Polymer Composites最新文献

{"title":"Understanding the impact of different nanofillers on electrical, thermal, and surface properties of corona‐aged silicone rubber nanocomposites","authors":"N. Kavitha, J. Manoj Dhivakar, N. P. G. Bhavani, Ramanujam Sarathi, Stefan Kornhuber","doi":"10.1002/pc.29065","DOIUrl":"https://doi.org/10.1002/pc.29065","url":null,"abstract":"<jats:label/>In the present work, the impact of corona aging on the dielectric, thermal, and surface properties of silicone rubber filled with different nanofillers such as alumina (Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>), aluminum trihydrate (ATH), boron nitride (BN), and titania (TiO<jats:sub>2</jats:sub>) are studied. The surface degradation of the silicone rubber nanocomposites after corona aging is evaluated through contact angle measurement, atomic force microscopy (AFM) studies, and by water droplet‐initiated corona inception voltage studies. Alumina filled silicone rubber shows less reduction in surface and hydrophobic properties after corona aging. Water droplet initiated corona inception voltage (CIV) under negative DC voltage is much higher than under positive DC and AC voltages. Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>/TiO<jats:sub>2</jats:sub>‐ filled silicone rubber samples show better CIV performance. The Dielectric Response Spectroscopy (DRS) indicates that TiO<jats:sub>2</jats:sub> filled silicone rubber insulating material possesses higher permittivity at lower frequencies. Boron nitride added composites have high thermal conductivity whereas ATH filled silicone rubber composites shows higher decay rate, as observed through laser‐induced thermography studies. A significantly high surface leakage current is observed in all samples after corona aging. The Space Charge Limited Current (SCLC) studies clearly indicate that inclusion of nano‐fillers resulted in an increase in crossover voltage and trap density values compared to base silicone rubber.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> filled silicone rubber exhibits lower surface roughness even after corona aging.</jats:list-item> <jats:list-item>High thermal conductive composites show better performance even after corona aging.</jats:list-item> <jats:list-item>ATH, and BN filled silicone rubber have improved thermal conductivity by 35.2% and 76.3%.</jats:list-item> <jats:list-item>TiO<jats:sub>2</jats:sub> filler added silicone rubber exhibits high permittivity with low tan δ.</jats:list-item> <jats:list-item>Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> filled silicone rubber has minimal surface and volume leakage current</jats:list-item> <jats:list-item>Crossover voltage and the trap density get enhanced on addition of fillers to the base polymer.</jats:list-item> </jats:list>","PeriodicalId":20375,"journal":{"name":"Polymer Composites","volume":"66 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142254033","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}

{"title":"Investigation on damage behaviors of carbon fiber‐reinforced nylon 6 thermoplastic composite laminates using acoustic emission and digital image correlation techniques","authors":"Jixin Zhu, Kejun Hu, Wenqin Han, Qinghe Shi, Yingming Wang, Fengling Zhao, Fuxian Zhu","doi":"10.1002/pc.29063","DOIUrl":"https://doi.org/10.1002/pc.29063","url":null,"abstract":"<jats:label/>The objective of this paper is to analyze the mechanical properties and damage mechanisms of carbon fiber‐reinforced polyamide thermoplastic composite laminates. Four specimens with different ply orientations were designed for open‐hole tensile experiments, and interlaminar toughness experiments including double cantilever beam and end‐notched flexural were carried out. The experimental process was monitored synchronously using acoustic emission, and the strain field changes of the tensile specimens were captured using digital image correlation technology. The unsupervised clustering of the peak frequencies of the acoustic emission signals based on the K‐means++ algorithm was employed to ascertain the peak frequency ranges corresponding to the various damage modes. Typical signals from different specimens were selected, and the gray wolf algorithm was used to optimize the variational modal parameters to decompose the signals. The waveform characteristics, frequency components, and Hilbert spectra of each damage mode were given. The correlation analysis of the intrinsic mode function (IMF) components of the same damage in different specimens demonstrated that the IMF components exhibited high similarity. By analyzing the time series changes in the energy of each damage mode in different specimens, the contribution of different damage modes to the evolution of laminated plate damage was evaluated.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>The mechanical properties of CF/PA6 laminates were investigated based on open‐hole tensile specimens and pre‐cracked delamination specimens.</jats:list-item> <jats:list-item>Unsupervised clustering of AE peak frequencies using K‐means++ to establish the relationship between peak frequencies and damage patterns.</jats:list-item> <jats:list-item>AE counts and cumulative energy were used to assess damage evolution.</jats:list-item> <jats:list-item>By identifying a single damage signal and providing a more intuitive treatment of the damage energy evolution.</jats:list-item> </jats:list>","PeriodicalId":20375,"journal":{"name":"Polymer Composites","volume":"66 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253710","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}

{"title":"Hygrothermal aging effects on the mechanical behaviors of twill‐woven carbon fiber composite laminates with flame‐retardant epoxy resin","authors":"Jinru Zhong, Junwei Ma, Weikang Sun, Zuxiang Lei, Binbin Yin","doi":"10.1002/pc.29070","DOIUrl":"https://doi.org/10.1002/pc.29070","url":null,"abstract":"<jats:label/>Composite structures are frequently exposed to varying hygrothermal environments, which can lead to the deterioration of their mechanical properties. This study explores the effects of hygrothermal aging on the mechanical behaviors of twill‐woven carbon fiber composite laminates, with a particular focus on laminates with flame‐retardant epoxy resin (CF_FR)—a relatively underexplored area. The findings reveal several key insights: (1) CF_FR exhibit more pronounced aging damage compared to those with general epoxy resin (CF_G), primarily due to higher moisture absorption, which results in increased surface swelling and internal delamination. (2) Hygrothermal aging enhances the impact resistance of both types of laminates by increasing peak force, particularly at higher temperatures, thereby reducing impact‐induced damage. (3) CF_FR suffers greater reductions in compressive and compression after impact (CAI) strength following aging, with CAI strength decreasing by 36.3% for flame‐retardant laminates and 14.8% for CF_G after immersion at 70°C. (4) Significant local buckling is observed in the swollen regions of CF_FR under compressive loading, indicating an heightened vulnerability to structural instability after aging. These findings offer valuable insights into the performance of composite materials under prolonged moisture exposure, particularly in safety‐critical applications where both flame retardancy and mechanical integrity are crucial.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>More aging damage is captured from laminates with flame‐retardant epoxy resin</jats:list-item> <jats:list-item>Aging temperatures alleviate LVI induced damage and improve the peak force</jats:list-item> <jats:list-item>Compressive and CAI strength are affected after prolonged aging conditions</jats:list-item> <jats:list-item>CAI strength of CF_FR decreases by 36.3% after exposure to the 70°C water bath</jats:list-item> <jats:list-item>Significant local buckling is observed in CF_FR under compressive loading</jats:list-item> </jats:list>","PeriodicalId":20375,"journal":{"name":"Polymer Composites","volume":"6 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253705","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}

{"title":"Effect of fiber surface treatment with silane coupling agents and carbon nanotubes on mechanical properties of carbon fiber reinforced polyamide 6 composites","authors":"Haoqiang Du, Guijun Xian, Jingwei Tian, Zirong Ma, Chenggao Li, Meiyin Xin, Yunfeng Zhang","doi":"10.1002/pc.29035","DOIUrl":"https://doi.org/10.1002/pc.29035","url":null,"abstract":"<jats:label/>The mechanical properties of carbon fiber (CF) reinforced thermoplastic polymer composites are primarily governed by the interphase between CFs and matrix. However, the inherent inertness of CF surfaces combined with the high viscosity and processing temperatures of thermoplastic resin often result in relatively weak interfacial bonding. This study aims to enhance the interfacial adhesion of carbon fiber reinforced polyamide 6 composites to improve their mechanical properties. CFs were de‐sized and oxidized, followed by re‐sizing with silanized carbon nanotubes. Fracture morphology and composition analysis of the fibers were conducted, and the fibers were subsequently incorporated into composites for mechanical testing. Results revealed a 20.0% increase in tensile strength, a 25.11% increase in flexural strength, and a 24.88% increase in interlaminar shear strength for the resized‐carbon fiber reinforced polyamide 6 composites compared to the pristine‐carbon fiber reinforced polyamide composites. The cross‐sectional morphology of the modified composites exhibited a zig‐zag fracture pattern. Dynamic mechanical analysis indicated that the modified fibers required higher activation energy for the free movement of the polyamide 6 molecular chain. These findings suggest that surface treatment enhances the interfacial adhesive between CF and resin, thereby significantly improving the mechanical properties of carbon fiber reinforced polyamide 6 composites.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>An efficient and reliable carbon fiber surface treatment method is proposed.</jats:list-item> <jats:list-item>Surface modification improves surface chemical activity of carbon fibers.</jats:list-item> <jats:list-item>Composites show substantial improvements in mechanical properties.</jats:list-item> <jats:list-item>Interfacial performance enhancement mechanism of composite was revealed.</jats:list-item> </jats:list>","PeriodicalId":20375,"journal":{"name":"Polymer Composites","volume":"96 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214527","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}

{"title":"The effect of aging on the mechanical properties of bulk molding compound with different fiber lengths","authors":"Tsung‐Han Hsieh, Ting‐Yu Chang, Chih‐Chia Chen, Shang‐Nan Tsai","doi":"10.1002/pc.29067","DOIUrl":"https://doi.org/10.1002/pc.29067","url":null,"abstract":"<jats:label/>Bulk molding compound (BMC) manufactured using fiber reinforced polymers (FRPs) has attracted extensive attention and is widely used because of its capability to fabricate structures with complex shapes. This study investigated the effects of aging on the mechanical properties of BMC composites made using an epoxy matrix and discontinuous carbon fibers of varying lengths. Tensile, compressive, and flexural tests were conducted. The results showed that longer fibers did not necessarily increase the moduli and strengths of BMC composites due to stress concentrations resulting from the curling and entanglement of the longer fibers. When aged, BMC composites using shorter carbon fibers exhibited more significant reductions in moduli and strengths due to higher void contents, resulting in more severe matrix epoxy degradation. When comparing epoxy and BMC, BMC experienced greater reductions in moduli and strengths even though carbon fiber, a type of artificial fiber, should be less affected by aging. This is because aging not only degraded the matrix epoxy but also affected the adhesion between the fibers and the matrix, leading to a larger displacement of the fibers, resulting in a more severe reduction in the mechanical properties of the BMC composites.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>BMC composites were manufactured using epoxy and discontinuous carbon fibers.</jats:list-item> <jats:list-item>Longer fibers did not necessarily increase strengths due to entanglement.</jats:list-item> <jats:list-item>BMC using shorter fibers had more voids and hence degraded more severely.</jats:list-item> <jats:list-item>BMC showed greater strength reductions than epoxy due to matrix degradation.</jats:list-item> <jats:list-item>Degradation of matrix epoxy affected the adhesion between fibers and matrix.</jats:list-item> </jats:list>","PeriodicalId":20375,"journal":{"name":"Polymer Composites","volume":"26 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214528","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}

{"title":"3D‐printed graphene‐reinforced composites: Opportunities and challenges","authors":"R. Banupriya, T. P. Jeevan, H. V. Divya, T. G. Yashas Gowda, G. A. Manjunath","doi":"10.1002/pc.29068","DOIUrl":"https://doi.org/10.1002/pc.29068","url":null,"abstract":"3D printing, also known as additive manufacturing, is an innovative technology that allows for the construction of complex, three‐dimensional structures layer by layer using digital plans. This technology has transformed industries including as aerospace, automotive, healthcare, and consumer items by allowing for rapid prototyping, customization, and the manufacture of complex geometries. Graphene, a single layer of carbon atoms organized in a hexagonal lattice, is well‐known for its superior electrical and thermal conductivity, as well as its great tensile strength. When graphene is mixed with composite materials, it greatly improves their mechanical and functional properties, resulting in composites with higher strength, conductivity, lower weight, and greater durability. The combination of 3D printing and graphene‐reinforced composites creates new opportunities for the production of high‐performance, application‐specific structures. This review identifies key advancements in the synthesis, processing, and application of these composites, while also addressing critical challenges such as material dispersion, scalability, and the impact of graphene on the 3D printing process itself. A significant conclusion of this review is the recognition that overcoming these challenges is not only feasible but essential for harnessing the full potential of 3D‐printed graphene‐reinforced composites across diverse industrial sectors. The unique contribution of this work lies in providing a comprehensive roadmap for future research, guiding efforts to bridge current gaps and drive innovation in this emerging field.","PeriodicalId":20375,"journal":{"name":"Polymer Composites","volume":"5 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214558","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}

{"title":"Improved hydrolytic resistance of polylactide biocomposite films reinforced by rice husk before and after accelerated aging","authors":"Wei Wang, Guangchao Ye, Ying Zhang, Xiujie Bian, Peng Lin, Yuanyuan Dong, Pengfei Hao, Xiang Wang","doi":"10.1002/pc.29010","DOIUrl":"https://doi.org/10.1002/pc.29010","url":null,"abstract":"<jats:label/>The enhanced durability of biobased polylactide (PLA) is a critical prerequisite for it to be considered a viable alternative to petroleum‐based polymers for long‐term applications. Leveraging the performance improvements achieved through interface construction, PLA‐biomass composites have garnered considerable interest and have been widely utilized as a completely degradable material. The hydrolytic behavior of PLA biocomposites in photo‐hydrothermal environments was examined in this study in relation to the impact of biomass components and the specifically designed interface. We observed that biomass could act as an effective stabilizer in the composites, leading to a 25.6% reduction in the hydrolysis reaction rate constant. This stabilization occurs as biomass impedes the diffusion of water molecules and the extension of PLA molecular chains across various hydrothermal environments, thereby enhancing the hydrolytic resistance of PLA. The intriguing aspect is that this stabilizing effect of biomass could be moderated by an interface created through surface treatment, which facilitates enhanced transfer of active small molecules during the photolysis‐hydrolysis process. Consequently, this approach presents a novel method for producing PLA biocomposites that offers excellent hydrolytic resistance, an adjustable degradation cycle, and expected potential applications in advanced packaging and agricultural domains.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>Biomass significantly enhances the hydrolysis resistance of polylactide (PLA) biocomposites.</jats:list-item> <jats:list-item>This stability boosts due to the obstructive and shielding effects of biomass.</jats:list-item> <jats:list-item>Effective interface could regulate the usable life of PLA biocomposites.</jats:list-item> <jats:list-item>The role that biomass/ interfaces play also applies to PLA photodegradation.</jats:list-item> <jats:list-item>Photo‐hydrolysis mechanism is not affected by biomass or designed interface.</jats:list-item> </jats:list>","PeriodicalId":20375,"journal":{"name":"Polymer Composites","volume":"38 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214554","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}

{"title":"Multi‐scale elastic properties of 2.5D woven composites with void defects","authors":"Wang Wang, Zhongde Shan, Zheng Sun, Zitong Guo","doi":"10.1002/pc.29038","DOIUrl":"https://doi.org/10.1002/pc.29038","url":null,"abstract":"<jats:label/>2.5D woven composite material inevitably produces void defects in its production process, which will seriously reduce its mechanical properties and reduce its service life. In this paper, the effects of void defects on the mechanical properties of 2.5D woven composites were studied by multi‐scale analysis. An improved Halpin‐Tsai semi‐empirical model is proposed to calculate the elastic properties of yarns with porous defects and verified by finite element method. A microscale representative volume unit (RVE) for predicting the elastic constants of composites with pore defects is established. Theoretical analysis and finite element analysis were used to verify the micro scale, and finite element analysis and experiment were used to verify the micro scale. The effect of porosity on the elastic properties of micro‐scale RVE was studied in detail. The results show that the model is reasonable and accurate in predicting the mechanical properties of yarns and composites. In addition, the effect of porosity on the mechanical properties of 2.5D woven composites is significant.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>An improved Halpin‐Tsai semi‐empirical model is proposed, which makes the microscale theoretical analysis of 2.5D woven composites better consistent with the finite element analysis.</jats:list-item> <jats:list-item>The void position obstructs the stress transfer of the matrix, and the stress concentration phenomenon also occurs.</jats:list-item> <jats:list-item>The void content has an effect on the mechanical properties of composites at both micro and micro scales.</jats:list-item> </jats:list>","PeriodicalId":20375,"journal":{"name":"Polymer Composites","volume":"21 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214557","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}

{"title":"Manufacturing and characterization of continuous carbon fiber reinforced polyphenylene sulfide filaments via melt impregnation method","authors":"Gizem Sidim, Mustafa Dogu, Belma Ozbek","doi":"10.1002/pc.29021","DOIUrl":"https://doi.org/10.1002/pc.29021","url":null,"abstract":"<jats:label/>The utilization of continuous fiber‐reinforced thermoplastic composites (CFRTP) in additive manufacturing technology (AM) is envisioned to enable the production of high‐performance parts with enhanced mechanical properties. In the production of CFRTP filaments, ensuring proper impregnation plays a crucial role in improving the characteristics of the produced filament. Carbon fiber (CF) reinforced polyphenylene sulfide (PPS) composites find applications in secondary aerospace parts, automotive structural parts, and chemical process applications. Continuous CF‐reinforced PPS filaments enable the production of lightweight, high‐performance parts with mechanical strength, heat, and chemical resistance in AM. In the present study, continuous CF‐reinforced PPS filaments were produced using the melt impregnation method for use in fused deposition modeling technology. Filament diameter, geometrical evenness, and effective fiber impregnation are important criteria in filament production. An impregnation mold was designed and manufactured to provide impregnation. The influence of three different pin angles (56°, 70°, and 82°) on impregnation and mechanical properties has been investigated by developing an impregnation die for CFRTP filament production. Tensile testing, fiber content analysis, optical microscopy, and scanning electron microscope analysis were performed on the produced filaments. Furthermore, increasing the pin angle leads to an increase in both the spreading and impregnation of fibers.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>Impregnation die for effective wetting of fibers with polymer.</jats:list-item> <jats:list-item>Significance of pin angle in fiber spreading and wetting with polymer.</jats:list-item> <jats:list-item>Application of test standards for fiber content.</jats:list-item> </jats:list>","PeriodicalId":20375,"journal":{"name":"Polymer Composites","volume":"2 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214555","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}

{"title":"A review on the ductility design method of fiber‐reinforced polymer bar and future prospects","authors":"Yunbo Xu, Yu Zhang, Haitang Zhu, Danying Gao, Daotian Qin, Liangping Zhao","doi":"10.1002/pc.29036","DOIUrl":"https://doi.org/10.1002/pc.29036","url":null,"abstract":"<jats:label/>In this paper, the ductility design methods of fiber‐reinforced polymer (FRP) bars were reviewed. It was observed that the graded fracture theory was typically used as the ductility design method of hybrid fiber‐reinforced polymer (HFRP) bar. However, the ductile HFRP bar designed based on the graded fracture theory had the inherent defects of low modulus of elasticity, high yield strain, and post‐yielded sudden drop in stress, which prevented its large‐scale application in civil engineering. In order to eliminate these deficiencies, the authors proposed a novel design concept for a single‐type FRP bar. This novel single‐type FRP bar consisted of highly aligned discontinuous fiber and continuous fiber. The failure mode of this discontinuous/continuous single‐type FRP bar was different from that of the ductile HFRP bar designed based on the graded fracture theory of composite. The tensile ductility of discontinuous/continuous single‐type FRP bar originated from the debonding and stable pull‐out of the discontinuous fiber layer under increasing load. As a result, the post‐yielded sudden drop in stress can be removed for the ductile HFRP bar designed based on the graded fracture theory of composite. In addition, the yield strain can be controlled by adjusting the length of discontinuous fiber layer. In addition, the design configuration, innovative production process, and corresponding theoretical calculations of this novel single‐type FRP bar will be presented in the future.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>The ductility design methods of fiber‐reinforced polymer bars were reviewed.</jats:list-item> <jats:list-item>Deficiencies of ductile HFRP bar composed of continuous fibers were reported.</jats:list-item> <jats:list-item>A novel discontinuous/continuous single‐type FRP bar was foreseen.</jats:list-item> </jats:list>","PeriodicalId":20375,"journal":{"name":"Polymer Composites","volume":"20 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214559","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}