SIP (Cross-ministerial Strategic Innovation Promotion Program) - SM4I (Structural Materials for Innovation) was established by the Council for Science, Technology and Innovation (CSTI) of the Japanese Cabinet Office, as one of the national R&D subjects to realize scientific and technological innovation strategically under its initiative. Under this SIP - SM4I, our project, "Innovative Aircraft Polymer Matrix Composites (iAPMC)" started in 2014 as a five-year project. The main purpose of this project is to develop high-rate production aircraft CFRP products and quality assurance technology for next-generation CFRP aircraft structures. This project consists of five research units, (1) OoA CFRP (Airframe) Unit, (2) Low-cost Autoclave CFRP (Airframe) Unit, (3) CFRTP (Engine) Unit, (4) High-Temperature CFRP (Engine) Unit, and (5) Academic Support and Material Evaluation Unit. This presentation provides a summary of recent results in this project. Especially, optical fiber sensor based integrated in-process process monitoring methodology is presented with some successful examples which cannot be provided by conventional material characterization methods. Precise in-process material property data are obtained and fed into the process simulation code for better prediction of CFRP structures to avoid many trials and errors in the development of new CFRP materials for high-rate production.
{"title":"Integrated In-Process Monitoring of High-Rate Production CFRP Structures for Material Quality Assurance","authors":"N. Takeda","doi":"10.12783/ASC33/25996","DOIUrl":"https://doi.org/10.12783/ASC33/25996","url":null,"abstract":"SIP (Cross-ministerial Strategic Innovation Promotion Program) - SM4I (Structural Materials for Innovation) was established by the Council for Science, Technology and Innovation (CSTI) of the Japanese Cabinet Office, as one of the national R&D subjects to realize scientific and technological innovation strategically under its initiative. Under this SIP - SM4I, our project, \"Innovative Aircraft Polymer Matrix Composites (iAPMC)\" started in 2014 as a five-year project. The main purpose of this project is to develop high-rate production aircraft CFRP products and quality assurance technology for next-generation CFRP aircraft structures. This project consists of five research units, (1) OoA CFRP (Airframe) Unit, (2) Low-cost Autoclave CFRP (Airframe) Unit, (3) CFRTP (Engine) Unit, (4) High-Temperature CFRP (Engine) Unit, and (5) Academic Support and Material Evaluation Unit. This presentation provides a summary of recent results in this project. Especially, optical fiber sensor based integrated in-process process monitoring methodology is presented with some successful examples which cannot be provided by conventional material characterization methods. Precise in-process material property data are obtained and fed into the process simulation code for better prediction of CFRP structures to avoid many trials and errors in the development of new CFRP materials for high-rate production.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115700991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Characterization of Cohesive Zone Laws Using Digital Image Correlation","authors":"B. Vossen, A. Makeev","doi":"10.12783/asc33/25977","DOIUrl":"https://doi.org/10.12783/asc33/25977","url":null,"abstract":"","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114525750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Higuchi, T. Yokozeki, T. Okabe, T. Nagashima, T. Aoki
In recent years, freedom in design of composite microstructure has been improved because of the development of the manufacturing technology of various cross-sectional carbon fibers. Therefore, numerous candidates of composite microstructure must be considered for microscopic optimization of composite. To this end, this study develops mesh-free microscale simulation tool consisting of two kinds of computational techniques; homogenization method and extended finite element method (XFEM). For the evaluation of an effect of microstructure on the macroscopic mechanical and fracture properties, homogenization method was introduced. Additionally, the composite microstructure (i.e., fiber / matrix interface) is able to be modeled independently of the mesh by the XFEM. The proposed tool makes it possible to conduct comprehensive numerical investigation into various composite microstructures without remeshing.
{"title":"Microscale Simulation of Composites with Various Microstructures by Using eXtended Finite Element Method (XFEM)","authors":"R. Higuchi, T. Yokozeki, T. Okabe, T. Nagashima, T. Aoki","doi":"10.12783/ASC33/26070","DOIUrl":"https://doi.org/10.12783/ASC33/26070","url":null,"abstract":"In recent years, freedom in design of composite microstructure has been improved because of the development of the manufacturing technology of various cross-sectional carbon fibers. Therefore, numerous candidates of composite microstructure must be considered for microscopic optimization of composite. To this end, this study develops mesh-free microscale simulation tool consisting of two kinds of computational techniques; homogenization method and extended finite element method (XFEM). For the evaluation of an effect of microstructure on the macroscopic mechanical and fracture properties, homogenization method was introduced. Additionally, the composite microstructure (i.e., fiber / matrix interface) is able to be modeled independently of the mesh by the XFEM. The proposed tool makes it possible to conduct comprehensive numerical investigation into various composite microstructures without remeshing.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"2014 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114717359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Floris-Jan van Zanten, Caleb R. Pupo, D. Barazanchy, M. Tooren
Variable stiffness composites are composite structures in which some of the plies are steered, the tow paths are allowed to change orientation within the ply. Finding the optimal fiber orientation, and corresponding tow paths, is possible through the lamination parameters framework and the manufacturing finite element mesh framework (MFEM). In this article the implementation of the 2D MFEM framework is extended to incorporate the optimization of 3D shell structures. Both the optimization methodology and the tow path planner for 3D surfaces are presented and discussed here.
{"title":"Fiber Angle Optimization and Tow Path Planning on 3D Curved Surfaces Using the Multiple Mesh Approach","authors":"Floris-Jan van Zanten, Caleb R. Pupo, D. Barazanchy, M. Tooren","doi":"10.12783/ASC33/26010","DOIUrl":"https://doi.org/10.12783/ASC33/26010","url":null,"abstract":"Variable stiffness composites are composite structures in which some of the plies are steered, the tow paths are allowed to change orientation within the ply. Finding the optimal fiber orientation, and corresponding tow paths, is possible through the lamination parameters framework and the manufacturing finite element mesh framework (MFEM). In this article the implementation of the 2D MFEM framework is extended to incorporate the optimization of 3D shell structures. Both the optimization methodology and the tow path planner for 3D surfaces are presented and discussed here.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116960644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Nguyen, Avinkrishnan A. Vijayachandran, P. Davidson, A. Waas
In this paper, we investigate Mode-I and Mode-II delamination behavior of Discontinuous Fiber Composites (DFCs). Owing to the complex heterogeneous mesostructure in DFCs, conventional testing methodologies such as the double cantilever beam (DCB) and end-notched flexure (ENF) tests used to characterize Mode-I and Mode-II interlaminar failure may fail to characterize the non-linear behavior during delamination. This is because DCB and ENF tests based on Linear Elastic Fracture Mechanics (LEFM) models, fails to account for the quasi-brittleness of DFCs. As a result, this approach may not be able to capture the variation in the Fracture Process Zone (FPZ) which becomes large due the distributed damage in the platelets. Hence, there is a need to account for this non-linear behavior of the FPZ to effectively estimate the delamination fracture energy. This paper proposes an experimental investigation on the effects of the FPZ on the inter-laminar delamination of DFCs. To shed light on the role of the FPZ size versus the structure size and geometry, geometrically-scaled DCB and ENF specimens were tested. The results show a significant size effect. While for small sizes the specimens exhibit a limited strength reduction by the presence of the crack (which indicates a pseudo-ductile behaviour), the failure becomes more and more brittle for larger sizes. Future work will focus on the understanding of this phenomenon leveraging stochastic Finite Element modelling and quasi-brittle fracture mechanics.
{"title":"Experimental Study of In-plane Shear Response of Interface Toughened Carbon Fiber Composites","authors":"M. Nguyen, Avinkrishnan A. Vijayachandran, P. Davidson, A. Waas","doi":"10.12783/ASC33/26001","DOIUrl":"https://doi.org/10.12783/ASC33/26001","url":null,"abstract":"In this paper, we investigate Mode-I and Mode-II delamination behavior of Discontinuous Fiber Composites (DFCs). Owing to the complex heterogeneous mesostructure in DFCs, conventional testing methodologies such as the double cantilever beam (DCB) and end-notched flexure (ENF) tests used to characterize Mode-I and Mode-II interlaminar failure may fail to characterize the non-linear behavior during delamination. This is because DCB and ENF tests based on Linear Elastic Fracture Mechanics (LEFM) models, fails to account for the quasi-brittleness of DFCs. As a result, this approach may not be able to capture the variation in the Fracture Process Zone (FPZ) which becomes large due the distributed damage in the platelets. Hence, there is a need to account for this non-linear behavior of the FPZ to effectively estimate the delamination fracture energy. This paper proposes an experimental investigation on the effects of the FPZ on the inter-laminar delamination of DFCs. To shed light on the role of the FPZ size versus the structure size and geometry, geometrically-scaled DCB and ENF specimens were tested. The results show a significant size effect. While for small sizes the specimens exhibit a limited strength reduction by the presence of the crack (which indicates a pseudo-ductile behaviour), the failure becomes more and more brittle for larger sizes. Future work will focus on the understanding of this phenomenon leveraging stochastic Finite Element modelling and quasi-brittle fracture mechanics.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125754103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Stochastic Structural Finite Element Model for Trabecular Bone and other Structural Foams","authors":"Saif Alrafeek, J. Jastifer, P. Gustafson","doi":"10.12783/ASC33/26143","DOIUrl":"https://doi.org/10.12783/ASC33/26143","url":null,"abstract":"","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124800713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Numerical Model to Simulate Void Dynamics During Processing of Honeycomb Core Sandwich Structures with Prepreg Face-Sheets","authors":"N. Kermani, P. Šimáček, M. Erdal, S. Advani","doi":"10.12783/asc33/25991","DOIUrl":"https://doi.org/10.12783/asc33/25991","url":null,"abstract":"","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129758382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Composite laminates possess heterogeneous microstructures which make characterization and modeling a great challenge, particularly in their failure response to different loadings. One of the most emerging research areas involves the development of a robust, high-fidelity, physics-based model to predict the progressive damage response of composites under mechanical loading. In the literature, many failure models have been developed with a view to predicting various failure modes observed in composites, including fiber breakage, fiber kinking, matrix cracking, and delamination between plies. Digital image correlation (DIC) techniques have been widely used to identify hot spots and failure evolution by tracking the surface strain histories. Although this method can capture crack propagation, the application is limited to determining surface intra-ply damage, and the resolution is generally not fine enough to capture the failure at the fiber level. The most viable approach to produce data of value for the formulation and validation of composite material models would need to be fully 3-D and in-situ. In this experiment, a proof of concept approach to study carbon fiber laminates with 3-D X-ray tomography and in-situ tensile loading is proposed and developed. Test results revealed information regarding through-ply cracking and its impact on catastrophic failure of the specimen. Based on the results of this experiment, the implementation of 3-D data correlation (digital volume correlation) can be evaluated as a way to quantify the load- and time-based material changes that lead to failure. Additionally, other types of loadings including temperature, compressive loading, and 3-point/4-point bending can be considered for future studies.
{"title":"3-D X-ray Tomography for In-Situ Characterization of Progressive Damage Response of Carbon Fiber Laminates Subject to Mechanical Loadings","authors":"J. Favata, Dianyun Zhang, S. Shahbazmohamadi","doi":"10.12783/ASC33/25962","DOIUrl":"https://doi.org/10.12783/ASC33/25962","url":null,"abstract":"Composite laminates possess heterogeneous microstructures which make characterization and modeling a great challenge, particularly in their failure response to different loadings. One of the most emerging research areas involves the development of a robust, high-fidelity, physics-based model to predict the progressive damage response of composites under mechanical loading. In the literature, many failure models have been developed with a view to predicting various failure modes observed in composites, including fiber breakage, fiber kinking, matrix cracking, and delamination between plies. Digital image correlation (DIC) techniques have been widely used to identify hot spots and failure evolution by tracking the surface strain histories. Although this method can capture crack propagation, the application is limited to determining surface intra-ply damage, and the resolution is generally not fine enough to capture the failure at the fiber level. The most viable approach to produce data of value for the formulation and validation of composite material models would need to be fully 3-D and in-situ. In this experiment, a proof of concept approach to study carbon fiber laminates with 3-D X-ray tomography and in-situ tensile loading is proposed and developed. Test results revealed information regarding through-ply cracking and its impact on catastrophic failure of the specimen. Based on the results of this experiment, the implementation of 3-D data correlation (digital volume correlation) can be evaluated as a way to quantify the load- and time-based material changes that lead to failure. Additionally, other types of loadings including temperature, compressive loading, and 3-point/4-point bending can be considered for future studies.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128647272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sandwich structures are extensively used in wind turbine blade shell structures design to reduce total blade weight while providing buckling resistance. In this paper, a novel methodology to analyze the initiation of inter-fiber failure (IFF) and IFF induced local delamination in sandwich face-sheet laminate under full blade fatigue test is proposed. The detrimental influence of in-plane shear stress on IFF initiation under multiaxial fatigue loading was accounted for using a strength-based knockdown factor approach. The initiation of the local delamination was analyzed by a Fracture Mechanics model, where energy release rate (ERR) was studied as the delamination driving force. It is found that the critical ERR for local delamination depends on face-sheet laminate layup as well as resultant forces. The proposed methodology provides a very simple but useful method for evaluating the potential associated damage of blade structure during fatigue testing and it can also be extended to analyze the static loading scenario.
{"title":"A Methodology for the Analysis of the Initiation of Inter-Fiber Failure and Local Delamination in Wind Turbine Blade Shell Sandwich Structures","authors":"Linqi Zhuang, L. Mailly, Lars Hedegaard, Y. Huang","doi":"10.12783/ASC33/26132","DOIUrl":"https://doi.org/10.12783/ASC33/26132","url":null,"abstract":"Sandwich structures are extensively used in wind turbine blade shell structures design to reduce total blade weight while providing buckling resistance. In this paper, a novel methodology to analyze the initiation of inter-fiber failure (IFF) and IFF induced local delamination in sandwich face-sheet laminate under full blade fatigue test is proposed. The detrimental influence of in-plane shear stress on IFF initiation under multiaxial fatigue loading was accounted for using a strength-based knockdown factor approach. The initiation of the local delamination was analyzed by a Fracture Mechanics model, where energy release rate (ERR) was studied as the delamination driving force. It is found that the critical ERR for local delamination depends on face-sheet laminate layup as well as resultant forces. The proposed methodology provides a very simple but useful method for evaluating the potential associated damage of blade structure during fatigue testing and it can also be extended to analyze the static loading scenario.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129374253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yukihiro Sato, M. Kashiwagi, K. Miura, Y. Nonaka, T. Abe, K. Takagi
Strength of compression after impact is one of the most important design criteria for structures using laminated fiber-reinforced plastics. Effects of face-on impact damage on compressive strength have been widely studied over the past decades. However, knowledge about effects of edge-on impact damage is limited compared to that of face-on impact. Therefore, in this study, edge-on impact tests and compression after edge-on impact (CAEI) tests were conducted. In addition, intralaminar fracture toughness (energy) of compressive failure of fiber (0°) and matrix (90°) was obtained by single edge notched compression tests and VCCT analysis, since intralaminar failure properties seem to be essential from our previous work. The obtained toughness was used in progressive damage analysis (PDA) of CAEI failure. In the PDA, CAEI failure was simulated under several modelling assumption of impact damage, including delamination and intralaminar pre-crack. As a result, CAEI strength was predicted with relatively small error when intralaminar pre-crack was included as impact damage. Although modelling assumption of impact damage, such as information about crack length or cracking ply, has to be validated based on experimental observation as future task, utility to predict CAEI strength by modelling impact damage as pre-crack was shown.
{"title":"Effect of Intralaminar Failure Properties on Compressive Strength of CFRP Structure after Edge-on Impact","authors":"Yukihiro Sato, M. Kashiwagi, K. Miura, Y. Nonaka, T. Abe, K. Takagi","doi":"10.12783/asc33/26067","DOIUrl":"https://doi.org/10.12783/asc33/26067","url":null,"abstract":"Strength of compression after impact is one of the most important design criteria for structures using laminated fiber-reinforced plastics. Effects of face-on impact damage on compressive strength have been widely studied over the past decades. However, knowledge about effects of edge-on impact damage is limited compared to that of face-on impact. Therefore, in this study, edge-on impact tests and compression after edge-on impact (CAEI) tests were conducted. In addition, intralaminar fracture toughness (energy) of compressive failure of fiber (0°) and matrix (90°) was obtained by single edge notched compression tests and VCCT analysis, since intralaminar failure properties seem to be essential from our previous work. The obtained toughness was used in progressive damage analysis (PDA) of CAEI failure. In the PDA, CAEI failure was simulated under several modelling assumption of impact damage, including delamination and intralaminar pre-crack. As a result, CAEI strength was predicted with relatively small error when intralaminar pre-crack was included as impact damage. Although modelling assumption of impact damage, such as information about crack length or cracking ply, has to be validated based on experimental observation as future task, utility to predict CAEI strength by modelling impact damage as pre-crack was shown.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"102 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127125355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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