The Experts below are selected from a list of 288 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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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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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).
Paolo Sebastiano Valvo - One of the best experts on this subject based on the ideXlab platform.
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an enhanced beam theory model of the mixed mode Bending mmb test part i literature review and mechanical model
Meccanica, 2013Co-Authors: Stefano Bennati, Paolo Fisicaro, Paolo Sebastiano ValvoAbstract:The paper presents a mechanical model of the Mixed-Mode Bending (MMB) test used to assess the Mixed-Mode interlaminar fracture toughness of composite laminates. The laminated specimen is considered as an assemblage of two sublaminates partly connected by an elastic–brittle interface. The problem is formulated through a set of 36 differential equations, accompanied by suitable boundary conditions. Solution of the problem is achieved by separately considering the two subproblems related to the symmetric and antisymmetric parts of the loads, which for symmetric specimens correspond to fracture modes I and II, respectively. Explicit expressions are determined for the interfacial stresses, internal forces, and displacements.
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an enhanced beam theory model of the mixed mode Bending mmb test part ii applications and results
Meccanica, 2013Co-Authors: Stefano Bennati, Paolo Fisicaro, Paolo Sebastiano ValvoAbstract:The paper presents an enhanced beam-theory (EBT) model of the Mixed-Mode Bending (MMB) test, whereby the specimen is considered as an assemblage of two sublaminates partly connected by an elastic–brittle interface. Analytical expressions for the compliance, energy release rate, and mode mixity are deduced. A compliance calibration strategy enabling numerical or experimental evaluation of the interface elastic constants is also presented. Furthermore, analytical expressions for the crack length correction parameters—analogous to those given by the corrected beam-theory (CBT) model for unidirectional laminated specimens—are furnished for multidirectional laminated specimens, as well. Lastly, an example application to experimental data reduction is presented.
Chiara Bisagni - One of the best experts on this subject based on the ideXlab platform.
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numerical study of quasi static and fatigue delamination growth in a post buckled composite stiffened panel
Composites Part B-engineering, 2020Co-Authors: Antonio Raimondo, S A Doesburg, Chiara BisagniAbstract:In this work, an approach based on the Virtual Crack Closure Technique, included in the commercial finite element code ABAQUS, is adopted to study the propagation of delamination in composite structures under quasi-static and fatigue loads. The methodology, originally capable of simulating only delamination under quasi-static loads, has recently been extended introducing the possibility to analyze damage progression under fatigue load condition. The approach is assessed on simple specimens, Double Cantilever Beam and Mixed Mode Bending test, comparing the results with literature data. Afterwards, the behavior of a single-stringer specimen with an initial delamination is numerically investigated considering compressive loading conditions. At first, the single-stringer specimen is analyzed under quasi-static compressive load showing a clear correlation between local buckling phenomena and delamination growth. Then, a cyclic compressive load is applied such that the specimen switches between pre- and post-buckling conditions in a single load cycle. The outcomes of the numerical analyses are compared with the experimental data obtained from an experimental test campaign previously performed, showing the advantages of the adopted numerical technique but also the limitations that need to be addressed to properly analyze this phenomenon.
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analysis of local stress ratio for delamination in composites under fatigue loads
AIAA Journal, 2020Co-Authors: Antonio Raimondo, Chiara BisagniAbstract:An approach based on the cohesive zone model for analyzing delamination in composite laminates under cyclic fatigue loading is presented. The proposed technique, called “min-max load approach,” is able to dynamically capture the local stress ratio during the progression of delamination. The possibility to know the local stress ratio is relevant in all the situations where its value is different from the applied load ratio and cannot be determined a priori. The methodology analyzes in a single finite element analysis two identical models with two different constant loads, the minimum and the maximum load of the fatigue cycle. The two models interact with each other, exchanging information to calculate the crack growth rate. At first, the approach has been validated in simulations of mode I and Mixed-Mode propagation using double cantilever beam and Mixed-Mode Bending tests. Then, to prove the effectiveness of the developed methodology, a modified version of the Mixed-Mode Bending test has been analyzed. Mode I and mode II components of the load are decoupled and applied independently, resulting in a local stress ratio different from the applied load ratio. The results obtained from the simulations, compared with the analytical model obtained using the corrected beam theory, show that the proposed approach is able to predict the local stress ratio and thereby to correctly evaluate the crack growth rate during the propagation of the damage.
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a numerical approach for the evaluation of the local stress ratio in fatigue driven delamination analysis
AIAA Scitech 2019 Forum, 2019Co-Authors: Antonio Raimondo, Chiara BisagniAbstract:An approach based on the cohesive zone model for analyzing fatigue-driven delamination in composite structures under cyclic loading is presented. The proposed technique, called “Min-Max Load Approach”, is able to dynamically capture the local stress ratio during the evolution of damage. The possibility to know the local stress ratio is relevant in all the situations where its value is different from the applied load ratio and cannot be determined a priori. In a single Finite Element analysis, two identical models are analyzed with two different constant loads, the minimum and the maximum load during the fatigue cycle. The implemented methodology allows the two models to interact with each other, by exchanging information to correctly calculate the crack growth rate. At first, the approach has been validated in simulations of mode I and Mixed-Mode propagation by using Double Cantilever Beam and Mixed-Mode Bending. Then, to prove the effectiveness of the developed methodology, a modified version of the Mixed-Mode Bending test has been numerically investigated. In this test, the mode I and mode II components of the load are decoupled and applied independently, resulting in a local stress ratio different from the applied load ratio.
Stefano Bennati - One of the best experts on this subject based on the ideXlab platform.
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an enhanced beam theory model of the mixed mode Bending mmb test part i literature review and mechanical model
Meccanica, 2013Co-Authors: Stefano Bennati, Paolo Fisicaro, Paolo Sebastiano ValvoAbstract:The paper presents a mechanical model of the Mixed-Mode Bending (MMB) test used to assess the Mixed-Mode interlaminar fracture toughness of composite laminates. The laminated specimen is considered as an assemblage of two sublaminates partly connected by an elastic–brittle interface. The problem is formulated through a set of 36 differential equations, accompanied by suitable boundary conditions. Solution of the problem is achieved by separately considering the two subproblems related to the symmetric and antisymmetric parts of the loads, which for symmetric specimens correspond to fracture modes I and II, respectively. Explicit expressions are determined for the interfacial stresses, internal forces, and displacements.
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an enhanced beam theory model of the mixed mode Bending mmb test part ii applications and results
Meccanica, 2013Co-Authors: Stefano Bennati, Paolo Fisicaro, Paolo Sebastiano ValvoAbstract:The paper presents an enhanced beam-theory (EBT) model of the Mixed-Mode Bending (MMB) test, whereby the specimen is considered as an assemblage of two sublaminates partly connected by an elastic–brittle interface. Analytical expressions for the compliance, energy release rate, and mode mixity are deduced. A compliance calibration strategy enabling numerical or experimental evaluation of the interface elastic constants is also presented. Furthermore, analytical expressions for the crack length correction parameters—analogous to those given by the corrected beam-theory (CBT) model for unidirectional laminated specimens—are furnished for multidirectional laminated specimens, as well. Lastly, an example application to experimental data reduction is presented.