The Experts below are selected from a list of 267 Experts worldwide ranked by ideXlab platform
Zhiyong Cai - One of the best experts on this subject based on the ideXlab platform.
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Quasi-Static Compression and Low-Velocity Impact Behavior of Tri-Axial Bio-Composite Structural Panels Using a Spherical Head
Materials (Basel Switzerland), 2017Co-Authors: John F. Hunt, Shaoqin Gong, Zhiyong CaiAbstract:This paper presents experimental results of both quasi-static compression and low-velocity impact behavior for tri-axial bio-composite Structural Panels using a spherical load head. Panels were made having different core and face configurations. The results showed that Panels made having either carbon fiber fabric composite faces or a foam-filled core had significantly improved impact and compressive performance over Panels without either. Different localized impact responses were observed based on the location of the compression or impact relative to the tri-axial Structural core; the core with a smaller Structural element had better impact performance. Furthermore, during the early contact phase for both quasi-static compression and low-velocity impact tests, the Panels with the same configuration had similar load-displacement responses. The experimental results show basic compression data could be used for the future design and optimization of tri-axial bio-composite Structural Panels for potential impact applications.
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Orthogonal model and experimental data for analyzing wood-fiber-based tri-axial ribbed Structural Panels in bending
European Journal of Wood and Wood Products, 2017Co-Authors: John F. Hunt, Shaoqin Gong, Zhiyong CaiAbstract:This paper presents an analysis of 3-dimensional engineered Structural Panels (3DESP) made from wood-fiber-based laminated paper composites. Since the existing models for calculating the mechanical behavior of core configurations within sandwich Panels are very complex, a new simplified orthogonal model (SOM) using an equivalent element has been developed. This model considers both linear and nonlinear geometrical effects when used to analyze the mechanical properties of 3DESP by transforming repeated elements from a tri-axial ribbed core for bending. Two different conditions were studied in comparison with finite element method (FEM) and I-beam equation. The results showed the SOM was consistent with FEM and the experimental result and were more accurate than the I-beam equation. The SOM considering nonlinear geometric deformation needed more computational effort and was found to match well with a FEM model and had slightly better accuracy compared with the linear SOM. Compared with FEM, the parameters in the linear SOM were easier to modify for predicting point-by-point bending performance. However, while the FEM can provide advanced characteristics of the 3DESP such as strain distribution, the linear SOM provided acceptable deformation accuracy and is proposed for preliminary design with multiple parameters. FEM should be applied for advanced analyses.
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Simplified analytical model and balanced design approach for light-weight wood-based Structural panel in bending
Composite Structures, 2016Co-Authors: Jinghao Li, John F. Hunt, Shaoqin Gong, Zhiyong CaiAbstract:This paper presents a simplified analytical model and balanced design approach for modeling light-weight wood-based Structural Panels in bending. Because many design parameters are required to input for the model of finite element analysis (FEA) during the preliminary design process and optimization, the equivalent method was developed to analyze the mechanical performance of Panels based on experimental results. The bending deflection, normal strain and shear strain of the Panels with various configurations were investigated using four point bending test. The results from the analytical model matched well with the experimental data, especially, the prediction for maximum deflection of the Panels under failure load. The normal strain and shear strain calculated by the model also agreed with the experimental data. The failure criterion was determined by the failure modes using a 3-dimensional diagram with apparent normal and shear strain. For demonstration, Panels 1 and 2 with a fixed core were modeled using the balanced design approach for optimal face thickness. The results showed that both the 3-dimensional diagram and analytical model provided similar thickness results, which were verified by the FEA for wood-based Structural Panels.
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testing and evaluation of a slot and tab construction technique for light weight wood fiber based Structural Panels under bending
Journal of Testing and Evaluation, 2016Co-Authors: John F. Hunt, Shaoqin Gong, Zhiyong CaiAbstract:This paper presented construction and strain distributions for light-weight wood-fiber-based Structural Panels with tri-grid core made from phenolic impregnated laminated paper composites under bending. A new fastening configuration of slots in the faces and tabs on the core was applied to the face/core interfaces of the sandwich panel in addition to epoxy resin. Both normal strain gages and shear strain gages were attached on these Panels to analyze inside strain distributions by third point load bending test. The purpose of the bending test was to investigate the various strain distributions of Panels with different face/core configurations that identified the critical failure modes for future design. In this research, four Panels with different configurations were constructed to analyze the influence of strain distributions for bending behavior. Either maximum localized normal strain or shear strain were used to judge failures and associated failure modes through observation. Test results of strain distribution showed normal strain was primarily carried by both top and bottom faces. As bending load increased, compression buckling occurred on the top surface of some Panels with thinner faces. Face thickness and stiffness significantly affected the strength of the panel as evident by nonlinear strain behavior. Meanwhile, the shear strain was primarily taken by the ribs in the Structural core, and shear failure always occurred in the longitudinal linear ribs of core with thicker faces. The shear strain in the cross ribs was approximately half that of the longitudinal linear ribs in the same section of shear zone, which was consistent with the geometric formula. The problem of panel imperfections resulting in either face compression buckling or rib shear buckling could be overcome by further design optimization, and the analytical modeling for bending design and evaluation was presented.
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Bending analyses for 3D engineered Structural Panels made from laminated paper and carbon fabric
Composites Part B: Engineering, 2013Co-Authors: John F. Hunt, Zhiyong Cai, Xianyan ZhouAbstract:Abstract This paper presents analysis of a 3-dimensional engineered Structural panel (3DESP) having a tri-axial core structure made from phenolic impregnated laminated-paper composites with and without high-strength composite carbon-fiber fabric laminated to the outside of both faces. Both I-beam equations and finite element method were used to analyze four-point bending of the Panels. Comparisons were made with experimental Panels. In this study, four experimental Panels were fabricated and analyzed to determine the influence of the carbon-fiber on bending performance. The materials properties for finite element analyses (FEA) and I-beam equations were obtained from either the manufacturer or in-house material tensile tests. The results of the FEA and I-beam equations were used to compare with the experimental 3DESP four-point bending tests. The maximum load, face stresses, shear stresses, and apparent modulus of elasticity were determined. For the I-beam equations, failure was based on maximum stress values. For FEA, the Tsai-Wu strength failure criterion was used to determine Structural materials failure. The I-beam equations underestimated the performance of the experimental Panels. The FEA-estimated load values were generally higher than the experimental Panels exhibiting slightly higher panel properties and load capacity. The addition of carbon-fiber fabric to the face of the Panels influenced the failure mechanism from face buckling to panel shear at the face–rib interface. FEA provided the best comparison with the experimental bending results for 3DESP.
John F. Hunt - One of the best experts on this subject based on the ideXlab platform.
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Quasi-Static Compression and Low-Velocity Impact Behavior of Tri-Axial Bio-Composite Structural Panels Using a Spherical Head
Materials (Basel Switzerland), 2017Co-Authors: John F. Hunt, Shaoqin Gong, Zhiyong CaiAbstract:This paper presents experimental results of both quasi-static compression and low-velocity impact behavior for tri-axial bio-composite Structural Panels using a spherical load head. Panels were made having different core and face configurations. The results showed that Panels made having either carbon fiber fabric composite faces or a foam-filled core had significantly improved impact and compressive performance over Panels without either. Different localized impact responses were observed based on the location of the compression or impact relative to the tri-axial Structural core; the core with a smaller Structural element had better impact performance. Furthermore, during the early contact phase for both quasi-static compression and low-velocity impact tests, the Panels with the same configuration had similar load-displacement responses. The experimental results show basic compression data could be used for the future design and optimization of tri-axial bio-composite Structural Panels for potential impact applications.
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Orthogonal model and experimental data for analyzing wood-fiber-based tri-axial ribbed Structural Panels in bending
European Journal of Wood and Wood Products, 2017Co-Authors: John F. Hunt, Shaoqin Gong, Zhiyong CaiAbstract:This paper presents an analysis of 3-dimensional engineered Structural Panels (3DESP) made from wood-fiber-based laminated paper composites. Since the existing models for calculating the mechanical behavior of core configurations within sandwich Panels are very complex, a new simplified orthogonal model (SOM) using an equivalent element has been developed. This model considers both linear and nonlinear geometrical effects when used to analyze the mechanical properties of 3DESP by transforming repeated elements from a tri-axial ribbed core for bending. Two different conditions were studied in comparison with finite element method (FEM) and I-beam equation. The results showed the SOM was consistent with FEM and the experimental result and were more accurate than the I-beam equation. The SOM considering nonlinear geometric deformation needed more computational effort and was found to match well with a FEM model and had slightly better accuracy compared with the linear SOM. Compared with FEM, the parameters in the linear SOM were easier to modify for predicting point-by-point bending performance. However, while the FEM can provide advanced characteristics of the 3DESP such as strain distribution, the linear SOM provided acceptable deformation accuracy and is proposed for preliminary design with multiple parameters. FEM should be applied for advanced analyses.
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improved fatigue performance for wood based Structural Panels using slot and tab construction
Composites Part A-applied Science and Manufacturing, 2016Co-Authors: John F. Hunt, Jinghao Li, Shaoqin GongAbstract:Abstract This paper presents static and fatigue bending behavior for a wood-based Structural panel having a slot and tab (S/T) construction technique. Comparisons were made with similarly fabricated Panels without the S/T construction technique. Experimental results showed that both types of Panels had similar bending properties in the static tests. However, the Panels with S/T construction had better fatigue results. The failure modes were different for the two fabrication techniques. The Panels without S/T debonded at the core:face interface. Whereas, the Panels with S/T had cracks that propagated within the rib of the core after debonding damage at the core:face interface. The fatigue deflection-life relationship indicated that the S/T construction improved the connection between the faces and core. The S/T construction decreased the deflection growth rate that delayed panel failure. The fatigue stress-life relationship or degradation was better for the Panels with S/T construction than the Panels without the S/T construction.
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Simplified analytical model and balanced design approach for light-weight wood-based Structural panel in bending
Composite Structures, 2016Co-Authors: Jinghao Li, John F. Hunt, Shaoqin Gong, Zhiyong CaiAbstract:This paper presents a simplified analytical model and balanced design approach for modeling light-weight wood-based Structural Panels in bending. Because many design parameters are required to input for the model of finite element analysis (FEA) during the preliminary design process and optimization, the equivalent method was developed to analyze the mechanical performance of Panels based on experimental results. The bending deflection, normal strain and shear strain of the Panels with various configurations were investigated using four point bending test. The results from the analytical model matched well with the experimental data, especially, the prediction for maximum deflection of the Panels under failure load. The normal strain and shear strain calculated by the model also agreed with the experimental data. The failure criterion was determined by the failure modes using a 3-dimensional diagram with apparent normal and shear strain. For demonstration, Panels 1 and 2 with a fixed core were modeled using the balanced design approach for optimal face thickness. The results showed that both the 3-dimensional diagram and analytical model provided similar thickness results, which were verified by the FEA for wood-based Structural Panels.
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testing and evaluation of a slot and tab construction technique for light weight wood fiber based Structural Panels under bending
Journal of Testing and Evaluation, 2016Co-Authors: John F. Hunt, Shaoqin Gong, Zhiyong CaiAbstract:This paper presented construction and strain distributions for light-weight wood-fiber-based Structural Panels with tri-grid core made from phenolic impregnated laminated paper composites under bending. A new fastening configuration of slots in the faces and tabs on the core was applied to the face/core interfaces of the sandwich panel in addition to epoxy resin. Both normal strain gages and shear strain gages were attached on these Panels to analyze inside strain distributions by third point load bending test. The purpose of the bending test was to investigate the various strain distributions of Panels with different face/core configurations that identified the critical failure modes for future design. In this research, four Panels with different configurations were constructed to analyze the influence of strain distributions for bending behavior. Either maximum localized normal strain or shear strain were used to judge failures and associated failure modes through observation. Test results of strain distribution showed normal strain was primarily carried by both top and bottom faces. As bending load increased, compression buckling occurred on the top surface of some Panels with thinner faces. Face thickness and stiffness significantly affected the strength of the panel as evident by nonlinear strain behavior. Meanwhile, the shear strain was primarily taken by the ribs in the Structural core, and shear failure always occurred in the longitudinal linear ribs of core with thicker faces. The shear strain in the cross ribs was approximately half that of the longitudinal linear ribs in the same section of shear zone, which was consistent with the geometric formula. The problem of panel imperfections resulting in either face compression buckling or rib shear buckling could be overcome by further design optimization, and the analytical modeling for bending design and evaluation was presented.
Shaoqin Gong - One of the best experts on this subject based on the ideXlab platform.
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Quasi-Static Compression and Low-Velocity Impact Behavior of Tri-Axial Bio-Composite Structural Panels Using a Spherical Head
Materials (Basel Switzerland), 2017Co-Authors: John F. Hunt, Shaoqin Gong, Zhiyong CaiAbstract:This paper presents experimental results of both quasi-static compression and low-velocity impact behavior for tri-axial bio-composite Structural Panels using a spherical load head. Panels were made having different core and face configurations. The results showed that Panels made having either carbon fiber fabric composite faces or a foam-filled core had significantly improved impact and compressive performance over Panels without either. Different localized impact responses were observed based on the location of the compression or impact relative to the tri-axial Structural core; the core with a smaller Structural element had better impact performance. Furthermore, during the early contact phase for both quasi-static compression and low-velocity impact tests, the Panels with the same configuration had similar load-displacement responses. The experimental results show basic compression data could be used for the future design and optimization of tri-axial bio-composite Structural Panels for potential impact applications.
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Orthogonal model and experimental data for analyzing wood-fiber-based tri-axial ribbed Structural Panels in bending
European Journal of Wood and Wood Products, 2017Co-Authors: John F. Hunt, Shaoqin Gong, Zhiyong CaiAbstract:This paper presents an analysis of 3-dimensional engineered Structural Panels (3DESP) made from wood-fiber-based laminated paper composites. Since the existing models for calculating the mechanical behavior of core configurations within sandwich Panels are very complex, a new simplified orthogonal model (SOM) using an equivalent element has been developed. This model considers both linear and nonlinear geometrical effects when used to analyze the mechanical properties of 3DESP by transforming repeated elements from a tri-axial ribbed core for bending. Two different conditions were studied in comparison with finite element method (FEM) and I-beam equation. The results showed the SOM was consistent with FEM and the experimental result and were more accurate than the I-beam equation. The SOM considering nonlinear geometric deformation needed more computational effort and was found to match well with a FEM model and had slightly better accuracy compared with the linear SOM. Compared with FEM, the parameters in the linear SOM were easier to modify for predicting point-by-point bending performance. However, while the FEM can provide advanced characteristics of the 3DESP such as strain distribution, the linear SOM provided acceptable deformation accuracy and is proposed for preliminary design with multiple parameters. FEM should be applied for advanced analyses.
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improved fatigue performance for wood based Structural Panels using slot and tab construction
Composites Part A-applied Science and Manufacturing, 2016Co-Authors: John F. Hunt, Jinghao Li, Shaoqin GongAbstract:Abstract This paper presents static and fatigue bending behavior for a wood-based Structural panel having a slot and tab (S/T) construction technique. Comparisons were made with similarly fabricated Panels without the S/T construction technique. Experimental results showed that both types of Panels had similar bending properties in the static tests. However, the Panels with S/T construction had better fatigue results. The failure modes were different for the two fabrication techniques. The Panels without S/T debonded at the core:face interface. Whereas, the Panels with S/T had cracks that propagated within the rib of the core after debonding damage at the core:face interface. The fatigue deflection-life relationship indicated that the S/T construction improved the connection between the faces and core. The S/T construction decreased the deflection growth rate that delayed panel failure. The fatigue stress-life relationship or degradation was better for the Panels with S/T construction than the Panels without the S/T construction.
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Simplified analytical model and balanced design approach for light-weight wood-based Structural panel in bending
Composite Structures, 2016Co-Authors: Jinghao Li, John F. Hunt, Shaoqin Gong, Zhiyong CaiAbstract:This paper presents a simplified analytical model and balanced design approach for modeling light-weight wood-based Structural Panels in bending. Because many design parameters are required to input for the model of finite element analysis (FEA) during the preliminary design process and optimization, the equivalent method was developed to analyze the mechanical performance of Panels based on experimental results. The bending deflection, normal strain and shear strain of the Panels with various configurations were investigated using four point bending test. The results from the analytical model matched well with the experimental data, especially, the prediction for maximum deflection of the Panels under failure load. The normal strain and shear strain calculated by the model also agreed with the experimental data. The failure criterion was determined by the failure modes using a 3-dimensional diagram with apparent normal and shear strain. For demonstration, Panels 1 and 2 with a fixed core were modeled using the balanced design approach for optimal face thickness. The results showed that both the 3-dimensional diagram and analytical model provided similar thickness results, which were verified by the FEA for wood-based Structural Panels.
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testing and evaluation of a slot and tab construction technique for light weight wood fiber based Structural Panels under bending
Journal of Testing and Evaluation, 2016Co-Authors: John F. Hunt, Shaoqin Gong, Zhiyong CaiAbstract:This paper presented construction and strain distributions for light-weight wood-fiber-based Structural Panels with tri-grid core made from phenolic impregnated laminated paper composites under bending. A new fastening configuration of slots in the faces and tabs on the core was applied to the face/core interfaces of the sandwich panel in addition to epoxy resin. Both normal strain gages and shear strain gages were attached on these Panels to analyze inside strain distributions by third point load bending test. The purpose of the bending test was to investigate the various strain distributions of Panels with different face/core configurations that identified the critical failure modes for future design. In this research, four Panels with different configurations were constructed to analyze the influence of strain distributions for bending behavior. Either maximum localized normal strain or shear strain were used to judge failures and associated failure modes through observation. Test results of strain distribution showed normal strain was primarily carried by both top and bottom faces. As bending load increased, compression buckling occurred on the top surface of some Panels with thinner faces. Face thickness and stiffness significantly affected the strength of the panel as evident by nonlinear strain behavior. Meanwhile, the shear strain was primarily taken by the ribs in the Structural core, and shear failure always occurred in the longitudinal linear ribs of core with thicker faces. The shear strain in the cross ribs was approximately half that of the longitudinal linear ribs in the same section of shear zone, which was consistent with the geometric formula. The problem of panel imperfections resulting in either face compression buckling or rib shear buckling could be overcome by further design optimization, and the analytical modeling for bending design and evaluation was presented.
Jinghao Li - One of the best experts on this subject based on the ideXlab platform.
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improved fatigue performance for wood based Structural Panels using slot and tab construction
Composites Part A-applied Science and Manufacturing, 2016Co-Authors: John F. Hunt, Jinghao Li, Shaoqin GongAbstract:Abstract This paper presents static and fatigue bending behavior for a wood-based Structural panel having a slot and tab (S/T) construction technique. Comparisons were made with similarly fabricated Panels without the S/T construction technique. Experimental results showed that both types of Panels had similar bending properties in the static tests. However, the Panels with S/T construction had better fatigue results. The failure modes were different for the two fabrication techniques. The Panels without S/T debonded at the core:face interface. Whereas, the Panels with S/T had cracks that propagated within the rib of the core after debonding damage at the core:face interface. The fatigue deflection-life relationship indicated that the S/T construction improved the connection between the faces and core. The S/T construction decreased the deflection growth rate that delayed panel failure. The fatigue stress-life relationship or degradation was better for the Panels with S/T construction than the Panels without the S/T construction.
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Simplified analytical model and balanced design approach for light-weight wood-based Structural panel in bending
Composite Structures, 2016Co-Authors: Jinghao Li, John F. Hunt, Shaoqin Gong, Zhiyong CaiAbstract:This paper presents a simplified analytical model and balanced design approach for modeling light-weight wood-based Structural Panels in bending. Because many design parameters are required to input for the model of finite element analysis (FEA) during the preliminary design process and optimization, the equivalent method was developed to analyze the mechanical performance of Panels based on experimental results. The bending deflection, normal strain and shear strain of the Panels with various configurations were investigated using four point bending test. The results from the analytical model matched well with the experimental data, especially, the prediction for maximum deflection of the Panels under failure load. The normal strain and shear strain calculated by the model also agreed with the experimental data. The failure criterion was determined by the failure modes using a 3-dimensional diagram with apparent normal and shear strain. For demonstration, Panels 1 and 2 with a fixed core were modeled using the balanced design approach for optimal face thickness. The results showed that both the 3-dimensional diagram and analytical model provided similar thickness results, which were verified by the FEA for wood-based Structural Panels.
Julien Hugon - One of the best experts on this subject based on the ideXlab platform.
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Vibration damping in sandwich Panels
Journal of Materials Science, 2008Co-Authors: Mahmoud R Maheri, Julien HugonAbstract:Currently, there is incomplete knowledge of the damping level and its sources in satellite structures and a suitable method to model it constitutes a necessary step for reliable dynamic predictions. As a first step of a damping characterization, the damping of honeycomb Structural Panels, which is identified as a main contributor to global damping, has been considered by ALCATEL SPACE. In this work, the inherent vibration damping mechanism in sandwich Panels, including those with both aluminium and carbon fibre-reinforced plastic (CFRP) skins, is considered. It is first shown how the theoretical modal properties of the sandwich panel can be predicted from the stiffness and damping properties of its constituent components using the basic laminate theory, a first-order shear deformation theory and a simple discretization method. Next, a finite-element transcription of this approach is presented. It is shown to what extent this method can be implemented using a finite-element software package to predict the overall damping value of a sandwich honeycomb panel for each specific mode. Few of the many theoretical models used to predict natural frequencies of plates are supported by experimental data and even fewer for damping values. Therefore, in a second, experimental part, the Rayleigh–Ritz method and NASTRAN (finite-element software used by ALCATEL SPACE) predicted modal characteristics (frequency and damping) are compared with the experimentally obtained values for two specimens of typical aluminium core honeycomb Panels (aluminium and CFRP skins) used by ALCATEL SPACE as Structural Panels. It is shown through these results that the method (theoretical and finite element) is satisfactory and promising.
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Vibration damping in sandwich Panels
Journal of Materials Science, 2008Co-Authors: Mahmoud R Maheri, R D Adams, Julien HugonAbstract:Currently, there is incomplete knowledge of the damping level and its sources in satellite structures and a suitable method to model it constitutes a necessary step for reliable dynamic predictions. As a first step of a damping characterization, the damping of honeycomb Structural Panels, which is identified as a main contributor to global damping, has been considered by ALCATEL SPACE. In this work, the inherent vibration damping mechanism in sandwich Panels, including those with both aluminium and carbon fibre-reinforced plastic (CFRP) skins, is considered. It is first shown how the theoretical modal properties of the sandwich panel can be predicted from the stiffness and damping properties of its constituent components using the basic laminate theory, a first-order shear deformation theory and a simple discretization method. Next, a finite-element transcription of this approach is presented. It is shown to what extent this method can be implemented using a finite-element software package to predict the overall damping value of a sandwich honeycomb panel for each specific mode. Few of the many theoretical models used to predict natural frequencies of plates are supported by experimental data and even fewer for damping values. Therefore, in a second, experimental part, the Rayleigh–Ritz method and NASTRAN (finite-element software used by ALCATEL SPACE) predicted modal characteristics (frequency and damping) are compared with the experimentally obtained values for two specimens of typical aluminium core honeycomb Panels (aluminium and CFRP skins) used by ALCATEL SPACE as Structural Panels. It is shown through these results that the method (theoretical and finite element) is satisfactory and promising.
