今日更新：Composite Structures 4 篇，Composites Part A: Applied Science and Manufacturing 6 篇，Composites Part B: Engineering 3 篇，Composites Science and Technology 5 篇
Composite Structures
Shear performance of GFRP reinforced UHPC short beams
Omar Salman, Farid Abed, Yazan Alhoubi
doi:10.1016/j.compstruct.2024.118637
GFRP增强UHPC短梁的抗剪性能
This paper investigated experimentally the shear performance of ultra-high-performance concrete (UHPC) deep beams reinforced longitudinally with glass fiber reinforced polymer (GFRP) bars without web reinforcements. Ten beams were cast, in which seven were longitudinally reinforced with GFRP bars, while the remaining three were reinforced with steel bars for comparison. All beams had similar lengths and widths of 2000 mm and 150 mm, respectively, while the depths varied. The test parameters included the effective depth (d), shear span-to-depth ratio (a/d), number of longitudinal bars, and longitudinal reinforcement ratio (ρ). All the GFRP reinforced beams had higher shear capacities and lower post cracking stiffness than their steel counterparts. The experimental results show that varying the test parameters have a significant impact on the shear capacity of the beams. For instance, decreasing the a/d ratio for the GFRP reinforced beams from 1.8 to 1.5 and from 1.8 to 1.1 increased the load carrying capacity by 33 % and 95 %, respectively. The experimental results for the shear capacity were compared against the predictions obtained using the strut and tie method as per the ACI-318–19 and CSA-S806-12 codes. The failure load predictions by the ACI and CSA code showed the same trends as those shown in the experimental results. Moreover, both codes were conservative in predicting the shear capacities.
Metal/polymer-based composites hybrid (MPH) structures combine the high strength of metals with the low density of polymer-based composites, making them widely used in automotive applications. However, the random characteristics of the microgeometry at the pretreated MPH interface have made it challenging to predict its interface bonding failure probability accurately and quickly. This paper presents an advanced FE2 prediction method for bonding performance of MPH interface based on multi-fidelity regression and artificial neural networks (ANNs). When compared to experimental fracture mechanics results for failure mode I and II, the prediction errors for peak loads are 3.9 % and 5.6 %, respectively. At same time, the computational efficiency is over 6 times higher than that of traditional FE2 methods. Additionally, how interface microstructure parameters affect the tensile/shear performance, crack initiation, and propagation directions are investigated at the micro-scale. Under combined tensile/shear loads, the propagation mechanisms of interface microgeometry uncertainties in MPH are revealed theoretically. An interface design method with a high adhesion probability is proposed, identifying high load-bearing areas within the feasible design domain under bending loads for MPH structures. This provides a quickly accessible parameter matching scheme during conceptual design, offering a theoretical foundation for the application of MPH structures in engineering fields.
Modified cure cycles for increased fatigue performance of fiber metal laminates
Johannes Wiedemann, Selim Mrzljak, Josef Koord, Christian Hühne, Frank Walther
doi:10.1016/j.compstruct.2024.118631
改进固化周期以提高金属纤维层压板的疲劳性能
Modified (MOD) cure cycles that deviate from the manufacturer’s recommended cure profile can reduce the inherent thermally induced residual stresses (TRS) in fiber metal laminates (FML). Literature shows that MOD cycles do not adversely affect the material properties but enhance the quasi-static material strength. However, the literature does not comprehensively discuss the impact of MOD cycles on material performance during cyclic fatigue loading. This paper, therefore, investigates how MOD cycles influence the fatigue characteristics of different FML layups made of carbon fiber-reinforced polymer (CFRP) and steel. The experimental results confirm that the quasi-static material strength and the modulus of the FML are increased when using MOD cure cycles. The evaluation of fatigue tests with digital image correlation, thermography, and electrical resistance measurements of notched specimens shows that a reduction of TRS delays damage initiation in the metal facesheets and decreases the crack growth rate until facesheet failure. The results further show that layup-dependent parameters, the maximum stress in the metal sheets, and metal sheet thickness significantly govern the evolution of fatigue damage. In summary, modified cure cycles are an efficient tool to enhance the quasi-static and fatigue performance of CFRP-steel hybrid laminates.
Investigation on the energy absorption characteristics of novel graded auxetic re-entrant honeycombs
Zhao Zhang, Yiwen Gu, Hengan Wu, Qingpeng Chen
doi:10.1016/j.compstruct.2024.118633
新型梯度增氧重入式蜂窝吸能特性研究
In this work, innovative graded auxetic re-entrant honeycombs constructed by adjusting the geometric parameters of a core unit cell are proposed, and their deformation modes and energy absorption characteristics with different impact speeds are systematically investigated. The novel graded design utilizes structural hierarchy on the meso-scale and functional gradient on the macro-scale. The numerical simulation models are verified by comparing the experimental results. The results show that compared with the ungraded honeycomb (URH), one of the graded honeycombs (GRHs), named GRH1, can greatly improve the specific energy absorption by 36.4%, 10.8%, and 6.00% for the quasi-static, low, and high-speed impact at a strain of 0.6. At the same time, the initial peak stress of GRH1 is decreased by 43.2% and 27.1% compared with that of URH for low and high-speed impact, respectively. It could be indicated that the GRH1 was an ideal energy-absorbing structure. This work provides a new route for designing graded auxetic honeycombs with enough insight to understand the deformation mechanism of the structures, which could be used in lightweight buffer protective systems.
This study evaluates the influence of a thermal treatment of a basalt fiber on capillary wicking tests and in-plane permeability experiments, under several pressure differences. The impact of the treatment was characterized at three scales: microscopic, to determine the fiber surface energy; mesoscopic, to estimate an equivalent capillary pressure ( P c a p ) of the fabric in spontaneous impregnation; and macroscopic, to determine the saturated ( K s a t ) and unsaturated ( K u n s a t ) permeability of the fibrous preform at the process scale. Results at the microscopic scale showed that the thermal treatment increased the polarity of the fiber by 22% and decreased its surface roughness. Capillary wicking tests showed that the treated fabric presents a better affinity with water, increasing P c a p by 68%. At the process scale, permeability experiments showed the increase of K s a t and K u n s a t after treatment. Finally, results of capillary pressure ( Δ P γ ) showed a dominance of capillary effects under the negative pressure difference.
本研究评估了几种压力差下玄武岩纤维的热处理对毛细管吸湿试验和平面渗透性试验的影响。对处理的影响进行了三个尺度的表征:微观的，以确定纤维的表面能;介观，估计织物在自发浸渍时的等效毛细管压力（P ca P）；宏观上，确定纤维预制体在工艺尺度上的饱和（K sat）和不饱和（K unsat）渗透率。微观结果表明，热处理使纤维极性提高22%，表面粗糙度降低。毛细吸湿试验表明，经处理后的织物具有较好的亲水性，P - c - a - P提高68%。在工艺尺度上，渗透率实验表明，处理后的K s at和K u n s at均有所增加。最后，毛细管压力(Δ P γ)结果显示，在负压差下，毛细管效应占主导地位。
Analyses and control of interphase structures and adhesion properties of epoxy resin/epoxy resin for development of CFRP adhesion systems
In the adhesion of carbon fiber reinforced plastics (CFRP), the boundary regions were composed of only epoxy resins of CFRP matrix and adhesives, and their similar epoxy structures pose significant difficulty in studying the adhesion mechanism. Herein, we focused on structure and properties of laminates of epoxy resin substrates and adhesives with different curing conditions of substrates. We prepared laminates using deuterated epoxy adhesives or fluorinated epoxy adhesives, and their boundary regions were identified through confocal Raman scattering measurements. The regions were distributed into “penetration” and “interphase”. In particular, the penetration phase is a key of the adhesion properties. The penetration behaviors strongly depended on the crosslinking densities of the adherends, suggesting that the penetration regions would be directly impacted by the curing conditions of the substrates and molecular size of epoxy adhesive precursors. Our findings provide insights into novel designs of the reliable adhesion-based manufacturing systems of CFRP.
Constructing house-of-cards-like networks with BNNS confined in interlocking Al2O3 platelet skeletons for thermally conductive epoxy composites
Fanjun Guo, Tao You, Kangle Xue, Jun Li, Li Liu, Yudong Huang
doi:10.1016/j.compositesa.2024.108513
在热传导环氧复合材料中，用限制在互锁Al2O3血小板骨架中的BNNS构建卡屋状网络
The construction of 3D filler networks is an effective strategy to improve the thermal conductivity of epoxy resins, yet it is still severely limited by the disconnection of conduction channels. In this contribution, an original interlocking hybrid skeleton with continuous conduction channels was developed by assembling BNNS into an in situ-formed interlocking Al2O3 platelet skeleton using commercial polyurethane as a template, where large intergranular contact areas of Al2O3 platelets were established by sintering to greatly decrease the contact thermal resistance. Besides, the interlocking Al2O3 skeleton coupled with BNNS under hydrogen bonding endowed further improvement of its thermal conductivity. The optimized Al2O3/BNNS/EP composite displayed an excellent thermal conductivity of 5.01 W/mK at 15.3 vol% of Al2O3 and 11.4 vol% of BNNS loading, far higher than that of neat epoxy resin by 1904.0 %. Meanwhile, the interlocking hybrid skeleton provided the epoxy resin with low dielectric loss, satisfactory thermal stability and flame retardancy.
A multifunctional epoxy composites based on cellulose nanofiber/carbon nanotube aerogels: Simultaneously enhancing fire-safety, thermal conductive and photothermal performance
Jiali Yan, Miaojun Xu, Xinrui Hu, Lubin Liu, Xixi Xiao, Bin Li
doi:10.1016/j.compositesa.2024.108514
基于纤维素纳米纤维/碳纳米管气凝胶的多功能环氧复合材料:同时增强防火、导热和光热性能
As 5G technology develops and electronic power density increases, preparing epoxy resin (EP) composites with excellent fire-safety, thermostability, and thermal conductivity remains challenging. Herein, hexaphenoxy cyclotriphosphazene and poly(piperazine methylphosphonic acid pentaerythritol ester) were used as synergistic flame retardants (FR) for EP. The cellulose nanofiber/carboxylated multiwalled carbon nanotubes aerogels (CCA80) were prepared and immersed into the EP and FR mixture to obtain EP/CCA80/FR composites. Compared with neat EP, the limiting oxygen index of EP/CCA80/6 wt% FR increased by 38.9 %, the total heat release and CO2 production rate decreased by 30.61 % and 39.47 %, respectively, achieving the UL-94 V-0 rating. Moreover, its thermal conductivity was 1.06 W · m−1·K−1, 457.9 % higher than neat EP, while maintaining excellent electrical insulation. Its surface temperature maintained at 94.5 °C under 1.0 kW·m−2 irradiation for 2 h, exhibiting good photothermal conversion capability and photobleaching resistance. A novel fabrication methodology of multifunctional EP composites for high-performance electronic component was proposed.
Pulp fibre foams: Morphology and mechanical performance
Markus Wagner, Veronika Biegler, Sebastian Wurm, Georg Baumann, Alexander Bismarck, Florian Feist
doi:10.1016/j.compositesa.2024.108515
纸浆纤维泡沫:形态和机械性能
Cellulose (pulp) fibre foams serve as bio-based alternative to fossil-based cellular lightweight materials. The mechanical properties of cellulose fibre foams are inferior compared with traditional polymer foams and available information is often limited on compression properties. We present a comprehensive analysis of cellulose fibre foams with densities ranging from 60 to 130 kg/m3, examining their compression, tensile, flexural, and shear properties. Key findings include a high mean zenithal fibre angle which decreases with increasing density, as well as a high strain rate amplification (SRA) in compressive strength, which also decreases with increasing density. With respect to formulation, the addition of carboxymethyl cellulose (CMC) enhanced fibre dispersion, bubble homogeneity of the wet foam, and dimensional stability of the end-product.These results provide a foundation for numerical models and advance the understanding of cellulose pulp fibre foams, highlighting their potential for certain applications.
Vibro-acoustic Characterization of Functionally Graded Multiwalled Carbon Nanotube composite cylindrical panels: An experimental approach
R. Kiran Kumar Reddy, AR Veerappan, Nivish george
doi:10.1016/j.compositesa.2024.108518
功能梯度多壁碳纳米管复合圆柱形板的振动声学特性:实验方法
This study experimentally investigates the vibro-acoustic properties of Functionally Graded Multiwalled Carbon Nanotubes (FG-V MWCNT) Glass Fiber Reinforced Polymer composite cylindrical panels, a topic often explored through numerical methods. A novel process methodology is introduced to realize FG-V MWCNT composites, and the results are compared with those of uniformly distributed and conventional composites. Using an in-house developed experimental setup, the natural frequencies, mode shapes, acceleration, and Sound Pressure Levels (SPL) are measured. The FG-V MWCNT composites demonstrate a notable enhancement in fundamental frequency (21.13%) and a reduction in SPL in the lower frequency range compared to conventional composites. The proposed material composition and process methodology show potential for creating lightweight, structurally efficient large airframe components.
Microwave absorption presents a challenge for the design of metamaterials, which is critical for the stealth and electromagnetic compatibility. To address this, a novel design strategy for patterns is proposed to enhance the wave absorption, which is tortuosity and connectivity. Utilizing the carbon ink composite and genetic algorithm, multi-layer coding metamaterials (MCMs) are designed to satisfy diverse engineering specifications, with reflectivity tests confirming their efficacy. Temperature alternation experiments simulate frequent environmental changes, and the absorptivity of MCMs is compared to evaluate their resilience. This approach ensures the designed MCMs maintain performance and stability under variable thermal conditions, offering a robust solution for advanced applications.
Damage characterization and modelling of FRP laminated composites subjected to external edge-on impact
Nian Li, Jian Du, Hsiao Mun Lee, Weiling Liu, Yangyan Zheng, Heow Pueh Lee
doi:10.1016/j.compositesb.2024.111879
玻璃钢层合复合材料受外缘冲击的损伤表征和建模
This paper presents both experimental and numerical investigations into the edge-on impact behavior of T700/YPH307 composite laminates with varying lay-up designs and impact energy levels. Various non-destructive testing techniques, including visual inspection, ultrasonic C-scanning and X-ray computed tomography (CT), were used to detect the post-impact damage status and further reveal its 3D spatial distribution. A continuum damage mechanics (CDM) model, incorporating in-plane shear nonlinearity, fracture plane angle within anisotropic materials, as well as fiber kinking failure in longitudinal compression, was established using an explicit solver. Detailed comparison of the experimental and numerical results was conducted in mechanical response curves and failure mechanisms, where a good agreement was observed. Parameter analyses on the in-situ strengths and the friction coefficient were also performed, offering guidelines for the edge-on impact modelling. Failure mechanisms induced by edge-on impact typically exhibit two distinct features: a highly localized debris wedge, which can be regarded as a trigger in the subsequent occurrence of damage, and the bending fracture of the outer plies resulting from the wedge effect during the oscillating stage of an impact force plateau. Besides, higher impact energy exacerbated internal damage, while the influence of the lay-ups was relatively limited.
The extensive application of ceramic matrix composites has always been limited due to the long-period and expensive process. Hence, this research introduces a rapid manufacturing method named as ViSfP-TiCOP (High Viscosity Solvent-free Precursor Combined Elemental Titanium Controlled Pyrolysis). The solvent-free precursor possesses high viscosity (30°C, 106mPa·S) and wide molecular weight distribution (Mz/Mw=3.3), accomplishing stable loading of inorganic fillers. Simultaneously, the elementary titanium and ZrB2, as the active and inert filler, are dopped into the precursor to control the pyrolysis. The ViSfP-TiCOP technique offers a rapid method to manufacture CMCs under pressureless and low pyrolysis temperature conditions (1200°C). Comparing to the addition of ZrB2, the precursor with titanium provides an exceptional ceramic yield of 87wt%, leading a notable enhancement in the rate of densification. This high densification efficiency is attributed to an in-situ titanium gas-phase reaction, besides with the high degree of cross-linking and low volatile of precursor. After undergoing three cycles of impregnation-pyrolysis, the porosity of C/SiBCN-Ti was discovered to be below 10 Vol%, whereas that of C/SiBCN-25wt%ZrB2 still remained as high as 20.91 Vol%. The ViSfP-TiCOP technology can provide guidance for low-cost and rapid preparation of CMCs.
Crushing behavior of GFRP composite-reinforced PVC tubes: Experimental testing and numerical simulation
Khaled Yousif, Aamir Dean, Elsadig Mahdi
doi:10.1016/j.compscitech.2024.110903
GFRP复合增强PVC管的破碎性能:实验测试和数值模拟
This paper introduces glass fiber reinforced polymer (GFRP)-reinforced Polyvinyl Chloride (PVC) tubes, both corrugated and non-corrugated, designed as energy absorber devices. The PVC tubes were externally and internally reinforced with GFRP composite oriented at ± 4 5 ∘ and subjected to quasi-static axial compression tests. Results indicated that all reinforced tubes exhibited significantly higher load-bearing capacity, energy absorption capability, and crushing force efficiency compared to standard PVC tubes. Among the tested specimens, externally reinforced corrugated tubes demonstrated the highest specific energy absorption (SEA), surpassing other configurations by 17.5 kJ/kg when considering both pre- and post-crushing stages combined. However, these corrugated specimens showed instability during crushing, reflected in poor instantaneous crush force efficiency (iCFE) and the lowest iCFE among the composite tubes, with an average decrease of 43.59%. The corrugation notably increased the initial peak load, enhancing energy absorption in the pre-crushing stage without compromising the stability of crush force efficiency (CFE). Additionally, the combination of external and internal reinforcement significantly improved CFE and iCFE. Consequently, the PVC tubes combining corrugation with both external and internal reinforcement emerged as the best-performing configuration among all tested tubes. Furthermore, a 3D Finite Element (FE) model was developed using ABAQUS FE code with user-defined subroutines to simulate the crushing process. The constitutive models and numerical procedures employed are detailed. The FE model’s predictions showed a satisfactory correlation with experimental results, providing valuable insights into the crushing mechanics and offering a predictive tool for future design optimizations.
3D printing, leakage-proof, and flexible phase change composites for thermal management application
Siyuan Qiu, Yajiao Li, Yi An, Wenhao Wang, Yuanmin Chen, Ke Chen, Daming Wu, Jingyao Sun
doi:10.1016/j.compscitech.2024.110905
用于热管理应用的3D打印，防泄漏和柔性相变复合材料
Phase change composites (PCCs) have attracted much attention in the fields of thermal management due to their high latent heat. However, their risk of leakage and poor shape designability greatly limit their industrial applications. Therefore, there is an urgent need to develop leakage-proof and customizable PCCs to meet the emerging requirements of thermal management applications. Some scholars have proposed the concept of preparing PCCs by 3D printing technology, aiming to meet customized thermal management requirements of various electronic devices. Nevertheless, the phase change material leaking of PCCs under high temperature is still a tough problem to solve. In this study, expanded graphite (EG) is used as the carrier for paraffin wax (PW), which names as EP can tightly enveloping PW in its porous structure. Then, an innovative carbomer gel ink is prepared for 3D printing using EP and short carbon fiber (SCF) as thermal conductive fillers. Freeze-drying and polydimethylsiloxane (PDMS) infiltrating procedures are furtherly performed to ensure the flexibility of final PCCs samples. A maximum thermal conductivity of 2.89 W/(m·K) is obtained when the content of SCF/EP filler is 10 wt%. Importantly, the flexible PCCs prepared through this method effectively prevent the PW leaking during thermal management applications, thereby avoiding the consequent safety risks and enhancing the lifespan of electronic devices. This work opens up a promising pathway for the rapid fabrication of leakage-proof, customizable and flexible PCCs.
In this paper, a fatigue-creep damage model that can take into account the interaction of fatigue and creep damage is proposed under high temperature cyclic loading. In the proposed model, the effect of temperature on creep damage, the variation of creep damage under different high temperature cyclic loading conditions, and fatigue-creep interaction damage are considered. In addition, in order to accurately describe the creep behavior of unidirectional laminates with different orientations, the damage mechanism of unidirectional laminates was also analyzed. The creep and fatigue test results at different temperatures showed that the proposed creep rupture time model and the fatigue-creep damage model considering the damage mechanisms can successfully predict the creep and fatigue lives of unidirectional laminates at high temperature, and the prediction results are in good agreement with the experimental data.
Fraction-Dependent Filler Network in Silicone Rubber: Unraveling Abrupt Enhancement in Rheological Properties via Solvent Extraction and DLS Study
Qiuyu Long, Longjin Huang, Xueyan Zhao, Yuying Li, Yewei Xu, Yi Sun, Chunhua Zhu, Yu Liu
doi:10.1016/j.compscitech.2024.110895
硅橡胶中组分依赖的填料网络:通过溶剂萃取和DLS研究揭示了流变性能的突然增强
A pivotal nanofiller network will be constructed by the filler loading threshold inside the silicone rubber, leading to abrupt enhancement in the rheological properties of the composites. However, the contribution of the nanofiller network to the performance mutation is poorly understood due to lack of direct evidence to recognise the formation of filler networks. This work quantitatively investigated the filler aggregation network in solvent-extracted monodisperse silica-filled polydimethylsiloxane (PDMS) composites to interpret the rheological properties. The results indicated that, when filler loadings reach 60 phr, the size of the filler network reaches its maximum (1280.5 nm), significantly increasing the storage modulus (166 kPa) and Payne effect (163 kPa), due to the formation of a filler network confirmed by Dynamic Light Scattering (DLS) and scanning electron microscope (SEM) observation. The reduction in aggregate size observed with longer extraction times is because of the collapse of the nanofiller network, which occurs as the polymer chains are removed. The aggregates reappear in a monodisperse form as the extraction duration reaches 20 days. This confirms that filler aggregates of interconnected polymer chains can form a well-developed network structure that effectively supports and transfers stresses. This contributes to an in-depth understanding of the formation mechanism of nanofiller networks, aiding the advancement of high-performance polymer nanocomposites.
Investigations on the Leak Resistance Performance and the Difference Mechanism of Composite Materials under Several Typical Curing Processes
Shu Liu, Lihua Zhan, Bolin Ma, Weitao Chen, Dechao Zhang, Shunming Yao, Chuan Du
doi:10.1016/j.compscitech.2024.110901
几种典型固化工艺下复合材料抗漏性能及差异机理研究
This study aims to investigate the leak resistance of carbon fiber composite products formed by various typical curing processes. Firstly, the leak rates of specimens produced through different curing methods were measured, and the defect were statistically analyzed. After that, the simulation approach was applied to numerically study the impact of these defect characteristics on leak rates was examined from the three factors of porosity, void distribution and void morphology, specimen with prefabricated defects was prepared, and its leak performance were tested to validate the simulation results. Finally, the differences in leak resistance among specimens under different curing processes were analyzed from the perspective of curing defects, and specific defect characteristics contributing to enhanced leak resistance were identified.
