Pub Date : 2024-06-07DOI: 10.1177/00219983241260880
M. Zolfakkar, Nabil El-Tayeb, Taher Halawa
Sustainable production and consumption, carried to materials and engineering applications, translates to a need for recyclable, reusable, and/or biodegradable materials. With its lower cost, lighter weight, and less carbon footprint compared to traditional glass and carbon fiber composites, natural fiber-reinforced composites are drawing more attention from the scientific community and the industrial sector. The natural fiber’s high variability and relatively inferior mechanical properties necessitate comprehensive characterization for accurate evaluation of their properties and fitness for different applications. In this research, various locally grown natural fibers (Flax, Jute, and Luffa) were sourced, characterized, and used to synthesize natural fiber-reinforced epoxy composites. The tensile, flexural, impact properties, and erosion resistance of the composites was evaluated. Compared to the other natural fiber composites, the Jute-Epoxy composite achieved the highest tensile strength and tensile modulus with 31 MPa and 4.8 GPa respectively; Jute-Epoxy also achieved the highest flexural strength and flexural modulus, with and 60 MPa and 2.4 GPa respectively. This superior mechanical performance is due to the relatively high strength of the Jute fiber and its high adhesion to the matrix, which is supported by fractographic evidence. Luffa-Epoxy composites in general had the lowest properties of all the tested materials. The erosion test results showed that the Jute-Epoxy composites had the highest erosion resistance of all the tested materials; with 30% more erosion resistance compared to glass-fiber epoxy composites. Based on the experimental results of the investigation and similar previous research, the current and potential applications of natural fiber composites were discussed.
{"title":"Towards sustainable composites: Evaluation of mechanical properties, erosion behavior and applications of natural fiber-epoxy composites","authors":"M. Zolfakkar, Nabil El-Tayeb, Taher Halawa","doi":"10.1177/00219983241260880","DOIUrl":"https://doi.org/10.1177/00219983241260880","url":null,"abstract":"Sustainable production and consumption, carried to materials and engineering applications, translates to a need for recyclable, reusable, and/or biodegradable materials. With its lower cost, lighter weight, and less carbon footprint compared to traditional glass and carbon fiber composites, natural fiber-reinforced composites are drawing more attention from the scientific community and the industrial sector. The natural fiber’s high variability and relatively inferior mechanical properties necessitate comprehensive characterization for accurate evaluation of their properties and fitness for different applications. In this research, various locally grown natural fibers (Flax, Jute, and Luffa) were sourced, characterized, and used to synthesize natural fiber-reinforced epoxy composites. The tensile, flexural, impact properties, and erosion resistance of the composites was evaluated. Compared to the other natural fiber composites, the Jute-Epoxy composite achieved the highest tensile strength and tensile modulus with 31 MPa and 4.8 GPa respectively; Jute-Epoxy also achieved the highest flexural strength and flexural modulus, with and 60 MPa and 2.4 GPa respectively. This superior mechanical performance is due to the relatively high strength of the Jute fiber and its high adhesion to the matrix, which is supported by fractographic evidence. Luffa-Epoxy composites in general had the lowest properties of all the tested materials. The erosion test results showed that the Jute-Epoxy composites had the highest erosion resistance of all the tested materials; with 30% more erosion resistance compared to glass-fiber epoxy composites. Based on the experimental results of the investigation and similar previous research, the current and potential applications of natural fiber composites were discussed.","PeriodicalId":15489,"journal":{"name":"Journal of Composite Materials","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141372129","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 : 2024-06-04DOI: 10.1177/00219983241257666
Chase Mortensen, Devin Nielsen, Syed Zulfiqar Hussain Shah, Juhyeong Lee
This study presents experimental and numerical investigations on the quasi-static compressive responses of various subscale Miura-foldcore composites. A series of quasi-static compression tests were conducted on standard Miura foldcore specimens fabricated using carbon/epoxy woven fabric prepregs. Representative volume element (RVE) models, incorporating periodic boundary conditions (PBCs), were developed to predict the size-dependent compressive response of subscale Miura foldcores. The effective properties of the carbon/epoxy woven fabric composite used in this study were calculated using the NASA multiscale analysis tool (NASMAT) via two-step homogenization process. The FE model exhibited comparable agreement with experimental results, showcasing variations of less than 7% and 12% in maximum compressive load and compressive stiffness, respectively. The implementation of PBC in the foldcore RVE models improved modeling accuracy by <4%, but drastically increased total computational time (>50%). The periodic pattern of foldcore unit-cells, where two single foldcore unit-cells were placed in parallel or perpendicular, imposed geometric constraints, resulting in small variations in predicted stress and strain distribution contours. The key findings highlighted in this study suggest that a 1 × 1 foldcore unit-cell model without PBC is sufficient to predict accurate quasi-static compressive responses of foldcore composites. This study advances the understanding of subscale Miura-foldcore composites and provides valuable insights into the limitations associated with the use of PBC in foldcore RVE models. The findings also offer a practical guide for fabricating and analyzing traditional Miura folding patterns, promoting a more efficient and accurate approach for optimizing foldcore composite designs considering both structural performance and manufacturability.
{"title":"Effects of periodic sequential arrangement of subscale miura-foldcore under quasi-static compression","authors":"Chase Mortensen, Devin Nielsen, Syed Zulfiqar Hussain Shah, Juhyeong Lee","doi":"10.1177/00219983241257666","DOIUrl":"https://doi.org/10.1177/00219983241257666","url":null,"abstract":"This study presents experimental and numerical investigations on the quasi-static compressive responses of various subscale Miura-foldcore composites. A series of quasi-static compression tests were conducted on standard Miura foldcore specimens fabricated using carbon/epoxy woven fabric prepregs. Representative volume element (RVE) models, incorporating periodic boundary conditions (PBCs), were developed to predict the size-dependent compressive response of subscale Miura foldcores. The effective properties of the carbon/epoxy woven fabric composite used in this study were calculated using the NASA multiscale analysis tool (NASMAT) via two-step homogenization process. The FE model exhibited comparable agreement with experimental results, showcasing variations of less than 7% and 12% in maximum compressive load and compressive stiffness, respectively. The implementation of PBC in the foldcore RVE models improved modeling accuracy by <4%, but drastically increased total computational time (>50%). The periodic pattern of foldcore unit-cells, where two single foldcore unit-cells were placed in parallel or perpendicular, imposed geometric constraints, resulting in small variations in predicted stress and strain distribution contours. The key findings highlighted in this study suggest that a 1 × 1 foldcore unit-cell model without PBC is sufficient to predict accurate quasi-static compressive responses of foldcore composites. This study advances the understanding of subscale Miura-foldcore composites and provides valuable insights into the limitations associated with the use of PBC in foldcore RVE models. The findings also offer a practical guide for fabricating and analyzing traditional Miura folding patterns, promoting a more efficient and accurate approach for optimizing foldcore composite designs considering both structural performance and manufacturability.","PeriodicalId":15489,"journal":{"name":"Journal of Composite Materials","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141266579","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 : 2024-06-03DOI: 10.1177/00219983241260881
Yasin Akın, Memduh Kara
Composite pipe is preferred over metal and other materials for water supply, liquid chemical transport, and fuel and gas transport. This is because composite pipes are more corrosion resistant, have a high strength/density ratio, high stiffness/density ratio, and more durable than metal pipes. The properties of the composite pipes employed may differ based on the operating environment. Therefore, determining the properties of the composite pipe according to the working environment is extremely important for its lifespan. The thickness of the samples is increased in line with different needs (such as increased strength). Increasing the thickness of samples, especially those exposed to different environmental conditions, and investigating the changes that will occur in the physical and mechanical properties of the samples are another important situation. In this investigation, glass fiber (GFRP) reinforced epoxy composite pipes have been examined, which were manufactured using the filament winding method with different layers [±55°]. To determine their properties in different working environments, the GFRP composite pipes were subjected to hydrothermal aging in pure water at 80°C for several days (7, 14, 21, and 28). The changes in their mechanical properties under working conditions were determined through hoop tensile strength tests and low velocity impact tests applied at different energy levels. The experimental results show that the tangential stress values increased by 10.59% as the number of layers increased. As the aging time increased, the durability of the 6-layer composite pipe decreased by 17.69%. Furthermore, the ability of the aged pipes to withstand damage was evaluated, revealing that the aging process exacerbated the damage within the pipes.
{"title":"Mechanical strength and low-velocity impact behavior of glass fiber reinforced filament wound pipes with different number of layers after hydrothermal aging","authors":"Yasin Akın, Memduh Kara","doi":"10.1177/00219983241260881","DOIUrl":"https://doi.org/10.1177/00219983241260881","url":null,"abstract":"Composite pipe is preferred over metal and other materials for water supply, liquid chemical transport, and fuel and gas transport. This is because composite pipes are more corrosion resistant, have a high strength/density ratio, high stiffness/density ratio, and more durable than metal pipes. The properties of the composite pipes employed may differ based on the operating environment. Therefore, determining the properties of the composite pipe according to the working environment is extremely important for its lifespan. The thickness of the samples is increased in line with different needs (such as increased strength). Increasing the thickness of samples, especially those exposed to different environmental conditions, and investigating the changes that will occur in the physical and mechanical properties of the samples are another important situation. In this investigation, glass fiber (GFRP) reinforced epoxy composite pipes have been examined, which were manufactured using the filament winding method with different layers [±55°]. To determine their properties in different working environments, the GFRP composite pipes were subjected to hydrothermal aging in pure water at 80°C for several days (7, 14, 21, and 28). The changes in their mechanical properties under working conditions were determined through hoop tensile strength tests and low velocity impact tests applied at different energy levels. The experimental results show that the tangential stress values increased by 10.59% as the number of layers increased. As the aging time increased, the durability of the 6-layer composite pipe decreased by 17.69%. Furthermore, the ability of the aged pipes to withstand damage was evaluated, revealing that the aging process exacerbated the damage within the pipes.","PeriodicalId":15489,"journal":{"name":"Journal of Composite Materials","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141270571","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 : 2024-06-01DOI: 10.1177/00219983241260555
Mariam A. Al-Dhaheri, Wesley J. Cantwell, Imad Barsoum, Rehan Umer
In this study, the Time-Temperature-Crystallinity Superposition Principle (TTCSP) was applied to determine the viscoelastic behavior of Thermo-rheological Complex Materials (TCM), specifically Carbon fibre/Poly-Ether-Ketone-Ketone (CF/PEKK) composites. The study investigated the effects of various parameters on the viscoelastic behavior of the composites, such as the degree of crystallinity after different melting temperatures, relaxation, and crystallization times. The TTCSP was utilized on the relaxation data to generate great-grand master curves for the degree of crystallinity for different laminate lay-ups. Hot press forming was employed to manufacture samples under different processing conditions, including various melting and cold crystallization temperatures. Differential Scanning Calorimetry (DSC) was employed to calculate the degree of crystallinity of CF/PEKK composites, while the Dynamic Mechanical Analyzer (DMA) was used to obtain the relaxation data. The generated great-grand master curves proved effective in predicting the relaxation behavior of the composites consolidated using single and double hold cycles at different melting temperatures and crystallization times, respectively. The great-grand master curves presented in this study can serve as valuable tool to calibrate key viscoelastic and/or thermo-viscoelastic material models for aerospace-grade CF/PEKK composites. These models are crucial for simulations aimed at predicting residual stresses and process-induced deformations during the thermoforming process.
{"title":"Characterization of relaxation behaviour of CF/PEKK aerospace composites using the time-temperature-crystallinity superposition principle","authors":"Mariam A. Al-Dhaheri, Wesley J. Cantwell, Imad Barsoum, Rehan Umer","doi":"10.1177/00219983241260555","DOIUrl":"https://doi.org/10.1177/00219983241260555","url":null,"abstract":"In this study, the Time-Temperature-Crystallinity Superposition Principle (TTCSP) was applied to determine the viscoelastic behavior of Thermo-rheological Complex Materials (TCM), specifically Carbon fibre/Poly-Ether-Ketone-Ketone (CF/PEKK) composites. The study investigated the effects of various parameters on the viscoelastic behavior of the composites, such as the degree of crystallinity after different melting temperatures, relaxation, and crystallization times. The TTCSP was utilized on the relaxation data to generate great-grand master curves for the degree of crystallinity for different laminate lay-ups. Hot press forming was employed to manufacture samples under different processing conditions, including various melting and cold crystallization temperatures. Differential Scanning Calorimetry (DSC) was employed to calculate the degree of crystallinity of CF/PEKK composites, while the Dynamic Mechanical Analyzer (DMA) was used to obtain the relaxation data. The generated great-grand master curves proved effective in predicting the relaxation behavior of the composites consolidated using single and double hold cycles at different melting temperatures and crystallization times, respectively. The great-grand master curves presented in this study can serve as valuable tool to calibrate key viscoelastic and/or thermo-viscoelastic material models for aerospace-grade CF/PEKK composites. These models are crucial for simulations aimed at predicting residual stresses and process-induced deformations during the thermoforming process.","PeriodicalId":15489,"journal":{"name":"Journal of Composite Materials","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141196640","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 : 2024-06-01DOI: 10.1177/00219983241261065
Tomás Barros Vasconcelos, José Leandro Correia Alves, Evans Paiva da Costa Ferreira, Raimundo Carlos Silverio Freire Júnior, José Daniel Diniz Melo
Double-double (DD) configuration has been proposed as a new concept in which a double set of double helix [±ϕ/± ψ]n angles are stacked up to form a composite laminate. This concept promises significant advantages over conventional layups for composite design optimization and manufacturing. This experimental study evaluated the performance of two elastically in-plane equivalent glass/epoxy laminates suited for wind turbine blade applications: a quadriaxial (Quad) [±45/(0/90)3]s and a double-double (DD) [±15/±75]4T. Mechanical tests were performed under cyclic uniaxial tensile-tensile load using unnotched and open hole specimens. Delamination initiating from the free edges resulted in premature failure of the unnotched DD specimens. For open hole specimens, fatigue tests results obtained from both stacking sequences showed similar performance. Ultimately, the study presented constitutes a valuable contribution to the understanding of fatigue behavior of double-double glass/epoxy laminates subjected to tensile cyclic loading.
{"title":"Static and fatigue behavior of double-double glass/epoxy laminates","authors":"Tomás Barros Vasconcelos, José Leandro Correia Alves, Evans Paiva da Costa Ferreira, Raimundo Carlos Silverio Freire Júnior, José Daniel Diniz Melo","doi":"10.1177/00219983241261065","DOIUrl":"https://doi.org/10.1177/00219983241261065","url":null,"abstract":"Double-double (DD) configuration has been proposed as a new concept in which a double set of double helix [±ϕ/± ψ]<jats:sub>n</jats:sub> angles are stacked up to form a composite laminate. This concept promises significant advantages over conventional layups for composite design optimization and manufacturing. This experimental study evaluated the performance of two elastically in-plane equivalent glass/epoxy laminates suited for wind turbine blade applications: a quadriaxial (Quad) [±45/(0/90)<jats:sub>3</jats:sub>]<jats:sub>s</jats:sub> and a double-double (DD) [±15/±75]<jats:sub>4T</jats:sub>. Mechanical tests were performed under cyclic uniaxial tensile-tensile load using unnotched and open hole specimens. Delamination initiating from the free edges resulted in premature failure of the unnotched DD specimens. For open hole specimens, fatigue tests results obtained from both stacking sequences showed similar performance. Ultimately, the study presented constitutes a valuable contribution to the understanding of fatigue behavior of double-double glass/epoxy laminates subjected to tensile cyclic loading.","PeriodicalId":15489,"journal":{"name":"Journal of Composite Materials","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141196637","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 : 2024-06-01DOI: 10.1177/00219983241259130
Muhammad Ali Bablu, Nicholas E Nowak, James M Manimala
The possibility of enhancing the ballistic performance of aramid fabrics such as Kevlar through the impregnation of nanoparticles is well established. In this study, the influence of the nanoparticle’s specifications such as size, shape, and material on the underlying mechanisms is investigated. A colloid-based treatment process is used to impregnate dry nanoparticles into Kevlar fabric. Using a customized gas gun rig, neat and treated samples are tested to determine the kinetic energy absorbed. Silica, alumina, and zinc oxide nanoparticles ranging from 10 to 125 nm, with spherical or cylindrical shape are considered. Silica treated samples perform significantly better (83% increase in energy absorbed vs neat fabric) than alumina or zinc oxide treated samples, likely due to greater agglomeration between yarn interfaces leading to enhanced frictional mechanisms. The exit-face damaged zone area acts as a surrogate for energy absorbed as it correlates well across all samples. Compared to samples with three layers treated individually, samples with three layers treated together display a 21% enhancement in the energy absorbed. Specific energy absorbed for three layers treated together with 80-nm silica is nearly 3 times higher than that for the neat fabric. Samples with three layers treated together with 80-nm silica provide the same performance as the neat fabric for a projectile that is nearly 70 m/s faster. Hybrid structural materials such as nanoparticle-fabric composites offer a promising route to enhance ballistic performance without weight penalty, while being amenable to multifunctional applications.
{"title":"Role of particle material and geometry in the ballistic performance of nanoparticle-impregnated Kevlar fabric","authors":"Muhammad Ali Bablu, Nicholas E Nowak, James M Manimala","doi":"10.1177/00219983241259130","DOIUrl":"https://doi.org/10.1177/00219983241259130","url":null,"abstract":"The possibility of enhancing the ballistic performance of aramid fabrics such as Kevlar through the impregnation of nanoparticles is well established. In this study, the influence of the nanoparticle’s specifications such as size, shape, and material on the underlying mechanisms is investigated. A colloid-based treatment process is used to impregnate dry nanoparticles into Kevlar fabric. Using a customized gas gun rig, neat and treated samples are tested to determine the kinetic energy absorbed. Silica, alumina, and zinc oxide nanoparticles ranging from 10 to 125 nm, with spherical or cylindrical shape are considered. Silica treated samples perform significantly better (83% increase in energy absorbed vs neat fabric) than alumina or zinc oxide treated samples, likely due to greater agglomeration between yarn interfaces leading to enhanced frictional mechanisms. The exit-face damaged zone area acts as a surrogate for energy absorbed as it correlates well across all samples. Compared to samples with three layers treated individually, samples with three layers treated together display a 21% enhancement in the energy absorbed. Specific energy absorbed for three layers treated together with 80-nm silica is nearly 3 times higher than that for the neat fabric. Samples with three layers treated together with 80-nm silica provide the same performance as the neat fabric for a projectile that is nearly 70 m/s faster. Hybrid structural materials such as nanoparticle-fabric composites offer a promising route to enhance ballistic performance without weight penalty, while being amenable to multifunctional applications.","PeriodicalId":15489,"journal":{"name":"Journal of Composite Materials","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141196580","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 : 2024-06-01DOI: 10.1177/00219983241244565
Xiaohe Wang, Zengqiang Cao, Yingjiang Guo
A novel dynamic installation (DI) method is proposed to improve the problems of severe installation damage, small installable interference size, and low installation efficiency of traditional static installation (SI) methods for installing interference bolts in composite bolted structures. The stress distribution and CFRP damage around the hole wall due to interference fitting and subsequent cyclic loading were predicted by finite element simulations. In addition, the fatigue life of DI and SI specimens was evaluated and the fatigue failure mechanisms were discussed. The results showed that the DI method provides a visible improvement in fatigue life, which is about 4 times that of the SI interference specimens and 38 times that of the non-interference specimen. In addition, DI introduces relatively higher average residual compressive stresses than SI, especially at the inlet of the laminate, which also results in a more uniform distribution along the axial direction of DI specimens. Micromorphological analysis of the specimens after fatigue failure indicated that the uniform stress distribution and low initial installation damage at the assembly interface introduced by the DI method during interference fit prevents severe delamination and crack propagation in joints subjected to external cyclic loading, such as the SI specimen. Severe extrusion deformation of the hole wall and matrix crushing are the main failure modes of DI specimens. Therefore, it is necessary to improve the interference installation method of composite materials.
提出了一种新型动态安装（DI）方法，以改善传统静态安装（SI）方法在复合材料螺栓结构中安装过盈螺栓时存在的安装损伤严重、可安装过盈尺寸小和安装效率低等问题。通过有限元模拟预测了过盈配合和后续循环载荷导致的孔壁周围应力分布和 CFRP 损伤。此外，还评估了 DI 和 SI 试样的疲劳寿命，并讨论了疲劳失效机制。结果表明，DI 方法明显提高了疲劳寿命，约为 SI 过盈试样的 4 倍，非过盈试样的 38 倍。此外，DI 带来的平均残余压应力相对高于 SI，尤其是在层压板的入口处，这也导致 DI 试样沿轴向的分布更加均匀。疲劳失效后试样的微观形态分析表明，DI 方法在过盈配合过程中引入的均匀应力分布和装配界面上较低的初始安装损伤，可防止在承受外部循环载荷的接头（如 SI 试样）中出现严重的分层和裂纹扩展。孔壁的严重挤压变形和基体破碎是 DI 试样的主要失效模式。因此，有必要改进复合材料的过盈安装方法。
{"title":"Effect of interference installation method on interfacial properties and fatigue failure behavior of bolted composite joints","authors":"Xiaohe Wang, Zengqiang Cao, Yingjiang Guo","doi":"10.1177/00219983241244565","DOIUrl":"https://doi.org/10.1177/00219983241244565","url":null,"abstract":"A novel dynamic installation (DI) method is proposed to improve the problems of severe installation damage, small installable interference size, and low installation efficiency of traditional static installation (SI) methods for installing interference bolts in composite bolted structures. The stress distribution and CFRP damage around the hole wall due to interference fitting and subsequent cyclic loading were predicted by finite element simulations. In addition, the fatigue life of DI and SI specimens was evaluated and the fatigue failure mechanisms were discussed. The results showed that the DI method provides a visible improvement in fatigue life, which is about 4 times that of the SI interference specimens and 38 times that of the non-interference specimen. In addition, DI introduces relatively higher average residual compressive stresses than SI, especially at the inlet of the laminate, which also results in a more uniform distribution along the axial direction of DI specimens. Micromorphological analysis of the specimens after fatigue failure indicated that the uniform stress distribution and low initial installation damage at the assembly interface introduced by the DI method during interference fit prevents severe delamination and crack propagation in joints subjected to external cyclic loading, such as the SI specimen. Severe extrusion deformation of the hole wall and matrix crushing are the main failure modes of DI specimens. Therefore, it is necessary to improve the interference installation method of composite materials.","PeriodicalId":15489,"journal":{"name":"Journal of Composite Materials","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141393151","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}
Automated fiber placement (AFP) in situ consolidation (ISC) of thermoplastic composite possess the potential to reduce manufacturing costs and improve manufacturing efficiency. The properties of composite manufactured by the ISC are affected by several mechanisms including polymer degradation, crystallization, intimate contact, polymer healing and void dynamics. All these mechanisms are directly affected by the temperature history. Consequently, the control and accurate measurement of temperature history during ISC are particularly important for improving the properties of composite. In this study, a simplified three-dimensional transient heat transfer model was established. The effect of tool temperature and placement speed on the temperature history and peak temperature were predicted. Simultaneously, an online temperature monitoring system was built and the optical Fiber Bragg Grating sensors (FBGS) was used to measure the temperature history. The results indicated that the predicted results of the model were consistent with the measured results, the error was below 8%. In addition, the temperature history of layers was significantly affected by the tool temperature and placement speed. The temperature of the layers decreased to near the tool temperature after cooling, and a higher tool temperature increasing its peak temperature because of the reduce of the cooling rate. On the contrary, an increase in placement speed will reduce the peak temperature of the layers.
{"title":"Simulation and on-line monitoring using optical fiber Bragg grating sensors of temperature history during laser-assisted automated fiber placement","authors":"Dacheng Zhao, Weiping Liu, Jiping Chen, Songhao Zhu, Yang Yang, Guangquan Yue","doi":"10.1177/00219983241259849","DOIUrl":"https://doi.org/10.1177/00219983241259849","url":null,"abstract":"Automated fiber placement (AFP) in situ consolidation (ISC) of thermoplastic composite possess the potential to reduce manufacturing costs and improve manufacturing efficiency. The properties of composite manufactured by the ISC are affected by several mechanisms including polymer degradation, crystallization, intimate contact, polymer healing and void dynamics. All these mechanisms are directly affected by the temperature history. Consequently, the control and accurate measurement of temperature history during ISC are particularly important for improving the properties of composite. In this study, a simplified three-dimensional transient heat transfer model was established. The effect of tool temperature and placement speed on the temperature history and peak temperature were predicted. Simultaneously, an online temperature monitoring system was built and the optical Fiber Bragg Grating sensors (FBGS) was used to measure the temperature history. The results indicated that the predicted results of the model were consistent with the measured results, the error was below 8%. In addition, the temperature history of layers was significantly affected by the tool temperature and placement speed. The temperature of the layers decreased to near the tool temperature after cooling, and a higher tool temperature increasing its peak temperature because of the reduce of the cooling rate. On the contrary, an increase in placement speed will reduce the peak temperature of the layers.","PeriodicalId":15489,"journal":{"name":"Journal of Composite Materials","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141196582","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 : 2024-05-31DOI: 10.1177/00219983241256334
Mohammad Javad Ramezani
This study examined the impact behavior of carbon/epoxy and glass/epoxy composite laminates with 2, 4, and 6 mm thicknesses under low-velocity tests. The investigation involved subjecting the composite laminates under small-impact loads using spherical, cylindrical, and conical steel projectiles, each weighing 3 g. The impacts conducted at 29.5, 36.5, and 51 m/s velocities. This investigation modeled using finite element (FE) methods and analytical approaches. In the analytical method, the mass and spring model used for the impact of small projectiles. The research findings revealed that, in 2 mm thick carbon/epoxy composite laminates, the maximum deflection at the mid-point induced by a spherical projectile was 1.37 mm. This value exhibited a 48.91% and 19.13% increase compared to impacts with cylindrical and conical projectiles, respectively. Additionally, a comprehensive examination of delamination across all samples indicated the maximum delamination occurrence in glass/epoxy samples, showcasing lower impact resistance than carbon/epoxy laminates. Notably, with an increase in thickness, the delamination phenomenon in the samples exhibited a decreasing trend. In addition, the maximum value of delamination in the composite laminates were with spherical, conical, and cylindrical projectiles respectively, and also, there was an excellent convergence between FE and analytical results.
{"title":"The investigation of deflection behavior in carbon/epoxy and glass/epoxy composite laminates under low-velocity impact with small projectiles","authors":"Mohammad Javad Ramezani","doi":"10.1177/00219983241256334","DOIUrl":"https://doi.org/10.1177/00219983241256334","url":null,"abstract":"This study examined the impact behavior of carbon/epoxy and glass/epoxy composite laminates with 2, 4, and 6 mm thicknesses under low-velocity tests. The investigation involved subjecting the composite laminates under small-impact loads using spherical, cylindrical, and conical steel projectiles, each weighing 3 g. The impacts conducted at 29.5, 36.5, and 51 m/s velocities. This investigation modeled using finite element (FE) methods and analytical approaches. In the analytical method, the mass and spring model used for the impact of small projectiles. The research findings revealed that, in 2 mm thick carbon/epoxy composite laminates, the maximum deflection at the mid-point induced by a spherical projectile was 1.37 mm. This value exhibited a 48.91% and 19.13% increase compared to impacts with cylindrical and conical projectiles, respectively. Additionally, a comprehensive examination of delamination across all samples indicated the maximum delamination occurrence in glass/epoxy samples, showcasing lower impact resistance than carbon/epoxy laminates. Notably, with an increase in thickness, the delamination phenomenon in the samples exhibited a decreasing trend. In addition, the maximum value of delamination in the composite laminates were with spherical, conical, and cylindrical projectiles respectively, and also, there was an excellent convergence between FE and analytical results.","PeriodicalId":15489,"journal":{"name":"Journal of Composite Materials","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141196564","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}
The use of hollow glass particle-filled fiber-reinforced composites for aircraft applications requires proper understanding of their behavior under in-service temperature conditions in order to exploit their usage in the exterior parts of aircraft and other space vehicles. In this study, the glass fiber reinforced composites containing 0–30 vol% of glass microspheres were subjected to testing for monotonic tensile and flexural loading from room temperature to the test temperature (40°C – 120°C). The evolution of microscopic damage under different temperatures was elucidated by digital image correlation (DIC) strain fields. The strain fields revealed a transition from homogeneous to non-homogeneous pattern as the temperature increases due to softening of the matrix. As the glass microsphere contents in the matrix increased, the tensile and flexural properties of the composites decreased, and their reduction was highest for the specimen containing a 30 vol% microsphere by volume. The tensile properties are slightly decreased by increasing the temperature. The tensile specimens tested at room temperature exhibited limited delamination and fiber pullout, while extensive delamination and fiber splitting occurred in the specimens tested at 120°C. The flexural results of the glass fiber reinforced composite specimens exposed at 120°C demonstrated a considerable decrease in flexural strength compared with room temperature for 0 vol%, 10 vol%, 20 vol% and 30 vol% glass microsphere volume fraction. Finally, the Weibull parametric investigation was performed to model the degradation of modulus for various GMS contents with temperature variations.
{"title":"Mechanical behavior of glass fiber-reinforced hollow glass particles filled epoxy composites under thermal loading","authors":"Anandakumar Paramasivam, Krishnan Kanny, Mohan Turup Pandurangan, Velmurugan Ramachandran","doi":"10.1177/00219983241259113","DOIUrl":"https://doi.org/10.1177/00219983241259113","url":null,"abstract":"The use of hollow glass particle-filled fiber-reinforced composites for aircraft applications requires proper understanding of their behavior under in-service temperature conditions in order to exploit their usage in the exterior parts of aircraft and other space vehicles. In this study, the glass fiber reinforced composites containing 0–30 vol% of glass microspheres were subjected to testing for monotonic tensile and flexural loading from room temperature to the test temperature (40°C – 120°C). The evolution of microscopic damage under different temperatures was elucidated by digital image correlation (DIC) strain fields. The strain fields revealed a transition from homogeneous to non-homogeneous pattern as the temperature increases due to softening of the matrix. As the glass microsphere contents in the matrix increased, the tensile and flexural properties of the composites decreased, and their reduction was highest for the specimen containing a 30 vol% microsphere by volume. The tensile properties are slightly decreased by increasing the temperature. The tensile specimens tested at room temperature exhibited limited delamination and fiber pullout, while extensive delamination and fiber splitting occurred in the specimens tested at 120°C. The flexural results of the glass fiber reinforced composite specimens exposed at 120°C demonstrated a considerable decrease in flexural strength compared with room temperature for 0 vol%, 10 vol%, 20 vol% and 30 vol% glass microsphere volume fraction. Finally, the Weibull parametric investigation was performed to model the degradation of modulus for various GMS contents with temperature variations.","PeriodicalId":15489,"journal":{"name":"Journal of Composite Materials","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141196639","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}
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