今日更新：Composite Structures 10 篇，Composites Part A: Applied Science and Manufacturing 1 篇，Composites Science and Technology 3 篇
Composite Structures
An experimental-analytical investigation of particle size effect on the mode I fracture behavior of polymer/graphene nanocomposites
Sara Amirahmadi, Sankha Aditya, Samit Roy
doi:10.1016/j.compstruct.2024.118420
颗粒尺寸对聚合物/石墨烯纳米复合材料I型断裂行为影响的实验分析研究
Due to their outstanding specific mechanical and functional properties, the engineering use of polymer nanocomposites and their carbon composites is becoming increasingly pervasive. Current and potential applications include micro- and flexible electronics, energy storage devices, and the use as reinforcement for advanced carbon fiber composites for light-weighting of aerospace and mechanical structures, thereby reducing their fuel consumption and carbon footprint. While a large amount of data and models regarding the effect of the weight fraction of nanoplatelets on the mechanical properties of nanocomposites is currently available in the literature, an aspect often overlooked is the scaling of the fracture behavior and the related particle size effects. Not only is the lack of understanding of size effects in nanomaterials hindering the full exploitation of their properties, it is also a serious issue since the design of large nanocomposite structures or small-scale electronic components requires capturing the scaling of their mechanical properties and developing predictive capabilities. This paper aims at filling this knowledge gap by proposing a novel analytical and experimental approach to investigate particle size effects in nanocomposites at and leveraging the acquired knowledge to improve their fracture properties, from the nanoscale all the way to the macroscale. To this end, crack initiation fracture toughness data for graphene/epoxy nanocomposite are presented as a function of nanoparticle size and weight fraction and compared with model predictions using a novel analytical model based on enhanced crack-tip shielding effect due to the reduced nanoparticle size. Extensive fracture test data are presented for model calibration and model verification.
The 3-dimensional shape morphing is desired in applications such as aerospace, soft robotics and medical devices. Via the arrangement of auxetic cells, this paper proposes a box-shaped morphing block concept consisting of 2-dimensional metamaterial to realize 3D shape morphing driven through the structural buckling approach. Firstly, the expansion, bending and twisting deformation modes of the morphing block distinguished by varied Poisson’s ratio arrangement of the auxetic face cells on boundary lattices are introduced. Then, we verify the deployment of 3D deformation through a series of quasi-static tensile experiments, which present a good agreement with our simulation results and demonstrate the effectiveness of induced buckling mechanism. Finally, more complex morphing features are realized by a hybrid combination of the different deformation modes, while their deployment mechanisms are discussed. This morphing block concept with tailorable shape-shifting capability can be an excellent candidate in the 3D morphing structure application.
SiCp/Al composites from conventional to empowered machining: Mechanisms and processability
Dewei Liu, Changhe Li, Peiming Xu, Wei Wang, Yanbin Zhang, Min Yang, Xin Cui, Benkai Li, Mingzheng Liu, Teng Gao, Yusuf Suleiman Dambatta, Aiguo Qin
doi:10.1016/j.compstruct.2024.118433
SiCp/Al复合材料从传统加工到强化加工:机理和可加工性
SiCp/Al composites, known for their outstanding properties, are widely used in aerospace, automotive, and other fields. Despite extensive research, a complete theoretical framework and evaluation system for processing these composites have not yet been established. To enhance their processability, it is crucial to understand how processing-induced characteristics affect their machinability and to establish a robust evaluation system. This study addresses this gap by first reviewing the influence of particle properties on the mechanical properties of SiCp/Al composites. Next, both conventional and advanced machining mechanisms are analyzed, and the processability based on the cutting/grinding forces and surface roughness is evaluated. The results show that advanced machining techniques significantly improve processability compared to conventional methods. The ultrasonic elliptical vibration-assisted turning of the 25 vol% SiCp/Al6061 composites resulted in an 82.4% reduction in the cutting force. Laser-assisted turning of 45 vol% SiCp/Al composites achieved an 89.8% improvement in surface roughness (Sa). Finally, we identify research gaps and future challenges in processing SiCp/Al composites, providing technical support and theoretical guidance for both industry and academia.
This study is focused on applying a topology optimization-driven design procedure on a predefined radial design domain to generate bio-inspired radially graded porous structures which are suitable to be used as energy absorbers and lightweight structures, bone scaffolds and implants in biomechanical applications. A topology optimization method is applied on two predefined design domains as well as a theoretical design approach based on geometrical parameters. In this regard, the optimized structures are geometrically studied and the design areas are formulated parametrically. The topology-optimized graded structures have been manufactured using the SLA 3D printing technology for sample compression tests. Numerical and experimental approaches are applied to them simultaneously and the finite element analyses (FEA) are verified. Finally, a parametric study is done to study the effects of the design variables on the architecture of generated designs and their mechanical properties, revealing a non-linear relation between design variables and properties. This study proposes a theoretical design method based on a topology-optimized design domain. A parametric study has been done, which allows designers to produce various geometries and choose the best one according to their needs. The design step is followed by mechanical characterization of the novel radial structures using experimentally-validated FE analyses.
Parametric optimization framework for designing sandwich panels with auxetic core subjected to impact load
Edinilson A. Costa, Larissa Driemeier
doi:10.1016/j.compstruct.2024.118436
抗冲击夹层板减芯设计的参数化优化框架
An auxetic material can use the negative Poisson ratio to make the impact area denser and better absorb energy. This unique behavior can be exploited for building sandwich panels that absorb more energy per unit of weight. This work proposes a methodology to design lightweight auxetic-core sandwich panels with enhanced impact energy absorption capability. The method is based on an optimization framework whose function is a parameterized Finite Element model of a 3D auxetic structure. Metamodeling is used instead of direct optimization. The performance of different surrogate models, including Artificial Neural Networks, are computed and the best-ranked model is used for the subsequent optimization task carried-out with the aid of a genetic algorithm. The applicability of the framework is demonstrated by creating a sandwich panel with a 3D reentrant auxetic core subjected to a ballistic load, which is 36% lighter than the baseline design and 28% thinner than the literature reference honeycomb sandwich.
The bond strength and failure mode of fibre-reinforced polymer (FRP) bars embedded in ultra-high-performance concrete (UHPC) and ultra-high-performance seawater sea sand concrete (UHPSSC) are significant to ensure the structural integrity of FRP-UHPC/UHPSSC structures. Given the multiplicity influencing bond interaction, conventional methods face challenges in developing predictive models and equations. For precise prediction and comprehensive investigation of bond performance in FRP-UHPC/UHPSSC, this paper employed an effective approach utilising extreme gradient boosting (XGBoost) technique to predict bond strength and failure mode. Two XGBoost predictive models were established based on a dataset comprising 542 data points with 14 input parameters. The developed models demonstrated reliable performances through an exhaustive assessment. SHAP (SHapley Additive exPlanations) analysis was employed to study the influences of input variables considering the bond mechanism. Specifically, the bonded-length-to-diameter ratio is pivotal in bond strength prediction, followed by FRP surface properties, concrete compressive strength and cover-to-diameter ratio; while cover-to-diameter ratio, bar diameter and concrete compressive strength stand out in failure mode prediction. Furthermore, explicit SHAP-based bond strength predictive equations were derived for concrete splitting and pullout failures. The developed model and equation demonstrate a closer approximation to experimental results compared to that in ACI 440.1R-15
纤维增强聚合物(FRP)筋在高性能混凝土(UHPC)和高性能海水海砂混凝土(UHPSSC)中的粘结强度和破坏模式对保证FRP-UHPC/UHPSSC结构的完整性具有重要意义。考虑到影响键相互作用的多样性，传统方法在建立预测模型和方程方面面临挑战。为了准确预测和全面研究FRP-UHPC/UHPSSC的粘结性能，本文采用了一种有效的方法，利用极端梯度增强(XGBoost)技术来预测粘结强度和破坏模式。基于包含542个数据点和14个输入参数的数据集，建立了两个XGBoost预测模型。通过详尽的评估，所开发的模型显示了可靠的性能。采用SHapley加性解释(SHapley Additive explanatory, SHapley可加性解释)分析，考虑键合机制，研究输入变量的影响。具体而言，粘结长径比是预测粘结强度的关键，其次是FRP表面性能、混凝土抗压强度和覆盖直径比;而覆盖直径比、钢筋直径和混凝土抗压强度在破坏模式预测中较为突出。此外，导出了基于shap的混凝土劈裂和拉拔破坏的显式粘结强度预测方程。与aci440.1 r -15相比，所建立的模型和方程更接近实验结果
Damage characterization of CFRP /steel double-lap bonded joints based on AE and DIC
Zhiyuan Zhang, Changhang Xu, Jing Xie, Xueying Sun, Wenao Wang, Na Li
doi:10.1016/j.compstruct.2024.118441
基于声发射和DIC的CFRP /钢双搭接接头损伤表征
CFRP/steeljoints are commonly used in construction and can cause unpredictable damage when subjected to external loading. However, it is still challenging tocharacterize the damage evolution behavior of joints under different loads. In this study, acoustic emission (AE) and digital image correlation (DIC) techniques are used to monitor the damaged state of joints, and a decision tree (DT) algorithm was proposed. From the monitoring results of AE and DIC, it can be found that the damage process of the joint is divided into three stages and is mainly accompanied by four damage modes, namely adhesive failure, cohesive failure, skin failure, and steel deformation. In addition, it also reveals that the AE signal is more sensitive to the early damage of the joint, while the DIC is more sensitive to the late damage of the joint. The identification results of the DT algorithm show that the main damage mechanisms of the joints under the tensile loading conditions are adhesive failure and cohesive failure, while the primary damage mechanism under the bending loading conditions is adhesive failure. The combination of these two techniques successfully enables the damage characterization of joints and provides a framework for analyzing the damage mechanisms of joints.
Compression-compression fatigue tests were carried out to study the compressive fatigue damage mechanisms of a carbon/glass hybrid composite laminate with a manufacturing-induced wrinkle defect. As reported in literature, thin wrinkled composite laminates could show sensibly different fatigue behaviours and damage mechanisms in the presence of tension and compression cyclic loadings. The sensitivities of composites to tension and compression cyclic loadings were not the same. In this study, the damage modes and cracking sequence of a thick wrinkled laminate were identified by the strain fields from digital image correlation (DIC). Acoustic emission (AE) and infrared (IR) thermography were used to detect the damages and explore the potential capabilities of non-destructive evaluation methods when applied to detection of fatigue induced damages in composite structures under operational cyclic loadings. Two primary damage modes were identified and detected before the final failure of the laminate i.e. debonding between the resin-rich layer and the laminate and interlaminar cracks. Debonding occurred earlier than interlaminar cracking. Out-of-plane stresses due to fibre waviness drove the initiation of these damages. Under the settings of AE in this study AE captured early debonding activities but did not detect the micro damage accumulating before the formation of interlaminar crack. Interlaminar crack initiation was tracked by IR thermography at cross-section of the specimen based on the distinct temperature localisations that occur with this micro damage. No distinct temperature localisations occurred during the formation of debonding as it is mode-I driving under compression-compression cyclic loading, so IR thermography did not detect the debonding crack. The results of this study show the potential of using complementary non-destructive damage evaluation methods to inspect early damages in composite structures. The early detection of damages would give early warning signs before the damages become critical. It is found that AE and IR thermography should be used as complementary tools to detect different damage modes.
Energy absorption assessment of recovered shapes in 3D-printed star hourglass honeycombs: Experimental and numerical approaches
Amin Farrokhabadi, Houyu Lu, Xin Yang, Ali Rauf, Reza Talemi, Amir Hossein Behravesh, Seyyed Kaveh Hedayati, Dimitrios Chronopoulos
doi:10.1016/j.compstruct.2024.118444
3d打印星形沙漏蜂窝恢复形状的能量吸收评估:实验和数值方法
This study provides an experimental and numerical evaluation of the energy absorption performance of a 3D-printed star hourglass honeycomb structure with a novel design made from pure and reinforced PLA by chopped carbon fibers and continuous glass fiber. The study further investigates the energy absorption response of this structure after the shape recovery due to thermal stimuli under the quasi-static compressive loading. As an additive manufacturing process, Fused Deposition Modeling is used to produce the specimens with pure and reinforced PLA filament. The difference in the nonlinear response of PLA due to plasticity and damage in tension and compression loading directions, as a feature that helps the shape recovery, is considered in mechanical response analysis using the Finite Element approach. Then, in the obtained results distinguish constitutive laws in tension and compression mechanical properties are employed leading to a failure model using the appropriate algorithm consistent with the experiments. According to the obtained results which reveal good agreement regarding the experimental results, by designing appropriate auxetic configuration selecting suitable geometry parameters, and employing the proper material with diverse properties in tension and compression directions, it is possible to fabricate a lattice structure inherits the shape recovery after the compression deformation which exhibits acceptable energy absorption performance even the second shape recovery.
A novel strategy for constructing electro-conductive segregated network of polyphenylene sulfide-based foam enables electromagnetic shielding effectiveness
Xinyi Liu, Zun Yuan, Yuanchun Zhang, Ping Xu, Xiaowen Zhao, Yun Yu, Lin Ye
doi:10.1016/j.compstruct.2024.118446
一种新型的聚苯硫醚基泡沫导电隔离网络构建策略，使其具有良好的电磁屏蔽效果
Developing polyphenylene sulfide (PPS)-based electromagnetic shielding foam is significant to broaden its applications in aerospace, electronic communications, etc., while introducing too many conductive fillers induced poor foaming ability of PPS. In this work, the skinless PPS foamed beads (S-PPS) were prepared, and coated with epoxy (EP)/carbon nanotubes (CNT) conductive interface layer, while the porous structure of bead surface greatly enhanced interface interaction between the two phases by forming interfacial mechanical interlocking structure with high adhesive strength. Thereby S-PPS@EP/CNT foam with conductive segregated network was obtained by surface adhesion-assisted molding method of supercritical CO2 (scCO2) bead foaming. CNTs were dispersed uniformly and entangled with each other in interface layer, and the conductivity of interface layer and S-PPS@EP/CNT foam increased remarkably with extremely low percolation threshold, attributed to confined distribution of CNTs in interface layer, and perfect conductive segregated network formed at lower CNT content. With increasing CNT content, the complex permittivity, dielectric loss factor and conductivity of foams increased, so that the ability to attenuate electromagnetic waves through polarization loss and conductivity loss was enhanced, showing significantly improved electromagnetic shielding performance and absorption-based shielding mechanism. This work provided a facile and innovative way for fabrication of PPS-based electromagnetic shielding foam.
Composites Part A: Applied Science and Manufacturing
Integrating experimental and numerical analyses for microscale tensile behavior of ceramic particle reinforced TRIP steel composites: A study on local deformation and damage evolution
This study investigates deformation, interfacial, and particle damage in a magnesium-partially stabilized zirconia (Mg-PSZ) particle-reinforced transformation-induced plasticity (TRIP) steel composite using SEM in situ tensile tests and finite element simulations. The simulation models employ an elastic model for ceramic particles and a Johnson-Cook plastic model for the matrix, considering individual perfect cohesive zone model (CZM) and combined CZM/extended finite element method (XFEM) models along the interface. The simulation and experimental results are qualitatively and quantitatively consistent for the initiation and evolution of interfacial and particle failure with a relative error in crack length of only 4.6 %. Furthermore, crack propagation analysis by the debonding angle reveals that damage starts earlier with a sharper particle geometry. Prioritizing non-linear interfacial morphologies in particles and controlling reinforcement edges perpendicular to the loading can achieve lower and constrained debonding angles, thereby continuing to provide a strengthening effect and finally enhancing material behavior.
Additive manufacturing of fiber-reinforced thermosetting composites is of great importance for various applications. However, improving the quality of the fiber/matrix interface under various additive manufacturing processes is still in the early stages. Herein, for the first time, we report the coaxial direct ink writing of zinc oxide (ZnO) functionalized continuous carbon fiber-reinforced thermosetting polymer composites. Both elastomeric and rigid thermosetting polymers reinforced with ZnO functionalized continuous carbon fiber composites can be printed into single filaments with turning angles and multi-layer tall arbitrary structures. The printed ZnO functionalized epoxy composites achieve Young's modulus of 3.69 GPa, which is 15.3% higher than pristine fiber-reinforced composites. The printed composite exhibits resistance under various environmental conditions. Additionally, ZnO functionalization significantly enhanced the fiber-matrix interface strength, with improvements of 57%. The reduced modulus of ZnO functionalized fibers is 174% higher than that of pristine fibers. ZnO nanowires enhance the heating transfer rate of carbon fibers by 17% within the same heating time. Our innovative coaxial direct ink writing offers a general strategy for multi-material printing, laying the groundwork for future additive manufacturing of functional composite devices and structures with enhanced performance.
Customizable 3D-printed decoupled structural lithium-ion batteries with stable cyclability and mechanical robustness
Xu Ma, Yinhua Bao, Na Li, Bo Lu, Yicheng Song, Junqian Zhang, Daining Fang
doi:10.1016/j.compscitech.2024.110783
可定制的3d打印解耦结构锂离子电池，具有稳定的可循环性和机械稳健性
Structural batteries are considered one of the promising strategies for improving the endurance of electric vehicles. However, the trade-off between load-bearing capability and electrochemical performance remains a significant challenge. This paper proposes an efficient 3D printing-assisted fabrication strategy for high-performance structural batteries with customizable geometric configurations. The composite structural battery sample shows a bending modulus of 24.5 GPa, which could withstand maximum tensile stress and three-point bending stress of 155 MPa (specific tensile strength of 88340 N m kg-1) and 123 MPa (specific bending strength of 61553 N m kg-1). Meanwhile, it can achieve a high energy density of 120 Wh kg-1 and 210 Wh L-1 (3.5 mA cm-2) and superior capacity retention of up to 92% after 500 cycles (10.5 mA cm-2). More importantly, the in-situ mechanical-electrochemical test demonstrates exceptional performance, retaining an ultra-high capacity of 98.7% under a tensile stress of 80 MPa, and maintaining a capacity retention rate of 97 % with an average capacity decay per cycle of only 0.18 % under a bending stress of 96.3 MPa. In addition, finite element analysis is also used to verify the failure mechanism of the battery under bending load. Meanwhile, the fabricated structural battery can be applied to autonomous mobile robots, showing the multifunction energy storage and load-bearing. As a result, this work showcases the great potential of incorporating high-performance structural batteries into engineering applications such as small-scale warehousing, logistics equipment, and intelligent robotics.
结构电池被认为是提高电动汽车续航能力的有前途的策略之一。然而，在承载能力和电化学性能之间的权衡仍然是一个重大挑战。本文提出了一种高效的3D打印辅助制造策略，用于具有可定制几何结构的高性能结构电池。复合材料结构电池样品的弯曲模量为24.5 GPa，可承受最大拉伸应力155 MPa(比拉伸强度88340 N m kg-1)和三点弯曲应力123 MPa(比弯曲强度61553 N m kg-1)。同时，它可以实现120 Wh kg-1和210 Wh L-1 (3.5 mA cm-2)的高能量密度，并在500次循环(10.5 mA cm-2)后保持高达92%的卓越容量。更重要的是，原位力学电化学测试显示了优异的性能，在80 MPa的拉伸应力下保持了98.7%的超高容量，在96.3 MPa的弯曲应力下保持了97%的容量保持率，平均每循环容量衰减仅为0.18%。此外，还采用有限元分析验证了电池在弯曲载荷作用下的失效机理。同时，制造的结构电池可应用于自主移动机器人，显示出多功能储能和承载能力。因此，这项工作展示了将高性能结构电池纳入小型仓储、物流设备和智能机器人等工程应用的巨大潜力。
Loading rate effect on the shear behavior of the carbon fiber/epoxy interface
Carbon fiber (CF)/epoxy (EP) composites are widely used in structural components. Quasistatic and dynamic shear experiments were designed and conducted to investigate the effect of the loading rate on the shear behavior of the CF/EP interface. Using numerical simulation, the accuracy of the new shear testing methods to test the shear behavior of interface under both quasistatic and dynamic loading conditions was verified. The shear failure stress increases with increasing loading rate, and the failure mode of the CF/EP interface changes from fiber-matrix debonding to almost entirely brittle fracture of the matrix and fiber-matrix debonding. The proposed dynamic shear test method is promising for testing the shear behavior of interface between two kinds of materials or phases, and the shift in the failure mode is a consequence of the effect of the loading rate on the shear behavior of the CF/EP interface.
