Pub Date : 2025-02-17DOI: 10.1016/j.compositesa.2025.108773
D. Thomson , M. Ploeckl , J. Hoffmann , M. Lißner , C. Pohl , G. Quino , K. Ramakrishnan , M. Toenjes , H. Cui , N. Petrinic
A comprehensive literature review on the rate dependency of unidirectional CFRP composites has been carried out. Starting with the micro-scale constituents, literature data on the effect of loading rate on stiffness, strength, and fracture properties have been compared. While carbon fibres showed no significant rate effects, the rate dependency of the strength and stiffness properties was found consistent across various polymer matrix materials. In contrast, there was a general lack of consensus on the rate dependency of the matrix fracture properties.
At the macroscopic scale, the rate effects on the composite strength and stiffness properties were found to remain consistent across different combinations of constituent materials, while conflicting reports have been found on the rate dependency of the fracture properties. Finally, it has been shown that the rate dependency of composite strength and stiffness properties can be related to the constituent properties through established homogenisation theories and failure criteria.
{"title":"A review of the effect of loading rate on the mechanical properties of unidirectional carbon fibre reinforced polymer composites","authors":"D. Thomson , M. Ploeckl , J. Hoffmann , M. Lißner , C. Pohl , G. Quino , K. Ramakrishnan , M. Toenjes , H. Cui , N. Petrinic","doi":"10.1016/j.compositesa.2025.108773","DOIUrl":"10.1016/j.compositesa.2025.108773","url":null,"abstract":"<div><div>A comprehensive literature review on the rate dependency of unidirectional CFRP composites has been carried out. Starting with the micro-scale constituents, literature data on the effect of loading rate on stiffness, strength, and fracture properties have been compared. While carbon fibres showed no significant rate effects, the rate dependency of the strength and stiffness properties was found consistent across various polymer matrix materials. In contrast, there was a general lack of consensus on the rate dependency of the matrix fracture properties.</div><div>At the macroscopic scale, the rate effects on the composite strength and stiffness properties were found to remain consistent across different combinations of constituent materials, while conflicting reports have been found on the rate dependency of the fracture properties. Finally, it has been shown that the rate dependency of composite strength and stiffness properties can be related to the constituent properties through established homogenisation theories and failure criteria.</div></div>","PeriodicalId":282,"journal":{"name":"Composites Part A: Applied Science and Manufacturing","volume":"193 ","pages":"Article 108773"},"PeriodicalIF":8.1,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143520269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-16DOI: 10.1016/j.compositesa.2025.108809
Mohsen Barmouz , Bahman Azarhoushang
To tackle the challenge of high shrinkage in sintered additively manufactured parts, a novel approach involving the modification of the printing composition through the incorporation of glass fibers was proposed. Experimental evaluations demonstrated the effectiveness of this method, revealing a substantial improvement in the dimensional and geometrical accuracy of the fabricated parts. By incorporating 12 % short glass fibers into the composition, the shrinkage was significantly reduced, achieving an impressive 0.1 %.
{"title":"A novel method based on composite alteration to reduce the shrinkage of the sintering process of additively manufactured parts","authors":"Mohsen Barmouz , Bahman Azarhoushang","doi":"10.1016/j.compositesa.2025.108809","DOIUrl":"10.1016/j.compositesa.2025.108809","url":null,"abstract":"<div><div>To tackle the challenge of high shrinkage in sintered additively manufactured parts, a novel approach involving the modification of the printing composition through the incorporation of glass fibers was proposed. Experimental evaluations demonstrated the effectiveness of this method, revealing a substantial improvement in the dimensional and geometrical accuracy of the fabricated parts. By incorporating 12 % short glass fibers into the composition, the shrinkage was significantly reduced, achieving an impressive 0.1 %.</div></div>","PeriodicalId":282,"journal":{"name":"Composites Part A: Applied Science and Manufacturing","volume":"192 ","pages":"Article 108809"},"PeriodicalIF":8.1,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-16DOI: 10.1016/j.compositesa.2025.108808
Abins Aziz, T. Jihad Thashreef, Bijily Balakrishnan, Shihabudheen M. Maliyekkal
The study demonstrates the development of a novel and sustainable sizing agent to improve the mechanical properties and compatibility of E-glass fibers (EGF) in cement composites. The sizing agent comprises chitosan (a biopolymer), graphene oxide and a calcium precursor. The graphene oxide and calcium ions help reinforce and crosslink chitosan fibers, enhancing the composite’s mechanical strength and bonding with the cement matrix. The tensile strength and the fracture strain of modified EGFs increased by 1.47 and 1.52 times, respectively. Due to the high deformation capability of the composite, the study revealed that the coating remains intact until the glass fiber fractures. Digital image correlation measurements on GFRC specimens confirm a strong bond between the coating and concrete matrix. The XPS and ATR-IR spectroscopy analyses confirm the interaction between surface-modified EGFs and cement matrix. The nanocomposite offers a sustainable alternative to conventional sizing employed in EGFs for GFRC applications.
{"title":"Calcium-reinforced graphene oxide-biopolymer nanocomposite: A novel and sustainable sizing agent for enhancing E-glass fibers strength and adhesion in cement composites","authors":"Abins Aziz, T. Jihad Thashreef, Bijily Balakrishnan, Shihabudheen M. Maliyekkal","doi":"10.1016/j.compositesa.2025.108808","DOIUrl":"10.1016/j.compositesa.2025.108808","url":null,"abstract":"<div><div>The study demonstrates the development of a novel and sustainable sizing agent to improve the mechanical properties and compatibility of E-glass fibers (EGF) in cement composites. The sizing agent comprises chitosan (a biopolymer), graphene oxide and a calcium precursor. The graphene oxide and calcium ions help reinforce and crosslink chitosan fibers, enhancing the composite’s mechanical strength and bonding with the cement matrix. The tensile strength and the fracture strain of modified EGFs increased by 1.47 and 1.52 times, respectively. Due to the high deformation capability of the composite, the study revealed that the coating remains intact until the glass fiber fractures. Digital image correlation measurements on GFRC specimens confirm a strong bond between the coating and concrete matrix. The XPS and ATR-IR spectroscopy analyses confirm the interaction between surface-modified EGFs and cement matrix. The nanocomposite offers a sustainable alternative to conventional sizing employed in EGFs for GFRC applications.</div></div>","PeriodicalId":282,"journal":{"name":"Composites Part A: Applied Science and Manufacturing","volume":"192 ","pages":"Article 108808"},"PeriodicalIF":8.1,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143463291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-02-15DOI: 10.1016/j.compositesa.2025.108807
Yajing Wang , Xiuchen Wang , Miaomiao Kang , Zhihui Zhang , Yichen Yang , Wei Zeng , Zhe Liu
Graphene has attracted attention in the field of electromagnetic stealth due to its excellent electrical properties. In this work, we first describe how microwave absorption properties can be enhanced by using graphene to construct heterogeneous interfaces and structural defects through conventional composite preparation methods. Meanwhile, the infrared stealth performance is discussed by tuning the charge density and Fermi energy levels of graphene as well as by constructing three-dimensional porous structures. Then, the current state of research on microwave and infrared stealth based on metamaterials and metasurface structure design strategies is reviewed. In addition, the research progress of radar-infrared compatible stealth technology using three strategies of material composite, metamaterial and metasurface structure design is summarized. Finally, the advantages and limitations of graphene-based stealth materials prepared using different strategies are analyzed, as well as the current challenges.
{"title":"Recent advances in graphene-based materials for radar and infrared stealth application","authors":"Yajing Wang , Xiuchen Wang , Miaomiao Kang , Zhihui Zhang , Yichen Yang , Wei Zeng , Zhe Liu","doi":"10.1016/j.compositesa.2025.108807","DOIUrl":"10.1016/j.compositesa.2025.108807","url":null,"abstract":"<div><div>Graphene has attracted attention in the field of electromagnetic stealth due to its excellent electrical properties. In this work, we first describe how microwave absorption properties can be enhanced by using graphene to construct heterogeneous interfaces and structural defects through conventional composite preparation methods. Meanwhile, the infrared stealth performance is discussed by tuning the charge density and Fermi energy levels of graphene as well as by constructing three-dimensional porous structures. Then, the current state of research on microwave and infrared stealth based on metamaterials and metasurface structure design strategies is reviewed. In addition, the research progress of radar-infrared compatible stealth technology using three strategies of material composite, metamaterial and metasurface structure design is summarized. Finally, the advantages and limitations of graphene-based stealth materials prepared using different strategies are analyzed, as well as the current challenges.</div></div>","PeriodicalId":282,"journal":{"name":"Composites Part A: Applied Science and Manufacturing","volume":"192 ","pages":"Article 108807"},"PeriodicalIF":8.1,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143428137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-02-14DOI: 10.1016/j.compositesa.2025.108796
Vivek Richards Pakkam Gabriel , Patrik Fernberg , Janis Varna
The effect of test temperature, maximum stress, and stress-ratio on transverse cracking development in cross-ply laminates subjected to tension–tension cyclic loading was analysed. A two-parameter Weibull distribution model was used to predict transverse cracking, wherein the Weibull scale parameter was assumed to be test temperature and number of cycles dependent. By introducing an equivalent stress in the model, it was possible to account for the effect of the stress ratio in cyclic loading over a range of different loading conditions. To verify the model, tests on temperature resistant cross-ply composites were performed at room temperature and at 150 °C with different stress levels and local 90-layer stress ratios. For both test temperatures, increase in stress level increased the transverse cracking tendency. At 150 °C, despite the lower maximum thermo-mechanical ply-stress level compared to room temperature, transverse cracking tendency was found to be higher.
分析了试验温度、最大应力和应力比对承受拉伸循环载荷的交叉层压板横向裂纹发展的影响。采用双参数 Weibull 分布模型预测横向开裂，其中假设 Weibull 比例参数与试验温度和循环次数有关。通过在模型中引入等效应力，可以在一系列不同的加载条件下考虑循环加载中应力比的影响。为了验证该模型，我们在室温和 150 ° C 条件下，以不同的应力水平和局部 90 层应力比对耐温交叉层复合材料进行了测试。在这两种试验温度下，应力水平的增加都会加剧横向开裂趋势。在 150 °C 时，尽管层间最大热机械应力水平低于室温，但横向开裂趋势却更高。
{"title":"Transverse cracking in non-crimp fabric cross-ply laminate under tension–tension cyclic loading at room and elevated temperature","authors":"Vivek Richards Pakkam Gabriel , Patrik Fernberg , Janis Varna","doi":"10.1016/j.compositesa.2025.108796","DOIUrl":"10.1016/j.compositesa.2025.108796","url":null,"abstract":"<div><div>The effect of test temperature, maximum stress, and stress-ratio on transverse cracking development in cross-ply laminates subjected to tension–tension cyclic loading was analysed. A two-parameter Weibull distribution model was used to predict transverse cracking, wherein the Weibull scale parameter was assumed to be test temperature and number of cycles dependent. By introducing an equivalent stress in the model, it was possible to account for the effect of the stress ratio in cyclic loading over a range of different loading conditions. To verify the model, tests on temperature resistant cross-ply composites were performed at room temperature and at 150 °C with different stress levels and local 90-layer stress ratios. For both test temperatures, increase in stress level increased the transverse cracking tendency. At 150 °C, despite the lower maximum thermo-mechanical ply-stress level compared to room temperature, transverse cracking tendency was found to be higher.</div></div>","PeriodicalId":282,"journal":{"name":"Composites Part A: Applied Science and Manufacturing","volume":"192 ","pages":"Article 108796"},"PeriodicalIF":8.1,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper introduces a novel inverse design framework that combines a convolutional neural network (CNN) surrogate for the phase field fracture model with a differentiable simulator to optimize two-phase composite microstructures. The CNN surrogate accurately predicts the damage-influenced stress fields from the composite microstructure images, whereas the simulator generates these images given the composite material design parameters, preserving crucial gradient information. This integration enables efficient optimization of microstructure designs through gradient descent-based methods. We demonstrate that our framework can significantly enhance the uniaxial tensile strength of microstructures beyond the limits of the training set. Interestingly, the optimized fiber arrangements for unidirectional and bidirectional strength match with common human-designed (hexagonal and diamond) arrangements. The application of the framework to microstructures with a pre-existing crack highlights its practical viability for targeted material design, where a small amount of second-phase material can be included for significant gains in tensile strength.
{"title":"An inverse design framework for optimizing tensile strength of composite materials based on a CNN surrogate for the phase field fracture model","authors":"Yuxiang Gao , Ravindra Duddu , Soheil Kolouri , Abhinav Gupta , Pavana Prabhakar","doi":"10.1016/j.compositesa.2025.108758","DOIUrl":"10.1016/j.compositesa.2025.108758","url":null,"abstract":"<div><div>This paper introduces a novel inverse design framework that combines a convolutional neural network (CNN) surrogate for the phase field fracture model with a differentiable simulator to optimize two-phase composite microstructures. The CNN surrogate accurately predicts the damage-influenced stress fields from the composite microstructure images, whereas the simulator generates these images given the composite material design parameters, preserving crucial gradient information. This integration enables efficient optimization of microstructure designs through gradient descent-based methods. We demonstrate that our framework can significantly enhance the uniaxial tensile strength of microstructures beyond the limits of the training set. Interestingly, the optimized fiber arrangements for unidirectional and bidirectional strength match with common human-designed (hexagonal and diamond) arrangements. The application of the framework to microstructures with a pre-existing crack highlights its practical viability for targeted material design, where a small amount of second-phase material can be included for significant gains in tensile strength.</div></div>","PeriodicalId":282,"journal":{"name":"Composites Part A: Applied Science and Manufacturing","volume":"192 ","pages":"Article 108758"},"PeriodicalIF":8.1,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143421130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-13DOI: 10.1016/j.compositesa.2025.108805
Mohammad Rouhi Moghanlou, Elaheh Azizian-Farsani, Ali Mahmoudi, Michael M Khonsari
A thermodynamic approach for accelerated fatigue characterization of additively manufactured continuous carbon fiber (CCF)-reinforced thermoplastics produced via fused filament fabrication (FFF) is presented. Specifically, we applied the concept of fracture fatigue entropy (FFE) to run-stop-cooldown (RSC) cyclic tests to efficiently predict fatigue life across both low- and high-cycle regions (104 – 107 cycles) while minimizing experimental workload. Results are presented for two fiber orientations: unidirectional (0°) and [0°/90°/±45°]s specimens. Elastic properties are established via tensile tests, and RSC tests are performed to assess the cyclic plastic strain energy and its associated temperature variations via thermographic measurements, leading to fatigue limit prediction. Through extensive tension–tension fatigue test accounting for internal friction, the study revealed average FFE values of 3.10 MJ/m3K and 3.67 MJ/m3K for 0° and [0°/90°/±45°]s specimens, respectively. These values are valid for low- and high-cycle fatigue regimes. A comparison between the experimental results and analytical predictions confirmed FFE’s capability for S-N curve prediction while highlighting the significant role of fiber orientation in cyclic response. Additionally, the steady-state temperature rise (ΔTss) was found to be significantly affected by fiber orientation, ranging from 0.3 °C in unidirectional to 14.6 °C in multidirectional specimens under the same applied load.
{"title":"Accelerated fatigue characterization of additively manufactured continuous carbon fiber reinforced thermoplastic: A thermodynamic approach","authors":"Mohammad Rouhi Moghanlou, Elaheh Azizian-Farsani, Ali Mahmoudi, Michael M Khonsari","doi":"10.1016/j.compositesa.2025.108805","DOIUrl":"10.1016/j.compositesa.2025.108805","url":null,"abstract":"<div><div>A thermodynamic approach for accelerated fatigue characterization of additively manufactured continuous carbon fiber (CCF)-reinforced thermoplastics produced via fused filament fabrication (FFF) is presented. Specifically, we applied the concept of fracture fatigue entropy (FFE) to run-stop-cooldown (RSC) cyclic tests to efficiently predict fatigue life across both low- and high-cycle regions (10<sup>4</sup> – 10<sup>7</sup> cycles) while minimizing experimental workload. Results are presented for two fiber orientations: unidirectional (0°) and [0°/90°/±45°]<sub>s</sub> specimens. Elastic properties are established via tensile tests, and RSC tests are performed to assess the cyclic plastic strain energy and its associated temperature variations via thermographic measurements, leading to fatigue limit prediction. Through extensive tension–tension fatigue test accounting for internal friction, the study revealed average FFE values of 3.10 MJ/m<sup>3</sup>K and 3.67 MJ/m<sup>3</sup>K for 0° and [0°/90°/±45°]<sub>s</sub> specimens, respectively. These values are valid for low- and high-cycle fatigue regimes. A comparison between the experimental results and analytical predictions confirmed FFE’s capability for S-N curve prediction while highlighting the significant role of fiber orientation in cyclic response. Additionally, the steady-state temperature rise (Δ<em>T<sub>ss</sub></em>) was found to be significantly affected by fiber orientation, ranging from 0.3 °C in unidirectional to 14.6 °C in multidirectional specimens under the same applied load.</div></div>","PeriodicalId":282,"journal":{"name":"Composites Part A: Applied Science and Manufacturing","volume":"192 ","pages":"Article 108805"},"PeriodicalIF":8.1,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143428138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-02-13DOI: 10.1016/j.compositesa.2025.108804
Ellen L. Heeley , Neil Reynolds , William Hamby , Catherine A. Kelly , Michael J. Jenkins , Darren J. Hughes
The effect of manufacturing conditions on the morphology of an industrially-processed 11-ply polyamide/glass fibre (PA66-GF60) laminate was investigated. Through-thickness temperature variation during the manufacturing process (pre-heating, stamp forming, demoulding) was revealed via eight inter-ply thermocouples. Thermal and X-ray analysis provided insights into process-induced polymer crystallinity and morphology through the laminate thickness. Cooling rates up to ∼ 2100 °C/min were observed in outer plies, compared to ∼ 420 °C/min for inner plies. A self-heating exothermal phenomenon was observed during crystallisation of the inner layers, leading to increased core crystallinity. X-ray diffraction revealed differences in preferred polymer orientation between the plies. For the inner plies, additional mobility from slower cooling leads to partially oriented crystallites along the glass fibre axis and a well-developed lamellar macromorphology. The rapidly cooled outer plies showed unoriented morphology, without long-range ordering. The work provides detailed understanding of polymer morphology for an industrially-relevant high-volume manufacturing process for thermoplastic matrix components.
{"title":"Effect of manufacturing conditions on morphology development in rapid stamp formed polyamide/glass fibre composite laminate components","authors":"Ellen L. Heeley , Neil Reynolds , William Hamby , Catherine A. Kelly , Michael J. Jenkins , Darren J. Hughes","doi":"10.1016/j.compositesa.2025.108804","DOIUrl":"10.1016/j.compositesa.2025.108804","url":null,"abstract":"<div><div>The effect of manufacturing conditions on the morphology of an industrially-processed 11-ply polyamide/glass fibre (PA66-GF60) laminate was investigated. Through-thickness temperature variation during the manufacturing process (pre-heating, stamp forming, demoulding) was revealed via eight inter-ply thermocouples. Thermal and X-ray analysis provided insights into process-induced polymer crystallinity and morphology through the laminate thickness. Cooling rates up to ∼ 2100 °C/min were observed in outer plies, compared to ∼ 420 °C/min for inner plies. A self-heating exothermal phenomenon was observed during crystallisation of the inner layers, leading to increased core crystallinity. X-ray diffraction revealed differences in preferred polymer orientation between the plies. For the inner plies, additional mobility from slower cooling leads to partially oriented crystallites along the glass fibre axis and a well-developed lamellar macromorphology. The rapidly cooled outer plies showed unoriented morphology, without long-range ordering. The work provides detailed understanding of polymer morphology for an industrially-relevant high-volume manufacturing process for thermoplastic matrix components.</div></div>","PeriodicalId":282,"journal":{"name":"Composites Part A: Applied Science and Manufacturing","volume":"192 ","pages":"Article 108804"},"PeriodicalIF":8.1,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143428136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-12DOI: 10.1016/j.compositesa.2025.108799
Jiaming Liu , Dong Quan , Jiaying Pan , Xuemin Wang , Xi Yang , Guoqun Zhao
Encouraging advancement in the ultrasonic welding of thermoset composites (TSCs) was recently achieved by co-curing weldable thermoplastic coupling layers (CLs) onto their surfaces. However, obvious temperature inhomogeneity at the welding interface easily leads to thermally decomposition of epoxy matrix and irreparable defects in the welds. This study proposed a strategy for producing high-quality ultrasonically-welded TSC joints by utilizing novel-structured thermoplastic meshes as energy directors (EDs). Compared to prevalent film EDs, the usage of mesh EDs significantly promoted the heat generation efficiency and temperature distribution uniformity at welding interfaces. The maximum temperature of TSCs reached during welding processes decreased from 373.7 °C to 216.7 °C with reduced welding time by 32.4 %. These phenomena effectively prevented thermally decomposed epoxy matrix, and resulted in high-quality welding lines with remarkable lap-shear strength, i.e. reaching a maximum value of 31.1 MPa. Overall, this study presents a promising strategy for developing robust TSC joints by tailoring ED structures.
{"title":"High-efficiency ultrasonic welding of CF/epoxy joints with enhanced strength upon tailoring the energy director structure","authors":"Jiaming Liu , Dong Quan , Jiaying Pan , Xuemin Wang , Xi Yang , Guoqun Zhao","doi":"10.1016/j.compositesa.2025.108799","DOIUrl":"10.1016/j.compositesa.2025.108799","url":null,"abstract":"<div><div>Encouraging advancement in the ultrasonic welding of thermoset composites (TSCs) was recently achieved by co-curing weldable thermoplastic coupling layers (CLs) onto their surfaces. However, obvious temperature inhomogeneity at the welding interface easily leads to thermally decomposition of epoxy matrix and irreparable defects in the welds. This study proposed a strategy for producing high-quality ultrasonically-welded TSC joints by utilizing novel-structured thermoplastic meshes as energy directors (EDs). Compared to prevalent film EDs, the usage of mesh EDs significantly promoted the heat generation efficiency and temperature distribution uniformity at welding interfaces. The maximum temperature of TSCs reached during welding processes decreased from 373.7 °C to 216.7 °C with reduced welding time by 32.4 %. These phenomena effectively prevented thermally decomposed epoxy matrix, and resulted in high-quality welding lines with remarkable lap-shear strength, i.e. reaching a maximum value of 31.1 MPa. Overall, this study presents a promising strategy for developing robust TSC joints by tailoring ED structures.</div></div>","PeriodicalId":282,"journal":{"name":"Composites Part A: Applied Science and Manufacturing","volume":"192 ","pages":"Article 108799"},"PeriodicalIF":8.1,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143421131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-02-12DOI: 10.1016/j.compositesa.2025.108802
Miracle Hope Adegun , Kit-Ying Chan , Heng Zhang , Yunfei Yang , Xiaomeng Zhao , Xuili Dong , Xi Shen , Jinglei Yang , Jang-Kyo Kim
High interfacial thermal resistance (ITR) between thermally conductive nanofillers and polymer matrix, and lack of good orientation of nanofillers are primary limiting factors in harnessing their inherent thermal conductivity in polymer nanocomposites. Thus, exploiting ultrahigh thermal conductivities of nanofillers involves developing methods or mechanisms that can minimize the ITR. In this work, boron nitride nanosheets (BNNS)/polyvinyl alcohol (PVA) nanocomposite films with segregation-induced interconnection among BNNS are fabricated by a sequential unidirection freeze-casting (UFC) technique. A PVA aerogel is first made by UFC followed by infiltrating functionalized BNNS into its pores and microchannels which is subjected to a second UFC process. The composite aerogel is subsequently hot pressed to compact the available pore channels for reduced ITR arising from better contact between the segregated BNNS cell walls. The resulting segregated BNNS/PVA (SBP) nanocomposite film with 40 wt% BNNS exhibits high thermal conductivity of 5.2 W/mK, which is about 267 % higher than the nanocomposite film containing dispersed BNNS made by conventional UFC. The SBP film also possessed high electrical insulation characteristics and a very low dielectric loss of at a frequency of 1 kHz, properties arising directly from the segregated BNNS. The sequential UFC provides an effective method to incorporate aligned and interconnected BNNS through segregation for enhanced thermal conductivity and electrical resistivity for thermal management in microelectronics and integrated circuits.
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