Pub Date : 2024-09-16DOI: 10.1016/j.compstruct.2024.118567
Ballistic protection extensively employs curved ultra-high-molecular-weight polyethylene (UHMWPE) laminates to conform to protective targets. However, ballistic tests have indicated that the curvature of laminates increases back-face deformation, diminishing ballistic performance, while the mechanism behind this curvature effect on back-face deformation remains unclear. In this paper, the back-face deformation of curved UHMWPE laminates, including apex displacement and the boundary of the deformation region, are systematically studied through numerical simulation and theoretical analysis. Firstly, a numerical model of curved UHMWPE laminates under the high-speed impact is established. The numerical results indicate that as the curvature increases, the deformation region becomes more concentrated, resulting in a larger apex displacement. Secondly, as the curvature increases from zero, the deformation mode of curved laminates changes from membrane stretching dominated to a combination of membrane stretching and bending. Finally, considering the change in the deformation mode, a theoretical analysis for the propagation of bending waves in an orthotropic curved plate is conducted to reveal the relationship between curvature and back-face deformation. The theoretical analysis shows that increasing curvature slows bending wave speed, reducing in-plane deformation region movement, thus increasing apex displacement. This study is expected to help design curved UHMWPE laminates with better ballistic performance.
{"title":"Analyzing the back-face deformation of curved UHMWPE composite laminate under high-speed impact","authors":"","doi":"10.1016/j.compstruct.2024.118567","DOIUrl":"10.1016/j.compstruct.2024.118567","url":null,"abstract":"<div><p>Ballistic protection extensively employs curved ultra-high-molecular-weight polyethylene (UHMWPE) laminates to conform to protective targets. However, ballistic tests have indicated that the curvature of laminates increases back-face deformation, diminishing ballistic performance, while the mechanism behind this curvature effect on back-face deformation remains unclear. In this paper, the back-face deformation of curved UHMWPE laminates, including apex displacement and the boundary of the deformation region, are systematically studied through numerical simulation and theoretical analysis. Firstly, a numerical model of curved UHMWPE laminates under the high-speed impact is established. The numerical results indicate that as the curvature increases, the deformation region becomes more concentrated, resulting in a larger apex displacement. Secondly, as the curvature increases from zero, the deformation mode of curved laminates changes from membrane stretching dominated to a combination of membrane stretching and bending. Finally, considering the change in the deformation mode, a theoretical analysis for the propagation of bending waves in an orthotropic curved plate is conducted to reveal the relationship between curvature and back-face deformation. The theoretical analysis shows that increasing curvature slows bending wave speed, reducing in-plane deformation region movement, thus increasing apex displacement. This study is expected to help design curved UHMWPE laminates with better ballistic performance.</p></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0263822324006950/pdfft?md5=b1c4a9c6975ba974aa03c28568cf61f8&pid=1-s2.0-S0263822324006950-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142271840","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 : 2024-09-16DOI: 10.1016/j.compstruct.2024.118586
A homogenized constitutive model for the compressible multi-layer structure of battery (CMLSB) under external loading is essential for optimizing the structural design of electric assemblies. Currently, there is no specific constitutive model that is both mechanically explanatory and operationally applicable to CMLSB under varied loading conditions. In this study, due to limited understanding of the in-plane behavior of CMLSB, an analytical model was developed to investigate plasticity in this specific direction using the strain probing method. The observed plastic characteristics inspired the formulation of a novel two-dimensional constitutive framework for CMLSB in the in-plane direction.
By integrating this new constitutive framework with one-dimensional plastic descriptions, a hybrid constitutive model was introduced and implemented in finite element software. Calibration and validation of the model were performed using a commercial pouch cell battery and its segments under various loading conditions. Finite element simulations with the hybrid model demonstrated remarkable accuracy in predicting the mechanical behavior of the cell under various in-plane and out-of-plane compression scenarios. Additionally, simulations were carried out to analyze the impact of cell packaging and air pressure. The new hybrid battery model is considered a user-friendly, physically interpretable, and high-fidelity tool, poised to significantly facilitate the comprehensive design of electric devices.
{"title":"Plasticity analysis and a homogenized constitutive model of compressible multi-layer structure of battery","authors":"","doi":"10.1016/j.compstruct.2024.118586","DOIUrl":"10.1016/j.compstruct.2024.118586","url":null,"abstract":"<div><p>A homogenized constitutive model for the compressible multi-layer structure of battery (CMLSB) under external loading is essential for optimizing the structural design of electric assemblies. Currently, there is no specific constitutive model that is both mechanically explanatory and operationally applicable to CMLSB under varied loading conditions. In this study, due to limited understanding of the in-plane behavior of CMLSB, an analytical model was developed to investigate plasticity in this specific direction using the strain probing method. The observed plastic characteristics inspired the formulation of a novel two-dimensional constitutive framework for CMLSB in the in-plane direction.</p><p>By integrating this new constitutive framework with one-dimensional plastic descriptions, a hybrid constitutive model was introduced and implemented in finite element software. Calibration and validation of the model were performed using a commercial pouch cell battery and its segments under various loading conditions. Finite element simulations with the hybrid model demonstrated remarkable accuracy in predicting the mechanical behavior of the cell under various in-plane and out-of-plane compression scenarios. Additionally, simulations were carried out to analyze the impact of cell packaging and air pressure. The new hybrid battery model is considered a user-friendly, physically interpretable, and high-fidelity tool, poised to significantly facilitate the comprehensive design of electric devices.</p></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0263822324007141/pdfft?md5=45fdddd00f68428507367042fccb4f8c&pid=1-s2.0-S0263822324007141-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142272520","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 : 2024-09-16DOI: 10.1016/j.compstruct.2024.118564
This paper addresses reduced order homogenization of composites with strength difference (SD) effects in elastoplasticity coupled to damage, while containing several well-known plasticity criteria as special cases. We extend two approaches for this purpose: 1. nonuniform transformation field analysis (NTFA by Michel and Suquet, 2003) and 2. a recent variant called cluster-based NTFA (CNTFA by Ri et al., 2021), and conduct a comparative study on them. For the NTFA approach, a space–time decomposition is done separately for volumetric and deviatoric inelastic strain fields. A coupled model is derived for the present case to govern the evolution of resulting reduced variables. For the CNTFA approach, a clustering analysis is additionally performed for a spatial decomposition of the micro-domain. Unlike the NTFA, the online analysis is formulated as a unified minimization problem, which does not require a major adaptation for the present case. For both approaches, localization rules are deduced from the superposition principle and then homogenized to obtain the effective responses. FE-based implementation is presented in detail for both approaches. Numerical results show that both approaches provide a striking acceleration rate against conventional FE computations. The CNTFA predictions are more accurate than the NTFA ones by involving clustered microscopic fields in the online analysis, thus resulting into a slightly increased memory requirement.
{"title":"Reduced order homogenization of composites with strength difference effects in elastoplasticity coupled to damage","authors":"","doi":"10.1016/j.compstruct.2024.118564","DOIUrl":"10.1016/j.compstruct.2024.118564","url":null,"abstract":"<div><p>This paper addresses reduced order homogenization of composites with strength difference (SD) effects in elastoplasticity coupled to damage, while containing several well-known plasticity criteria as special cases. We extend two approaches for this purpose: 1. nonuniform transformation field analysis (NTFA by Michel and Suquet, 2003) and 2. a recent variant called cluster-based NTFA (CNTFA by Ri et al., 2021), and conduct a comparative study on them. For the NTFA approach, a space–time decomposition is done separately for volumetric and deviatoric inelastic strain fields. A coupled model is derived for the present case to govern the evolution of resulting reduced variables. For the CNTFA approach, a clustering analysis is additionally performed for a spatial decomposition of the micro-domain. Unlike the NTFA, the online analysis is formulated as a unified minimization problem, which does not require a major adaptation for the present case. For both approaches, localization rules are deduced from the superposition principle and then homogenized to obtain the effective responses. FE-based implementation is presented in detail for both approaches. Numerical results show that both approaches provide a striking acceleration rate against conventional FE computations. The CNTFA predictions are more accurate than the NTFA ones by involving clustered microscopic fields in the online analysis, thus resulting into a slightly increased memory requirement.</p></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0263822324006925/pdfft?md5=a9fddea32725573af2cf15dad60abc22&pid=1-s2.0-S0263822324006925-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142242501","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 : 2024-09-15DOI: 10.1016/j.compstruct.2024.118569
Glass fiber reinforced polymer (GFRP), used in insulating components like insulation rods, needs to withstand both high voltage and large dynamic mechanical fatigue during operation. In this paper, the effects of tension–compression fatigue loads on the dielectric properties of GFRP under various fatigue cycles and stress levels are investigated. The results show that DC conductivity has a strong negative correlation with stiffness, while breakdown strength is showing a positive correlation. Fatigue-induced internal damage could cause continuous charge accumulation and enhanced interfacial polarization, leading to the increase of dielectric constant by 46.89% and the reduction of breakdown strength by 15.05%, when the fatigue span ratio reaches 80% under 40% stress level. Understanding the evolution of dielectric properties of GFRP under dynamic mechanical fatigue conditions is helpful for ensuring the safe and stable operation of electrical power equipment subjected to both high voltage and fatigue loads.
{"title":"Dielectric behavior and breakdown strength of glass fiber reinforced epoxy composites under dynamic mechanical fatigue","authors":"","doi":"10.1016/j.compstruct.2024.118569","DOIUrl":"10.1016/j.compstruct.2024.118569","url":null,"abstract":"<div><div>Glass fiber reinforced polymer (GFRP), used in insulating components like insulation rods, needs to withstand both high voltage and large dynamic mechanical fatigue during operation. In this paper, the effects of tension–compression fatigue loads on the dielectric properties of GFRP under various fatigue cycles and stress levels are investigated. The results show that DC conductivity has a strong negative correlation with stiffness, while breakdown strength is showing a positive correlation. Fatigue-induced internal damage could cause continuous charge accumulation and enhanced interfacial polarization, leading to the increase of dielectric constant by 46.89% and the reduction of breakdown strength by 15.05%, when the fatigue span ratio reaches 80% under 40% stress level. Understanding the evolution of dielectric properties of GFRP under dynamic mechanical fatigue conditions is helpful for ensuring the safe and stable operation of electrical power equipment subjected to both high voltage and fatigue loads.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0263822324006974/pdfft?md5=e4f352cd8d9c136ffd6a6bc420698173&pid=1-s2.0-S0263822324006974-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312102","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 : 2024-09-15DOI: 10.1016/j.compstruct.2024.118575
Creep resistance is critical for ensuring the dimensional stability and safe operation of composite components. However, the creep resistance of short fiber reinforced thermoplastic composites has been rarely reported and that of the composites manufactured by conventional extrusion compounding combined with injection molding is kind of low. In this work, in order to address this issue, two short carbon fiber-reinforced polyetherimide (SCF/PEI) composites named respectively as SCF/PEIE and SCF/PEIS are prepared by both conventional extrusion compounding and our newly developed solution mixing method combined with injection molding. The solution mixing method involves the dispersion and mixing of carbon fibers within a PEI solution and allows for the retention of longer fiber lengths. Experimentally, the creep behaviors of the SCF/PEI composites were examined through tensile and flexural creep testing at various stress levels in a wide temperature range. Theoretically, the creep behaviors were characterized by employing the Schapery model and the time–temperature superposition principle (TTSP), and the impact of fiber length retention on creep resistance was quantitatively analyzed using the Fu-Lauke model. The results demonstrate that compared to the SCF/PEIE composite, the SCF/PEIS composite exhibits a higher creep fracture stress level (175 MPa) and a more extensive linear viscoelastic region (0–85 MPa) at room temperature. Furthermore, the SCF/PEIS composite was observed to have a significantly longer secondary creep stage at an elevated temperature of 210 °C. Overall, the creep resistance of the newly manufactured SCF/PEIS is significantly superior to that of the SCF/PEIE, which effectively extends the service life and operational capacity of injection-molded SCF/PEI composites.
{"title":"Improved creep resistance of short carbon fiber reinforced polyetherimide composite by solution mixing method","authors":"","doi":"10.1016/j.compstruct.2024.118575","DOIUrl":"10.1016/j.compstruct.2024.118575","url":null,"abstract":"<div><p>Creep resistance is critical for ensuring the dimensional stability and safe operation of composite components. However, the creep resistance of short fiber reinforced thermoplastic composites has been rarely reported and that of the composites manufactured by conventional extrusion compounding combined with injection molding is kind of low. In this work, in order to address this issue, two short carbon fiber-reinforced polyetherimide (SCF/PEI) composites named respectively as SCF/PEI<sub>E</sub> and SCF/PEI<sub>S</sub> are prepared by both conventional extrusion compounding and our newly developed solution mixing method combined with injection molding. The solution mixing method involves the dispersion and mixing of carbon fibers within a PEI solution and allows for the retention of longer fiber lengths. Experimentally, the creep behaviors of the SCF/PEI composites were examined through tensile and flexural creep testing at various stress levels in a wide temperature range. Theoretically, the creep behaviors were characterized by employing the Schapery model and the time–temperature superposition principle (TTSP), and the impact of fiber length retention on creep resistance was quantitatively analyzed using the Fu-Lauke model. The results demonstrate that compared to the SCF/PEI<sub>E</sub> composite, the SCF/PEI<sub>S</sub> composite exhibits a higher creep fracture stress level (175 MPa) and a more extensive linear viscoelastic region (0–85 MPa) at room temperature. Furthermore, the SCF/PEI<sub>S</sub> composite was observed to have a significantly longer secondary creep stage at an elevated temperature of 210 °C. Overall, the creep resistance of the newly manufactured SCF/PEI<sub>S</sub> is significantly superior to that of the SCF/PEI<sub>E</sub>, which effectively extends the service life and operational capacity of injection-molded SCF/PEI composites.</p></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0263822324007037/pdfft?md5=77a73cbee94c58440a072fbf0f9b49a5&pid=1-s2.0-S0263822324007037-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142272522","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 : 2024-09-14DOI: 10.1016/j.compstruct.2024.118577
SiCf/SiC ceramic matrix composites with excellent thermal stability, light weight and oxidation resistance have become key components in advanced aircraft engines. Nanofluid minimal quantity lubrication (NMQL) exhibits significant potential in enhancing heat transfer and lubrication efficiency during the grinding process. The technological challenge lies in thoroughly investigating the theoretical variation rule of grinding force, assisted by nanofluid minimal quantity lubrication, and subsequently achieving low-damage machining of SiCf/SiC composites. In this study, a prediction model for the grinding force during NMQL-assisted grinding was established, integrating diverse lubrication methods, grinding wheel geometric parameters, wear degree, process parameters, the anisotropy and damage degree of SiCf/SiC composites. The model was subsequently experimentally validated through grinding tests conducted on SiCf/SiC composites under various conditions, including dry grinding (DG), flood grinding (FG), minimum quantity lubrication (MQL), and carbon nanotube nanofluids (NMQL-CNTs), across multiple grinding depths. The present investigation’s grinding force forecasting model is evidenced to possess high accuracy of precision, showcasing mean deviations of 6.64 % and 11.97 % in the perpendicular (Fn) and tangential (Ft) grinding force components, respectively. Additionally, employing NMQL-CNTs facilitates the achievement of minimal grinding force and surface finish quality. At depths of 0.4 mm and 0.6 mm during grinding, the mean Fn magnitudes under the NMQL-CNTs lubrication approach underwent a decrease of 66.7 % and 74.5 %, respectively, in contrast, the mean Ft magnitudes experienced a reduction of 55 % and 67.2 %, correspondingly, in comparison to the DG lubrication technique. Notwithstanding the consistency in the material’s brittle removal mechanism across varying lubrication strategies, the NMQL-CNTs approach effectively alleviates fiber abrasion. Concisely, the research presented herein provides foundational theoretical insights and practical technological assistance for the achievement of low damage SiCf/SiC composite processing.
{"title":"Nanofluid minimum quantity lubrication assisted grinding force model considering anisotropy of SiCf/SiC ceramic matrix composites","authors":"","doi":"10.1016/j.compstruct.2024.118577","DOIUrl":"10.1016/j.compstruct.2024.118577","url":null,"abstract":"<div><p>SiC<sub>f</sub>/SiC ceramic matrix composites with excellent thermal stability, light weight and oxidation resistance have become key components in advanced aircraft engines. Nanofluid minimal quantity lubrication (NMQL) exhibits significant potential in enhancing heat transfer and lubrication efficiency during the grinding process. The technological challenge lies in thoroughly investigating the theoretical variation rule of grinding force, assisted by nanofluid minimal quantity lubrication, and subsequently achieving low-damage machining of SiC<sub>f</sub>/SiC composites. In this study, a prediction model for the grinding force during NMQL-assisted grinding was established, integrating diverse lubrication methods, grinding wheel geometric parameters, wear degree, process parameters, the anisotropy and damage degree of SiC<sub>f</sub>/SiC composites. The model was subsequently experimentally validated through grinding tests conducted on SiC<sub>f</sub>/SiC composites under various conditions, including dry grinding (DG), flood grinding (FG), minimum quantity lubrication (MQL), and carbon nanotube nanofluids (NMQL-CNTs), across multiple grinding depths. The present investigation’s grinding force forecasting model is evidenced to possess high accuracy of precision, showcasing mean deviations of 6.64 % and 11.97 % in the perpendicular (F<sub>n</sub>) and tangential (F<sub>t</sub>) grinding force components, respectively. Additionally, employing NMQL-CNTs facilitates the achievement of minimal grinding force and surface finish quality. At depths of 0.4 mm and 0.6 mm during grinding, the mean F<sub>n</sub> magnitudes under the NMQL-CNTs lubrication approach underwent a decrease of 66.7 % and 74.5 %, respectively, in contrast, the mean F<sub>t</sub> magnitudes experienced a reduction of 55 % and 67.2 %, correspondingly, in comparison to the DG lubrication technique. Notwithstanding the consistency in the material’s brittle removal mechanism across varying lubrication strategies, the NMQL-CNTs approach effectively alleviates fiber abrasion. Concisely, the research presented herein provides foundational theoretical insights and practical technological assistance for the achievement of low damage SiC<sub>f</sub>/SiC composite processing.</p></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0263822324007050/pdfft?md5=0e5aa32502cd5c9cfa83c9c9ce083b05&pid=1-s2.0-S0263822324007050-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142242403","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 : 2024-09-14DOI: 10.1016/j.compstruct.2024.118581
Structural electromagnetic wave (EMW) absorbing composites play a critical role in both civilian and military applications. However, traditional sandwich honeycomb EMW absorbing composites have poor out-of-plane mechanical properties and load-bearing performance.This study introduces the development of a three-dimensional honeycomb woven composite (3DHWC) that integrates EMW absorption and load-bearing capabilities. A weaving loom was used to fabricate a three-dimensional honeycomb woven structure fabric (3DHSWF) with varying structural parameters. Subsequently, the composites were formed using carbon black (CB), multi-walled carbon nanotubes (MWCNTs), and carbonyl iron powder (CIP) as hybrid absorbers, epoxy resin as the matrix, combined with the vacuum-assisted resin transfer molding (VARTM) process. Testing confirmed the material’s excellent EMW absorption and mechanical properties, achieving a maximum reflection loss (RL) of −30.9 dB and an adequate EMW absorption bandwidth (EAB) of 14.58 GHz. The maximum bending load reached 5799.1 N, with no delamination observed in the samples. This material demonstrates outstanding EMW absorption performance and exhibits superior load-bearing capacity while maintaining structural integrity. Our research provides valuable insights into the design of honeycomb EMW absorbing composites, offering significant advancements in EMW absorption efficiency and bending mechanical properties.
{"title":"Design-manufacturing-performance of electromagnetic absorbing/load bearing three-dimensional honeycomb woven composites","authors":"","doi":"10.1016/j.compstruct.2024.118581","DOIUrl":"10.1016/j.compstruct.2024.118581","url":null,"abstract":"<div><p>Structural electromagnetic wave (EMW) absorbing composites play a critical role in both civilian and military applications. However, traditional sandwich honeycomb EMW absorbing composites have poor out-of-plane mechanical properties and load-bearing performance.This study introduces the development of a three-dimensional honeycomb woven composite (3DHWC) that integrates EMW absorption and load-bearing capabilities. A weaving loom was used to fabricate a three-dimensional honeycomb woven structure fabric (3DHSWF) with varying structural parameters. Subsequently, the composites were formed using carbon black (CB), multi-walled carbon nanotubes (MWCNTs), and carbonyl iron powder (CIP) as hybrid absorbers, epoxy resin as the matrix, combined with the vacuum-assisted resin transfer molding (VARTM) process. Testing confirmed the material’s excellent EMW absorption and mechanical properties, achieving a maximum reflection loss (RL) of −30.9 dB and an adequate EMW absorption bandwidth (EAB) of 14.58 GHz. The maximum bending load reached 5799.1 N, with no delamination observed in the samples. This material demonstrates outstanding EMW absorption performance and exhibits superior load-bearing capacity while maintaining structural integrity. Our research provides valuable insights into the design of honeycomb EMW absorbing composites, offering significant advancements in EMW absorption efficiency and bending mechanical properties.</p></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0263822324007098/pdfft?md5=b77e1a4a63ef449fdf596835d18f2e53&pid=1-s2.0-S0263822324007098-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142272521","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 : 2024-09-14DOI: 10.1016/j.compstruct.2024.118573
The R-curve and fiber bridging phenomenon in mode-I fracture of glass-fiber reinforced laminates at different temperatures are investigated in this study, aiming to reveal their changes with temperature. The mode-I fracture experiments are carried out by adopting double cantilever beam (DCB) configuration at −55 ℃, 23 ℃ and 80 ℃. Fiber bridging is observed during the tests. The R-curve and bridging traction are quantitatively analyzed, from which the relationship between the R-curve and fiber bridging phenomenon, and temperature is obtained. It is found that fiber bridging effect is enhanced with the increase of temperature. The bridging traction of specimens tested at 80 ℃ is significantly higher than that at −55 ℃ and 23 ℃. An R-curve model considering both temperature and fiber bridging effects is proposed. In addition, bilinear and tri-linear traction-separation relations (TSLs) are utilized to establish a numerical model for the simulation of delamination growth behavior with the consideration of the temperature-dependent effect on the mechanical properties of composite materials. When using the bilinear TSL, the fiber bridging is considered by integrating the resulted R-curve into finite element model via a user-defined USDFLD subroutine. Effects of initial interface stiffness, interface strength and viscosity coefficient on simulated results are numerically investigated. Finally, applicability of the established numerical models is illustrated by comparisons between the simulations and the test results.
本研究探讨了不同温度下玻璃纤维增强层压板模态-I断裂的R曲线和纤维架桥现象,旨在揭示它们随温度的变化。采用双悬臂梁(DCB)结构在-55 ℃、23 ℃和 80 ℃下进行了模态-I断裂实验。测试过程中观察到了纤维架桥现象。对 R 曲线和架桥牵引力进行了定量分析,从中得出了 R 曲线和纤维架桥现象与温度之间的关系。结果发现,纤维架桥效应随着温度的升高而增强。80 ℃ 试样的架桥牵引力明显高于 -55 ℃ 和 23 ℃ 试样。提出了一个同时考虑温度和纤维架桥效应的 R 曲线模型。此外,考虑到温度对复合材料机械性能的影响,利用双线性和三线性牵引分离关系(TSL)建立了分层生长行为模拟数值模型。在使用双线性 TSL 时,通过用户定义的 USDFLD 子程序将生成的 R 曲线集成到有限元模型中,从而考虑了纤维桥接问题。数值研究了初始界面刚度、界面强度和粘度系数对模拟结果的影响。最后,通过比较模拟结果和测试结果,说明了所建立的数值模型的适用性。
{"title":"Temperature-dependent R-curve and traction-separation relation in mode-I fracture of GFRP laminates","authors":"","doi":"10.1016/j.compstruct.2024.118573","DOIUrl":"10.1016/j.compstruct.2024.118573","url":null,"abstract":"<div><p>The <em>R</em>-curve and fiber bridging phenomenon in mode-I fracture of glass-fiber reinforced laminates at different temperatures are investigated in this study, aiming to reveal their changes with temperature. The mode-I fracture experiments are carried out by adopting double cantilever beam (DCB) configuration at −55 ℃, 23 ℃ and 80 ℃. Fiber bridging is observed during the tests. The <em>R-</em>curve and bridging traction are quantitatively analyzed, from which the relationship between the <em>R</em>-curve and fiber bridging phenomenon, and temperature is obtained. It is found that fiber bridging effect is enhanced with the increase of temperature. The bridging traction of specimens tested at 80 ℃ is significantly higher than that at −55 ℃ and 23 ℃. An <em>R</em>-curve model considering both temperature and fiber bridging effects is proposed. In addition, bilinear and tri-linear traction-separation relations (TSLs) are utilized to establish a numerical model for the simulation of delamination growth behavior with the consideration of the temperature-dependent effect on the mechanical properties of composite materials. When using the bilinear TSL, the fiber bridging is considered by integrating the resulted <em>R</em>-curve into finite element model via a user-defined USDFLD subroutine. Effects of initial interface stiffness, interface strength and viscosity coefficient on simulated results are numerically investigated. Finally, applicability of the established numerical models is illustrated by comparisons between the simulations and the test results.</p></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0263822324007013/pdfft?md5=de4cc5f4081e8286e078635d49771844&pid=1-s2.0-S0263822324007013-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142242402","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 : 2024-09-14DOI: 10.1016/j.compstruct.2024.118572
In this study, a multi-scale modeling framework that spans from molecular chains to macroscopic structure was proposed for a typical particle-filled polymer composite (HTPB propellants). The cohesive zone model (CZM) is utilized in the RVE model of HTPB propellants to capture the debonding phenomena at the AP/HTPB interface. For the HTPB matrix, a free energy function based on the Gaussian chain network is employed. To depict the chain scission behavior, the phase fracture (PF) method along with gradient-damage theory is introduced. Subsequently, microscale fracture behavior under uniaxial tensile load was investigated based on the constructed RVE model, and a phenomenological macroscopic damage model was developed correspondingly. In this developed model, two damage factors related to the debonding of AP/HTPB interface and the growth of voids in matrix are introduced respectively. Thus, it can not only predict the macroscopic stress–strain response, but also can give the microscopic damage evolution information. Overall, this multi-scale modeling framework can offer us a deeper insight into the microstructural changes and the resulting macroscopic mechanical behavior of HTPB propellants.
{"title":"Multi-scale modeling of damage evolution for particle-filled polymer composites","authors":"","doi":"10.1016/j.compstruct.2024.118572","DOIUrl":"10.1016/j.compstruct.2024.118572","url":null,"abstract":"<div><p>In this study, a multi-scale modeling framework that spans from molecular chains to macroscopic structure was proposed for a typical particle-filled polymer composite (HTPB propellants). The cohesive zone model (CZM) is utilized in the RVE model of HTPB propellants to capture the debonding phenomena at the AP/HTPB interface. For the HTPB matrix, a free energy function based on the Gaussian chain network is employed. To depict the chain scission behavior, the phase fracture (PF) method along with gradient-damage theory is introduced. Subsequently, microscale fracture behavior under uniaxial tensile load was investigated based on the constructed RVE model, and a phenomenological macroscopic damage model was developed correspondingly. In this developed model, two damage factors related to the debonding of AP/HTPB interface and the growth of voids in matrix are introduced respectively. Thus, it can not only predict the macroscopic stress–strain response, but also can give the microscopic damage evolution information. Overall, this multi-scale modeling framework can offer us a deeper insight into the microstructural changes and the resulting macroscopic mechanical behavior of HTPB propellants.</p></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0263822324007001/pdfft?md5=a19a88cbbab9e619cf9a1879bed4a234&pid=1-s2.0-S0263822324007001-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142242404","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 : 2024-09-14DOI: 10.1016/j.compstruct.2024.118578
This paper derives the exact general elasticity solution for functionally graded rectangular beams subjected to arbitrary normal and tangential loads and with arbitrary end constraints. The general solution consists of bending moments and their integrals and derivatives, along with load-independent function sequences of the longitudinal coordinate. The method for determining function sequences has been established based on the stress function method. General solution formulas for stresses, strains and displacements have been derived and used to solve explicit special solutions for six cases involving concentrated forces, uniformly loads, and quadratically distributed loads with different displacement constraints scenarios. The results obtained are compared with existing exact solutions and those of Euler–Bernoulli and Timoshenko beams, and the errors of the latter two are analysed.
{"title":"Elasticity solutions for functionally graded beams with arbitrary distributed loads","authors":"","doi":"10.1016/j.compstruct.2024.118578","DOIUrl":"10.1016/j.compstruct.2024.118578","url":null,"abstract":"<div><p>This paper derives the exact general elasticity solution for functionally graded rectangular beams subjected to arbitrary normal and tangential loads and with arbitrary end constraints. The general solution consists of bending moments and their integrals and derivatives, along with load-independent function sequences of the longitudinal coordinate. The method for determining function sequences has been established based on the stress function method. General solution formulas for stresses, strains and displacements have been derived and used to solve explicit special solutions for six cases involving concentrated forces, uniformly loads, and quadratically distributed loads with different displacement constraints scenarios. The results obtained are compared with existing exact solutions and those of Euler–Bernoulli and Timoshenko beams, and the errors of the latter two are analysed.</p></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":null,"pages":null},"PeriodicalIF":6.3,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0263822324007062/pdfft?md5=a10b3530982041672b9a56fc582a4fd6&pid=1-s2.0-S0263822324007062-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142242498","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}