on the ideXlab platform.
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dynamic bridging mechanisms of through thickness reinforced composite laminates in mixed Mode Delamination
Composites Part A-applied Science and Manufacturing, 2018Co-Authors: Hao Cui, Mehdi Yasaee, Stephen R Hallett, Ivana K Partridge, G Allegri, Nik PetrinicAbstract:Abstract Delamination resistance of composite laminates can be improved with through-thickness reinforcement such as Z-pinning. This paper characterises the bridging response of individual carbon fibre/BMI Z-pins in mixed Mode Delamination at high loading rate using a split Hopkinson bar system. The unstable failure process in quasi-static tests, was also captured with high sampling rate instruments to obtain the complete bridging response. The energy dissipation of the Z-pins were analysed, and it was found that the efficacy of Z-pinning in resisting Delamination growth decreased with an increase in mixed Mode ratio, with a transition from pull-out to pin rupture occurring. The Z-pin efficacy decreased with loading rate for all Mode mix ratios, due to the changing in failure surface with loading rate and rate-dependent frictional sliding.
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Dynamic bridging mechanisms of through-thickness reinforced composite laminates in mixed Mode Delamination Part A Applied science and manufacturing
Composites, 2018Co-Authors: Hao Cui, Mehdi Yasaee, Stephen R Hallett, Ivana K Partridge, G Allegri, Nik PetrinicAbstract:Delamination resistance of composite laminates can be improved with through-thickness reinforcement such as Z-pinning. This paper characterises the bridging response of individual carbon fibre/BMI Z-pins in mixed Mode Delamination at high loading rate using a split Hopkinson bar system. The unstable failure process in quasi-static tests, was also captured with high sampling rate instruments to obtain the complete bridging response. The energy dissipation of the Z-pins were analysed, and it was found that the efficacy of Z-pinning in resisting Delamination growth decreased with an increase in mixed Mode ratio, with a transition from pull-out to pin rupture occurring. The Z-pin efficacy decreased with loading rate for all Mode mix ratios, due to the changing in failure surface with loading rate and rate-dependent frictional sliding.
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mixed Mode cohesive law for z pinned composite analyses
Computational Materials Science, 2013Co-Authors: Hao Cui, Sotiris Koussios, Adriaan BeukersAbstract:A coupled cohesive zone Model is here developed for Modeling the Z-pin reinforcement in composite laminates; both the interlaminar failure and the failure of Z-pins themselves were incorporated in the work. The Mode I and Mode II bridging response component of the Z-pins during mixed Mode Delamination are represented by two unrelated traction–separation laws, and a new method for Modeling the Z-pin bridging response with cohesive elements is introduced. The standard Mode I, II and mixed Mode Delamination toughness tests are analyzed for Z-pinned composite laminates. Comparison between the numerical simulations and experimental results demonstrates the applicability and validity of the present Model. The Modeling methodology is easy to be carried out and flexible enough to account for different Z-pin density and distribution, which can also be extended to simulation of other through thickness reinforcements or rivet joint. The present Model showed path dependence in mixed Mode Delamination, which may be further utilized to account for the failure when normal and shear load is not increased proportionally with each other.
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Bridging micromechanisms of Z-pin in mixed Mode Delamination
Composite Structures, 2011Co-Authors: Hao Cui, Sotiris Koussios, Adriaan BeukersAbstract:A numerical Model for analyzing the bridging mechanisms of Z-pining in composite laminates is presented. Main failure Modes of the Z-pin are: debonding between the Z-pin and matrix, split and rupture of the Z-pin material; these have been taken into account here. The cohesive zone Model was utilized to simulate splitting and rupturing within the Z-pin. The interfacial contact between the Z-pin and matrix was assumed to be initially bonded, followed by debonding and frictional sliding. The present Model is validated by Mode I experiments; the Mode II simulation is verified by similar Z-pin shear tests. It is observed that the shear bridging force component increases with the Mode II ratio, while the Mode I bridging response decreases slightly with the Mode II ratio. An enhanced frictional zone is located near the Delamination surface. The Mode II bridging force in cross-ply laminates is higher than that in UD laminates, while the Z-pin is more likely to rupture in cross-ply laminates when the Mode II ratio is relatively high. The presented Model can be used to evaluate the Z-pin bridging response. The calculated bridging force is suitable for analyzing the mechanical performance of Z-pinned structures.
Marion Bartsch - One of the best experts on this subject based on the ideXlab platform.
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Simulation and experimental validation of mixed Mode Delamination in multidirectional CF/PEEK laminates under fatigue loading
International Journal of Solids and Structures, 2011Co-Authors: Parya Naghipour, Marion Bartsch, Heinz VoggenreiterAbstract:Cyclic mixed Mode Delamination in multidirectional composite laminates subjected to high cycle fatigue loading has been investigated by numerical simulations and cyclic mixed Mode bending experiments. The numerical Model includes lamina and interface elements. The description of the Delamination crack growth rate is based on the cyclic degradation of bilinear interface elements linking the evolution of the damage variable with the Delamination crack growth rate. The constitutive cyclic damage Model is calibrated by means of mixed Mode fatigue experiments and reproduces the experimental results successfully and with minor error. It is concluded that only with implementing a cyclic damage variable in the cohesive interface element the experimentally observed crack growth and stiffness degradation can be captured properly. Scanning electron microscopy of fracture surfaces after cyclic loading revealed that abrasion of crack bridging surface roughness is the main microscopical cause of weakening and degradation of the interface.
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effect of fiber angle orientation and stacking sequence on mixed Mode fracture toughness of carbon fiber reinforced plastics numerical and experimental investigations
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010Co-Authors: Parya Naghipour, Marion Bartsch, Heinz Voggenreiter, Liudmila Chernova, Joachim HausmannAbstract:Abstract This paper focuses on the effect of fiber orientation and stacking sequence on the progressive mixed Mode Delamination failure in composite laminates using fracture experiments and finite element (FE) simulations. Every laminate is Modelled numerically combining damageable layers with defined fiber orientations and cohesive zone interface elements, subjected to mixed Mode bending. The numerical simulations are then calibrated and validated through experiments, conducted following standardized mixed Mode Delamination tests. The numerical Model is able to successfully capture the experimentally observed effects of fiber angle orientations and variable stacking sequences on the global load–displacement response and mixed Mode inter-laminar fracture toughness of the various laminates. For better understanding of the failure mechanism, fracture surfaces of laminates with different stacking sequences are also studied using scanning electron microscopy (SEM).
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effect of fiber angle orientation and stacking sequence on mixed Mode fracture toughness of carbon fiber reinforced plastics numerical and experimental investigations
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010Co-Authors: Parya Naghipour, Marion Bartsch, Heinz Voggenreiter, Liudmila Chernova, Joachim HausmannAbstract:Abstract This paper focuses on the effect of fiber orientation and stacking sequence on the progressive mixed Mode Delamination failure in composite laminates using fracture experiments and finite element (FE) simulations. Every laminate is Modelled numerically combining damageable layers with defined fiber orientations and cohesive zone interface elements, subjected to mixed Mode bending. The numerical simulations are then calibrated and validated through experiments, conducted following standardized mixed Mode Delamination tests. The numerical Model is able to successfully capture the experimentally observed effects of fiber angle orientations and variable stacking sequences on the global load–displacement response and mixed Mode inter-laminar fracture toughness of the various laminates. For better understanding of the failure mechanism, fracture surfaces of laminates with different stacking sequences are also studied using scanning electron microscopy (SEM).
Adriaan Beukers - One of the best experts on this subject based on the ideXlab platform.
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mixed Mode cohesive law for z pinned composite analyses
Computational Materials Science, 2013Co-Authors: Hao Cui, Sotiris Koussios, Adriaan BeukersAbstract:A coupled cohesive zone Model is here developed for Modeling the Z-pin reinforcement in composite laminates; both the interlaminar failure and the failure of Z-pins themselves were incorporated in the work. The Mode I and Mode II bridging response component of the Z-pins during mixed Mode Delamination are represented by two unrelated traction–separation laws, and a new method for Modeling the Z-pin bridging response with cohesive elements is introduced. The standard Mode I, II and mixed Mode Delamination toughness tests are analyzed for Z-pinned composite laminates. Comparison between the numerical simulations and experimental results demonstrates the applicability and validity of the present Model. The Modeling methodology is easy to be carried out and flexible enough to account for different Z-pin density and distribution, which can also be extended to simulation of other through thickness reinforcements or rivet joint. The present Model showed path dependence in mixed Mode Delamination, which may be further utilized to account for the failure when normal and shear load is not increased proportionally with each other.
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Bridging micromechanisms of Z-pin in mixed Mode Delamination
Composite Structures, 2011Co-Authors: Hao Cui, Sotiris Koussios, Adriaan BeukersAbstract:A numerical Model for analyzing the bridging mechanisms of Z-pining in composite laminates is presented. Main failure Modes of the Z-pin are: debonding between the Z-pin and matrix, split and rupture of the Z-pin material; these have been taken into account here. The cohesive zone Model was utilized to simulate splitting and rupturing within the Z-pin. The interfacial contact between the Z-pin and matrix was assumed to be initially bonded, followed by debonding and frictional sliding. The present Model is validated by Mode I experiments; the Mode II simulation is verified by similar Z-pin shear tests. It is observed that the shear bridging force component increases with the Mode II ratio, while the Mode I bridging response decreases slightly with the Mode II ratio. An enhanced frictional zone is located near the Delamination surface. The Mode II bridging force in cross-ply laminates is higher than that in UD laminates, while the Z-pin is more likely to rupture in cross-ply laminates when the Mode II ratio is relatively high. The presented Model can be used to evaluate the Z-pin bridging response. The calculated bridging force is suitable for analyzing the mechanical performance of Z-pinned structures.