首页/文章/ 详情

【新文速递】2024年2月14日复合材料SCI期刊最新文章

15天前浏览587

   

今日更新:Composites Part A: Applied Science and Manufacturing 2 篇,Composites Part B: Engineering 2 篇,Composites Science and Technology 2 篇

Composites Part A: Applied Science and Manufacturing

Methodology to Establish a Forming Process Window for Thermoset Aligned Discontinuous Fiber Composites

Loren J. Tomlin, Thomas A. Cender, Steven Sauerbrunn, Suresh G. Advani

doi:10.1016/j.compositesa.2024.108064

为热固性排列不连续纤维复合材料建立成型工艺窗口的方法学

Highly aligned discontinuous fiber composites have been pursued with the goal of achieving high performance properties with the formability of short fiber composites. The feedstock consists of a highly aligned discontinuous fiber preform which can be combined with thermoplastic or thermoset resins to create prepreg that can extend in the fiber direction. With this added benefit of lamina extensibility in the fiber direction, a methodology is needed to determine the degradation of material quality with applied forming strain. A framework is established to define a forming process window which sets the optimal process conditions—temperature and strain rate—for maintaining lamina uniformity after deformation. Digital image correlation was used to measure strain uniformity for samples stretched in uniaxial tension at constant temperature and strain rate. The experimental results show that forming strain rate should increase with increasing process temperature. The process window established in this work will be used to ensure that material uniformity can be optimized in manufacturing trials and other material characterization evaluations.

高度对齐的非连续纤维复合材料的目标是在短纤维复合材料可成型性的基础上实现高性能特性。这种原料由高度对齐的非连续纤维预型件组成,可与热塑性或热固性树脂结合,制成可在纤维方向延伸的预浸料。有了纤维方向层状延伸性这一附加优势,就需要一种方法来确定材料质量随施加成型应变而下降的情况。我们建立了一个框架来定义成型工艺窗口,该窗口设定了最佳工艺条件--温度和应变率,以保持变形后的薄片均匀性。使用数字图像相关技术测量了在恒定温度和应变率下单轴拉伸样品的应变均匀性。实验结果表明,成型应变率应随着加工温度的升高而增加。这项工作中建立的工艺窗口将用于确保在制造试验和其他材料表征评估中优化材料的均匀性。


A metal-based microencapsulated phase change material (MEPCM) with high thermal conductivity, electrical insulation and flame retardancy and its application in epoxy resin

Yuanyuan Chen, Chenwu Shi, Xiaojie Guo, Chunyao Qing, Deqiu Zou

doi:10.1016/j.compositesa.2024.108081

 

具有高导热性、电绝缘性和阻燃性的金属基微胶囊相变材料 (MEPCM) 及其在环氧树脂中的应用

Using the “double-layer coating, sacrificial inner layer” method, MEPCM with a thermal expansion void was prepared by encapsulating Sn particles into a magnesium hydroxide shell. The results showed that MEPCM exhibited better thermal reliability than those without a thermal expansion void. More importantly, the Sn was selected as the core material that MEPCM was enabled to have large volume latent heat (425.2 J/cm3) and high thermal conductivity (10.06 W/m·K), and magnesium hydroxide was chosen as the shell material that MEPCM was given great heat absorption ability (260 J/g), excellent electrical insulation performance and flame retardancy. By adding 20 vol% MEPCM to EP, the thermal conductivity of the composite improved 164.9%. The volume resistivity of EP/MEPCM was 2.1×1012 Ω·cm. The pHRR and THR of EP/MEPCM composite were only 471.64 kW/m2 and 12.95 m2, respectively. The existence of MEPCM enhanced the thermal conductivity, electrical insulation performance and flame retardancy of EP.

采用 "双层涂层,牺牲内层 "的方法,将锡颗粒封装到氢氧化镁外壳中,制备出了具有热膨胀空隙的 MEPCM。结果表明,与没有热膨胀空隙的 MEPCM 相比,MEPCM 具有更好的热可靠性。更重要的是,选择锡作为核心材料,可使 MEPCM 具有较大的体积潜热(425.2 J/cm3)和较高的热导率(10.06 W/m-K);选择氢氧化镁作为外壳材料,可使 MEPCM 具有较强的吸热能力(260 J/g)、优异的电绝缘性能和阻燃性。在 EP 中加入 20 Vol% 的 MEPCM 后,复合材料的导热率提高了 164.9%。EP/MEPCM 的体积电阻率为 2.1×1012 Ω-cm。EP/MEPCM 复合材料的 pHRR 和 THR 分别仅为 471.64 kW/m2 和 12.95 m2。MEPCM 的存在提高了 EP 的导热性、电绝缘性能和阻燃性。


Composites Part B: Engineering

End-of-Life wind turbine blades: Review on recycling strategies

Francesca Spini, Paolo Bettini

doi:10.1016/j.compositesb.2024.111290

报废风力涡轮机叶片:回收战略回顾

The review focuses on End-of-Life (EoL) strategies, with a primary emphasis on recycling techniques, to manage fiber reinforced thermoset polymer waste from decommissioned wind turbine blades. Wind energy has recently become one of the most important sources of electricity. Over the next few years, further growth is expected, leading to increasing amounts of EoL waste, and especially composite waste, which is difficult to recycle. Glass fiber reinforced polymer (GFRP) is the predominant composite material used in blades. However, the increasing size of next-generation wind turbine blades is also driving the adoption of carbon fiber reinforced polymer (CFRP). GFRP is often recycled through cement kiln process or mechanically due to its low-cost. Thus, research is needed on cost-effective methods that can recover valuable glass fibers. On the other hand, CFRP is a high-value material, justifying the use of high-cost recycling approaches compared to virgin fiber production.

这篇综述主要介绍报废(EoL)策略,重点是回收技术,以管理退役风力涡轮机叶片产生的纤维增强热固性聚合物废物。风能最近已成为最重要的电力来源之一。在未来几年内,预计风能将进一步增长,从而产生越来越多的 EoL 废物,尤其是难以回收利用的复合材料废物。玻璃纤维增强聚合物(GFRP)是叶片中使用的主要复合材料。然而,下一代风力涡轮机叶片尺寸的不断增大也推动了碳纤维增强聚合物(CFRP)的采用。由于成本低廉,GFRP 通常通过水泥窑工艺或机械方法进行回收。因此,需要研究可回收有价值玻璃纤维的经济有效的方法。另一方面,CFRP 是一种高价值材料,与原始纤维生产相比,有理由使用高成本回收方法。


Study on HAZ extension characteristics during laser ablation of CFRP based on dimensional analysis

Han Liang, Shusen Zhao, Haijun Yu, Lu Jiang, Zhiyan Zhang, Xuechun Lin

doi:10.1016/j.compositesb.2024.111295

 

基于尺寸分析的 CFRP 激光烧蚀过程中 HAZ 拉伸特性研究

Heat affected zone (HAZ) is one of the key factors in evaluating quality in laser processing of carbon fiber reinforced polymer (CFRP). To achieve a systematic and quantitative description of continuous wave (CW) and pulsed wave (PW) laser ablation of CFRP, dimensional analysis was applied to establish the HAZ extension models. The HAZ morphology and fracture microstructure were characterized, and the characteristics of the ablation plume and gas diffusion were observed. The HAZ extension models show good prediction effect on HAZ and the key dimensionless numbers that determine the HAZ are found. Relating the dimensionless numbers to the HAZ extension characteristics provides a quantitative optimization direction for avoiding excessive ablation. Differences in the heat accumulation process of CW laser and PW laser ablation are concluded, which lead to complex comprehensive effect among the parameters. The resulting differences in the effects of CW and PW laser parameters on the HAZ are comparatively studied. PW laser ablation under the parameters of high repetitive frequency and low scanning speed is found to exhibit the properties of CW laser in the HAZ extension characteristics including size and morphology.

热影响区(HAZ)是评估碳纤维增强聚合物(CFRP)激光加工质量的关键因素之一。为了系统、定量地描述连续波(CW)和脉冲波(PW)激光烧蚀碳纤维增强聚合物的过程,应用尺寸分析法建立了热影响区扩展模型。对 HAZ 形态和断口微观结构进行了表征,并观察了烧蚀羽流和气体扩散的特征。HAZ扩展模型对HAZ显示出良好的预测效果,并找到了决定HAZ的关键无量纲数。将无量纲数与热影响区扩展特征联系起来,为避免过度烧蚀提供了定量优化方向。总结出 CW 激光和 PW 激光烧蚀的热积累过程存在差异,从而导致参数之间产生复杂的综合效应。比较研究了 CW 和 PW 激光参数对 HAZ 影响的差异。结果发现,在高重复频率和低扫描速度的参数下,PW 激光烧蚀在 HAZ 的扩展特征(包括尺寸和形态)方面具有 CW 激光的特性。


Composites Science and Technology

Electrostatically self-assembled three-dimensional conductive network for highly sensitive and reliable skin-like strain sensor

Shengkai Li, Jian Tang, Yudong Liu, Jing Hua, Jinhui Liu

doi:10.1016/j.compscitech.2024.110493

 

静电自组装三维导电网络,用于制造高灵敏度、高可靠性的类肤应变传感器

In recent years, flexible strain sensors have garnered significant attention in industrial manufacturing and daily life. Sensitivity and reliability are two crucial characteristics of flexible strain sensors in practical applications, and they depend on the development of the sensor's internal conductive network. However, the aggregation phenomenon of conductive fillers in the elastic matrix has a serious impact on the construction of a developed conductive network. In this work, we have designed electropositive amino-functionalized carbon nanotubes (CNTs-p) based on the electrostatic self-assembly of electronegative MXene in the aqueous phase. Compared to the use of surfactants, the electrical modulation of carbon nanotubes through chemical bonding modification is more robust and the electrostatic self-assembly with MXene is more stable. CNTs-p and MXene were self-assembled by electrostatic attraction in butyl latex and uniformly dispersed in the latex. Following demulsification, the polymer composite film (MXene&CNTs-p/IIR) with a three-dimensional conductive network was obtained. The skin-like strain sensor, which utilizes the conductive composite film, demonstrates high sensitivity (gauge factor (GF) = 35137 that is among the highest values for the reported strain sensor), remarkable reliability (The signal monitoring capability remains after 15000 cycles), and excellent responsiveness (62 ms). Additionally, the skin-like strain sensor boasts a wide detection range (0–431%) and unprecedented stability, enabling strain sensing functionality in a wide temperature range of -10—100 °C, as well as strong acid (pH = 1) and strong alkali (pH = 11) environment. The preparation of MXene&CNTs-p/IIR provides a safe, environmentally friendly and effective method for improving the sensitivity and reliability of flexible sensors in wearable intelligent electronics and health detection.

近年来,柔性应变传感器在工业制造和日常生活中备受关注。灵敏度和可靠性是柔性应变传感器在实际应用中的两个关键特性,而这两个特性取决于传感器内部导电网络的发展。然而,导电填料在弹性基体中的聚集现象严重影响了导电网络的构建。在这项工作中,我们基于电负性 MXene 在水相中的静电自组装,设计出了电正性氨基功能化碳纳米管(CNTs-p)。与使用表面活性剂相比,通过化学键修饰对碳纳米管进行电学调制的效果更强,与 MXene 的静电自组装也更稳定。CNTs-p 和 MXene 通过静电吸引在丁基胶乳中自组装,并均匀地分散在胶乳中。破乳后,得到了具有三维导电网络的聚合物复合薄膜(MXene&CNTs-p/IIR)。利用该导电复合薄膜制成的类肤应变传感器具有高灵敏度(测量系数 (GF) = 35137,是目前已报道的应变传感器中最高值之一)、卓越的可靠性(15000 次循环后仍能保持信号监测能力)和出色的响应速度(62 毫秒)。此外,这种类似皮肤的应变传感器还具有很宽的检测范围(0-431%)和前所未有的稳定性,可在 -10-100 °C 的宽温度范围以及强酸(pH = 1)和强碱(pH = 11)环境中实现应变传感功能。MXene&CNTs-p/IIR 的制备为提高可穿戴智能电子产品和健康检测领域柔性传感器的灵敏度和可靠性提供了一种安全、环保和有效的方法。


Construction of micro-nano hybrid structure based on carbon nanotube whisker and alumina for thermally conductive yet electrically insulating silicone rubber composites

Xiaowang Ji, Zhaoyu Lu, Junyan Wang, Neng Ye, Huan Zhang, Letian Zhou, Jingchao Li, Yonglai Lu

doi:10.1016/j.compscitech.2024.110495

 

构建基于碳纳米管晶须和氧化铝的微纳混合结构,用于导热和绝缘硅橡胶复合材料

High-performance electronics urgently need more effective thermally conductive rubber composites to solve interfacial heat transfer problems in the thermal management systems. Tiny amounts nanocarbon materials (NCM) can significantly improve the thermal conductivity of conventional ceramic-filled rubber composites, but the volume exclusion effect of micrometer ceramic fillers makes NCM highly susceptible to the formation of the conductive pathways, which inevitably leads to the substantial decrease in the volume resistivity of the materials, posing a safety hazard, such as short circuits, to electronic devices. Here, we report an electrostatic self-assembly method to prepare CNW@n-Al2O3 hybrids by loading nano-alumina (n-Al2O3) onto carbon nanotube whiskers (CNW) and co-filling them with micrometer alumina (m-Al2O3) to silicone rubber, constructing a micro-nano-multi-level hybrid network structure, which can fully utilize the high thermal conductivity while shielding the electrical conductivity of CNW. The resulting composite filled with 2 phr of CNW@n-Al2O3 exhibits a significantly enhanced thermal conductivity of 1.137 W/(m·K) and a high volume resistance of 1.323 × 109 Ω cm, and is proved to be used as an excellent thermal interface material to assist the heat dissipation of the microelectronic chip. This study provides a facile and effective strategy for the design of thermally conductive yet electrically insulating rubber composites filled with CNW, which shows a bright application prospect in the thermal management of high-performance electronic devices.

高性能电子产品迫切需要更有效的导热橡胶复合材料来解决热管理系统中的界面传热问题。微量纳米碳材料(NCM)可显著提高传统陶瓷填充橡胶复合材料的导热性能,但微米级陶瓷填料的体积排斥效应使 NCM 极易形成导电通路,从而不可避免地导致材料的体积电阻率大幅下降,给电子设备带来短路等安全隐患。在此,我们报告了一种制备 CNW@n-Al2O3 混合材料的静电自组装方法,即在碳纳米管晶须(CNW)上负载纳米氧化铝(n-Al2O3),并在硅橡胶中共同填充微米氧化铝(m-Al2O3),构建微纳多层次混合网络结构,从而在屏蔽 CNW 导电性的同时充分利用其高热传导性。填充了 2 phr 的 CNW@n-Al2O3 的复合材料的热导率显著提高,达到 1.137 W/(m-K),体积电阻高达 1.323 × 109 Ω cm,可用作优良的热界面材料,帮助微电子芯片散热。该研究为设计填充了氯化萘的导热绝缘橡胶复合材料提供了一种简便有效的策略,在高性能电子设备的热管理方面具有广阔的应用前景。



来源:复合材料力学仿真Composites FEM
ACTMechanicalSystemDeform复合材料化学电力电子ADS芯片风能材料试验
著作权归作者所有,欢迎分享,未经许可,不得转载
首次发布时间:2024-11-06
最近编辑:15天前
Tansu
签名征集中
获赞 3粉丝 0文章 679课程 0
点赞
收藏
作者推荐

【新文速递】2024年2月18日固体力学SCI期刊最新文章

今日更新:International Journal of Solids and Structures 1 篇,Mechanics of Materials 1 篇,International Journal of Plasticity 2 篇,Thin-Walled Structures 4 篇International Journal of Solids and StructuresWet adhesion on rough surfaces: A JKR model with thermodynamic considerationsYi Sun, Zongda Xie, Peiying He, Guozhuang Xu, Xiufeng Wangdoi:10.1016/j.ijsolstr.2024.112714 粗糙表面上的湿附着力:考虑热力学因素的 JKR 模型Understanding wet adhesion is vital for advancing technologies such as underwater robotics, aquatic microsystems, and sweat-interfaced devices. It involves the formation of a liquid bridge with a meniscus between two solid surfaces. This phenomenon has a significant impact on surface adhesion, particularly in relation to roughness. Determining the profile of this liquid bridge is critical for accurately characterizing wet adhesion. In this paper, we propose a JKR mechanical model combined with a thermodynamic approach to investigate adhesive contact between a spherical indenter and an axisymmetric wavy surface in a wetting environment. The numerical solution for the pull-off force is obtained by considering parameters such as waviness, roughness, liquid volume, and liquid surface energy. Experimental validation is conducted to support the theoretical findings and provide insights into wet adhesion mechanisms on rough surfaces.了解湿附着力对于水下机器人、水下微系统和汗液界面设备等技术的发展至关重要。它涉及在两个固体表面之间形成带有半月板的液桥。这种现象对表面附着力有重大影响,特别是与粗糙度有关。确定这种液桥的轮廓对于准确表征湿附着力至关重要。在本文中,我们提出了一种结合热力学方法的 JKR 机械模型,用于研究球形压头与轴对称波浪形表面在湿润环境中的粘附接触。通过考虑波浪度、粗糙度、液体体积和液体表面能等参数,得到了拉脱力的数值解。实验验证为理论结论提供了支持,并为粗糙表面的湿粘附机制提供了启示。Mechanics of MaterialsNotes on smooth and singular volumetric growthVladimir Goldshtein, Reuven Segevdoi:10.1016/j.mechmat.2024.104950关于平稳和奇异体积增长的说明The material structure of bodies undergoing growth is considered. In the geometric framework of a general differential manifold modeling the physical space and a fiber bundle modeling spacetime, body points may be defined for any extensive property for which a smooth flux field exists, even if the property is not conserved. Singular flux fields are considered using the notion of a de Rham current. Writing a generalized balance law using the boundary of the current corresponding to a singular flux field, surface growth is unified with volumetric growth.研究考虑了正在生长的物体的物质结构。在模拟物理空间的一般微分流形和模拟时空的纤维束的几何框架中,可以为存在平滑通量场的任何广泛属性定义体点,即使该属性不守恒。奇异通量场是用德拉姆电流的概念来考虑的。利用奇异通量场对应的电流边界写出广义平衡定律,就可以将表面增长与体积增长统一起来。International Journal of PlasticityGurson-Cohesive Modeling (GCM) for 3D Ductile Fracture SimulationJihyuk Park, Soondo Kweon, Kyoungsoo Parkdoi:10.1016/j.ijplas.2024.103914用于三维韧性断裂模拟的古尔松粘合剂模型 (GCM)A Gurson-Cohesive Model (GCM) is proposed to investigate 3D ductile fracture accounting for the void growth, coalescence, and complete failure phenomena. The proposed model idealizes the ductile fracture process as continuum damage evolution, cohesive crack initiation, nonlinear softening along the crack surface, and complete failure. The Gurson model is employed to describe continuum damage with void growth, while the cohesive zone model is utilized to introduce discontinuous cracks and represent nonlinear softening behavior along the crack surfaces. The transition from the continuum damage to discontinuous crack is taken into account systematically using a porosity-based crack initiation criterion considering stress triaxiality. The computational results successfully reproduced the experimental results of fracture tests with 15-5 PH steel and structural carbon steel 20 within the unified modeling framework. Furthermore, strong and stable convergence of global and local responses (e.g., load-displacement curve, area reduction, crack tip location) are demonstrated under the mesh refinement without the aid of any ad hoc characteristic length scale parameter in the simulations.本文提出了一种古尔松内聚模型(GCM),用于研究三维韧性断裂,其中考虑了空隙增长、凝聚和完全破坏现象。该模型将韧性断裂过程理想化为连续损伤演化、内聚裂纹起始、沿裂纹表面的非线性软化和完全破坏。采用 Gurson 模型来描述空隙增长的连续损伤,而采用内聚区模型来引入不连续裂纹并表示沿裂纹表面的非线性软化行为。考虑到应力的三轴性,使用基于孔隙率的裂纹起始准则系统地考虑了从连续损伤到非连续裂纹的过渡。在统一建模框架内,计算结果成功再现了 15-5 PH 钢和结构碳钢 20 的断裂试验结果。此外,在网格细化的情况下,全局和局部响应(如载荷-位移曲线、面积减小、裂纹尖端位置)的收敛性强且稳定,而不需要在模拟中使用任何特别的特征长度尺度参数。A physics-based plasticity study of the mechanism of inhomogeneous strain evolution in dual phase 600 steelMohammad Hasan Joudivand Sarand, I. Burc Misirliogludoi:10.1016/j.ijplas.2024.103918 双相 600 钢中不均匀应变演变机制的物理塑性研究In this study, we employ a physics-based crystal plasticity finite element method (CPFEM) approach to study the microstructural response of DP600 steel to various loading types. With the pursued approach, it is possible link microstructural changes in the dual phase (DP) steel to its macroscopic response in a convenient and efficient manner. Microstructural data were acquired first from experimental work via the electron backscattered diffraction (EBSD) method. DP crystallographic features were then fed to a numerical hybrid calculation subroutine combining a comprehensive physics-based crystal plasticity scheme for ferrite along with an isotropic plasticity scheme for martensite defined on a single-layer representative volume element (RVE). The developed single-layer 3D mode, while allowing for high computational efficiency, can capture the stress/strain distribution, revealing the microscopic features of the deformation process including the physical evolution of the dislocation density, retexturing, and morphology. The single-layer RVE physics-based method employed herein establishes the strong correlation between morphology, dislocation density and deformation response of the material under various loading types. Specifically, findings reveal that the tendency of the ferrite phase neighboring the martensite regions in the DP steel to retexture is much more profound than pure ferrite when subjected to the same loading conditions, pointing out to the steep strain gradients in the former component. Martensite phase facilitates considerable heterogeneity in the stress and strain distribution, increases the misorientation polarization as well as leading to local strain hardening in the neighboring ferrite volume that stem from profound increase in spatial dislocation density. Stress-strain curves under various loading schemes are simulated and discussed in the light of the experimental findings in literature, revealing the dependence of the microstructural evolution on the loading type.在本研究中,我们采用基于物理学的晶体塑性有限元法(CPFEM)来研究 DP600 钢的微观结构对各种加载类型的响应。采用这种方法,可以方便有效地将双相钢(DP)的微观结构变化与其宏观响应联系起来。首先通过电子反向散射衍射(EBSD)方法从实验工作中获取微观结构数据。然后,将 DP 晶体特征输入数值混合计算子程序,该子程序结合了基于物理学的铁素体晶体塑性综合方案和定义在单层代表体积元素 (RVE) 上的马氏体各向同性塑性方案。所开发的单层三维模式在实现高计算效率的同时,还能捕捉应力/应变分布,揭示变形过程的微观特征,包括位错密度、重纹理和形态的物理演变。本文采用的基于物理的单层 RVE 方法确定了形态、位错密度和材料在不同加载类型下的变形响应之间的紧密相关性。具体地说,研究结果表明,在相同的加载条件下,DP 钢中邻近马氏体区域的铁素体相的再质化趋势比纯铁素体更明显,这表明前者存在陡峭的应变梯度。马氏体相促进了应力和应变分布的显著异质性,增加了错取向极化,并导致邻近铁素体体积的局部应变硬化,这源于空间位错密度的显著增加。根据文献中的实验结果,模拟并讨论了各种加载方案下的应力-应变曲线,揭示了微观结构演变对加载类型的依赖性。Thin-Walled StructuresA bistable honeycomb mechanical metamaterial with transformable Poisson's ratio and tunable vibration isolation propertiesBoya Xiao, Yu Liu, Wenshuai Xu, Rongyao Wei, Meng Chen, Heng Jiangdoi:10.1016/j.tws.2024.111718具有可变泊松比和可调隔振特性的双稳态蜂窝机械超材料With the increasing demand for vibration-isolation structures with tunable and multifunctional properties driven by the rapid development of complex engineering applications, metamaterials have emerged as promising candidates for this purpose owing to their extraordinary properties derived from their unique structural configurations. Owing to their unique deformation mechanisms, negative Poisson's ratio structures have been extensively studied in terms of vibration isolation and energy absorption; however, research on their performance tunability remains lacking. This paper describes a bistable honeycomb mechanical metamaterial (BHMM) consisting of cosine-shaped beams, which exhibits transformable Poisson's ratio and tunable vibration isolation properties. The proposed structure exhibited bistable properties, i.e., undergoing a configuration transition under external forces and retaining its existing configuration after the loading was removed. Furthermore, the two stable configurations exhibited distinctive elastic vibration characteristics, allowing the manipulation of elastic wave propagation on a subwavelength scale via local resonant mechanisms. Overall, this study presents a design methodology for multi-performance tunable metamaterials that satisfy the demands of the external environment. For example, the tunable vibration-isolation property of metamaterial makes it intriguing safety protection structures during crash events.随着复杂工程应用的快速发展,对具有可调谐和多功能特性的隔振结构的需求与日俱增,超材料因其独特的结构配置而具有非凡的特性,已成为实现这一目的的有前途的候选材料。由于其独特的变形机制,负泊松比结构在隔振和能量吸收方面得到了广泛的研究;然而,有关其性能可调性的研究仍然缺乏。本文介绍了一种由余弦形梁组成的双稳态蜂窝机械超材料(BHMM),它具有可变泊松比和可调隔振特性。所提出的结构具有双稳态特性,即在外力作用下发生构型转换,并在卸载后保持现有构型。此外,这两种稳定构型还表现出独特的弹性振动特性,可通过局部共振机制在亚波长尺度上操纵弹性波的传播。总之,本研究提出了一种满足外部环境要求的多性能可调超材料的设计方法。例如,超材料的可调谐隔振特性使其在碰撞事件中成为耐人寻味的安全保护结构。Numerical analysis and design methods of grout-filled GFRP tube repaired corroded CHS T-jointsHongfei Chang, Xiaoyu Yan, Wenkang Zuo, Junwu Xia, Tao Yudoi:10.1016/j.tws.2024.111719灌浆填充 GFRP 管修复腐蚀 CHS T 型接头的数值分析和设计方法This study explores the compressive behavior of Grout-Filled GFRP Tube (GFGT) repaired corroded circular hollow section (CHS) T-joints. Finite element models of GFGT repaired corroded joints were developed, validated, and utilized to examine the influence of the joint geometric, material, and chord end stress parameters on the compressive strength and repairing efficiency of the joints. The findings reveal that the ultimate strength of the GFGT repaired joint increases with a thicker GFRP tube, a lower repaired chord section hollow ratio, a higher grout strength, and a longer repaired range. By optimizing the repairing parameters of the grout-filled GFRP tube, the compressive strength of GFGT repaired corroded joints with 16% and 32% corrosion rates can be up to increase to 164% and 147% of the uncorroded counterparts, respectively. The chord end stress exerts a similar but weaker effect on the repaired joints than on the unrepaired joints. A series of suggestions were proposed for repairing joints with different corrosion degrees to achieve a 20% ultimate strength enhancement compared to uncorroded joints. The compressive strength degradation rate of corroded joints was accurately predicted by the design method in the CIDECT and prEN guidelines. The feasibility of the guideline formulae to evaluate the strength reduction rate caused by the chord end preload was verified. A design method to predict the compressive strength of GFGT repaired corroded joints was proposed.本研究探讨了灌浆填充 GFRP 管 (GFGT) 修复腐蚀的圆形空心截面 (CHS) T 型接头的抗压行为。研究开发、验证并使用了 GFGT 修复腐蚀接头的有限元模型,以检验接头几何参数、材料参数和 弦端应力参数对接头抗压强度和修复效率的影响。研究结果表明,GFGT 修复接头的极限强度随 GFRP 管的厚度、较低的修复弦截面中空比、较高的灌浆强度和较长的修复范围而增加。通过优化灌浆填充 GFRP 管的修复参数,腐蚀率分别为 16% 和 32% 的 GFGT 修复腐蚀接头的抗压强度可分别提高到未腐蚀接头的 164% 和 147%。弦端应力对修复接头的影响与未修复接头类似,但较弱。为修复不同腐蚀程度的接头提出了一系列建议,使其极限强度比未腐蚀接头提高 20%。根据 CIDECT 和 prEN 指南中的设计方法,可以准确预测腐蚀接头的抗压强度降解率。验证了准则公式在评估弦端预载引起的强度降低率方面的可行性。提出了一种预测 GFGT 修复过的腐蚀接头抗压强度的设计方法。Radial Force Analysis of Long Span Bridge with Trapezoidally Corrugated Steel WebsJilong Chai, Man Zhou, Yufeng Zhangdoi:10.1016/j.tws.2024.111720采用梯形波纹钢腹板的大跨度桥梁的径向力分析The study numerically and theoretically investigates the radial force effect of long span prestressed concrete (PC) box girders with trapezoidally corrugated steel webs (TCSWs). It reveals that under the influence of radial forces, the curved prestressing tendons in the bottom slab in long span box girder bridges with TCSWs exhibited higher levels of stress and deflection compared to conventional concrete box girder bridges due to the accordion effect of the TCSWs. Furthermore, this study simplifies the radial forces as concentrated forces of PC box girder with TCSWs. Based on this simplification, a formula is derived to accurately calculate the magnitude of these radial forces. Through parameter analysis of the power exponent in the equation defining the curve profile of the bottom slab, it was observed that lower power exponents result in more significant radial force effects. Finally, to eliminate the radial force effect, the study innovatively proposed an optimized structural scheme by adopting horizontal bottom slab at midspan and arranging horizontal diaphragms uniformly across the entire longitudinal span of the bridge. A contrastive study suggested that the horizontal arrangement of internal prestressing tendons in the bottom slab at midspan could effectively eliminate the negative impact of the radial force effects and greatly improve the overall bearing capacity of the box girders with TCSWs.本研究从数值和理论上研究了带有梯形波纹钢腹板(TCSW)的大跨度预应力混凝土(PC)箱梁的径向力效应。研究发现,在径向力的影响下,由于梯形波纹钢腹板的手风琴效应,与传统混凝土箱梁桥相比,采用梯形波纹钢腹板的大跨度箱梁桥底板中的弧形预应力筋表现出更高的应力和挠度水平。此外,本研究还将径向力简化为带 TCSW 的 PC 箱梁的集中力。基于这一简化,得出了一个公式来精确计算这些径向力的大小。通过对定义底板曲线轮廓的公式中的功率指数进行参数分析,发现功率指数越小,径向力效应越明显。最后,为了消除径向力效应,研究创新性地提出了一种优化结构方案,即在中跨采用水平底板,并在桥梁的整个纵向跨度上均匀布置水平隔墙。对比研究表明,在中跨底板上水平布置内预应力筋可有效消除径向力效应的负面影响,大大提高采用 TCSW 的箱梁的整体承载能力。Experimental and numerical investigations of a staged energy dissipation deviceWeizhi Xu, Yijie Cai, Tianyang Zhang, Shuguang Wang, Dongsheng Du, Li Wandoi:10.1016/j.tws.2024.111721分阶段消能装置的实验和数值研究Energy-dissipating devices (EDDs) are widely used in building structures to mitigate seismic disasters. This study designed a fully assembled friction-metal series damper which is one kind of the staged energy dissipation devices (SEDD). Quasi-static tests were conducted to examine the behaviour of the SEDDs. The influence of factors such as the configurations of the restrainers, pre-tightening force, and material of the metal strip module was investigated. The work behaviour of the SEDD consists of three stages: elastic, frictional energy dissipation, and metallic elastic–plastic energy dissipation stages. The experimental results verified the effectiveness of the predicted working mechanism and showed that the bearing capacity and energy dissipation of the SEDD increased with the configuration of the restrainers, pre-tightening force, and yield strength of the metal strip module. The experiment also showed that the rotation of the outer plates caused an unexpected force mode in the metal strip module. Subsequently, numerical models of the test specimens were built, and good agreement was observed between the numerical simulations and test results for the hysteresis performance, loading capacity, and stress distribution. To further improve the mechanical properties of the SEDD, an optimised model was established and studied. The SEDDs with optimised strip shapes and constraint conditions of the outer plate exhibited better mechanical performance, and their load capacities increased by 11% and 41%, respectively.消能装置(EDD)被广泛应用于建筑结构中,以减轻地震灾害。本研究设计了一种全装配式摩擦金属串联阻尼器,它是分阶段消能装置(SEDD)的一种。研究人员进行了准静态试验,以检验 SEDD 的性能。研究了限制器的配置、预紧力和金属带模块材料等因素的影响。SEDD 的工作行为包括三个阶段:弹性阶段、摩擦消能阶段和金属弹塑性消能阶段。实验结果验证了预测工作机制的有效性,并表明 SEDD 的承载能力和耗能随约束装置的配置、预紧力和金属带模块的屈服强度而增加。实验还表明,外板的旋转会导致金属带模块出现意外的受力模式。随后,建立了试样的数值模型,并观察到数值模拟和试验结果在滞后性能、承载能力和应力分布方面具有良好的一致性。为了进一步提高 SEDD 的机械性能,我们建立并研究了一个优化模型。优化了条带形状和外板约束条件的 SEDD 具有更好的机械性能,其承载能力分别提高了 11% 和 41%。来源:复合材料力学仿真Composites FEM

未登录
还没有评论
课程
培训
服务
行家
VIP会员 学习 福利任务 兑换礼品
下载APP
联系我们
帮助与反馈