【新文速递】2024年11月27日固体力学SCI期刊最新文章

今日更新：Composite Structures 6 篇，Composites Part B: Engineering 2 篇，Composites Science and Technology 1 篇Composite StructuresEffective flexoelectric properties of inclusion-based composites based on strain gradient theory and homogenization techniqueLiangliang Chu, Fuqi Zhou, Guansuo Duidoi:10.1016/j.compstruct.2024.118665基于应变梯度理论和均质化技术的包体基复合材料有效挠电性能研究This study focuses on enhancing flexoelectricity in composites and develops a new micromechanical analytical framework to determine the effective electromechanical properties of inclusion-based flexoelectric composites within the context of SGE. Initially, we specialize in studying isotropic materials and derive the governing Navier equations for the problem. Subsequently, we streamline these differential equations by introducing a Laplacian-type gradient state variable, departing from higher-order gradient-enrichment treatments. The study employs Green’s functions and stress polarization tensors for spherical inhomogeneities, deriving homogenized material properties through volumetric averages of microscopic properties weighted by displacement localization operators. The analytical scheme’s relevance is validated against results from reference models and experimental data. Effective composite properties are evaluated using numerical methods, with an emphasis on assessing the impact of reinforcement on these properties. Our findings lay the foundation for developing a micromechanical method to predict the electromechanical behavior of composites. Specifically, we demonstrate the efficacy of our proposed theory by deriving effective flexoelectric properties of particulate composites.本研究的重点是增强复合材料的挠曲电性能，并开发了一种新的微力学分析框架，以确定在SGE背景下基于内含物的挠曲电复合材料的有效机电性能。最初，我们专注于研究各向同性材料，并推导出该问题的控制Navier方程。随后，我们通过引入拉普拉斯型梯度状态变量来简化这些微分方程，脱离高阶梯度富集处理。该研究采用格林函数和应力极化张量来描述球面非均质性，通过位移局部化算子加权微观特性的体积平均来推导均质材料特性。通过参考模型和实验数据验证了分析方案的相关性。使用数值方法评估有效复合材料的性能，重点是评估增强对这些性能的影响。我们的发现为开发一种微力学方法来预测复合材料的机电行为奠定了基础。具体来说，我们通过推导颗粒复合材料的有效挠曲电性能来证明我们提出的理论的有效性。An ultrathin ultralight electromagnetic absorber based on shortcut glass-coated amorphous magnetic Fiber/Salisbury-like screenHui Ji, Hong Xiao, Xinyi Ruan, Jianying Chen, Guoliang Dai, Ni Wangdoi:10.1016/j.compstruct.2024.118667基于快速玻璃涂层非晶磁性纤维/索尔兹伯里屏的超薄超轻电磁吸收器A structural design methodology is proposed for an ultrathin, ultralight, and absorption-adjustable electromagnetic absorber. The proposed absorber (SFSL) consists of an absorbing layer with shortcut glass-coated amorphous magnetic fiber and a substrate layer with transmitting material. This absorber features a Salisbury-like screen structure and incorporates multiple loss mechanisms. By investigating the influence of fiber distribution, length, content, and substrate layer thickness on absorption performance, it has been determined that the weight per square meter and thickness of a single-layer SFSL can be lowered within 50 g/m2 and 1.5 mm respectively. Furthermore, the absorption intensity and bandwidth can be adjusted by manipulating these parameters. The SFSL exhibits resonant behavior similar to that of a metamaterial absorber; however, SFSL with randomly distributed fibers demonstrates broader and stronger absorption characteristics in the frequency range from 2 to18 GHz. Additionally, the thicknesses of the substrate layer and surface covering affect the electromagnetic response characteristics. This work provides a simple strategy for constructing an ultrathin and ultralight composite to achieve efficient absorption of electromagnetic waves.提出了一种超薄、超轻、吸光度可调电磁吸收体的结构设计方法。所提出的吸波器（SFSL）由具有近距离玻璃涂层的非晶磁性光纤的吸收层和具有透射材料的基板层组成。这种吸收器具有索尔兹伯里式的屏幕结构，并结合了多种损耗机制。通过研究纤维分布、长度、含量和衬底层厚度对吸光性能的影响，确定单层SFSL的每平方米重量和厚度分别可以降低在50 g/m2和1.5 mm以内。此外，可以通过控制这些参数来调节吸收强度和带宽。SFSL具有类似于超材料吸收体的谐振特性；而光纤随机分布的SFSL在2 ~ 18 GHz频率范围内具有更宽、更强的吸收特性。此外，衬底层和表面覆盖层的厚度也会影响电磁响应特性。这项工作为构建超薄和超轻的复合材料提供了一种简单的策略，以实现电磁波的有效吸收。Machine learning for nano-level defect detection in aligned random carbon nanotubes-reinforced electrically conductive nanocompositeIskander S. Akmanov, Stepan V. Lomov, Mikhail Y. Spasennykh, Sergey G. Abaimovdoi:10.1016/j.compstruct.2024.118651定向随机碳纳米管增强导电纳米复合材料纳米级缺陷检测的机器学习Machine learning allows fast nano-scale defect detection in polymer-impregnated aligned carbon nanotube (CNT) nanocomposites. Digital twins were populated by TEM-validated geometry; considered defects were flat cracks and close-to-spherical voids. Finite-element analysis of piezoresistive response was conducted by embedment of CNT network into matrix. Identification of a defect by change in CNT network piezoresistivity was challenged by: (1) randomness of CNTs’ shapes and placement, ML training happened on random realisations; (2) high strength of CNTs leading to the preservation of conductive paths along CNTs and changes only in conductivities of tunnelling contacts. “Artificial approximation“ was introduced to economise computer time multi-fold: ML was trained on cases with artificially degraded tunnelling conductivities within the defect. Three ML models: XGBoost, fully connected, and convolution neural networks were employed. All models managed the task for near-spherical voids, but performed poorly for flat cracks, due to the limited number of tunnelling contacts in crack volume. When trained on the mixed set of voids and cracks, both neural networks demonstrated the ability to learn the difference and detected even cracks, while XGBoost was not up to the challenge. By metrics, the convolutional neural network demonstrated the highest accuracy of predictions.机器学习允许在聚合物浸渍排列碳纳米管（CNT）纳米复合材料中快速检测纳米级缺陷。数字双胞胎由tem验证的几何图形填充；考虑的缺陷是平坦的裂纹和接近球形的空隙。将碳纳米管网络嵌入到矩阵中，进行了压阻响应的有限元分析。通过碳纳米管网络压电阻率的变化来识别缺陷面临以下挑战：(1)碳纳米管形状和位置的随机性，机器学习训练发生在随机实现上；(2)碳纳米管的高强度使得沿碳纳米管的导电路径得以保留，只改变了隧道触点的电导率。引入“人工近似”以节省计算机时间：ML在缺陷内人为降低隧道电导率的情况下进行训练。使用了三种ML模型：XGBoost、全连接和卷积神经网络。所有模型都可以处理近球形空洞的任务，但由于裂纹体积中隧道接触的数量有限，对于扁平裂纹表现不佳。当在空洞和裂缝的混合集上进行训练时，两种神经网络都表现出了学习差异的能力，甚至可以检测到裂缝，而XGBoost无法应对挑战。通过度量，卷积神经网络显示出最高的预测准确性。Experimental investigation of the behavior of UHPCFST under repeated eccentric compressionChunlei Yu, Min Yu, Lihua Xu, Liu Sumei, Zewen Sun, Jianqiao Yedoi:10.1016/j.compstruct.2024.118661反复偏心压缩下UHPCFST性能的实验研究This paper investigates the mechanical behavior of ultra-high-performance concrete-filled steel tubes (UHPCFST) under repeated eccentric compression. A total of 30 UHPCFST specimens are designed, fabricated, and tested. The design variables include steel tube thickness, UHPC type, loading eccentricity and load pattern. Failure modes, force-axial shortening curves, section strain distributions, lateral deflection distributions, bearing capacity and stiffness are studied. Three failure modes, i.e., steel tube bulge, compressive crush and tensile crack of the UHPC infill are observed. Specimens with larger loading eccentricity and thinner steel tube are more likely to exhibit all the three modes. Subjected to eccentric loading, the compressive strength and stiffness of the UHPCFST increase significantly with the increase of steel tube thickness and UHPC strength. In the case of repeated loading, stiffness degradation is observed. Existing formulas for the N-M curve and the eccentric compressive capacity are evaluated against the test results. A formula for eccentric compressive stiffness is derived based on the parabolic function assumption. Additionally, an empirical model is introduced to describe the force-axial shortening relationship of the UHPCFST under repeated eccentric compression, which may be applied in practical design and analysis.本文研究了超高性能钢管混凝土（UHPCFST）在反复偏心受压作用下的力学性能。共设计、制作和测试了30个UHPCFST试件。设计变量包括钢管厚度、UHPC类型、加载偏心和加载方式。研究了破坏模式、力-轴缩短曲线、截面应变分布、侧向挠度分布、承载力和刚度。观察到钢管胀裂、压碎和拉裂三种破坏模式。加载偏心率越大、钢管越薄的试件更容易出现三种模态。在偏心载荷作用下，随着钢管厚度的增加和UHPC强度的增加，UHPCFST的抗压强度和刚度显著增加。在重复加载的情况下，观察到刚度退化。根据试验结果对现有的N-M曲线和偏心抗压能力公式进行了评价。基于抛物线函数假设，导出了偏心抗压刚度的计算公式。此外，还引入了一个经验模型来描述UHPCFST在反复偏心压缩下的力-轴向缩短关系，该模型可用于实际设计和分析。Mechanical model analysis of column-footing joints with combined socket-corrugated pipe connectionXiaolong Si, Yanchen Song, Guangda Zhang, Qiang Han, Xiuli Du, Bin Liudoi:10.1016/j.compstruct.2024.118666套筒-波纹管组合式柱-基础节点力学模型分析The socket connection method is widely used in precast column, particularly in seismic regions. However, reducing the socket-depth to lower costs may lead to shear failure in the socketed part of the columns. To address this issue and achieve cost objectives, a new approach combines shallow sockets with corrugated pipes for column-footing joints. Comparative tests were conducted to investigate failure in columns with socket-corrugated pipe connections (SCPC), shallow sockets (SSC), and cast-in-place (CIP). Furthermore, finite element models were employed to validate the experimental and simplified model results. The findings suggest potential shear failure in shallow socket connections, which can be mitigated by using the combined socket-corrugated pipe method that alters force transmission paths. As the axial load ratio increases, both the ultimate lateral load capacity of the specimen and the local stresses at the column base increase. In addition, the ultimate lateral load capacity of the column and the stress of the connection reinforcement are increased by increasing the strength of the longitudinal reinforcement, consequently amplifying the extent of joint area damage. Finally, a simplified strut-and-tie model of the SCPC, validated against numerical and experimental data, accurately represents force paths, ultimate lateral load capacity and failure modes in socket joints.嵌套连接法在预制柱中得到了广泛的应用，特别是在震区。然而，为了降低成本而减小嵌套深度可能会导致柱嵌套部分的剪切破坏。为了解决这一问题并实现成本目标，一种新的方法将浅插座与波纹管结合起来用于柱基础连接。进行了对比试验，研究了嵌套-波纹管连接（SCPC）、浅嵌套（SSC）和现浇（CIP）柱的破坏情况。采用有限元模型对实验结果和简化模型结果进行了验证。研究结果表明，浅套筒连接的潜在剪切破坏可以通过使用改变力传递路径的套筒-波纹管组合方法来减轻。随着轴向荷载比的增大，试件的极限侧载能力和柱底局部应力均增大。此外，纵筋强度的增加增加了柱的极限侧载能力和连接筋的应力，从而扩大了节点区域的破坏程度。最后，通过数值和实验数据验证了SCPC的简化杆扎模型，该模型准确地反映了承插节点的受力路径、极限侧向载荷能力和破坏模式。Composites Part B: EngineeringFibre waviness reduction in thermoplastic pultrusion by using DREF yarnsMaissaloun El-Jakl, Louis Laberge Lebeldoi:10.1016/j.compositesb.2024.111908用DREF纱降低热塑性拉挤中的纤维波浪度Non-reactive thermoplastic pultrusion impregnation issues are mitigated by using hybrid input materials. Co-wound (CW) and commingled yarns are an assembly of continuous polymer and reinforcement fibres. Continuous thermoplastic fibres have shown to induce waviness in the reinforcement fibres during pultrusion due to their shrinkage at high temperature. DREF yarns are composed of a core of continuous reinforcement fibres onto which discontinuous polymer fibres are applied using the friction spinning process. This study, based on the application of 3N and 0N tension on CW and DREF yarns, aimed to highlight the contribution of discontinuous polymer fibres on reducing reinforcement waviness in pultruded rods. CW yarns’ reaction to heating showed continuous polyethylene terephthalate (PET) fibres shrinkage resulting in wavy glass fibres (GF). Conversely, the GF in DREF yarns remained straight. Pultrusion experiments with yarn tension of 3N were done to alleviate the GF waviness. However, the porosity was rather high at 4.2% for CW rods and 2.3% for DREF rods. Pultrusion experiments without tension showed lower porosity of level of 2.9% for CW yarns and as low as 1.1% for DREF yarns. However, CT-scan image indicated GF waviness in CW rods. GF in DREF rods remained straight. The in-plane shear strength reached 119 MPa. Thermoplastic pultrusion using DREF yarns resulted in composites without reinforcement fibre waviness, lower porosity level and superior shear strength.非反应性热塑性拉挤浸渍问题通过使用混合输入材料得到缓解。共卷纱和混纺纱是由连续聚合物和增强纤维组成的纱线。连续热塑性纤维由于在高温下收缩，在拉挤过程中会引起增强纤维的波纹。DREF纱线由连续的增强纤维芯组成，在其上采用摩擦纺丝工艺应用不连续的聚合物纤维。本研究基于3N和0N张力在CW和DREF纱线上的应用，旨在突出不连续聚合物纤维在减少拉挤棒中的增强波浪度方面的贡献。连续化纤对加热的反应表明，聚酯纤维连续收缩，形成波浪状的玻璃纤维。相反，DREF纱线中的GF保持直。为了减轻纤维的波纹，进行了纱线张力为3N的拉挤实验。然而，CW棒的孔隙率相当高，为4.2%，DREF棒为2.3%。无张力拉挤实验表明，连续化纤纱线的孔隙率为2.9%，而DREF纱线的孔隙率为1.1%。然而，ct扫描图像显示在CW棒GF波状。在DREF棒中GF保持直。面内抗剪强度达到119 MPa。采用DREF纱线进行热塑性拉挤制备的复合材料无增强纤维波纹，孔隙率低，抗剪强度高。A novel model for predicting deformation of thermoplastic composites during heat-pressing processJiezheng Qiu, Zhonghai Xu, Chaocan Cai, Dianyu Chen, Shiging Huang, Chunxing Hu, Xiaodong Hedoi:10.1016/j.compositesb.2024.111912一种预测热塑性复合材料热压变形的新模型Carbon fiber/polyetheretherketone (CF/PEEK) thermoplastic composites are widely used in the aerospace industry due to their excellent mechanical properties and high-temperature resistance. However, the research on heat-pressing deformation and residual stress during high-temperature and high-pressure heat-pressing processes in CF/PEEK was relatively deficient. In this paper, a framework coupled with crystallization kinetics, micromechanics and thermodynamics was developed to predict the heat-pressing deformations of CF/PEEK and it was conducted by UMAT, DISP and UEXPAN subroutines. Moreover, the predictive model was verified by experiments effectively. Finally, we compared the difference in residual stress distributions between symmetric and asymmetric lay-ups and found that the melting temperature, thickness, angle and sequence of layers have a significant impact on the heat-pressing deformation. This work provided an effective tool for predicting heat-pressing deformations, which is great of significance in the manufacturing and application of CF/PEEK.碳纤维/聚醚醚酮（CF/PEEK）热塑性复合材料因其优异的机械性能和耐高温性能而广泛应用于航空航天工业。然而，对CF/PEEK高温高压热压过程中的热压变形和残余应力的研究相对缺乏。本文建立了一个结合结晶动力学、微观力学和热力学的框架，通过UMAT、DISP和UEXPAN子程序对CF/PEEK的热压变形进行了预测。通过实验验证了该预测模型的有效性。最后，对比了对称层和非对称层的残余应力分布差异，发现熔化温度、层厚、层角和层序对热压变形有显著影响。该工作为预测CF/PEEK的热压变形提供了有效的工具，对CF/PEEK的制造和应用具有重要意义。Composites Science and TechnologyVascular Bundle-Structured Polymeric Composites with Fire-safe, Self-detecting and Heat Warning Capabilities for Power Batteries Thermal ManagementXinyan An, Nvfan Tang, Yilin Liu, Shiqiang Song, Chaoyue Chen, Guohao Han, Weizhen Li, Yong Zhangdoi:10.1016/j.compscitech.2024.110921 用于动力电池热管理的具有火灾安全、自探测和热预警能力的维管束结构聚合物复合材料The trend of miniaturization and integration poses challenges to the thermal management of electronic devices, requiring high thermal conductivity and potential fire safety, etc. In this study, inspired by plant vascular structure, we developed a polymer composite with a vertical vascular bundle structure via a sacrificial template method and subsequent assembly of transition metal carbides/nitrides (MXene) nanosheets and phytic acid (PA) coordinated cobalt ions (Co2+) complex. The embedded MXene and PA@Co exhibit multilayer multiscale structural features, forming heat transfer channels and protective cells within the composite. The resultant composites possess high out-of-plane thermal conductivity (∼1.54 W‧m-1‧k-1) and excellent flame retardancy, including self-extinguishing, and significantly reduced heat and smoke release. Interestingly, the MXene vascular bundle structure imparts heat early warning capabilities and intelligent damage self-detection, suggesting an effective means of preventing early-stage fires and real-time monitoring of composite structural and functional integrity. Such biomimetic strategies enable new insights into the designing of multifunctional, intelligent polymer composites.小型化和集成化的趋势对电子器件的热管理提出了挑战，要求高导热性和潜在的火灾安全等。在本研究中，受植物维管束结构的启发，我们通过牺牲模板法和随后的过渡金属碳化物/氮化物（MXene）纳米片和植酸（PA）配位钴离子（Co2+）配合物的组装，开发了具有垂直维管束结构的聚合物复合材料。嵌入的MXene和PA@Co表现出多层多尺度的结构特征，在复合材料内部形成传热通道和保护细胞。合成的复合材料具有高的面外导热系数（约1.54 W·m·1·k-1）和优异的阻燃性，包括自熄性，并显着减少热量和烟雾释放。有趣的是，MXene维管束结构具有热预警能力和智能损伤自检测能力，是预防早期火灾和实时监测复合材料结构和功能完整性的有效手段。这种仿生策略为多功能智能聚合物复合材料的设计提供了新的见解。来源：复合材料力学仿真Composites FEM