Pub Date : 2020-11-05DOI: 10.1080/20550340.2020.1838224
J. Ohlendorf, M. Richrath, J. Franke, M. Brink, K. Thoben
Abstract Current wind turbine rotor blades have a significant impact on the cost of the turbine, which is mainly a consequence of the manual process steps involved in blade production. The manual, labour-intensive production process leads to high tolerances and requires high safety and reliability factors. Especially in the case of offshore turbines with current and upcoming blade dimensions, automation will make the blades cost effective, quicker to produce and guarantees a higher quality. Here, we analyse the current blade structure and production processes and present a technical review of the existing automation approaches for the textile build-up process in industry and academia. Thereby we classify these approaches according to the different techniques based on the rotor blade structure parts. Graphical Abstract
{"title":"Towards automation of wind energy rotor blade production: a review of challenges and application examples","authors":"J. Ohlendorf, M. Richrath, J. Franke, M. Brink, K. Thoben","doi":"10.1080/20550340.2020.1838224","DOIUrl":"https://doi.org/10.1080/20550340.2020.1838224","url":null,"abstract":"Abstract Current wind turbine rotor blades have a significant impact on the cost of the turbine, which is mainly a consequence of the manual process steps involved in blade production. The manual, labour-intensive production process leads to high tolerances and requires high safety and reliability factors. Especially in the case of offshore turbines with current and upcoming blade dimensions, automation will make the blades cost effective, quicker to produce and guarantees a higher quality. Here, we analyse the current blade structure and production processes and present a technical review of the existing automation approaches for the textile build-up process in industry and academia. Thereby we classify these approaches according to the different techniques based on the rotor blade structure parts. Graphical Abstract","PeriodicalId":7243,"journal":{"name":"Advanced Manufacturing: Polymer & Composites Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82892348","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}
Pub Date : 2020-10-21DOI: 10.1080/20550340.2020.1834790
J. Shin, S. Nutt
Abstract The physical state of epoxy resin designed for vacuum infusion was assessed in situ by immersing a dielectric sensor into the resin pot. The measured ion viscosity of aged resin was directly converted to a degree-of-cure metric using a resin cure map constructed by correlating cure kinetics and dielectric analysis data. Next, an age-adjusted infusion process map was employed to define a nominal infusion window and to identify key process metrics. Finally, process simulations and flow contour maps were used to validate and refine the process map and to guide adjustment of infusion process parameters based on resin age and part size/geometry. The study describes a pathway to more efficient use of aged resin using in situ process diagnostics, cure map design, and process simulation. The methodology employed to evaluate resin age and to adjust process parameters accordingly can be extended to other composite manufacturing processes, including conventional prepreg processing. Graphic abstract
{"title":"In situ resin age assessment using dielectric analysis and resin cure map for efficient vacuum infusion","authors":"J. Shin, S. Nutt","doi":"10.1080/20550340.2020.1834790","DOIUrl":"https://doi.org/10.1080/20550340.2020.1834790","url":null,"abstract":"Abstract The physical state of epoxy resin designed for vacuum infusion was assessed in situ by immersing a dielectric sensor into the resin pot. The measured ion viscosity of aged resin was directly converted to a degree-of-cure metric using a resin cure map constructed by correlating cure kinetics and dielectric analysis data. Next, an age-adjusted infusion process map was employed to define a nominal infusion window and to identify key process metrics. Finally, process simulations and flow contour maps were used to validate and refine the process map and to guide adjustment of infusion process parameters based on resin age and part size/geometry. The study describes a pathway to more efficient use of aged resin using in situ process diagnostics, cure map design, and process simulation. The methodology employed to evaluate resin age and to adjust process parameters accordingly can be extended to other composite manufacturing processes, including conventional prepreg processing. Graphic abstract","PeriodicalId":7243,"journal":{"name":"Advanced Manufacturing: Polymer & Composites Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73607042","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}
Pub Date : 2020-10-15DOI: 10.1080/20550340.2020.1834789
W. Edwards, Patricio Martínez, S. Nutt
Abstract Out-of-autoclave/vacuum-bag-only (OoA/VBO) composite processing has emerged as an alternative to autoclave cure, addressing economic, environmental, and production flexibility limitations associated with autoclave production. VBO processing can produce defect-free components under ideal processing conditions; however, adverse process conditions (e.g. poor vacuum) commonly encountered in manufacturing environments result in unacceptably high scrap rates, preventing more widespread adoption of such techniques. This work explores how modifications to prepreg format can increase process robustness. A unidirectional (UD) prepreg was produced with a customized, discontinuous resin distribution, henceforth referred to as semipreg. The semipreg exhibited through-thickness permeability orders of magnitude greater than conventional hot-melt VBO prepregs. The semipreg also was less sensitive to variations in process conditions than conventional VBO prepreg. In situ process monitoring allowed observation and identification of two defect formation mechanisms arising during cure of the custom prepreg. Resin feature topography played a critical role in these mechanisms, indicating its importance to the design of next generation VBO semipregs. Graphic abstract
{"title":"Process robustness and defect formation mechanisms in unidirectional semipreg","authors":"W. Edwards, Patricio Martínez, S. Nutt","doi":"10.1080/20550340.2020.1834789","DOIUrl":"https://doi.org/10.1080/20550340.2020.1834789","url":null,"abstract":"Abstract Out-of-autoclave/vacuum-bag-only (OoA/VBO) composite processing has emerged as an alternative to autoclave cure, addressing economic, environmental, and production flexibility limitations associated with autoclave production. VBO processing can produce defect-free components under ideal processing conditions; however, adverse process conditions (e.g. poor vacuum) commonly encountered in manufacturing environments result in unacceptably high scrap rates, preventing more widespread adoption of such techniques. This work explores how modifications to prepreg format can increase process robustness. A unidirectional (UD) prepreg was produced with a customized, discontinuous resin distribution, henceforth referred to as semipreg. The semipreg exhibited through-thickness permeability orders of magnitude greater than conventional hot-melt VBO prepregs. The semipreg also was less sensitive to variations in process conditions than conventional VBO prepreg. In situ process monitoring allowed observation and identification of two defect formation mechanisms arising during cure of the custom prepreg. Resin feature topography played a critical role in these mechanisms, indicating its importance to the design of next generation VBO semipregs. Graphic abstract","PeriodicalId":7243,"journal":{"name":"Advanced Manufacturing: Polymer & Composites Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78684361","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}
Pub Date : 2020-10-07DOI: 10.1080/20550340.2020.1826772
I. Schiel, L. Raps, A. Chadwick, I. Schmidt, Manuel Simone, S. Nowotny
Abstract In recent years the use of thermoplastics has become popular in aerospace applications, with a primary focus on fiber-reinforced composites. Displaying greatly improved mechanical properties, new components using these materials still need to be characterized and their suitability for aviation applications demonstrated. A common restriction to the implementation of fiber-reinforced thermoplastic parts is the almost default autoclave manufacturing, which is both time consuming and expensive. Aiming for a more economical final product, this study utilizes a one-step in-situ Automated Fiber Placement (AFP) process to produce samples for mechanical and thermal characterization. The recently developed and highly popular material CF/LM-PAEK was used within this study, with the four major AFP processing parameters varied to assess material sensitivity. Test samples were manufactured using Design of Experiment (DoE). Subsequently, single lap shear (SLS) and differential scanning calorimetry (DSC) tests were performed to assess consolidation quality. With rising tooling temperature, both SLS strength and crystallinity increase up to 31 MPa and 25%, respectively. A post-manufacturing tempering process improved crystallinity of the tested CF/LM-PAEK specimens up to 29% and SLS strength up to 38 MPa. Within the tested parameter range, CF/LM-PAEK appeared to be unaffected by increasing layup speed, which is a promising aspect with regard to faster industrial production. Graphical Abstract
近年来，热塑性塑料在航空航天领域的应用越来越广泛，主要集中在纤维增强复合材料上。使用这些材料的新部件显示出大大改善的机械性能，但仍需要对其进行表征，并证明其在航空应用中的适用性。实现纤维增强热塑性塑料部件的一个常见限制是几乎默认的高压灭菌器制造，这既耗时又昂贵。为了获得更经济的最终产品，本研究利用一步原位自动纤维放置(AFP)工艺来生产用于机械和热表征的样品。本研究使用了最近开发和非常流行的材料CF/LM-PAEK，四个主要的AFP处理参数不同，以评估材料的敏感性。试验样品采用试验设计(Design of Experiment, DoE)制作。随后，进行单搭剪(SLS)和差示扫描量热(DSC)试验来评估固结质量。随着加工温度的升高，SLS的强度和结晶度分别增加了31 MPa和25%。制造后回火工艺使CF/LM-PAEK试样的结晶度提高了29%，SLS强度提高了38 MPa。在测试参数范围内，CF/LM-PAEK似乎不受增加上铺速度的影响，这对于更快的工业生产来说是一个有希望的方面。图形抽象
{"title":"An investigation of in-situ AFP process parameters using CF/LM-PAEK","authors":"I. Schiel, L. Raps, A. Chadwick, I. Schmidt, Manuel Simone, S. Nowotny","doi":"10.1080/20550340.2020.1826772","DOIUrl":"https://doi.org/10.1080/20550340.2020.1826772","url":null,"abstract":"Abstract In recent years the use of thermoplastics has become popular in aerospace applications, with a primary focus on fiber-reinforced composites. Displaying greatly improved mechanical properties, new components using these materials still need to be characterized and their suitability for aviation applications demonstrated. A common restriction to the implementation of fiber-reinforced thermoplastic parts is the almost default autoclave manufacturing, which is both time consuming and expensive. Aiming for a more economical final product, this study utilizes a one-step in-situ Automated Fiber Placement (AFP) process to produce samples for mechanical and thermal characterization. The recently developed and highly popular material CF/LM-PAEK was used within this study, with the four major AFP processing parameters varied to assess material sensitivity. Test samples were manufactured using Design of Experiment (DoE). Subsequently, single lap shear (SLS) and differential scanning calorimetry (DSC) tests were performed to assess consolidation quality. With rising tooling temperature, both SLS strength and crystallinity increase up to 31 MPa and 25%, respectively. A post-manufacturing tempering process improved crystallinity of the tested CF/LM-PAEK specimens up to 29% and SLS strength up to 38 MPa. Within the tested parameter range, CF/LM-PAEK appeared to be unaffected by increasing layup speed, which is a promising aspect with regard to faster industrial production. Graphical Abstract","PeriodicalId":7243,"journal":{"name":"Advanced Manufacturing: Polymer & Composites Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85323852","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}
Pub Date : 2020-09-01DOI: 10.1080/20550340.2020.1815276
D. Kim, S. Nutt
Abstract Out-time and moisture absorption in prepregs are generally unavoidable in an industrial setting, where prepreg layup can take weeks. The resin cross-linking and viscosity increase that occurs during out-time can reduce resin flow during a specified cure cycle, causing porosity. In this study, a flow-optimized cure cycle was developed, leveraging both flow level and time during out-of-autoclave (OoA) processing. First, predictive cure kinetics and viscosity models were used to model viscosity evolution under selected cure conditions, accounting for initial out-times and humidity conditioning. To quantify resin flow, an ‘effective flow number’ metric was defined as the integration of inverse viscosity evolution until the resin gelation point. The method described revealed that a rapid heating rate achieved by use of advanced tooling was essential to achieve a high effective flow number. The experimental results showed that the effective flow number is a useful criterion to limit flow-induced defects. The method presented also extends the boundary (by 175%) of the manufacturer’s specified out-life for OoA prepreg materials. Graphical Abstract
{"title":"Effective cure cycle development via flow optimization and advanced cure environments","authors":"D. Kim, S. Nutt","doi":"10.1080/20550340.2020.1815276","DOIUrl":"https://doi.org/10.1080/20550340.2020.1815276","url":null,"abstract":"Abstract Out-time and moisture absorption in prepregs are generally unavoidable in an industrial setting, where prepreg layup can take weeks. The resin cross-linking and viscosity increase that occurs during out-time can reduce resin flow during a specified cure cycle, causing porosity. In this study, a flow-optimized cure cycle was developed, leveraging both flow level and time during out-of-autoclave (OoA) processing. First, predictive cure kinetics and viscosity models were used to model viscosity evolution under selected cure conditions, accounting for initial out-times and humidity conditioning. To quantify resin flow, an ‘effective flow number’ metric was defined as the integration of inverse viscosity evolution until the resin gelation point. The method described revealed that a rapid heating rate achieved by use of advanced tooling was essential to achieve a high effective flow number. The experimental results showed that the effective flow number is a useful criterion to limit flow-induced defects. The method presented also extends the boundary (by 175%) of the manufacturer’s specified out-life for OoA prepreg materials. Graphical Abstract","PeriodicalId":7243,"journal":{"name":"Advanced Manufacturing: Polymer & Composites Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84257730","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}
Pub Date : 2020-08-10DOI: 10.1080/20550340.2020.1800194
D. Zebrine, M. Anders, T. Centea, S. Nutt
Abstract During co-cure of honeycomb core sandwich panels, composite facesheets are cured and concurrently bonded to the core, introducing complex interactions that can lead to unsatisfactory bond-line formation. In this work, an in situ co-cure fixture is employed to directly observe the adhesive during processing and identify defect formation mechanisms specific to the bond-line. Relating fillet quality to imposed core pressure reveals the non-linear effect of core pressure. High pressures suppressed voids; intermediate pressures resulted in void growth and entrapment within deformed fillets; and low pressures led to void rupture and small, irregular fillets. Experimental results aided in developing a model to predict void growth in the bond-line. The findings presented here provide insight into the physics controlling the adhesive bond-line evolution during co-cure, which can inform manufacturing decisions to produce higher-quality honeycomb core sandwich structures. Graphical Abstract
{"title":"Path-dependent bond-line evolution in equilibrated core honeycomb sandwich structures","authors":"D. Zebrine, M. Anders, T. Centea, S. Nutt","doi":"10.1080/20550340.2020.1800194","DOIUrl":"https://doi.org/10.1080/20550340.2020.1800194","url":null,"abstract":"Abstract During co-cure of honeycomb core sandwich panels, composite facesheets are cured and concurrently bonded to the core, introducing complex interactions that can lead to unsatisfactory bond-line formation. In this work, an in situ co-cure fixture is employed to directly observe the adhesive during processing and identify defect formation mechanisms specific to the bond-line. Relating fillet quality to imposed core pressure reveals the non-linear effect of core pressure. High pressures suppressed voids; intermediate pressures resulted in void growth and entrapment within deformed fillets; and low pressures led to void rupture and small, irregular fillets. Experimental results aided in developing a model to predict void growth in the bond-line. The findings presented here provide insight into the physics controlling the adhesive bond-line evolution during co-cure, which can inform manufacturing decisions to produce higher-quality honeycomb core sandwich structures. Graphical Abstract","PeriodicalId":7243,"journal":{"name":"Advanced Manufacturing: Polymer & Composites Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77979870","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}
Pub Date : 2020-08-04DOI: 10.1080/20550340.2020.1802685
Trisha Palit, T. Centea, M. Anders, D. Zebrine, S. Nutt
Abstract Potential links between pressure conditions during co-cure of honeycomb sandwich panels, the extent of gas flow through facesheet and bond-line, and the level of permeability in the cured skin were evaluated. Half-sandwich structures comprised of fiber-reinforced polymer facesheets, film adhesive, and core were fabricated using a custom-built lab fixture. Autoclave, bag, and core pressures were varied to produce controlled, constant pressure differences during cure, and the resulting skins were tested for permeability using a fixture constructed to measure gas flow rate across the skins and to locate gas flow pathways. Facesheet cross-sections were analyzed to evaluate porosity. Porosity and the number of gas flow pathways were correlated to permeability, but significant gas flow was possible without high void content or with few channels, as pressure differentials led to complex variations in permeability. Overall, the study provides new insights into gas transport during composites processing and manufacturing, and the results provide guidance for modifying manufacturing processes to ensure part quality.
{"title":"Permeability of co-cured honeycomb sandwich skins: effect of gas transport during processing","authors":"Trisha Palit, T. Centea, M. Anders, D. Zebrine, S. Nutt","doi":"10.1080/20550340.2020.1802685","DOIUrl":"https://doi.org/10.1080/20550340.2020.1802685","url":null,"abstract":"Abstract Potential links between pressure conditions during co-cure of honeycomb sandwich panels, the extent of gas flow through facesheet and bond-line, and the level of permeability in the cured skin were evaluated. Half-sandwich structures comprised of fiber-reinforced polymer facesheets, film adhesive, and core were fabricated using a custom-built lab fixture. Autoclave, bag, and core pressures were varied to produce controlled, constant pressure differences during cure, and the resulting skins were tested for permeability using a fixture constructed to measure gas flow rate across the skins and to locate gas flow pathways. Facesheet cross-sections were analyzed to evaluate porosity. Porosity and the number of gas flow pathways were correlated to permeability, but significant gas flow was possible without high void content or with few channels, as pressure differentials led to complex variations in permeability. Overall, the study provides new insights into gas transport during composites processing and manufacturing, and the results provide guidance for modifying manufacturing processes to ensure part quality.","PeriodicalId":7243,"journal":{"name":"Advanced Manufacturing: Polymer & Composites Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87561355","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}
Pub Date : 2020-07-02DOI: 10.1080/20550340.2020.1805689
Julian Seuffert, P. Rosenberg, L. Kärger, F. Henning, M. H. Kothmann, G. Deinzer
Abstract To increase the use of fiber reinforced lightweight structural components in the automotive industry, their manufacturing processes have to obtain demanding economic requirements. One possibility is to use Compression Resin Transfer Molding (CRTM), which is fast and can be highly automated. One disadvantage can be the very high cavity pressure during injection. To avoid this disadvantage, a pressure-controlled RTM (PC-RTM) process was developed. PC-RTM uses a variable mold gap height and an embedded pressure sensor to control the cavity pressure actively during mold filling. In this work, we investigate this process by experiments and simulations with varying initial mold gap and controlled cavity pressure. We show that PC-RTM is a viable manufacturing process with short cycle times and high robustness. Furthermore, the simulations are validated by comparison to the experiments and show the same process characteristics. Graphical Abstract
{"title":"Experimental and numerical investigations of pressure-controlled resin transfer molding (PC-RTM)","authors":"Julian Seuffert, P. Rosenberg, L. Kärger, F. Henning, M. H. Kothmann, G. Deinzer","doi":"10.1080/20550340.2020.1805689","DOIUrl":"https://doi.org/10.1080/20550340.2020.1805689","url":null,"abstract":"Abstract To increase the use of fiber reinforced lightweight structural components in the automotive industry, their manufacturing processes have to obtain demanding economic requirements. One possibility is to use Compression Resin Transfer Molding (CRTM), which is fast and can be highly automated. One disadvantage can be the very high cavity pressure during injection. To avoid this disadvantage, a pressure-controlled RTM (PC-RTM) process was developed. PC-RTM uses a variable mold gap height and an embedded pressure sensor to control the cavity pressure actively during mold filling. In this work, we investigate this process by experiments and simulations with varying initial mold gap and controlled cavity pressure. We show that PC-RTM is a viable manufacturing process with short cycle times and high robustness. Furthermore, the simulations are validated by comparison to the experiments and show the same process characteristics. Graphical Abstract","PeriodicalId":7243,"journal":{"name":"Advanced Manufacturing: Polymer & Composites Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76328310","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}
Pub Date : 2020-06-25DOI: 10.1080/20550340.2020.1779438
A. Rosenberger, Jean Hardt, D. Dragunski, Franciele Fernanda da Silva, P. Bittencourt, R. Bariccatti, E. Muniz, M. R. Simões, J. Caetano
Abstract The production of polymeric fibers by the electrospinning technique stands out as being simple, accessible, versatile and with potential use of polymer microfibers in many areas of science and technology. In this article, polymeric microfibers of PBAT/PLA and carbon nanotubes were obtained using a Fractional Factorial Design. The statistical results, the optical microscopy and scanning electron microscopy (SEM) showed that the addition of MWCNT’s had an influence in the diameter of the fibers (1.16 ± 0.22 µm), so that its incorporation decreased the value of the diameter, also they were more uniform and homogeneous. Besides, the MWCNT’s provided the fibers a better mechanical resistance, probably being inside the fibers, as well as showed in the analysis of wettability by contact angle. Graphical Abstract
{"title":"Use of experimental design to obtain polymeric microfibers with carbon nanotubes","authors":"A. Rosenberger, Jean Hardt, D. Dragunski, Franciele Fernanda da Silva, P. Bittencourt, R. Bariccatti, E. Muniz, M. R. Simões, J. Caetano","doi":"10.1080/20550340.2020.1779438","DOIUrl":"https://doi.org/10.1080/20550340.2020.1779438","url":null,"abstract":"Abstract The production of polymeric fibers by the electrospinning technique stands out as being simple, accessible, versatile and with potential use of polymer microfibers in many areas of science and technology. In this article, polymeric microfibers of PBAT/PLA and carbon nanotubes were obtained using a Fractional Factorial Design. The statistical results, the optical microscopy and scanning electron microscopy (SEM) showed that the addition of MWCNT’s had an influence in the diameter of the fibers (1.16 ± 0.22 µm), so that its incorporation decreased the value of the diameter, also they were more uniform and homogeneous. Besides, the MWCNT’s provided the fibers a better mechanical resistance, probably being inside the fibers, as well as showed in the analysis of wettability by contact angle. Graphical Abstract","PeriodicalId":7243,"journal":{"name":"Advanced Manufacturing: Polymer & Composites Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83254639","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}
Pub Date : 2020-04-02DOI: 10.1080/20550340.2020.1736864
S. Schechter, Lessa K. Grunenfelder, S. Nutt
Abstract Vacuum-bag-only (VBO) prepregs fabricated with discontinuous resin (semi-pregs) on a unidirectional fiber bed reportedly exhibit high through-thickness permeability and yield high-quality laminates, even under adverse process conditions, such as poor vacuum or long out-times. In this work, semi-pregs were fabricated using fiber beds of various weaves, fiber types, and areal weights (200–670 GSM). Flat and curved laminates were produced and characterized, confirming that porosity-free parts can be manufactured from a range of constituent materials using VBO semi-pregs. Contoured laminates were produced with negligible porosity, although a slight increase in bulk factor of prepreg plies was observed (Δ∼0.1). In addition, design considerations and limitations for the fabrication of semi-pregs were presented. The findings demonstrate that polymer film dewetting can be used effectively to produce semi-pregs that yield porosity-free laminates via VBO processing, imparting robustness to out-of-autoclave cure of prepreg laminates. Graphical Abstract
{"title":"Design and application of discontinuous resin distribution patterns for semi-pregs","authors":"S. Schechter, Lessa K. Grunenfelder, S. Nutt","doi":"10.1080/20550340.2020.1736864","DOIUrl":"https://doi.org/10.1080/20550340.2020.1736864","url":null,"abstract":"Abstract Vacuum-bag-only (VBO) prepregs fabricated with discontinuous resin (semi-pregs) on a unidirectional fiber bed reportedly exhibit high through-thickness permeability and yield high-quality laminates, even under adverse process conditions, such as poor vacuum or long out-times. In this work, semi-pregs were fabricated using fiber beds of various weaves, fiber types, and areal weights (200–670 GSM). Flat and curved laminates were produced and characterized, confirming that porosity-free parts can be manufactured from a range of constituent materials using VBO semi-pregs. Contoured laminates were produced with negligible porosity, although a slight increase in bulk factor of prepreg plies was observed (Δ∼0.1). In addition, design considerations and limitations for the fabrication of semi-pregs were presented. The findings demonstrate that polymer film dewetting can be used effectively to produce semi-pregs that yield porosity-free laminates via VBO processing, imparting robustness to out-of-autoclave cure of prepreg laminates. Graphical Abstract","PeriodicalId":7243,"journal":{"name":"Advanced Manufacturing: Polymer & Composites Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84136644","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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