Pub Date : 2022-08-25DOI: 10.1177/10996362221122701
Sean P. Engelstad, Z. Chen, V. Goyal
As an aircraft or spacecraft ascends, the atmospheric pressure drops. If the internal pressure is not released, a pressure differential develops on the facesheet. With an in-plane load from vehicle acceleration as well, the pressure and in-plane load may cause failure. Vented sandwich structures are strongly preferred since they release the internal pressure; however, special cases still require an unvented design. This paper provides an analysis and test methodology for unvented sandwich structures. Parametric studies of facesheet-core debonding and buckling were conducted via finite element analysis, considering geometric, material, and load parameters. Design curves based on the key nondimensional parameters were tuned to the data from the parametric study, providing a tool to predict facesheet-core debond failure. Examples of how to use the design curves in practical applications are provided.
{"title":"Analysis methodology for the assessment of unvented honeycomb sandwich structures subject to in-plane and pressure loads","authors":"Sean P. Engelstad, Z. Chen, V. Goyal","doi":"10.1177/10996362221122701","DOIUrl":"https://doi.org/10.1177/10996362221122701","url":null,"abstract":"As an aircraft or spacecraft ascends, the atmospheric pressure drops. If the internal pressure is not released, a pressure differential develops on the facesheet. With an in-plane load from vehicle acceleration as well, the pressure and in-plane load may cause failure. Vented sandwich structures are strongly preferred since they release the internal pressure; however, special cases still require an unvented design. This paper provides an analysis and test methodology for unvented sandwich structures. Parametric studies of facesheet-core debonding and buckling were conducted via finite element analysis, considering geometric, material, and load parameters. Design curves based on the key nondimensional parameters were tuned to the data from the parametric study, providing a tool to predict facesheet-core debond failure. Examples of how to use the design curves in practical applications are provided.","PeriodicalId":17215,"journal":{"name":"Journal of Sandwich Structures & Materials","volume":"25 1","pages":"95 - 111"},"PeriodicalIF":3.9,"publicationDate":"2022-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48352717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-20DOI: 10.1177/10996362221122047
Lekhani Tripathi, S. Behera, B. Behera
Numerical simulation along with experimental validation are used to investigate the flatwise compression behavior in the out-of-plane direction of several 3D woven honeycomb composites with varied cell geometry such as hexagonal (HX), triangular, and rectangular structures. For all the structures, the perimeter of the unit cell was kept constant. Edgewise compression and three-point bending behavior were compared experimentally for all three configurations. The flatwise compression behavior of honeycomb structures has been predicted using FEM on the LS-DYNA platform, and the results have been validated using experimental data. The predicted values are found to be in good agreement with the experimental results. Hexagonal honeycomb shows better results as compared to other cell structures as revealed by both experimental and numerical analysis.
{"title":"Numerical modeling of flatwise energy absorption behavior of 3D woven honeycomb composites with different cell structures","authors":"Lekhani Tripathi, S. Behera, B. Behera","doi":"10.1177/10996362221122047","DOIUrl":"https://doi.org/10.1177/10996362221122047","url":null,"abstract":"Numerical simulation along with experimental validation are used to investigate the flatwise compression behavior in the out-of-plane direction of several 3D woven honeycomb composites with varied cell geometry such as hexagonal (HX), triangular, and rectangular structures. For all the structures, the perimeter of the unit cell was kept constant. Edgewise compression and three-point bending behavior were compared experimentally for all three configurations. The flatwise compression behavior of honeycomb structures has been predicted using FEM on the LS-DYNA platform, and the results have been validated using experimental data. The predicted values are found to be in good agreement with the experimental results. Hexagonal honeycomb shows better results as compared to other cell structures as revealed by both experimental and numerical analysis.","PeriodicalId":17215,"journal":{"name":"Journal of Sandwich Structures & Materials","volume":"24 1","pages":"2047 - 2064"},"PeriodicalIF":3.9,"publicationDate":"2022-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42301225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-17DOI: 10.1177/10996362221122056
Xin Liu, Peiyan Yang, Ye Yuan, J. Qu
Due to its unique deformation form, Negative Poisson’s ratio sandwich structure has excellent energy absorption, but the low load capacity limits its engineering applications. In this paper, we design a new negative Poisson’s ratio rectangular tube periodic sandwich structure. There are many beams in this structure which appear plastic hinges when compressed. After further compression, the rectangular tube wall buckles and the core shrinks inward, which realizes that the structure exhibits high-performance energy absorption ability and excellent mechanical properties. Three-dimensional finite element model of sandwich structure with negative Poisson’s ratio of periodic rectangular tube quasi-static compression test and low-velocity impact were investigated by the use of ABAQUS/Explicit software. The accuracy of the simulation method was verified by the comparison of test and simulation results. Based on the validated numerical models were further investigated to comprehensively understand the influence of rectangular tube unit cell wall thickness (t) and cell height (h) on the load capacity and energy absorption capacity of the specimen. The energy absorption capacity and mechanical properties of the proposed negative Poisson’s ratio sandwich structure could be enhanced by optimizing the design of rectangular tube unit cell wall thickness (t) and rectangular tube unit cell height (h). The present findings offer insights into the application of negative Poisson’s ratio sandwich structure impact energy-absorbing structures in aerospace, automotive and other fields.
{"title":"Sandwich structure with negative Poisson’s ratio of periodic rectangular tube: Mechanical properties and energy absorption","authors":"Xin Liu, Peiyan Yang, Ye Yuan, J. Qu","doi":"10.1177/10996362221122056","DOIUrl":"https://doi.org/10.1177/10996362221122056","url":null,"abstract":"Due to its unique deformation form, Negative Poisson’s ratio sandwich structure has excellent energy absorption, but the low load capacity limits its engineering applications. In this paper, we design a new negative Poisson’s ratio rectangular tube periodic sandwich structure. There are many beams in this structure which appear plastic hinges when compressed. After further compression, the rectangular tube wall buckles and the core shrinks inward, which realizes that the structure exhibits high-performance energy absorption ability and excellent mechanical properties. Three-dimensional finite element model of sandwich structure with negative Poisson’s ratio of periodic rectangular tube quasi-static compression test and low-velocity impact were investigated by the use of ABAQUS/Explicit software. The accuracy of the simulation method was verified by the comparison of test and simulation results. Based on the validated numerical models were further investigated to comprehensively understand the influence of rectangular tube unit cell wall thickness (t) and cell height (h) on the load capacity and energy absorption capacity of the specimen. The energy absorption capacity and mechanical properties of the proposed negative Poisson’s ratio sandwich structure could be enhanced by optimizing the design of rectangular tube unit cell wall thickness (t) and rectangular tube unit cell height (h). The present findings offer insights into the application of negative Poisson’s ratio sandwich structure impact energy-absorbing structures in aerospace, automotive and other fields.","PeriodicalId":17215,"journal":{"name":"Journal of Sandwich Structures & Materials","volume":"24 1","pages":"2065 - 2082"},"PeriodicalIF":3.9,"publicationDate":"2022-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48698041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-14DOI: 10.1177/10996362221122046
Paul Murdy, Scott Hughes, D. Barnes
Various wind turbine blade components, such as shear webs and skins, commonly use fiber-reinforced composite sandwich structures with a core material like balsa or foam. During manufacturing, core gap defects may result from the misalignment of adjacent foam or balsa core sheets in the blade mold. It is important to understand the influence that core gaps have on the structural integrity of wind turbine blades and how to mitigate their influence. This research characterized the effects of core gap defects at the manufacturing and mechanical levels for both epoxy and next-generation thermoplastic composites. Common repair methods were assessed and compared. Multiple defect sizes were compared using temperature data gathered with thermocouples embedded during manufacturing to core gap defect characteristics obtained using image-mapping techniques, optical microscopy, and mechanical characterization by long beam flexure. Results showed that peak exothermic temperatures during curing were closely related to core gap size. The long beam flexure tests determined that transverse core gaps under pure bending loads can have a substantial effect on the ultimate facesheet strength of both epoxy and thermoplastic composite sandwich structures (up to 25% strength reduction), although the size of the defect itself had less of an influence on the magnitude of the strength reduction. The supporting image-mapping techniques indicated that the distortion of the composite facesheets by the core gaps contributed to the premature failures. The repair methods used in this study did very little to improve the ultimate strength of the sandwich panels that previously had core gap defects. The repair of the thermoplastic panel resulted in a further loss in ultimate facesheet strength. This research demonstrated that there is a vital need for the development of a compatible thermoplastic polymer repair resin system and appropriate resin specific repair procedures for the next generation of recyclable thermoplastic wind blades.
{"title":"Characterization and repair of core gap manufacturing defects for wind turbine blades","authors":"Paul Murdy, Scott Hughes, D. Barnes","doi":"10.1177/10996362221122046","DOIUrl":"https://doi.org/10.1177/10996362221122046","url":null,"abstract":"Various wind turbine blade components, such as shear webs and skins, commonly use fiber-reinforced composite sandwich structures with a core material like balsa or foam. During manufacturing, core gap defects may result from the misalignment of adjacent foam or balsa core sheets in the blade mold. It is important to understand the influence that core gaps have on the structural integrity of wind turbine blades and how to mitigate their influence. This research characterized the effects of core gap defects at the manufacturing and mechanical levels for both epoxy and next-generation thermoplastic composites. Common repair methods were assessed and compared. Multiple defect sizes were compared using temperature data gathered with thermocouples embedded during manufacturing to core gap defect characteristics obtained using image-mapping techniques, optical microscopy, and mechanical characterization by long beam flexure. Results showed that peak exothermic temperatures during curing were closely related to core gap size. The long beam flexure tests determined that transverse core gaps under pure bending loads can have a substantial effect on the ultimate facesheet strength of both epoxy and thermoplastic composite sandwich structures (up to 25% strength reduction), although the size of the defect itself had less of an influence on the magnitude of the strength reduction. The supporting image-mapping techniques indicated that the distortion of the composite facesheets by the core gaps contributed to the premature failures. The repair methods used in this study did very little to improve the ultimate strength of the sandwich panels that previously had core gap defects. The repair of the thermoplastic panel resulted in a further loss in ultimate facesheet strength. This research demonstrated that there is a vital need for the development of a compatible thermoplastic polymer repair resin system and appropriate resin specific repair procedures for the next generation of recyclable thermoplastic wind blades.","PeriodicalId":17215,"journal":{"name":"Journal of Sandwich Structures & Materials","volume":"24 1","pages":"2083 - 2100"},"PeriodicalIF":3.9,"publicationDate":"2022-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43602745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-11DOI: 10.1177/10996362221115052
M. Stanfield, Bradley Kuramoto, D. Adams
An open-hole compression test method has been developed to assess the notch sensitivity of sandwich composites under compression loading. This test method, in the process of being standardized by ASTM International, utilizes end loading as well as knife-edge side supports to provide out-of-plane restraint to specimen buckling. Finite element analyses focused on identifying a sandwich specimen geometry that minimized finite-width and finite-length effects on the stress concentration produced by the centrally-located through-hole. Geometric variables included the specimen width-to-hole diameter (w/D) and length-to-hole diameter (l/D) ratios. The sandwich configurations investigated consisted of a Nomex honeycomb core and carbon/epoxy facesheet laminates with a range of material orthotropy ratios. Numerical results were used to identify a candidate sandwich specimen geometry and optimal strain gage placements for use in specimen alignment. A series of mechanical tests were performed to evaluate the proposed specimen design, the proposed test fixture, and the recommended test procedure. The first set of experiments were performed using specimens with different hole diameters but the same specimen width and length. A second set of experiments used specimens with different lengths but with the same specimen width and open-hole. In addition, the use of specimen end potting of the core region was investigated to prevent facesheet separation and end brooming.
{"title":"Development and evaluation of the sandwich open-hole compression test","authors":"M. Stanfield, Bradley Kuramoto, D. Adams","doi":"10.1177/10996362221115052","DOIUrl":"https://doi.org/10.1177/10996362221115052","url":null,"abstract":"An open-hole compression test method has been developed to assess the notch sensitivity of sandwich composites under compression loading. This test method, in the process of being standardized by ASTM International, utilizes end loading as well as knife-edge side supports to provide out-of-plane restraint to specimen buckling. Finite element analyses focused on identifying a sandwich specimen geometry that minimized finite-width and finite-length effects on the stress concentration produced by the centrally-located through-hole. Geometric variables included the specimen width-to-hole diameter (w/D) and length-to-hole diameter (l/D) ratios. The sandwich configurations investigated consisted of a Nomex honeycomb core and carbon/epoxy facesheet laminates with a range of material orthotropy ratios. Numerical results were used to identify a candidate sandwich specimen geometry and optimal strain gage placements for use in specimen alignment. A series of mechanical tests were performed to evaluate the proposed specimen design, the proposed test fixture, and the recommended test procedure. The first set of experiments were performed using specimens with different hole diameters but the same specimen width and length. A second set of experiments used specimens with different lengths but with the same specimen width and open-hole. In addition, the use of specimen end potting of the core region was investigated to prevent facesheet separation and end brooming.","PeriodicalId":17215,"journal":{"name":"Journal of Sandwich Structures & Materials","volume":"25 1","pages":"77 - 94"},"PeriodicalIF":3.9,"publicationDate":"2022-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42468242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-08DOI: 10.1177/10996362221118067
Cao Y, Geng X, Han H, Lu Y, Wang J, Zhao C. Experimental and numerical investigation on the buckling of 3D printed sandwich structure with lattice core. Journal of Sandwich Structures & Materials. 2022 Jun 21. DOI: 10.1177/10996362221108974.
{"title":"Erratum to ‘Experimental and numerical investigation on the buckling of 3D printed sandwich structure with lattice core”","authors":"","doi":"10.1177/10996362221118067","DOIUrl":"https://doi.org/10.1177/10996362221118067","url":null,"abstract":"Cao Y, Geng X, Han H, Lu Y, Wang J, Zhao C. Experimental and numerical investigation on the buckling of 3D printed sandwich structure with lattice core. <i>Journal of Sandwich Structures & Materials</i>. 2022 Jun 21. DOI: 10.1177/10996362221108974.","PeriodicalId":17215,"journal":{"name":"Journal of Sandwich Structures & Materials","volume":"23 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2022-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138542346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-06DOI: 10.1177/10996362221118329
Zane J Smith, Demiana R Barsoum, Zachariah Arwood, D. Penumadu, R. Advíncula
Sandwich structured (SS) composites demonstrate considerable flexural stiffness and high strength-to-weight ratios and can be tailored as functional materials. Historically they have been constrained to specific material types and geometry due to limitations in manufacturing methods. However, employing additive manufacturing (AM), specifically direct ink writing (DIW), can provide an alternative method for making SS composites with complex and controllable micro and mesostructures with multifunctionality targeted at desired mechanical, thermal, and electrical properties. DIW, an extrusion-based AM technique, uses a viscous and thixotropic ink with desired components that, once printed, is cured to obtain the final complex net shape parts. In this paper, a novel hybrid AM technique is employed to manufacture SS composite materials containing bisphenol A-based epoxy core and carbon fiber reinforced polymer (CFRP) face sheets that are fabricated via DIW and vacuum infusion process (VIP), respectfully. We demonstrate that the fabrication of these SS composites can be tailored from a thermosetting material, from which additives and/or various lattice structures can be manufactured to achieve enhanced and desirable mechanical integrity with functional properties. Surface topology and mechanical testing techniques are used to characterize the fabricated hybrid SS composites to study and assess mechanical stability. A rheo-kinetic cure model was developed for the core material to allow for additive manufacturing process requirements while ensuring complete cross-linking for the thermoset-based core material. Because of the ability to obtain relatively small core-thickness and controlled architecture, this method now allows for fabricating layered micro-sandwich structures for realizing further light-weighting in relevant applications.
{"title":"Characterization of micro-sandwich structures via direct ink writing epoxy based cores","authors":"Zane J Smith, Demiana R Barsoum, Zachariah Arwood, D. Penumadu, R. Advíncula","doi":"10.1177/10996362221118329","DOIUrl":"https://doi.org/10.1177/10996362221118329","url":null,"abstract":"Sandwich structured (SS) composites demonstrate considerable flexural stiffness and high strength-to-weight ratios and can be tailored as functional materials. Historically they have been constrained to specific material types and geometry due to limitations in manufacturing methods. However, employing additive manufacturing (AM), specifically direct ink writing (DIW), can provide an alternative method for making SS composites with complex and controllable micro and mesostructures with multifunctionality targeted at desired mechanical, thermal, and electrical properties. DIW, an extrusion-based AM technique, uses a viscous and thixotropic ink with desired components that, once printed, is cured to obtain the final complex net shape parts. In this paper, a novel hybrid AM technique is employed to manufacture SS composite materials containing bisphenol A-based epoxy core and carbon fiber reinforced polymer (CFRP) face sheets that are fabricated via DIW and vacuum infusion process (VIP), respectfully. We demonstrate that the fabrication of these SS composites can be tailored from a thermosetting material, from which additives and/or various lattice structures can be manufactured to achieve enhanced and desirable mechanical integrity with functional properties. Surface topology and mechanical testing techniques are used to characterize the fabricated hybrid SS composites to study and assess mechanical stability. A rheo-kinetic cure model was developed for the core material to allow for additive manufacturing process requirements while ensuring complete cross-linking for the thermoset-based core material. Because of the ability to obtain relatively small core-thickness and controlled architecture, this method now allows for fabricating layered micro-sandwich structures for realizing further light-weighting in relevant applications.","PeriodicalId":17215,"journal":{"name":"Journal of Sandwich Structures & Materials","volume":"25 1","pages":"112 - 127"},"PeriodicalIF":3.9,"publicationDate":"2022-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47292168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-05DOI: 10.1177/10996362221118031
R. Moreira, Mfsf de Moura, R. Rocha, C. Oliveira
The objective of this work is to determine the fracture energy of a honeycomb/carbon-epoxy sandwich panel under mode II loading using the Asymmetric End-Notched Flexure (AENF) test. Experimental tests and numerical analyses aiming to validate all the procedures were performed. An equivalent crack length data reduction scheme was developed in order to simplify the experimental determination of the Resistance-curves (R-curves) using exclusively the load-displacement (P-δ) data. This strategy makes unnecessary the crack length monitoring during its propagation, which is hard to perform in mode II fracture tests. A mixed-mode I+II trapezoidal cohesive zone model was used for validating the proposed data reduction method. It was concluded that this methodology constitutes a suitable procedure for mode II fracture characterisation of debonding failure in composite sandwich panels.
{"title":"Mode II fracture characterisation of a honeycomb/carbon-epoxy sandwich panel using the asymmetric end-notched flexure test","authors":"R. Moreira, Mfsf de Moura, R. Rocha, C. Oliveira","doi":"10.1177/10996362221118031","DOIUrl":"https://doi.org/10.1177/10996362221118031","url":null,"abstract":"The objective of this work is to determine the fracture energy of a honeycomb/carbon-epoxy sandwich panel under mode II loading using the Asymmetric End-Notched Flexure (AENF) test. Experimental tests and numerical analyses aiming to validate all the procedures were performed. An equivalent crack length data reduction scheme was developed in order to simplify the experimental determination of the Resistance-curves (R-curves) using exclusively the load-displacement (P-δ) data. This strategy makes unnecessary the crack length monitoring during its propagation, which is hard to perform in mode II fracture tests. A mixed-mode I+II trapezoidal cohesive zone model was used for validating the proposed data reduction method. It was concluded that this methodology constitutes a suitable procedure for mode II fracture characterisation of debonding failure in composite sandwich panels.","PeriodicalId":17215,"journal":{"name":"Journal of Sandwich Structures & Materials","volume":"24 1","pages":"2030 - 2046"},"PeriodicalIF":3.9,"publicationDate":"2022-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41859406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-21DOI: 10.1177/10996362221115057
Eduardo Fischer Kerche, Bruno G Silveira Caldas, R. Carvalho, S. Amico
The object of this study is to investigate the influence of different fabrics’ configurations, of faced polyester-sisal fiber composites, on the mechanical behavior of a vacuum infused polyethylene terephthalate-foam core sandwich panel. Sisal-unidirectional (yarn and combed yarn fabrics) and plain weave fabrics were fabricated and the sandwiches’ performances were compared to faced polyester-unidirectional glass fabric. Comparisons about the morphological aspects and relations with mechanical behavior (flatwise and edgewise compression and 3-point bending) were performed. Different face sheets’ thickness was used for this purpose, aiming to correlate the results found for those sisal and glass sandwich panels. The main results showed that faced sisal fabrics/polyester present competitive performance and sometimes higher than those glass/polyester, due to differences on failure mechanisms of the panels.
{"title":"Mechanical response of sisal/glass fabrics reinforced polyester – polyethylene terephthalate foam core sandwich panels","authors":"Eduardo Fischer Kerche, Bruno G Silveira Caldas, R. Carvalho, S. Amico","doi":"10.1177/10996362221115057","DOIUrl":"https://doi.org/10.1177/10996362221115057","url":null,"abstract":"The object of this study is to investigate the influence of different fabrics’ configurations, of faced polyester-sisal fiber composites, on the mechanical behavior of a vacuum infused polyethylene terephthalate-foam core sandwich panel. Sisal-unidirectional (yarn and combed yarn fabrics) and plain weave fabrics were fabricated and the sandwiches’ performances were compared to faced polyester-unidirectional glass fabric. Comparisons about the morphological aspects and relations with mechanical behavior (flatwise and edgewise compression and 3-point bending) were performed. Different face sheets’ thickness was used for this purpose, aiming to correlate the results found for those sisal and glass sandwich panels. The main results showed that faced sisal fabrics/polyester present competitive performance and sometimes higher than those glass/polyester, due to differences on failure mechanisms of the panels.","PeriodicalId":17215,"journal":{"name":"Journal of Sandwich Structures & Materials","volume":"24 1","pages":"1993 - 2009"},"PeriodicalIF":3.9,"publicationDate":"2022-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47785774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-20DOI: 10.1177/10996362221116572
A. Nettles, W. Guin, Isabelle Sadowski
This study presents experimental results of compression after impact (CAI) testing of aluminum honeycomb core sandwich structure with face sheets made of quasi-isotropic carbon/epoxy with two orthogonal directions of testing. In a previous study examining the CAI strength of honeycomb sandwich structure,1 it was found that that specimens had different CAI strengths depending on whether the core was oriented in the “L” or “W” direction. Since the face sheets were quasi-isotropic and the core should not (theoretically) affect the CAI strength for a given amount of damage (if the specimens fail by face sheet failure), this result was puzzling. In the study presented in this paper, further CAI tests, along with open hole compression testing were used in an attempt to ferret out the cause of the differing CAI strengths in the aforementioned study. The results showed that the lower CAI strength values were not due to the core orientation, but to the change in the quasi-isotropic face sheet ply sequence due to the 90° rotation.
{"title":"The effects of loading direction on the compression after impact strength of quasi-isotropic face sheet honeycomb core sandwich structure","authors":"A. Nettles, W. Guin, Isabelle Sadowski","doi":"10.1177/10996362221116572","DOIUrl":"https://doi.org/10.1177/10996362221116572","url":null,"abstract":"This study presents experimental results of compression after impact (CAI) testing of aluminum honeycomb core sandwich structure with face sheets made of quasi-isotropic carbon/epoxy with two orthogonal directions of testing. In a previous study examining the CAI strength of honeycomb sandwich structure,1 it was found that that specimens had different CAI strengths depending on whether the core was oriented in the “L” or “W” direction. Since the face sheets were quasi-isotropic and the core should not (theoretically) affect the CAI strength for a given amount of damage (if the specimens fail by face sheet failure), this result was puzzling. In the study presented in this paper, further CAI tests, along with open hole compression testing were used in an attempt to ferret out the cause of the differing CAI strengths in the aforementioned study. The results showed that the lower CAI strength values were not due to the core orientation, but to the change in the quasi-isotropic face sheet ply sequence due to the 90° rotation.","PeriodicalId":17215,"journal":{"name":"Journal of Sandwich Structures & Materials","volume":"24 1","pages":"2013 - 2029"},"PeriodicalIF":3.9,"publicationDate":"2022-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45669136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：