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【新文速递】2024年4月15日复合材料SCI期刊最新文章

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今日更新:Composite Structures 4 篇,Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇

Composite Structures

Multi-scale concurrent topology optimization of cellular structures with multiple microstructures for minimizing dynamic response in the time domain

Jian Wang, Yan Zhang, Xiaoyu Wang, Xuyang Zheng, Zhiyong Ma, Wei-Hsin Liao, Nan Zhu, Qiang Gao

doi:10.1016/j.compstruct.2024.118124

多微结构元胞结构的多尺度并行拓扑优化,以实现时域动态响应最小化

This paper proposes a concurrent topology optimization method for optimizing the structures that are periodically filled with multiple microstructures excited by dynamic response in the time domain. At the macroscale, different microstructures are considered as different materials. To generate the various distribution of different microstructures, a multi-material interpolation approach based on the Solid Isotropic Material with Penalization (SIMP) is integrated. At the microscale, the energy-based homogenization method (EBHM) is employed to determine the macroscopic effective properties of the microstructures. All macroscale elements with identical material are represented by a distinct microstructure. For the proportional damping model, the HHT-α is implemented as a time integration technique to obtain the dynamic response of multi-scale and assumed multi-material structures. The objective function of the topology optimization problem is to minimize the mean dynamic compliance. Combined differentiate-then-discretize method with the adjoint variable method, the sensitivity analysis applies the gradient-based Zhang-Paulino-Ramos Jr. (ZPR) algorithm or Method of Moving Asymptotes (MMA) to update the design variables under multiple constraints in the time and space-discretized system. The proposed approach is numerically performed through 2D and 3D examples to demonstrate its effectiveness.

本文提出了一种并行拓扑优化方法,用于在时域动态响应激励下周期性填充多个微结构的结构优化。在宏观尺度上,不同的微观结构被认为是不同的材料。为了生成不同微观结构的不同分布,提出了一种基于固体各向同性材料惩罚(SIMP)的多材料插值方法。在微观尺度上,采用基于能量的均匀化方法(EBHM)来确定微观结构的宏观有效性质。所有具有相同材料的宏观元素都具有不同的微观结构。对于比例阻尼模型,HHT-α作为时间积分技术实现了多尺度和假设多材料结构的动态响应。拓扑优化问题的目标函数是使平均动态柔度最小。灵敏度分析将微分-离散化方法与伴随变量法相结合,采用基于梯度的Zhang-Paulino-Ramos Jr. (ZPR)算法或移动渐近线法(MMA)对时空离散化系统中多约束条件下的设计变量进行更新。通过二维和三维算例验证了该方法的有效性。


A generic design motif for metamaterials with controllable nonlinearity & guided deformation

Xiaofeng Geng, Zhipeng Zhao, Yingqing Guo, Jiqiang Wang, Hu Ding, Xingjian Jing

doi:10.1016/j.compstruct.2024.118125

具有可控非线性和导向变形的超材料的通用设计母题

Structure design motifs take an essential role in creating materials or metamaterials with superior mechanics or special functions. However, a fundamental question naturally arising and remaining unknown is related to how to effectively design an engineered material structure with “adjustable and predictable” nonlinear mechanic properties conveniently. Here we propose a very simple but versatile design motif, named as bq-structure, which can provide superior flexibility in achieving various nonlinear properties, including 200 % larger and designable ranges of quasi-zero stiffness, negative stiffness, and multi-stable stiffness, etc, that original material or traditional beam-based design motifs cannot provide. The proposed design motif has sufficient reliability in nonlinear manipulation with a “guided & controllable” manner instead of “trail-and-error attempts” existing in most existing ones. A prototyped vibration isolation unit can achieve a resonant frequency less than 1 Hz easily which cannot be done with many other methods of similar size and payload. Given the large elastic deforming capacity and ductility in structural scale, the superb nonlinearity regime is generally designable with various structure parameters, uniquely providing a superior optimization tool with this novel design motif considering various real application requirements for advanced materials design, energy storage or conversion, mechanical vibration mitigation, and robotic systems etc

结构设计图案在创造具有优越力学或特殊功能的材料或超材料方面起着至关重要的作用。然而,如何有效地、方便地设计具有“可调可预测”非线性力学性能的工程材料结构,是一个自然产生而又未知的基本问题。在这里,我们提出了一个非常简单但通用的设计母题,称为bq结构,它可以提供优越的灵活性,以实现各种非线性特性,包括200 %的可设计范围的准零刚度,负刚度和多稳定刚度等,这是原始材料或传统的基于梁的设计母题所不能提供的。本文提出的设计母题在非线性操作中具有足够的可靠性,具有“引导可控”的方式,而不是大多数现有设计母题存在的“跟踪-错误尝试”。原型隔振单元可以轻松实现小于1 Hz的谐振频率,这是许多其他类似尺寸和有效载荷的方法无法实现的。由于具有较大的弹性变形能力和结构尺度上的延展性,其优异的非线性体系通常可设计为各种结构参数,独特地为先进材料设计、能量存储或转换、机械振动缓解和机器人系统等各种实际应用需求提供了优越的优化工具


Fatigue and post-fatigue behavior of FRCM-concrete specimens under direct shear and bending conditions

Angelo Savio Calabrese, Pierluigi Colombi, Tommaso D'Antino

doi:10.1016/j.compstruct.2024.118129

直接剪切和弯曲条件下frcm -混凝土试件的疲劳及后疲劳行为

The combined effect of cyclic loading and steel rebar corrosion can determine the premature deterioration of reinforced concrete (RC) structures subjected to dynamic and environmental actions. The use of fabric-reinforced cementitious matrix composites (FRCM) is a promising solution to extend the fatigue life of RC structures. Externally bonded FRCMs are applied to the tension side of structural members to reduce the rebar stress level, thus delaying fatigue crack nucleation and/or propagation. A key aspect for the design of FRCM strengthening of these structures is the matrix-fiber bond behavior under fatigue loading. In this paper, a critical review of currently available studies on the fatigue behavior of FRCM-strengthened RC beams is presented. Then, the results of 25 bond tests on PBO FRCM-concrete specimens are provided and discussed. These tests include both single-lap direct shear and modified beam tests performed in quasi-static and cyclic mode. The results obtained show that the cyclic load may induce progressive debonding at the matrix-fiber interface with rupture of fiber filaments. Modified beam tests are more affected by these phenomena than direct shear tests. The rupture of fiber filaments is confirmed by the results of post-fatigue tests that show capacities lower than those of corresponding quasi-static tests.

循环荷载和钢筋腐蚀的共同作用可以决定钢筋混凝土结构在动力和环境作用下的过早劣化。纤维增强胶凝基复合材料(FRCM)是延长钢筋混凝土结构疲劳寿命的一种很有前途的方法。外粘结frp材料应用于构件受拉侧,以降低钢筋应力水平,从而延缓疲劳裂纹的形核和/或扩展。疲劳载荷下的基体-纤维粘结性能是frp加固设计的一个关键方面。本文对目前已有的frp增强RC梁疲劳性能研究进行了综述。给出了PBO frp -混凝土试件25次粘结试验结果并进行了讨论。这些试验包括在准静态和循环模式下进行的单搭接直剪和修改梁试验。结果表明:循环荷载可引起纤维-基体界面的渐进式剥离,纤维细丝断裂。修正梁试验比直接剪切试验受这些现象的影响更大。疲劳后试验结果证实了纤维长丝的断裂,其承载力低于相应的准静态试验结果。


Experimental and numerical analysis of low-velocity impact and compression after impact responses of novel 3D hybrid composites

Ke Wang, Farid Taheri

doi:10.1016/j.compstruct.2024.118133

新型三维混杂复合材料低速冲击和冲击后压缩响应的实验与数值分析

Rising environmental concerns and the push to cut carbon emissions have resulted in increased incorporation of lightweight materials to improve fuel efficiency across industries. Fiber Metal Laminates (FMLs), known for superior properties, are widely used in aerospace. In the same vein, the recently developed 3D Fiber-Metal Laminates (3DFMLs) with a 3D composite core have been demonstrated to offer remarkable performance despite fabrication challenges.Two innovative 3D hybrid composites (3DFML-PI and 3DHC-PI) are introduced. These FMLs integrate plastic inserts to overcome the fabrication hurdles experienced by the original 3DFMLs and enhance their mechanical properties. Notably, 3DFML-PI shows comparatively an exceptional impact resistance with a higher perforation threshold, highlighting the efficacy of plastic inserts. Additionally, 3DFML-PI exhibits higher compressive strength, suggesting improved consolidation of the 3D composites. Comparison of the compression-after-impact (CAI) performances also underscores the advantages of high flexural stiffness and localized damage. The research justifies further exploration and implementation of these innovative materials in practical applications requiring lightweight materials with high specific strength, stiffness, impact resistance, and economic sustainability.

日益严重的环境问题和减少碳排放的努力,导致各行各业越来越多地采用轻质材料,以提高燃油效率。金属纤维层压板(FMLs)以其优越的性能被广泛应用于航空航天领域。同样,最近开发的3D纤维-金属层压板(3DFMLs)具有3D复合材料核心,尽管在制造方面存在挑战,但已被证明具有卓越的性能。介绍了两种新型的三维复合材料3DFML-PI和3DHC-PI。这些FMLs集成了塑料插入件,克服了原始3DFMLs的制造障碍,提高了其机械性能。值得注意的是,3DFML-PI具有相对优异的抗冲击性,具有较高的穿孔阈值,突出了塑料镶件的有效性。此外,3DFML-PI具有更高的抗压强度,表明3D复合材料的固结得到改善。冲击后压缩(CAI)性能的比较也强调了高抗弯刚度和局部损伤的优势。这项研究证明了这些创新材料在实际应用中的进一步探索和实施,这些材料需要具有高比强度、刚度、抗冲击性和经济可持续性的轻质材料。


Composites Part A: Applied Science and Manufacturing

Uncut fiber analysis using fiber deflection and cutting forces in carbon fiber-reinforced plastics during rotation of the cutting tool

Dong-Gyu Kim, Seung-Han Yang

doi:10.1016/j.compositesa.2024.108206

利用切削刀具旋转过程中碳纤维增强塑料的纤维挠度和切削力对未切削纤维进行分析

Cutting, milling, and drilling during the manufacture of carbon fiber-reinforced plastics (CFRPs) is an active field of research. It is challenging to analyze cutting characteristics during cutting tool rotation because the chip thickness, fiber cutting angle, and specific cutting force change. Here, we used a mechanical model to study the cutting forces and fiber deflections that develop as the cutting tool rotates during CFRP milling. The fiber and matrix were modeled as a beam, and the cutting force and fiber deflection were analyzed according to the fiber cutting angle. We explored how uncut fiber status and surface roughness were affected. If the fiber deflection caused by transverse cutting forces was not eliminated before the cutting tool rotation angle attained 180°, some fibers were not cut. Serious defects developed when uncut fibers were not generated at certain fiber orientation angles.

碳纤维增强塑料(CFRPs)制造过程中的切削、铣削和钻孔是一个活跃的研究领域。由于切屑厚度、纤维切削角度和切削比力的变化,刀具旋转过程中的切削特性分析具有一定的挑战性。在这里,我们使用力学模型来研究CFRP铣削过程中刀具旋转时产生的切削力和纤维挠度。将纤维和基体建模为一根梁,根据纤维切割角度分析了切割力和纤维挠度。我们探索了未切割的纤维状态和表面粗糙度是如何受到影响的。如果在刀具旋转角度达到180°之前没有消除横向切削力引起的纤维挠曲,则部分纤维未被切割。在一定的纤维取向角度下,未切割的纤维产生时,会产生严重的缺陷。


Composites Part B: Engineering

Bamboo as a natural optimized fiber reinforced composite: interfacial mechanical properties and failure mechanisms

Xiaohan Chen, Xianke Wang, Xun Luo, Lin Chen, Yuquan Li, Jiarui Xu, Zengqian Liu, Chunping Dai, Hu Miao, Huanrong Liu

doi:10.1016/j.compositesb.2024.111458

竹作为一种天然优化纤维增强复合材料:界面力学性能及破坏机制

Bamboo is a typical natural fiber-reinforced composite with an optimized distribution of vascular bundles as reinforcement and parenchyma tissues as bio-matrix. The interfacial bonding performance between vascular bundles and parenchyma tissue is critical for the mechanical properties and failure mechanisms of bamboo. This study employed pull-out tests to determine the interfacial shear strength (IFSS) between bamboo vascular bundles and parenchyma tissue and evaluate the critical embedded lengths () of vascular bundles. The effects of embedded vascular bundle lengths on interfacial strength and failure behaviors were also investigated. The results revealed a  value of 2.51 mm, lower than the majority of plant fiber-reinforced composite materials, with an IFSS of around 20 MPa, surpassing most artificial bamboo fiber composites. The pull-out process of the vascular bundles involved elasticity, debonding, and sliding friction stage, where debonding energy absorption (DEA) outweighed frictional energy absorption (FEA) and increasing with embedded length. The primary failure features include interfacial debonding, parenchyma tissue ripping, delamination of fiber thin layers, and fiber breakage. Moreover, the parenchyma cells between the two fiber sheaths and at the top of the bamboo block readily detached. The interfacial failure mechanisms of bamboo included debonding, reinforcement, and matrix failure, with the proportions varying as the embedded length increased. Quantitative analysis of the interfaces structure and mechanical properties between vascular bundles and parenchyma tissues could provide a reference for the biomimicry of bamboo structures and the manufacturing of natural fiber-reinforced composite materials.

竹是一种典型的天然纤维增强复合材料,以维管束为增强材料,以薄壁组织为生物基质。维管束与薄壁组织之间的界面结合性能对竹材的力学性能和破坏机制至关重要。本研究采用拔除试验测定了竹材维管束与薄壁组织的界面剪切强度(IFSS),并评估了维管束的临界嵌入长度()。研究了嵌入维管束长度对界面强度和破坏行为的影响。结果表明,IFSS值为2.51 mm,低于大多数植物纤维增强复合材料,IFSS约为20 MPa,超过大多数人造竹纤维复合材料。维管束的拔出过程分为弹性阶段、脱粘阶段和滑动摩擦阶段,其中脱粘能量吸收(DEA)大于摩擦能量吸收(FEA),且随着埋置长度的增加而增加。主要的破坏特征包括界面脱粘、薄壁组织撕裂、纤维薄层脱层和纤维断裂。此外,两种纤维鞘之间和竹块顶部的薄壁细胞容易脱落。竹材界面破坏机制主要有脱粘破坏、加固破坏和基体破坏,其破坏比例随埋置长度的增加而变化。定量分析竹材维管束与薄壁组织之间的界面结构和力学性能,可为竹材结构的仿生学和天然纤维增强复合材料的制造提供参考。


Composites Science and Technology

A novel strategy to prepare rubber/clay nanocomposites via compounding clay gel into cocoamidopropyl betaine modified styrene butadiene rubber

Zilong Chen, Jian Li, Zhanxu Li, Jun Lin, Liqun Zhang, Shaojian He

doi:10.1016/j.compscitech.2024.110602

 

将粘土凝胶复配至椰酰胺丙基甜菜碱改性丁苯橡胶中制备橡胶/粘土纳米复合材料的新策略

In this study, high performance styrene-butadiene rubber (SBR)/clay nanocomposites (NCs) modified by cocoamidopropyl betaine (CAPB) are prepared via an efficient and facile strategy. CAPB-modified SBR was compounded with clay gel via gel compounding method to obtain SBR/clay composites. The effect of processing condition and CAPB on the mechanical properties of the SBR/clay composites was investigated. XRD and TEM results show that clay dispersion in SBR matrix is significantly improved due to the success of CAPB in the hydrophilic modification of SBR. The clay-SBR interaction is enhanced and more SBR molecular chains are adsorbed to the clay, significantly improving the mechanical properties of SBR/CAPB/clay NCs, as demonstrated by SEM and DMA. The maximum tensile strength of SBR/CAPB/clay NCs achieved 16.3 MPa at a clay loading of 40 phr, which is 10 times that of pure SBR. The tensile strength of the SBR/CAPB/clay NC incorporated with 20 phr clay has exceeded that of the SBR composite incorporated with 40 phr commercial organic clay. This work demonstrates that this strategy, which combines the CAPB-modification of SBR with the gel compounding method, is an effective and feasible method to improve the mechanical strength of SBR.

本研究采用高效、简便的方法制备了椰酰胺丙基甜菜碱(CAPB)改性的高性能丁苯橡胶(SBR)/粘土纳米复合材料(NCs)。采用凝胶复配法将改性SBR与粘土凝胶复配,得到SBR/粘土复合材料。研究了工艺条件和CAPB对SBR/粘土复合材料力学性能的影响。XRD和TEM结果表明,CAPB成功地对SBR进行了亲水性改性,显著改善了SBR基体中粘土的分散性。SEM和DMA分析表明,黏土与SBR的相互作用增强,更多的SBR分子链被吸附到黏土上,显著改善了SBR/CAPB/clay NCs的力学性能。SBR/CAPB/clay NCs在40 phr黏土加载下的最大抗拉强度达到16.3 MPa,是纯SBR的10倍。掺加20phr粘土的SBR/CAPB/clay NC的抗拉强度超过掺加40phr商用有机粘土的SBR复合材料。研究表明,将capb改性SBR与凝胶复合相结合的策略是提高SBR机械强度的有效可行的方法。


来源:复合材料力学仿真Composites FEM
ACTMechanicalSystemDeform振动疲劳断裂复合材料非线性拓扑优化通用航空航天ADS裂纹材料机器人多尺度仿生
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【新文速递】2024年4月17日复合材料SCI期刊最新文章

今日更新:Composite Structures 7 篇,Composites Part B: Engineering 5 篇,Composites Science and Technology 1 篇Composite StructuresNumerical and mechanical analysis of laminated PA11/twill basalt composites with enhanced flame behaviorIlaria Papa, Matteo Bruno, Francesco Napolitano, Luca Esposito, Valentina Lopresto, Pietro Russodoi:10.1016/j.compstruct.2024.118123增强火焰性能的PA11/斜纹玄武岩层压复合材料的数值与力学分析The development of new material configuration is a challenge which requires different steps of characterization. From the mechanical characterization, which is the starting point to determine the application fields, until the evaluation of the safety aspects in case of human contact use or in vehicle and building interiors. Nowadays, the integration with the numerical simulation is strategically important to make a further step in the obtainment of a model for rapid prevision of the mechanical response in different components. In this research study is provided a complete characterization of new composite material constituted by PA11 resin with flame retardant and basalt twill; the mechanical properties are evaluated through flexural and impact tests, also the fire resistance is assessed through the flammability test. Then a numerical model for mechanical response simulation was developed and compared with experimental results. This is driven by the need to expand the comprehension on the damage mechanisms generated by low velocity impacts. The results show an excellent behavior of this composite, with high fire resistance and mechanical properties which suggest proper use in aircraft interiors. Moreover, the good correspondence between numerical and experimental results gives a model which is suitable to design other PA11/basalt composite workpieces.新材料结构的开发是一个挑战,需要不同的表征步骤。从机械特性开始,这是确定应用领域的起点,直到评估人类接触使用或车辆和建筑物内部的安全方面。目前,将其与数值模拟相结合对于进一步获得快速预测不同部件力学响应的模型具有重要的战略意义。本研究提供了一种由PA11树脂与玄武岩斜纹布组成的新型阻燃复合材料的完整表征;通过弯曲试验和冲击试验对其力学性能进行了评定,并通过可燃性试验对其耐火性能进行了评定。建立了机械响应仿真的数值模型,并与实验结果进行了比较。这是由于需要扩大对低速撞击产生的损伤机制的理解。结果表明,该复合材料性能优异,具有较高的耐火性能和机械性能,适合用于飞机内饰。数值计算结果与试验结果吻合较好,该模型适用于其它PA11/玄武岩复合材料工件的设计。Mesoscopic finite element modeling of biaxial non-crimp fabric including representative stitch patternRuochen Zheng, Naim Naouar, Julien Colmars, Auriane Platzer, Bastian Schäfer, Fabrice Morestin, Luise Kärger, Philippe Boissedoi:10.1016/j.compstruct.2024.118126双轴不卷曲织物的细观有限元建模,包括代表性的针型A comprehensive understanding of the mechanical properties of carbon fiber reinforcements is necessary to accurately simulate forming processes. The parametrization of macroscopic models requires extensive experimental characterization for different deformation modes. In order to reduce experimental effort, this work proposes a mesoscopic model of bi-axial non-crimp fabric (Bi-NCF) that can be used for virtual material characterization. The fiber yarns are considered as a continuous medium and modeled with solid elements, and their mechanical behavior is described by a hyperelastic constitutive law dedicated to anisotropic fibrous media. The stitches are modeled with 2-node beam elements. This model is developed based on precise geometry measurements obtained from X-ray tomography results. An additional stitch pre-tension step is incorporated in the model to improve contact and simulate the tension induced by the sewing process. Experimental Picture Frame Tests are used to validate the model at mesoscale, while experimental and numerical Bias-extension Tests demonstrate its potential to simulate larger scales and effectively predict local defects.全面了解碳纤维增强材料的力学性能是准确模拟成形过程的必要条件。宏观模型的参数化需要对不同的变形模式进行大量的实验表征。为了减少实验工作量,本工作提出了一种可用于虚拟材料表征的双轴无卷曲织物(Bi-NCF)的介观模型。将纤维纱线视为一种连续介质,用实体单元进行建模,用各向异性纤维介质的超弹性本构律描述纤维纱线的力学行为。缝线采用2节点梁单元建模。该模型是基于从x射线断层扫描结果中获得的精确几何测量而开发的。在模型中加入了一个额外的缝线预张力步骤,以改善接触并模拟缝制过程引起的张力。实验相框测试用于中尺度上验证模型,而实验和数值偏差扩展测试则证明了该模型具有模拟更大尺度和有效预测局部缺陷的潜力。On characterization of transverse tensile properties of pultruded glass fiber-reinforced polymer (PGFRP) profiles based on non-standard short couponsYunhong Luo, Pan Zhang, Tao Yudoi:10.1016/j.compstruct.2024.118128基于非标准短条的拉挤玻璃纤维增强聚合物(PGFRP)型材横向拉伸性能表征Pultruded glass fiber-reinforced polymer (PGFRP) profiles, manufactured via a pultrusion process, are increasingly used in civil engineering. However, due to the anisotropic nature, their transverse material properties are weaker than the longitudinal ones, necessitating robust material characterization methods for transverse properties. Commercially available PGFRP profiles often have insufficiently large cross-sections for standard-sized transverse tensile tests, prompting the need to investigate the effect of coupon size on transverse tensile properties and propose a feasible shorter coupon size. This paper therefore aims to examine the coupon-size effects and propose suitable short coupon geometries for transverse tensile tests. Standard material characterization tests were conducted on channel-section PGFRP profiles, followed by transverse tensile tests on six types of non-standard short coupons. The effects of coupon width and gauge length on transverse tensile properties were evaluated and compared across six aspects, with potential failure mechanisms further explored using finite element analysis (FEA). The paper concludes by proposing a feasible short coupon configuration for transverse tensile tests.拉挤玻璃纤维增强聚合物(PGFRP)型材,通过拉挤工艺制造,越来越多地应用于土木工程。然而,由于其各向异性,其横向材料性能弱于纵向材料性能,因此需要对横向性能进行稳健的材料表征方法。商业上可用的PGFRP型材通常没有足够大的横截面进行标准尺寸的横向拉伸试验,这促使需要研究粘结层尺寸对横向拉伸性能的影响,并提出可行的更短的粘结层尺寸。因此,本文的目的是研究粘片尺寸效应,并提出适合横向拉伸试验的短粘片几何形状。对通道截面PGFRP型材进行了标准材料特性试验,然后对6种非标准短板进行了横向拉伸试验。从六个方面评估和比较了试件宽度和厚度对横向拉伸性能的影响,并利用有限元分析(FEA)进一步探讨了潜在的破坏机制。最后,提出了一种可行的横向拉伸试验短板结构。Anisotropic failure analysis of 2.5-D braided composites under compressionLinlin Deng, Ziqing Hao, Hongjun Ke, Hairun Wang, George Kardomateas, Liu Liudoi:10.1016/j.compstruct.2024.118130 2.5维编织复合材料压缩破坏的各向异性分析2.5-D braided high-alumina fabric-reinforced silica matrix composite materials are being developed as functional structural composites with thermal load-bearing capacity for the top thin face sheet of an integrated thermal protection system (TPS). This study seeks to elucidate the mechanical behavior of a 2.5-D braided top face sheet composite material subjected to off-axis compression, while the sandwich TPS is under deflection caused by the bending moment resulting from the temperature gradient in the thickness direction and the aerodynamic pressure on the top face sheet panel. The effective compressive modulus and ultimate strength along the warp direction are significantly lower than those along the weft direction. Both decrease as the off-axis loading angle increases, indicating anisotropy. A nonlinear compressive stress–strain response with extensive damage along the warp yarn direction, while the weft yarn direction exhibits a quasi-linear response with minor damage before fracture. Within the framework of continuum damage mechanics, fiber kinking and transverse inter-fiber cracking of fiber bundles with the linear damage evolution law are all considered simultaneously for the progressive damage model. To account for the interaction between multiple damage mechanisms in the fiber yarn, a joint degradation induced by multiple damage mechanisms is first proposed. The analysis reveals that the anisotropy of failure under compression is primarily due to the warp fiber bundle’s much larger undulation than the weft fiber bundle, which causes severe bending-dominated damage. Using the calibrated model, the qualitative effects of material thickness and yarn geometry size on the compressive mechanical properties of materials are analyzed.2.5维编织高铝纤维增强二氧化硅基复合材料是一种具有热承载能力的功能性结构复合材料,可用于集成热防护系统(TPS)的顶部薄面板。本研究旨在阐明2.5维编织顶面板复合材料在离轴压缩下,夹层TPS在厚度方向温度梯度和顶面板气动压力引起的弯矩引起的挠曲作用下的力学行为。有效压缩模量和极限强度沿经纱方向显著低于沿纬纱方向。随着离轴加载角的增大,两者均减小,表明各向异性。断裂前沿经纱方向为非线性压应力-应变响应,损伤广泛;纬纱方向为准线性响应,损伤较小。在连续损伤力学的框架下,渐进损伤模型同时考虑了纤维束的纤维扭结和纤维束的横向纤维间开裂,并遵循线性损伤演化规律。为了考虑纤维纱线中多种损伤机制之间的相互作用,首次提出了由多种损伤机制引起的联合退化。分析表明,压缩破坏的各向异性主要是由于经纱纤维束的波动比经纱纤维束大得多,造成了严重的弯曲主导损伤。利用标定后的模型,分析了材料厚度和纱线几何尺寸对材料压缩力学性能的定性影响。Flexible composite structure with customizable in-plane Poisson’s ratio under large deformationWenhao Zhao, Sanchun Lin, Shengjie Wang, Heng Yang, Jiaxing Wang, Hongshuai Leidoi:10.1016/j.compstruct.2024.118127大变形下面内泊松比可定制的柔性复合材料结构Regulating the inherent Poisson's ratio of soft elastic materials under large deformation is important for their application in emerging fields, such as morphing structures and stretchable electronics. In this study, we selected a composite in which an auxetic honeycomb was embedded in a soft material to regulate the in-plane Poisson's ratio. Based on a cantilever beam model, a theoretical model was established to guide the design optimization of composite structures. The macroscopic constitutive relation and in-plane Poisson's ratio of the composite structures with different configurations were predicted by the theoretical model, which were consistent with the finite element analysis results. In the 30% strain range, the slope of the Poisson's ratio–strain curve decreases with an increase in the length of the inclined bar, and the in-plane Poisson's ratio increases with an increase in the angle between the transverse bar and the inclined bar. In addition, we propose an optimization design method with the in-plane Poisson's ratio as the objective function and then optimize and fabricate a skin structure with an in-plane Poisson's ratio of approximately zero for the morphing wings. The achievements of this study provide theoretical guidance for regulating the in-plane Poisson's ratio of thin flexible layers.调节大变形软弹性材料的固有泊松比对于软弹性材料在变形结构和可拉伸电子等新兴领域的应用具有重要意义。在本研究中,我们选择了一种复合材料,在软材料中嵌入一个消声蜂窝来调节面内泊松比。基于悬臂梁模型,建立了指导复合材料结构设计优化的理论模型。理论模型预测了不同构型复合材料结构的宏观本构关系和面内泊松比,与有限元分析结果一致。在30%应变范围内,泊松比应变曲线的斜率随斜杆长度的增加而减小,面内泊松比随横杆与斜杆夹角的增加而增大。此外,提出了一种以面内泊松比为目标函数的优化设计方法,优化制作出了面内泊松比近似为零的变形翼蒙皮结构。研究成果为柔性薄层面内泊松比的调节提供了理论指导。Linear static, geometric nonlinear static and buckling analyses of sandwich composite beams based on higher-order refined zigzag theoryYu-Hsien Chen, Chung-De Chendoi:10.1016/j.compstruct.2024.118131基于高阶精细之字形理论的夹层组合梁线性静力、几何非线性静力及屈曲分析This study aims at developing finite element formulations based on higher-order refined zigzag theory (HRZT) to analyze sandwich composite beams under linear static bending, geometric nonlinearity and buckling. In HRZT, the higher-order terms associated with average shear strain and rotation due to zigzag are added based on refined zigzag theory (RZT). In linear static bending analysis, both C0 and C1 elements are developed. For the C0 element, an extra node is used in order to eliminate shear locking. For geometric nonlinear static analysis, the two-node C0 element is developed to solve the bending response with lateral loading and buckling response. The numerical results are compared with those calculated by 2D exact solutions, analytical solutions of HRZT and 2D models using commercial software. Various beam theories such as first-order shear deformation theory (FSDT), higher-order shear deformation theory (HSDT), RZT, and other types of higher-order zigzag theory are also introduced for comparisons. Through comprehensive comparisons with existing works on FEM or zigzag theories, the HRZT beam elements developed in this study exhibit superior accuracy and are free from shear locking in linear static analysis. Furthermore, the study also demonstrates that these elements achieve high accuracy in geometric nonlinear analysis and buckling analysis.本研究旨在开发基于高阶精炼之字形理论(HRZT)的有限元公式,以分析线性静态弯曲、几何非线性和屈曲情况下的夹层复合梁。在 HRZT 中,与平均剪切应变和人字形旋转相关的高阶项是在精炼人字形理论(RZT)的基础上添加的。在线性静态弯曲分析中,开发了 C0 和 C1 元素。对于 C0 元素,为了消除剪切锁定,使用了一个额外的节点。在几何非线性静态分析中,开发了双节点 C0 元素来解决带有横向载荷的弯曲响应和屈曲响应。数值结果与二维精确解、HRZT 分析解以及使用商业软件的二维模型计算的结果进行了比较。此外,还引入了各种梁理论,如一阶剪切变形理论(FSDT)、高阶剪切变形理论(HSDT)、RZT 和其他类型的高阶之字形理论进行比较。通过与现有有限元理论或之字形理论著作的综合比较,本研究开发的 HRZT 梁元素表现出更高的精度,并且在线性静力分析中不会出现剪切锁定。此外,研究还证明,这些元素在几何非线性分析和屈曲分析中也能达到很高的精度。Impact resistance of assembled plate-lattice auxetic structuresWei-Jing Wang, Wei-Ming Zhang, Meng-Fu Guo, Hang Yang, Li Madoi:10.1016/j.compstruct.2024.118132拼装板-格结构的抗冲击性能Auxetic materials are attracting increasing interest due to their extraordinary or even abnormal mechanical properties. Different from the traditional truss-lattice structures, this paper proposes a series of novel auxetic plate-lattice structures with an excellent auxetic effect. Utilizing a dual-materials glue-free assembly design involving hyperelastic and plastic materials, these plate-lattices exhibit numerous advantages such as disassembly, assembly, replacement, recyclability, reusability, excellent energy absorption, high specific stiffness, and impact resistance performances. Quasi-static/dynamic tests and simulations are conducted to assess mechanical properties, including elastic constants, deformation modes, and mechanical responses. Simultaneously, the effect of the principal geometric parameter, concave angle, on the structural response was analyzed with various impact velocities. Findings suggest that the concave angle influences the structural elastic constants under compressive loading. The stress–strain response exhibits a distinct dual-plateau phenomenon. Taking the A65 (concave angle is 65°) configuration as an example, the stress on the second plateau is approximately 2.7 times that of the first plateau, significantly enhancing the structure's energy absorption capability. Under dynamic impact loadings, different configurations and varying impact velocities affect the structure's energy absorption performance. This paper introduces a series of assemblable plate-lattice structures with an auxetic effect, offering design insights and guidance tailored to the convenient transportation, unconventional structures, and rapid assembly needs of lightweight, impact-resistant mechanical metamaterials.增塑型材料因其特殊甚至异常的力学性能而受到越来越多的关注。与传统的桁架-晶格结构不同,本文提出了一系列具有良好减震效果的新型板-晶格减震结构。利用双材料无胶组装设计,包括超弹性和塑料材料,这些板晶格具有许多优点,如拆卸,组装,更换,可回收性,可重复使用,出色的能量吸收,高比刚度和抗冲击性能。进行准静态/动态测试和模拟,以评估机械性能,包括弹性常数,变形模式和机械响应。同时,分析了不同冲击速度下,主要几何参数凹角对结构响应的影响。结果表明,在压缩载荷作用下,凹角会影响结构的弹性常数。应力应变响应表现出明显的双平台现象。以A65(凹角为65°)结构为例,第二平台的应力约为第一平台的2.7倍,结构的吸能能力显著增强。在动冲击载荷作用下,不同的结构形式和不同的冲击速度会影响结构的吸能性能。本文介绍了一系列具有辅助效应的可组装板-晶格结构,为轻量化、抗冲击的机械超材料的运输便利、非常规结构和快速装配需求提供了设计见解和指导。Composites Part B: EngineeringQuantitative assessment of whether phosphorus-based flame retardants are optimizing or degrading the fire hazard of aircraft carbon fiber/epoxy compositesBin Zou, Ziyan Qian, Zixuan Zhang, Weiyi Xing, Shangshang Zhong, Jiajun Li, Fukai Chu, Yongchun Kan, Jie Chen, Yuan Hudoi:10.1016/j.compositesb.2024.111413磷系阻燃剂是否优化或降低飞机碳纤维/环氧复合材料的火灾危险性的定量评估Fire hazards are a primary concern in aircraft accidents, and controlling combustible materials is pivotal in managing cabin fire risks. This work aims to elucidate the impact of widespread measures that introduce phosphorus-based flame retardants (PFRs) on the fire safety of carbon fiber epoxy composites (CF/EP). Firstly, the hazardous indicators for flame retardant CF/EP composites exhibit two categories of optimization and degradation, which are caused by the intrinsic feature, pyrolysis characteristics and chemical valence states of PFRs. Secondly, the fire hazards of composites are assessed by fusing the analytic network process and information weights guided by Nash Equilibrium theory. The method combines the merits of subjective and objective weights from dimensions of intrinsic hazards, interrelationships and data dispersion of indicators. Finally, the assessed fire hazard rankings under 35 and 65 kW/m2 both are EP > CF/EP16%DOPO-HQ > CF/EP > CF/EP7%DPO. In conclusion, DOPO-HQ (+1) primarily increases the fire hazard of CF/EP due to gas-phase flame-retardant effects, while DPO (+3) predominantly reduces the fire hazard of CF/EP by contributing to condensed-phase effects. This work highlights the contradictory effects of PFRs on the fire safety of CF/EP composites due to structure and thermal stability. The proposed ANP and IW hybridization method provides a theoretical foundation for selecting flame retardants and assessing material fire hazards comprehensively.火灾危险是飞机事故的首要问题,控制可燃材料是管理客舱火灾风险的关键。本工作旨在阐明引入磷基阻燃剂(PFRs)的广泛措施对碳纤维环氧复合材料(CF/EP)防火安全的影响。首先,阻燃CF/EP复合材料的危险指标呈现出两类优化和降解,这是由阻燃材料的内在特性、热解特性和化学价态决定的。其次,以纳什均衡理论为指导,融合分析网络过程和信息权重,对复合材料的火灾危险性进行评估;该方法从指标的内在危害、相互关系和数据离散度等方面综合了主客观权重的优点。35 kW/m2和65 kW/m2以下的火灾危险性排序为:EP > CF/EP16%DOPO-HQ > CF/EP > CF/EP7%DPO。综上所述,DOPO-HQ(+1)主要通过气相阻燃作用增加CF/EP的火灾危险性,而DPO(+3)主要通过促进凝聚相阻燃作用降低CF/EP的火灾危险性。这项工作强调了由于结构和热稳定性,PFRs对CF/EP复合材料防火安全性的矛盾影响。提出的ANP和IW杂交方法为阻燃剂的选择和材料火灾危险性的综合评估提供了理论基础。Bonding Strength Enhancement of a 30wt.%GF/PET–2024 Aluminium Alloy Joint by Synergistic Action of Multi-scale Mechanical Interlocking and Multiplex H-BondingShumei Lou, Baojia Cheng, Leyao Xu, Ben Ma, Haoyu Wang, Lina Lu, Xiping Lidoi:10.1016/j.compositesb.2024.111437 提高30wt的粘接强度。GF/ PET-2024铝合金多尺度机械联锁与多重h键协同作用接头In this study, micro-scale cellular and nano-scale labyrinth structures were obtained on the surface of A2024 aluminium alloy adherends through ultrasonic-aided corrosion using an FeCl3 etchant solution to significantly enhance the mechanical interlock of it and a 30 wt.% glass-fibre-enhanced polyethylene terephthalate substrate. The tensile shear strength of the 30wt.% GF/PET–A2024 joint was increased to 31.84 MPa. The subsequent treatment of an appropriate amount of KH-892/PVA transformed the surface of the aluminium alloy from hydrophobic to hydrophilic to significantly improve its wettability. Furthermore, this treatment generated multiplex hydrogen bonding of O-H…O…H-N at the interface, further improving the tensile shear strength of the joint up to 50.94 MPa, which is significantly higher than the values obtained using exiting methods. The tensile shear tests of a ring-shaped insulator specimen according to GB 7251-87 verified the improved fracture work equation herein and the bonding strength enhancement of the 30wt.%GF/PET–A2024 aluminium alloy joint treated by ultrasonic-aided corrosion with an FeCl3 etchant solution and pre-coating of an appropriate amount of KH-892/PVA.在本研究中,采用FeCl3蚀刻液对A2024铝合金粘附体表面进行超声辅助腐蚀,获得了微尺度的细胞和纳米尺度的迷宫结构,显著增强了A2024铝合金与30% wt.%玻璃纤维增强聚对苯二甲酸乙二醇酯基板的机械联锁。拉伸剪切强度30wt。% GF/ PET-A2024接头增大到31.84 MPa。后续处理适量的KH-892/PVA使铝合金表面由疏水性转变为亲水性,润湿性显著提高。此外,该处理在界面处形成了O- h…O…H-N的多重氢键,进一步提高了接头的抗拉剪切强度,达到50.94 MPa,显著高于现有方法。按照GB 7251-87标准对环形绝缘子试样进行了拉伸剪切试验,验证了改进后的断裂功方程和30wt的粘结强度提高。采用FeCl3蚀刻液和预涂适量KH-892/PVA对%GF/ PET-A2024铝合金接头进行超声辅助腐蚀处理。Enhancement of strength-ductility synergy in high-strength metastable β-titanium alloys through boron microalloyingDingxuan Zhao, Keer Li, Jixiong Liu, Rui Li, Wei Chen, Jinyu Zhang, Xiaoxiang Wang, Jian Wang, Jun Sundoi:10.1016/j.compositesb.2024.111449硼微合金化增强高强度亚稳β-钛合金的强度-延展性协同作用Metastable β-titanium (Ti) alloys have always attracted great attention due to the available ultra-high strength via precipitation strengthening, while they often succumb to a strength-ductility trade-off known as improving strength but degrading ductility. In this study, we exploit a novel strategy to address the issue in Ti-6Cr-5Mo-5V-4Al (Ti6554) high-strength metastable β-Ti alloy through the trace boron addition. It is found that an ultra-high strength ∼1600 MPa with elongation of ∼9 % is synchronously achieved with the addition of minor boron, corresponding to a ∼7 % increase in strength and ∼70 % improvement in ductility compared to the boron-free counterpart. Microstructural characterizations manifest that boron addition promotes almost complete transformation from abnormal β-grain region to normal β-grain region, which possesses better deformation accommodation capacity at the aged state. Meanwhile, TiB whiskers are produced and adhered by a layer of αs-film, creating a sandwiched structure architected by TiB whisker/αs-film/ the aged β-matrix. This unique structure not only effectively retards the deteriorative development of highly localized deformation propagating from the the aged β-matrix, but also sufficiently activates dislocation slip within TiB whiskers. These findings demonstrate a counterintuitive result that TiB intermetallic compound well-known as the susceptive brittleness can be harnessed in ductilizing materials, and also provide a practical strategy for enhancing plasticity of high-strength Ti alloys by microalloying design.由于可通过沉淀强化获得超高强度,可代谢β-钛(Ti)合金一直以来都备受关注,但它们往往会受到强度-韧性权衡的影响,即在提高强度的同时降低韧性。在本研究中,我们采用了一种新颖的策略,通过痕量添加硼来解决 Ti-6Cr-5Mo-5V-4Al (Ti6554) 高强度隐晶β-Ti 合金中的这一问题。研究发现,与不含硼的合金相比,添加微量硼后可同步达到 1600 兆帕的超高强度和 9 % 的伸长率,相当于强度提高了 7 %,延展性提高了 70 %。微观结构特征表明,硼的添加几乎促进了异常β晶粒区向正常β晶粒区的完全转变,而正常β晶粒区在老化状态下具有更好的变形容纳能力。与此同时,TiB 晶须产生并被一层 αs 薄膜粘附,从而形成了一种由 TiB 晶须/αs 薄膜/老化的 β 基质构成的夹层结构。这种独特的结构不仅能有效延缓从老化的β基质传播的高度局部变形的劣化发展,还能充分激活 TiB 晶须内的位错滑移。这些发现证明了一个反直觉的结果,即众所周知的易脆性 TiB 金属间化合物可以在延展材料中得到利用,同时也为通过微合金化设计增强高强度钛合金的塑性提供了一种实用策略。Effect of microscale C–S–H on the properties of Portland cement and hydration kinetics analysis at different curing temperaturesKang Li, Huajun Zhu, Zuhua Zhang, Zheyu Zhu, Zhifeng Yin, Qisheng Wu, Zhonghua Lidoi:10.1016/j.compositesb.2024.111461微尺度C-S-H对硅酸盐水泥性能的影响及不同养护温度下水化动力学分析Microscale calcium–silicate–hydrate (C–S–H) is easily accessible and readily storable, enabling a cleaner production process of cement-waste grinding and simple chemical synthesis technology. However, the temperature effects of microscale C–S–H require further exploration. In this study, we evaluated the impact of microscale C–S–H admixture on the properties of Portland cement at different curing temperatures. Microscale C–S–H can not only increase the early strength of cement pastes, but also achieve high strength in the long term. Adding microscale C–S–H to cement can effectively reduce the apparent activation energy Ea of hydration products and accelerate the reaction of C3S and C2S with water and form more hydration products. At a curing temperature of 10 oC, the microscale C–S–H increased the 1 d compressive strength by 70.0% and shortened the hydration induction period by 1.2 h. Microscale C–S–H also increased the 12 h hydration degree by 38.1%. Microscale C–S–H promoted the formation of CH and xonotlite-like C–S–H and changed the composition of hydrates, although the effects diminished with increasing curing temperature. This paper offers theoretical and fundamental data on the usage of microscale C–S–H as an admixture in cement-based materials.微尺度硅酸钙水合物(C-S-H)易于获取和储存,可实现水泥废料研磨的清洁生产工艺和简单的化学合成技术。然而,微尺度 C-S-H 的温度效应需要进一步探索。在这项研究中,我们评估了微尺度 C-S-H 掺合料在不同固化温度下对硅酸盐水泥性能的影响。微尺度 C-S-H 不仅能提高水泥浆的早期强度,还能获得长期高强度。在水泥中添加微尺度 C-S-H 可以有效降低水化产物的表观活化能 Ea,加速 C3S 和 C2S 与水的反应,形成更多的水化产物。在固化温度为 10 oC 时,微尺度 C-S-H 使 1 d 抗压强度提高了 70.0%,水化诱导期缩短了 1.2 h。微尺度 C-S-H 促进了 CH 和类 xonotlite C-S-H 的形成,并改变了水合物的组成,但随着固化温度的升高,其效果会减弱。本文提供了微尺度 C-S-H 用作水泥基材料外加剂的理论和基础数据。TGACharacterization of Multidirectional Carbon-nanotube-yarn/bismaleimide Laminates Under Tensile LoadingBritannia Vondrasek, Cecil Evers, Claire Jolowsky, Gregory M. Odegard, Zhiyong Liang, Michael Czabajdoi:10.1016/j.compositesb.2024.111465 拉伸载荷下多向碳纳米管-纱/双马来酰亚胺复合材料的tga表征Unidirectional, cross-ply, and quasi-isotropic composite laminates are made from continuous carbon nanotube (CNT) yarns with bismaleimide (BMI) resin. The laminates are highly graphitic and have low resin content. Elastic modulus and strength of CNT/BMI laminates and IM7/8552 carbon-epoxy laminates are measured using a scaled-down tensile test method. For CNT/BMI laminates, the variation in the measured tensile modulus is high and the laminates fail in a more gradual manner than IM7/8552 laminates. Microscopy of the failed specimens indicates that intra-yarn splitting is a common feature in all CNT/BMI laminates tested. The results of this investigation will inform the development of CNT yarn reinforced composites for structural applications.用碳纳米管(CNT)纱线和双马来酰亚胺(BMI)树脂制备了单向、交叉和准各向同性复合层压板。层压板的石墨含量高,树脂含量低。采用按比例缩小的拉伸试验方法测量了CNT/BMI层压板和IM7/8552碳-环氧层压板的弹性模量和强度。对于CNT/BMI层压板,测量的拉伸模量变化很大,层压板比IM7/8552层压板以更渐进的方式失效。显微镜检查失败的样品表明,纱线内分裂是所有CNT/BMI层压板测试的共同特征。该研究结果将为碳纳米管纱增强复合材料的结构应用提供参考。Composites Science and TechnologyA highly efficient self-consistent clustering analysis method with field refinement capability for the mesoscale damage behavior of 3D woven compositesSiyang Wu, Licheng Guo, Zhixing Li, Tao Zheng, Jinzhao Huang, Xiaojian Han, Fenghao Jia, Shihan Mandoi:10.1016/j.compscitech.2024.110609 三维编织复合材料细观损伤行为的高效自洽聚类分析方法To effectively balance the accuracy and efficiency in solving high-dimensional damage problems, a self-consistent clustering analysis framework with field refinement capability (RESCA) incorporating a mesoscale damage model, is developed to investigate the mesoscale failure behavior of 3D woven composites (3DWCs). The RESCA method includes three stages: offline stage, online stage and field refinement stage integrating damage information. In the third stage, a damage-related field refinement framework is proposed to achieve cluster-based field dehomogenization and efficiently reconstruct the voxel-based field information. The results indicate that the RESCA method can accurately predict the local stress concentration, the voxel-based damage field distribution and the damage accumulation process, which are not available with the traditional SCA method. Importantly, the RESCA method can improve the computational efficiency by 25∼55 times compared to the finite element analysis (FEA) method. The RESCA method has double advantages in the efficiency and accuracy for the damage analysis of 3DWCs.为了有效地平衡高维损伤问题的准确性和效率,开发了一个包含细观损伤模型的自一致聚类分析框架(RESCA)来研究三维编织复合材料(3DWCs)的细观破坏行为。RESCA方法包括三个阶段:离线阶段、在线阶段和集成损伤信息的现场精细化阶段。第三阶段,提出损伤相关场细化框架,实现基于聚类的场去均匀化,有效重构基于体素的场信息。结果表明,RESCA方法可以准确预测局部应力集中、基于体素的损伤场分布和损伤累积过程,这是传统SCA方法所无法实现的。重要的是,与有限元分析(FEA)方法相比,RESCA方法可以将计算效率提高25 ~ 55倍。RESCA方法在三维结构损伤分析中具有效率和精度双重优势。来源:复合材料力学仿真Composites FEM

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