{"title":"Full-Field Strain Patterns of Sandwich Beams of Different Length under Three-Point Bending","authors":"F. Chiang, Lingtao Mao, Rui Guo, Austin Giordano","doi":"10.12783/ASC33/26108","DOIUrl":"https://doi.org/10.12783/ASC33/26108","url":null,"abstract":"","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"12 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":"115109921","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}
S. Honda, Kosuke Takahashi, T. Higuchi, Ryotaro Takeuchi
The present study optimizes lay-up configurations and drop-off placements to maximize the failure strength of tapered laminates. A lookup table of stress components for calculation of Christensen’s criteria is prepared in advance for all possible combinations of 3-ply laminates which is the minimum structure of ply dropoff. Stress components at three corners of resin pockets modeled triangular are first obtained from the finite element analysis (FEA). Then, the optimization is conducted for the laminate which tapers from 16- to 8-ply by using a simple genetic algorithm method. Objective functions are evaluated by referring only stress indexes listed in the lookup table and the FEA are not performed during the optimization. Both thick and thin sections are limited to quasi-isotropic laminates with 45° increment angle, but a stacking sequence of plies is variable and optimized. Placement of ply drop-off are also design variables. It was revealed that 0° and 90° plies are dropped near the thick and thin sections for the optimum result. Experimental results validated that the optimum structure has higher failure strength than the reference one.
{"title":"Optimum Design of Lay-Up Configuration and Ply Drop-Off Placement for Tapered Composite Laminate","authors":"S. Honda, Kosuke Takahashi, T. Higuchi, Ryotaro Takeuchi","doi":"10.12783/ASC33/26033","DOIUrl":"https://doi.org/10.12783/ASC33/26033","url":null,"abstract":"The present study optimizes lay-up configurations and drop-off placements to maximize the failure strength of tapered laminates. A lookup table of stress components for calculation of Christensen’s criteria is prepared in advance for all possible combinations of 3-ply laminates which is the minimum structure of ply dropoff. Stress components at three corners of resin pockets modeled triangular are first obtained from the finite element analysis (FEA). Then, the optimization is conducted for the laminate which tapers from 16- to 8-ply by using a simple genetic algorithm method. Objective functions are evaluated by referring only stress indexes listed in the lookup table and the FEA are not performed during the optimization. Both thick and thin sections are limited to quasi-isotropic laminates with 45° increment angle, but a stacking sequence of plies is variable and optimized. Placement of ply drop-off are also design variables. It was revealed that 0° and 90° plies are dropped near the thick and thin sections for the optimum result. Experimental results validated that the optimum structure has higher failure strength than the reference one.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"6 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":"115450733","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}
In the present study, strain-rate dependence and temperature dependence of failure mode are numerically simulated by finite element analyses. In the analyses, interface failure and matrix failure are expressed by cohesive zone modeling and continuum damage mechanics, respectively. It is assumed that the damage initiates dependently of strain rate and temperature, and cohesive zone modeling is assumed to be temperature- and time-independent. In the continuum damage mechanics, Christensen’s failure criterion of multi-axial stress states for each strain rate are applied into the resin properties. Interfacial strength which is obtained by microbond test is introduced into cohesive zone modeling. When temperature is high and/or strain rate is low, matrix crack occurs very often and the failure mode is matrix-failuredominant mode. On the other hand, when temperature is low and/or strain rate is high, interface crack significant, i.e. failure mode becomes interface-crack-dominant mode.
{"title":"Failure Mode Transition in Transverse Tensile of UD-CFRP Under Various Temperatures and Strain rates","authors":"Mio Sato, Sakie Shirai, J. Koyanagi, Y. Ishida","doi":"10.12783/ASC33/26165","DOIUrl":"https://doi.org/10.12783/ASC33/26165","url":null,"abstract":"In the present study, strain-rate dependence and temperature dependence of failure mode are numerically simulated by finite element analyses. In the analyses, interface failure and matrix failure are expressed by cohesive zone modeling and continuum damage mechanics, respectively. It is assumed that the damage initiates dependently of strain rate and temperature, and cohesive zone modeling is assumed to be temperature- and time-independent. In the continuum damage mechanics, Christensen’s failure criterion of multi-axial stress states for each strain rate are applied into the resin properties. Interfacial strength which is obtained by microbond test is introduced into cohesive zone modeling. When temperature is high and/or strain rate is low, matrix crack occurs very often and the failure mode is matrix-failuredominant mode. On the other hand, when temperature is low and/or strain rate is high, interface crack significant, i.e. failure mode becomes interface-crack-dominant mode.","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":"124676983","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}
This work investigated the buckling stability of isogrid panels manufactured using fused deposition modelling (FDM). In particular, it verified the use of existing closed form analytical solutions and finite element analyses for predicting both global and local buckling loads and modes for these structures. FDM-produced isogrid samples were subjected to uniaxial quasi-static compression with boundary conditions approximating simple supports. Buckling values and mode shapes were obtained from Digital Image Correlation (DIC). The values obtained experimentally were compared to buckling loads calculated using finite element analysis and closed form solutions for orthotropic materials. Good agreement was obtained in comparing finite element analysis to experimental results for both global and local modes, while closed-form solutions compared well for the global modes for which the solutions were intended.
{"title":"Buckling Stability of Additively Manufactured Isogrid","authors":"S. Ananth, T. Whitney, E. Toubia","doi":"10.12783/ASC33/26164","DOIUrl":"https://doi.org/10.12783/ASC33/26164","url":null,"abstract":"This work investigated the buckling stability of isogrid panels manufactured using fused deposition modelling (FDM). In particular, it verified the use of existing closed form analytical solutions and finite element analyses for predicting both global and local buckling loads and modes for these structures. FDM-produced isogrid samples were subjected to uniaxial quasi-static compression with boundary conditions approximating simple supports. Buckling values and mode shapes were obtained from Digital Image Correlation (DIC). The values obtained experimentally were compared to buckling loads calculated using finite element analysis and closed form solutions for orthotropic materials. Good agreement was obtained in comparing finite element analysis to experimental results for both global and local modes, while closed-form solutions compared well for the global modes for which the solutions were intended.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"36 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":"123647828","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}
The ongoing demand to reduce the LCOE (Levelized Cost of Electricity) drives the wind industry to explore new technologies that will advance the state-of-the-art for composite wind blade manufacturing. These new technologies span the range from new resins and fibers, to improved blade designs, to innovative manufacturing techniques. However, since the introduction and widespread adoption of vacuumassisted resin-infusion techniques for blade making, there has been no significant change in the basic labor-intensive manufacturing process for wind blade production. In the current research, a Techno-Economic Model (TEM) and a complementary simulation of a generic wind blade manufacturing facility are developed. The TEM is sufficiently robust to take into account the very rapid product refresh cycle (and concurrent consumption of capital), differences in blade lengths, and the potential future composite technologies such as carbon fiber and thermoplastics that could impact the blade design and resulting manufacturing processes. To investigate the long-term costs and benefits, the TEM also takes into account the cash flows over a multi-year period so that the true value of improvements can be identified and used to justify capital investment in automation and other process changes. The complimentary simulation is built in DELMIA. DELMIA allows for a visual tool to evaluate how changes in the manufacturing steps will impact process flow and timing. The integration of these two models into a full Techno-Economic Analysis (TEA) provides a comprehensive tool to identify opportunities for increasing throughput and for exploring the impact of capital investments.
{"title":"Techno-Economic Model and Simulation for Wind Blade Manufacturing","authors":"S. Johnson, M. Polcari, J. Sherwood","doi":"10.12783/asc33/26009","DOIUrl":"https://doi.org/10.12783/asc33/26009","url":null,"abstract":"The ongoing demand to reduce the LCOE (Levelized Cost of Electricity) drives the wind industry to explore new technologies that will advance the state-of-the-art for composite wind blade manufacturing. These new technologies span the range from new resins and fibers, to improved blade designs, to innovative manufacturing techniques. However, since the introduction and widespread adoption of vacuumassisted resin-infusion techniques for blade making, there has been no significant change in the basic labor-intensive manufacturing process for wind blade production. In the current research, a Techno-Economic Model (TEM) and a complementary simulation of a generic wind blade manufacturing facility are developed. The TEM is sufficiently robust to take into account the very rapid product refresh cycle (and concurrent consumption of capital), differences in blade lengths, and the potential future composite technologies such as carbon fiber and thermoplastics that could impact the blade design and resulting manufacturing processes. To investigate the long-term costs and benefits, the TEM also takes into account the cash flows over a multi-year period so that the true value of improvements can be identified and used to justify capital investment in automation and other process changes. The complimentary simulation is built in DELMIA. DELMIA allows for a visual tool to evaluate how changes in the manufacturing steps will impact process flow and timing. The integration of these two models into a full Techno-Economic Analysis (TEA) provides a comprehensive tool to identify opportunities for increasing throughput and for exploring the impact of capital investments.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"26 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":"122716492","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}
A. Harman, D. Mollenhauer, P. Chang, P. Frezza, John Wang, W. Seneviratne
The principal means by which delamination may progress in appropriately designed composite aerospace structures is via Mode II fracture. This can arise near bolted and bonded joints, following in-service damage such as impact or following the inclusion of integrated electronics into the composite structure and manufacture-induced defects. A new specimen type based on the Transverse Cut Tension (TCT) test is proposed to allow the use of in-situ X-ray micro-computed tomography for observation of mode II fracture processes. The tomography seeks to non-destructively observe the progression of three dimensional crack front features that cannot be seen in typical aerospace composite tests. The paper comprises an account of the design using analytic and finite element methods and preliminary experimental verification. The results showed that the measured toughness of the miniaturized specimen compared well with published results for this material in the literature. In addition, a small period of stable fracture growth was found that would permit in-situ X-ray micro-tomography of progressing Mode II cracks. The work provides the means to observe three-dimensional Mode II crack fronts, potentially in the presence of friction effects, which will contribute to establishing a firmer basis for improved physics-based simulation development.
{"title":"Numerical and Experimental Assessment of a Modified Transverse Cut Tension (TCT) Specimen for In-Situ Loaded X-Ray Computed Tomography of Mode II Dominated Composite Damage Progression","authors":"A. Harman, D. Mollenhauer, P. Chang, P. Frezza, John Wang, W. Seneviratne","doi":"10.12783/ASC33/26024","DOIUrl":"https://doi.org/10.12783/ASC33/26024","url":null,"abstract":"The principal means by which delamination may progress in appropriately designed composite aerospace structures is via Mode II fracture. This can arise near bolted and bonded joints, following in-service damage such as impact or following the inclusion of integrated electronics into the composite structure and manufacture-induced defects. A new specimen type based on the Transverse Cut Tension (TCT) test is proposed to allow the use of in-situ X-ray micro-computed tomography for observation of mode II fracture processes. The tomography seeks to non-destructively observe the progression of three dimensional crack front features that cannot be seen in typical aerospace composite tests. The paper comprises an account of the design using analytic and finite element methods and preliminary experimental verification. The results showed that the measured toughness of the miniaturized specimen compared well with published results for this material in the literature. In addition, a small period of stable fracture growth was found that would permit in-situ X-ray micro-tomography of progressing Mode II cracks. The work provides the means to observe three-dimensional Mode II crack fronts, potentially in the presence of friction effects, which will contribute to establishing a firmer basis for improved physics-based simulation development.","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":"129964675","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}
The failure mechanisms of triaxially braided composite under in-plane tensile and compression loads are investigated in this study. The testing specimens are cut from a typical 8-layer 0°/±60° triaxially braided composite panel which is fabricated with Toray T700 carbon fiber and a toughened epoxy resin 3266. The quasi-static tension and compression loads that parallel or vertical to the 0° fibers are applied by using a Hydraulic testing machine, respectively. The Digital Image Correlation (DIC) technology is implemented to measure the displacement and strain fields of gauge section for both the tensile and compression tests. As a result, the failure mechanisms under different load conditions are elaborated contrastively.
{"title":"Tensile and Compressive Failure Behaviors of Triaxially Braided Composite","authors":"Zhenqiang Zhao, Chao Zhang, Yulong Li","doi":"10.12783/asc33/26151","DOIUrl":"https://doi.org/10.12783/asc33/26151","url":null,"abstract":"The failure mechanisms of triaxially braided composite under in-plane tensile and compression loads are investigated in this study. The testing specimens are cut from a typical 8-layer 0°/±60° triaxially braided composite panel which is fabricated with Toray T700 carbon fiber and a toughened epoxy resin 3266. The quasi-static tension and compression loads that parallel or vertical to the 0° fibers are applied by using a Hydraulic testing machine, respectively. The Digital Image Correlation (DIC) technology is implemented to measure the displacement and strain fields of gauge section for both the tensile and compression tests. As a result, the failure mechanisms under different load conditions are elaborated contrastively.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"27 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":"128296614","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}
W. Rodgers, Praveen Pasupuleti, Selina Zhao, A. Dereims, M. Doroudian, V. Aitharaju
{"title":"Draping Behavior of Non-Crimp Fabrics","authors":"W. Rodgers, Praveen Pasupuleti, Selina Zhao, A. Dereims, M. Doroudian, V. Aitharaju","doi":"10.12783/ASC33/25976","DOIUrl":"https://doi.org/10.12783/ASC33/25976","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":"128632720","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}
An important aspect of the design of composite structures is certification for damage tolerance. Current certification involves tests for low velocity impact (LVI) damage, and the residual compression strength after impact (CSAI). In this work, an adaptive fidelity shell (AFS) model is used to simulate this mutli-step LVI/CSAI process, improving previous LVI results. The two-step process is simulated to ensure that the damage is transferred correctly from one step (LVI) to the next (CSAI) correctly. Use of this model will enable efficient large-scale simulations of full structures with accurate estimations of damage and strength. The AFS model was used to simulate LVI and CSAI for two laminate stacking sequences from the ONR high fidelity database. The model shows promise, but further development is needed to fully capture damage processes seen in LVI/CSAI.
{"title":"Computationally Efficient Damage and Residual Strength Predictions using Progressive Damage Failure Analysis (PDFA) with an Enriched Shell Element","authors":"T. Goode, Mark McElroy, Nathan Sesar, M. Pankow","doi":"10.12783/ASC33/25908","DOIUrl":"https://doi.org/10.12783/ASC33/25908","url":null,"abstract":"An important aspect of the design of composite structures is certification for damage tolerance. Current certification involves tests for low velocity impact (LVI) damage, and the residual compression strength after impact (CSAI). In this work, an adaptive fidelity shell (AFS) model is used to simulate this mutli-step LVI/CSAI process, improving previous LVI results. The two-step process is simulated to ensure that the damage is transferred correctly from one step (LVI) to the next (CSAI) correctly. Use of this model will enable efficient large-scale simulations of full structures with accurate estimations of damage and strength. The AFS model was used to simulate LVI and CSAI for two laminate stacking sequences from the ONR high fidelity database. The model shows promise, but further development is needed to fully capture damage processes seen in LVI/CSAI.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"72 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":"124771097","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":"Investigation of Mode I Crack Growth of VARTM Carbon Composites Using Optical Fibers","authors":"D. A. Drake, R. Sullivan, K. Brown, S. Clay","doi":"10.12783/asc33/26128","DOIUrl":"https://doi.org/10.12783/asc33/26128","url":null,"abstract":"","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"14 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":"128927549","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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