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【新文速递】2023年11月24日复合材料SCI期刊最新文章

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今日更新:Composite Structures 8 篇,Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 2 篇

Composite Structures

Stochastic dynamics analysis of the rocket shell coupling system with circular plate fasteners based on spectro-geometric method

Xianjie Shi, Yong Yang, Xiaolong Zhu, Zhou Huang

doi:10.1016/j.compstruct.2023.117727

基于光谱几何法的圆板紧固件火箭壳体耦合系统随机动力学分析

A numerical analysis model is established to predict the stochastic dynamic characteristics of the rocket shell coupling system. The virtual springs are employed to deal with the boundary conditions and assemble the sub structures. Firstly, the energy functional expressions of the sub structures are deduced with the medium-thick shell theory. Thereafter the equivalent dynamic model of the rocket shell coupling system is obtained. With the consideration of the random acceleration load excitation, the stochastic dynamic responses of the rocket shell coupling system are derived by solving the analytical model with the spectro-geometric method. By comparing with the results obtained with other numerical methods, the effectiveness of the proposed equivalent analysis model is successfully verified. Last but not the least, the parametric analysis is carried out to investigate the influence of some core factors on the stochastic dynamic response of the rocket shell coupling system.

建立了一个数值分析模型来预测火箭壳体耦合系统的随机动态特性。采用虚拟弹簧来处理边界条件和组装子结构。首先,利用中厚壳理论推导出子结构的能量函数表达式。然后得到火箭壳体耦合系统的等效动力学模型。在考虑随机加速度载荷激励的情况下,利用谱几何法求解分析模型,得出了火箭壳体耦合系统的随机动态响应。通过与其他数值方法得到的结果进行比较,成功验证了所提出的等效分析模型的有效性。最后,还进行了参数分析,研究了一些核心因素对火箭壳体耦合系统随机动态响应的影响。


Effect of stitch density on the damage inhibition and compression strength after high-velocity impact of UHMWPE fiber composites

Yuhang Xiang, Zhongwei Zhang, Xiaoning Yang, Yuan Lin, Guokai Zhang, Chunming Song, Ziming Xiong

doi:10.1016/j.compstruct.2023.117728

缝合密度对超高分子量聚乙烯纤维复合材料高速冲击后的损伤抑制和压缩强度的影响

This paper investigates the effect of stitch density on the high-velocity impact damage inhibition and CAI (compression after impact) strength of UHMWPE (Ultra-High Molecular Weight Polyethylene) fiber composites. The damage response and compression behavior after impact were quantified and analyzed using CT scanning and DIC (Digital Image Correlation) techniques. The findings reveal that the delamination area of the composite plate with the stitch space of 1 cm reduces by 49.14% compared to the unstitched sample, and exhibits a 73.05% higher compressive load than the plate with a 4 cm stitch space. Notably, the 4 cm stitch composite plates demonstrate a significant advantage in energy absorption. However, the sparse stitch structure destroys the original structure inside the composite, resulting in a degradation of CAI performance. The study provides guidance for the practical design of composite materials with enhanced energy absorption and damage resistance.

本文研究了缝合密度对 UHMWPE(超高分子量聚乙烯)纤维复合材料的高速冲击损伤抑制和 CAI(冲击后压缩)强度的影响。利用 CT 扫描和 DIC(数字图像相关性)技术对冲击后的损伤响应和压缩行为进行了量化和分析。研究结果表明,与未缝合的样品相比,缝合间距为 1 厘米的复合材料板的分层面积减少了 49.14%,其压缩载荷比缝合间距为 4 厘米的复合材料板高 73.05%。值得注意的是,针距为 4 厘米的复合板在能量吸收方面具有显著优势。然而,稀疏的缝合结构破坏了复合材料内部的原始结构,导致 CAI 性能下降。这项研究为实际设计具有更强能量吸收能力和抗损坏能力的复合材料提供了指导。


Characterisation of the transverse shear behaviour of binder-stabilised preforms for wind turbine blade manufacturing

P.H. Broberg, F. Shakibapour, J. Jakobsen, E. Lindgaard, B.L.V. Bak

doi:10.1016/j.compstruct.2023.117738

用于风力涡轮机叶片制造的粘合剂稳定预成型件的横向剪切性能表征

Binder-stabilised preforms are being used increasingly in the production of large composite structures, such as wind turbine blades, to increase the throughput. The transverse shear behaviour of the preform is one of the driving factors in the development of wrinkling during manufacturing but has not previously been characterised in the literature. In this paper, the combined intra- and inter-ply deformations during transverse shearing of a binder-stabilised preforms for wind turbine blade manufacturing are characterised by a new test methodology. The results from two experimental campaigns are presented. In the first campaign, preform specimens are subjected to monotonic loading to a nominal transverse shear angle of 18.0° with three different deformation rates. The results show an increase in maximum load levels with greater deformation rates. In the second campaign, preform specimens are subjected to deformation-controlled cyclic loading with two different deformation amplitudes corresponding to a nominal transverse shear angle of 1.5° and 12.2°, respectively. During cyclic loading, permanent deformation is observed in all preform specimens and the maximum load at the 19th cycle is reduced to 48% of the maximum load at the first cycle for the tests with deformation amplitudes of 12.2°. 

为提高产量,粘合剂稳定预型件正越来越多地用于大型复合材料结构(如风力涡轮机叶片)的生产中。预型件的横向剪切行为是制造过程中产生皱褶的驱动因素之一,但以前的文献尚未对其进行描述。本文采用一种新的测试方法,对用于风力涡轮机叶片制造的粘合剂稳定预型件在横向剪切过程中的层内和层间综合变形进行了表征。本文介绍了两次实验活动的结果。在第一项试验中,预成型试样受到单调加载,名义横向剪切角为 18.0°,同时有三种不同的变形率。结果表明,变形率越大,最大载荷水平越高。在第二轮试验中,预成型试样受到变形控制循环加载,两种不同的变形幅度分别对应 1.5° 和 12.2° 的标称横向剪切角。在循环加载过程中,所有预成型试样都出现了永久变形,在变形幅度为 12.2°的试验中,第 19 个循环的最大荷载降低到了第一个循环最大荷载的 48%。


Semi-analytical dynamic modeling and vibration reduction topology optimization of the bolted thin plate with partially attached constrained layer damping

Rongfei Zhang, Wei Sun, Haitao Luo, Hui Zhang, Xiaofeng Liu

doi:10.1016/j.compstruct.2023.117739

带部分附着约束层阻尼的螺栓连接薄板的半分析动态建模和减振拓扑优化

In this paper, the double-lap bolted plate is used to simulate the fully unfolded state of solar panels, and the method of vibration suppression by attaching constrained layer damping (CLD) is studied. Firstly, based on the principle of interlaminar shear deformation, the semi-analytical dynamic model of the double-lap bolted thin plate with partial CLD is established by using Hamilton’s principle. The stress–strain relationship of the CLD is derived. Then, complex spring elements and modified mass are proposed to simulate the interface mechanical behavior and mass effect of the double-lap joint. Moreover, the orthogonal polynomial is introduced as the displacement admissible function. Based on the Evolutionary Structural Optimization (ESO) method, the topology optimization model of the bolted thin plate with CLD is established by taking the maximum sum of the modal loss factors as the optimization objective and the attachment volume as the constraint condition, and processing the optimized results in a convolutional way. After that, a case study is carried out, and the experimental system is established to prove the rationality of the semi-analytical model and attaching CLD to vibration reduction. Finally, the topology optimization is conducted, which verifies that the topology configuration has a better vibration reduction effect.

本文采用双搭接栓接薄板模拟太阳能电池板的完全展开状态,并研究了附加约束层阻尼(CLD)的振动抑制方法。首先,根据层间剪切变形原理,利用汉密尔顿原理建立了带部分 CLD 的双搭接螺栓薄板的半解析动力学模型。得出了 CLD 的应力-应变关系。然后,提出了复合弹簧元素和修正质量来模拟双搭接接头的界面力学行为和质量效应。此外,还引入了正交多项式作为位移容许函数。基于进化结构优化(ESO)方法,以模态损失因子最大和为优化目标,以附着体积为约束条件,建立了带有 CLD 的螺栓连接薄板的拓扑优化模型,并对优化结果进行了卷积处理。随后,进行了案例研究,并建立了实验系统,以证明半分析模型和附加 CLD 减振的合理性。最后,进行了拓扑优化,验证了拓扑配置具有更好的减振效果。


A homogenization method for natural frequencies and damping of sandwich panels based on representative volume elements

Chengyu Guan, Ruishen Lou, Yanhong Chen, Chengwei Qin, Zhiyuan Shi, Lihong Liang, Huimin Li

doi:10.1016/j.compstruct.2023.117740

基于代表体积元素的夹芯板固有频率和阻尼均质化方法

The existing representative volume element (RVE) homogenization method, grounded in finite element analysis, assumes a planar configuration for the sections of sandwich panels, implying rigidity. To accommodate non-planar displacements, this study introduces a novel homogenization method reliant on the displacements obtained from four-point bending and four-point torsion. The present method is employed to investigate the mode shapes, natural frequencies, and loss factors of sandwich panels utilizing an equivalent single-layer shell model. Validation of the present method is conducted through the analysis of lattice sandwich panels and corrugated sandwich panels incorporating viscoelastic layers. Comparative analyses encompassing the results of the experiment, the conventional solid model method, the present method, and the conventional plane method are undertaken. The universality of the present method is substantiated. The present method enhances the precision of natural frequency prediction.

以有限元分析为基础的现有代表体积元素(RVE)均质化方法假定夹芯板的截面为平面结构,这意味着刚性。为了适应非平面位移,本研究引入了一种新型均质化方法,该方法依赖于从四点弯曲和四点扭转中获得的位移。本方法利用等效单层壳体模型来研究夹芯板的模态振型、固有频率和损耗因子。通过分析包含粘弹性层的格状夹芯板和波纹夹芯板,对本方法进行了验证。对比分析包括实验结果、传统实体模型方法、本方法和传统平面方法。本方法的通用性得到了证实。本方法提高了固有频率预测的精度。


Dynamic response and design evaluation of circular CFT columns with ring-shaped voids under transverse impact

Qihan Shen, Tao Wu, Jingfeng Wang, Fengqin Wang, Weijun Zhu, Xinyu Peng

doi:10.1016/j.compstruct.2023.117743

带环形空隙的圆形 CFT 柱在横向冲击下的动态响应和设计评估

Presently, the research on the impact performance of the concrete-filled steel tubular (CFT) members has never considered the problem of void defect. Hence, this paper fosters a refined finite element (FE) model of the circular CFT column with ring-shaped voids under transverse impact, which considers the initial contact status of concrete. After validating the accuracy of FE models, the effects of void ratio, steel ratio, impact speed and mass of the drop hammer on the dynamic behaviour of the circular CFT column with ring-shaped voids are explored. Detailed impacting mechanisms of the defect column are acknowledged by elaborating its dynamic time history curves, failure morphology, impact force diffusion path, contact process, and stress/strain distribution rule. Calculation methods for evaluating the impact resistance of the circular CFT column with ring-shaped voids are proposed. The results declare that the appearance of ring-shaped voids would significantly weaken the impact resistance of the CFT column. The impact force and energy dissipation are greatly decreased with the increase in void ratio. Under the transverse impact, the steel tube would be seriously depressed due to the absence of effective support acted by concrete with ring-shaped void, and the core concrete would be heavily damaged in return.

目前,有关混凝土填充钢管(CFT)构件冲击性能的研究从未考虑过空隙缺陷问题。因此,本文对横向冲击下带有环形空隙的圆形 CFT 柱建立了精细的有限元(FE)模型,该模型考虑了混凝土的初始接触状态。在验证了有限元模型的准确性后,探讨了空隙率、钢筋率、冲击速度和落锤质量对带有环形空隙的圆形 CFT 柱动态行为的影响。通过阐述缺陷柱的动态时间历程曲线、破坏形态、冲击力扩散路径、接触过程和应力/应变分布规则,确认了缺陷柱的详细冲击机制。提出了评估带有环形空隙的圆形 CFT 柱抗冲击性的计算方法。结果表明,环形空隙的出现会大大削弱 CFT 柱的抗冲击性。随着空隙率的增加,冲击力和能量耗散都大大减小。在横向冲击力作用下,钢管会因环形空隙混凝土缺乏有效支撑而严重凹陷,核心混凝土也会随之受到严重破坏。


Performance and mechanisms of ultraviolet laser ablation of plain-woven CFRP composites

Yuze Hou, Jinxuan Bai, Fei Wang, Linmao Qian

doi:10.1016/j.compstruct.2023.117744

紫外线激光烧蚀平织 CFRP 复合材料的性能和机理

Plain-woven carbon-fiber-reinforced-polymer (CFRP) composites prove advantageous in designing and manufacturing aeronautic and aerospace structures due to their excellent mechanical properties. Their harsh service environment usually leads to aircraft surface pits, scratches, and other types of defects, which result in internal damages that reduce their strength, influencing their safety and reliability. With laser-controlled ablation, surface damage removal was implemented. However, the multiscale characteristics of plain-woven CFRP (macroscopic plain-woven textiles, mesoscopic fiber clusters, together with microscopic fiber and epoxy resin) lead to complex thermal-mechanical ablation action, prone to secondary surface damages and resin residue. Aiming at the requirement of high-performance removal of the damaged zone, a comprehensive investigation of the influence of laser ablation strategies, including the wavelength, defocus distance, scanning speed, hatch distance, scanning passes, etc., on generating morphologies was conducted. Results identified that the severe anisotropy of plain-woven CFRP gained a wide heat-affected zone (HAZ), which was restrained by adopting an ultraviolet (UV) laser ablation means. A high-quality laser ablation zone without visible resin residue and broken carbon fiber has been presented by one-pass laser ablation when a particular scarfing conditions combination was used. Meanwhile, a depth-controlled surface-forming approach was gained, accompanied by multiple laser scanning. Subsequently, a hybrid laser treatment strategy was provided for characteristic structure generation, and a novel stepwise structure was constructed for verification.

平织碳纤维增强聚合物(CFRP)复合材料因其优异的机械性能,在设计和制造航空航天结构方面具有优势。恶劣的使用环境通常会导致飞机表面出现凹坑、划痕和其他类型的缺陷,从而造成内部损坏,降低飞机强度,影响飞机的安全性和可靠性。通过激光控制烧蚀,可以消除表面损伤。然而,平织 CFRP 的多尺度特性(宏观平织织物、中观纤维簇、微观纤维和环氧树脂)导致复杂的热机械烧蚀作用,容易造成二次表面损伤和树脂残留。针对高效去除损伤区的要求,研究人员对激光烧蚀策略(包括波长、散焦距离、扫描速度、舱口距离、扫描次数等)对生成形态的影响进行了全面研究。结果表明,平织 CFRP 的各向异性严重,因此热影响区(HAZ)较宽,而采用紫外线(UV)激光烧蚀手段可抑制热影响区。在使用特定的剪切条件组合时,通过一次激光烧蚀可获得无可见树脂残留和碳纤维断裂的高质量激光烧蚀区。同时,通过多重激光扫描,获得了一种深度可控的表面成形方法。随后,提供了一种用于生成特征结构的混合激光处理策略,并构建了一种新颖的分步式结构以供验证。


Tunable and recoverable energy absorption of foam-embedded architected cellular composite material at multiple strain rates

Xianhua Yao, Ke Liu, Qing Dong, Xuanyou Li, Chunfeng Ma, Nan Hu

doi:10.1016/j.compstruct.2023.117745

泡沫嵌入式结构蜂窝复合材料在多种应变速率下的可调节、可恢复能量吸收能力

Cellular multistable architected material has been wieldy studied for its promising energy absorption applications for personnel protection, protective packaging, and crash mitigation. Despite the tailorable properties enabled by their geometric features, a major issue in the actual application is their lower strengths in the elastic behavior of the multistable architected material. Herein, a novel design strategy of strain rate-dependent architected cellular composite material (FACCM) is proposed, aiming to achieve enhanced energy-absorbing properties with the proposed composite system than the single material constituent. Guided by numerical simulations and experimental tests, the compressive behaviour of FACCM at multiple strain rates and the effect of filled foam on it with specific geometric parameters are characterized. The quasi-static performances of the FACCM specimens were evaluated both at the cell level and planar array level. Our results indicate that the strength, stiffness, and snap-through behaviour of multistable architected material can be significantly improved by the filled foam at elevated loading rates regardless of quasi-static loading or impact tests. The current study offers a new strategy for developing novel packing, shock absorption, and impact protection systems.

蜂窝多稳态结构材料在人员保护、防护包装和碰撞缓解等方面的能量吸收应用前景广阔,对其进行了大量研究。尽管其几何特征具有可定制的特性,但实际应用中的一个主要问题是多稳态结构材料的弹性行为强度较低。在此,我们提出了一种新颖的应变速率依赖性结构化蜂窝复合材料(FACCM)设计策略,旨在利用所提出的复合材料系统实现比单一材料成分更强的能量吸收性能。在数值模拟和实验测试的指导下,研究了 FACCM 在多种应变速率下的压缩行为,以及填充泡沫在特定几何参数下对其产生的影响。对 FACCM 试样的准静态性能进行了细胞级和平面阵列级评估。我们的研究结果表明,无论进行准静态加载还是冲击试验,在加载速率升高的情况下,填充泡沫都能显著改善多稳态结构材料的强度、刚度和穿透性能。目前的研究为开发新型包装、减震和冲击保护系统提供了一种新策略。


Composites Part A: Applied Science and Manufacturing

Insight into the enhanced interfacial adhesion of carbon fiber reinforced composites: a facile ferric ion and tannic acid self-assembly strategy

Wenlong Hu, Lulu Yang, Fangxin Wang, Jie Zhi, Hailing He, Chaojie Hu, Facai Wei, Shaohua Liu, Yan Li, Yu Cang, Bin Yang

doi:10.1016/j.compositesa.2023.107926

洞察碳纤维增强复合材料界面粘附力的增强:一种简便的铁离子和单宁酸自组装策略

Applications of carbon fiber reinforced polymer composites are subjected the poor interfacial adhesion due to the smooth and chemically inert of CF surface. In this work, we proposed an effective and simple approach to improve the interfacial properties between CF and matrix by self-assembling the ferric ion (Fe3+) and tannic acid (TA) on the carbon fiber surface within minutes. TA can rapidly coordinate with Fe3+ ions into three-dimensional Fe3+-TA complex networks, the morphologies of which were controlled by Fe3+/TA molar ratio and deposition cycles, which played a key role in the interfacial performance. As Fe3+/TA molar ratio is optimized to 4, Fe3+-TA complex aggregated to nano-sized bulges on the fiber surface, affording numerous mechanical interlocking points which can promote the stress transfer from matrix to fiber and induce the deflection of cracks. Moreover, breaking metal-ligand coordination bonds of Fe3+-TA complex as cracks propagate can dissipate lots of fracture energy, leading to the interfacial shear strength of Fe3+-TA complex modified CF/epoxy vinyl resin composites being improved by ∼80 % as compared with the pristine sample. This strategy is facile, mild, and eco-friendly, which opens a feasible avenue for enhancing the interfacial adhesion of CFRPs.

由于碳纤维表面光滑且无化学惰性,碳纤维增强聚合物复合材料的应用受到界面粘附性差的限制。在这项工作中,我们提出了一种有效而简单的方法,通过在几分钟内在碳纤维表面自组装铁离子(Fe3+)和单宁酸(TA)来改善碳纤维与基体之间的界面性能。TA 能与 Fe3+ 离子快速配位成三维的 Fe3+-TA 复合网络,其形态受 Fe3+/TA 摩尔比和沉积周期的控制,对界面性能起着关键作用。当 Fe3+/TA 摩尔比优化到 4 时,Fe3+-TA 复合物在纤维表面聚集成纳米级的隆起,提供了大量机械互锁点,可促进基体到纤维的应力传递并诱导裂纹偏转。此外,随着裂纹的扩展,Fe3+-TA 复合物金属配位键的断裂可耗散大量的断裂能量,从而使 Fe3+-TA 复合物改性 CF/ 环氧乙烯基树脂复合材料的界面剪切强度比原始样品提高了 80%。这种策略简便、温和、环保,为增强 CFRP 的界面粘合力开辟了一条可行的途径。


Composites Part B: Engineering

Unraveling the atomic-level manipulation mechanism of tin-based ternary anodes via hetero-anion engineering for stable sodium ion storage

Xiaoqin Cheng, Qiang Bai, Zhenxin Zhao, Huijun Li, Huanglin Dou, Shizhen Tian, Xiaomin Wang

doi:10.1016/j.compositesb.2023.111109

通过异阴离子工程揭示锡基三元阳极的原子级操纵机制,实现稳定的钠离子存储

The gradual retardation of heterogeneous interface reactions during extended cycling results in significant capacity loss, particularly in the initial few cycles. This is due to the inhomogeneous distribution and structural degradation of heterointerfaces. Currently, a range of atomic-level tuning strategies are employed to enhance the intrinsic transfer characteristics for sodium-ion batteries (SIBs). Herein, the defect-rich single-phase ternary tin sulfide selenide (SnSe1.33S0.67) anode is constructed via favorable heteroatom(S) introducing. Such a defective open structure employed as anodes for SIBs, delivers a superior rate performance of 452.3 mAh g−1 at 5.0 A g−1, and excellent cycling stability, with a capacity retention of 535.8 mAh g−1 after 500 cycles at 1.0 A g−1. The exceptional performance is attributed to the rapid diffusion of ions/electrons through lattice defects and heteroatom coexistence, as well as the high tolerance for volume changes resulting from optimized phase transition modes and enhanced structural rigidity, as demonstrated by experimental results and density functional theory (DFT) calculations. Through the heteroatoms injection strategy, this work offers deeper insights into the correlation between precise regulation of internal defects and superior storage performance in SIBs.

在延长的循环过程中,异质界面反应的逐渐延缓会导致显著的容量损失,尤其是在最初的几个循环中。这是由于异质界面的不均匀分布和结构退化造成的。目前,为了提高钠离子电池(SIB)的内在转移特性,人们采用了一系列原子级调整策略。本文通过引入有利的杂原子(S),构建了富含缺陷的单相三元硫化锡硒化物(SnSe1.33S0.67)阳极。这种缺陷开放结构被用作 SIB 的阳极,在 5.0 A g-1 的条件下具有 452.3 mAh g-1 的优异速率性能,并且具有出色的循环稳定性,在 1.0 A g-1 的条件下循环 500 次后容量保持率为 535.8 mAh g-1。实验结果和密度泛函理论(DFT)计算均证明,这种优异的性能归功于离子/电子通过晶格缺陷和杂原子共存的快速扩散,以及优化的相变模式和增强的结构刚性所带来的对体积变化的高耐受性。通过杂原子注入策略,这项研究深入揭示了精确调节内部缺陷与 SIB 优异存储性能之间的关系。


Composites Science and Technology

Room-to-low temperature thermo-mechanical behavior and corresponding constitutive model of liquid oxygen compatible epoxy composites

Yicheng Jiang, Ling liu, Jia Yan, Zhanjun Wu

doi:10.1016/j.compscitech.2023.110357

 

液氧兼容环氧复合材料的室温至低温热机械行为及相应的构成模型

The room-to-low temperature (RT-LT) mechanical behavior of liquid oxygen-compatible epoxy composites (LOC-EP) is of great importance in the strength analysis of lightweight liquid oxygen tanks. This article first explores the tensile-compressive mechanical behaviors of LOC-EP from RT down to −183 °C. The results show that compared with RT, the tensile strength, compressive strength, and elastic modulus at −183 °C increase by 44%, 109%, and 160% respectively. Secondly, based on the theories of molecular chain freezing degree and yield surface extension, a ductile-brittle transition T of −60 °C and a completely brittle T of −90 °C are obtained sequentially. Moreover, a universal thermal-mechanical constitutive model for EP is derived, and the constitutive model parameters of LOC-EP from RT to −183 °C are fitted and calibrated using Matlab. Finally, the proposed constitutive model is introduced into Abaqus through a user subroutine. On the one hand, three-dimensional one-element analyses demonstrate that the simulation curves are highly consistent with the experimental and Matlab-fitted curves (errors less than 3%) with good convergence/accuracy. On the other hand, the fracture modes obtained from macroscopic simulations of tensile and compressive specimens are also coherent with the experimental fracture modes.

液氧相容环氧复合材料(LOC-EP)的室温至低温(RT-LT)机械性能对轻质液氧罐的强度分析具有重要意义。本文首先探讨了液氧相容环氧复合材料在低温至-183 °C时的拉伸压缩力学行为。结果表明,与常温下相比,-183 °C时的拉伸强度、压缩强度和弹性模量分别增加了44%、109%和160%。其次,根据分子链凝固度和屈服面扩展理论,依次得到了-60 ℃的韧性-脆性转变 T 值和-90 ℃的完全脆性 T 值。此外,还推导出了 EP 的通用热力学组成模型,并使用 Matlab 对 LOC-EP 从 RT 到 -183 °C 的组成模型参数进行了拟合和校准。最后,通过用户子程序将所提出的构成模型引入 Abaqus。一方面,三维单元素分析表明,模拟曲线与实验曲线和 Matlab 拟合曲线高度一致(误差小于 3%),具有良好的收敛性/准确性。另一方面,从拉伸和压缩试样的宏观模拟中获得的断裂模式也与实验断裂模式一致。


Enhancement mechanism of epoxy resin by polyacrylic acid-modified 3D porous graphene: A microscopic and molecular dynamics perspective

Jinying Yu, Jiale Chen, Kefeng He, Lizhe Liang, Zhi Qun Tian

doi:10.1016/j.compscitech.2023.110363

 

聚丙烯酸改性三维多孔石墨烯增强环氧树脂的机理:微观和分子动力学视角

Graphene is a two-dimensional nanomaterial with remarkable strength and is a highly effective enhancer in polymer materials. However, the mechanisms underlying the enhancement between the enhancer and the base material remain uncertain. In this study, we have successfully prepared advanced epoxy nanocomposites by grafting polyacrylic acid onto 3D porous graphene (3DG). The covalent functionalization of 3DG has proven to be highly effective in preventing its aggregation within the epoxy matrix. The mechanical test results demonstrated a substantial enhancement in the tensile trength (41.04%), elastic modulus (43.23%), and impact strength (370.88%) of the epoxy resin upon the incorporation of polyacrylic acid-modified graphene (PAAMG). The fracture surfaces of the composites were examined using scanning electron microscopy, which provided insights into the enhancer's mechanism of enhancement. Notably, employing a range of molecular dynamic simulations and analyses, we found that PAAMG exhibits the ability to bifurcate cracks, thereby improving the mechanical properties of the material.

石墨烯是一种二维纳米材料,具有非凡的强度,是聚合物材料中一种高效的增强剂。然而,增强剂与基体材料之间的增强机制仍不确定。在本研究中,我们通过将聚丙烯酸接枝到三维多孔石墨烯(3DG)上,成功制备了先进的环氧纳米复合材料。事实证明,3DG 的共价官能化能有效防止其在环氧基质中聚集。力学测试结果表明,加入聚丙烯酸改性石墨烯(PAAMG)后,环氧树脂的拉伸强度(41.04%)、弹性模量(43.23%)和冲击强度(370.88%)均有大幅提高。使用扫描电子显微镜检查了复合材料的断裂表面,从而深入了解了增强剂的增强机理。值得注意的是,通过一系列分子动力学模拟和分析,我们发现 PAAMG 能够使裂缝分叉,从而改善材料的机械性能。



来源:复合材料力学仿真Composites FEM
ACTMechanicalSystemAbaqusDeform振动断裂复合材料碰撞化学拓扑优化通用航空航天电子裂纹理论材料太阳能分子动力学
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【新文速递】2023年11月28日固体力学SCI期刊最新文章

今日更新:Journal of the Mechanics and Physics of Solids 1 篇,International Journal of Plasticity 2 篇,Thin-Walled Structures 2 篇Journal of the Mechanics and Physics of SolidsFinding Transition State and Minimum Energy Path of Bistable Elastic Continua through Energy Landscape ExplorationsGuangchao Wan, Samuel J. Avis, Zizheng Wang, Xueju Wang, Halim Kusumaatmaja, Teng Zhangdoi:10.1016/j.jmps.2023.105503通过能量景观探索寻找双稳态弹性连续体的过渡态和最小能量路径Mechanical bistable structures have two stable equilibria and can transit between them under external stimuli. Due to their unique behaviors such as snap-through and substantial shape changes, bistable structures exhibit unprecedented properties compared to conventional structures and thus have found applications in various fields such as soft robots, morphing wings and logic units. To quantitatively predict the performance of bistable structures in these applications, it is desirable to acquire information about the minimum energy barrier and an energy-efficient transition path between the two stable states. However, there is still a general lack of efficient methodologies to obtain this information, particularly for elastic continua with complicated, unintuitive transition paths. To overcome this challenge, here we integrate energy landscape exploration algorithms into finite element method (FEM). We first utilize the binary image transition state search (BITSS) method to identify the saddle point and then perform nudged elastic band (NEB) calculations with initial guess based on the BITSS results to find the minimum energy path (MEP). This integrated strategy greatly helps the convergence of MEP calculations, which are highly nonlinear. Two representative cases are studied, including bistable buckled beams and a bistable unit of mechanical metamaterials, and the numerical results agree well with the previous works. Importantly, we numerically predict the complicated MEP of an asymmetric bistable unit of mechanical metamaterials and use experiments to demonstrate that following this MEP leads to successful transition between stable states while intuitive uniaxial compression fails to do so. Our work provides an effective numerical platform for identifying the minimum energy barrier and energy-efficient transition path of a bistable continuum, which can offer valuable guidance to the design of actuators, damping structures, energy harvesters, and mechanical metamaterials.机械双稳态结构具有两个稳定的平衡点,并能在外部刺 激下在两个平衡点之间转换。与传统结构相比,双稳态结构因其独特的行为(如快速穿透和大幅形状变化)而表现出前所未有的特性,并因此在软机器人、变形翅膀和逻辑单元等多个领域得到应用。为了定量预测双稳态结构在这些应用中的性能,最好能获得有关最小能量障碍和两个稳定状态之间的高能效过渡路径的信息。然而,目前仍然普遍缺乏获取这些信息的有效方法,特别是对于过渡路径复杂、不直观的弹性连续体。为了克服这一难题,我们在此将能量景观探索算法集成到有限元法(FEM)中。我们首先利用二元图像转换态搜索(BITSS)方法确定鞍点,然后根据 BITSS 的结果,利用初始猜测进行裸弹带(NEB)计算,以找到最小能量路径(MEP)。这种综合策略大大有助于高度非线性的 MEP 计算的收敛。我们研究了两种具有代表性的情况,包括双稳态屈曲梁和机械超材料的双稳态单元,数值结果与之前的研究结果非常吻合。重要的是,我们从数值上预测了机械超材料非对称双稳态单元的复杂 MEP,并通过实验证明,遵循这一 MEP 可以成功实现稳定状态之间的转换,而直观的单轴压缩则无法实现这一转换。我们的工作为确定双稳态连续体的最小能量障碍和高能效过渡路径提供了有效的数值平台,可为致动器、阻尼结构、能量收集器和机械超材料的设计提供有价值的指导。International Journal of PlasticityThe effect of electric current on dislocation activity in pure aluminum: a 3D discrete dislocation dynamics studyZhutian Xu, Xia'nan Li, Rui Zhang, Jun Ma, Diankai Qiu, Linfa Pengdoi:10.1016/j.ijplas.2023.103826电流对纯铝中位错活动的影响:三维离散位错动力学研究Introducing electric current into metals and alloys to improve their ductility and to reduce the hardening tendency has been widely adopted. Nevertheless, how the electricity affects the plastic deformation of those materials remains a critical issue with controversial opinions. To clarify the material plastic deformation subjected to electric current, or the so-called electroplastic behavior, an in-depth understanding of the dislocation evolution during that process is vital. From that motivation, three-dimensional dislocation dynamics simulations were carried out to explore the dislocation behavior during the uniaxial tensile deformation of pure aluminum with the introduction of electric current. The scattering process between electrons and dislocations was first captured by a physical model. The electron wind force and local heat effect were quantitatively analyzed by figuring out the momentum and the energy transferred during the interaction of electrons and dislocations respectively. The dislocation density evolution, the activation of different slip systems and the dislocation distribution were further analyzed based on the simulations. The dislocation density in the [111] direction is revealed to increase more significantly than [101] and [001] directions with the introduction of electric current. The results show that the current can reduce the flow stress by promoting the activation of the difficult-to-move dislocations. The activation effect reduces the dislocation tangling tendency and leads to more uniform dislocation distribution. Therefore, a reduction of the flow stress can be observed in EAT comparing to TAT, via the discrete dislocation dynamics simulations even though the dislocation densities are similar. The simulation results are also confirmed by the EAT and TAT experiment results and TEM observations.将电流引入金属和合金以提高其延展性并减少硬化趋势已被广泛采用。然而,电流如何影响这些材料的塑性变形仍是一个关键问题,众说纷纭。要弄清材料在电流作用下的塑性变形,即所谓的电塑性行为,深入了解这一过程中的位错演变至关重要。基于这一动机,我们进行了三维位错动力学模拟,以探索纯铝在引入电流的单轴拉伸变形过程中的位错行为。首先通过物理模型捕捉了电子和位错之间的散射过程。通过计算电子和位错相互作用过程中传递的动量和能量,分别定量分析了电子风力和局部热效应。在模拟的基础上,进一步分析了位错密度的演变、不同滑移系统的激活以及位错的分布。结果表明,引入电流后,[111]方向的位错密度比[101]和[001]方向增加得更明显。结果表明,电流能促进难以移动的位错活化,从而降低流动应力。激活效应降低了位错的缠结趋势,并使位错分布更加均匀。因此,通过离散位错动力学模拟可以观察到,即使位错密度相似,EAT 的流动应力也比 TAT 小。模拟结果也得到了 EAT 和 TAT 实验结果和 TEM 观察结果的证实。Evolution of recrystallization texture in medium to low stacking fault energy alloys: Experiments and simulationsGyan Shankar, Voolapalli Gayatri, Luis A. Barrales-Mora, S. Suwasdoi:10.1016/j.ijplas.2023.103827中低堆积断层能合金的再结晶纹理演变:实验与模拟The present work aims to investigate the evolution of static recrystallization microstructure and texture in medium to low stacking fault energy (SFE) alloys. In these categories of materials, the process of recrystallization becomes complex because of the presence of extensive deformation heterogeneity. Ni-xCo (40 and 60 wt.% Co) alloy has been chosen for this purpose, where Ni-40Co belongs to medium SFE, and Ni-60Co belongs to low SFE regimes. The effect of solid solution strengthening and deformed microstructural features on the mechanism of recrystallization are explored. Both the alloys were subjected to 50% cold-rolling reduction followed by isothermal annealing at 600°C. Recrystallization texture of Ni-40Co shows a non-uniform α-fibre having a peak intensity at the Goss component, whereas Ni-60Co shows uniform α-fibre texture. Both the alloys also show rotated cube (Rt C) and rotated Cu (Rt Cu) components after recrystallization. Apart from that Ni-60Co exhibits brass recrystallization (BR) texture component. The differences in the recrystallization texture in both the Ni-Co alloys are attributed to the role of different heterogeneous deformation features in the microstructure and transition from Cu-type to Bs-type as-deformed texture. The recrystallization microstructure is dominated by the formation of substantial annealing twin (Σ3) boundaries, which also produces many new orientations; thereby weaken the recrystallization texture. These experimental findings and the proposed mechanism were used as input to simulate the recrystallization microstructure and texture in the alloy using the parallelized cellular automata (CA) technique. Parallelized CA model has successfully predicted the evolution of recrystallization texture and microstructure through simulation except parallel annealing twin feature.本研究旨在探讨中低堆积断层能(SFE)合金中静态再结晶微观结构和纹理的演变。在这类材料中,由于存在广泛的变形异质性,再结晶过程变得复杂。为此选择了镍-钴(40 和 60 wt.%钴)合金,其中镍-40钴属于中堆错能合金,镍-60钴属于低堆错能合金。研究探讨了固溶强化和变形微观结构特征对再结晶机制的影响。两种合金都经过 50%的冷轧还原,然后在 600°C 等温退火。镍-40钴的再结晶纹理显示出不均匀的α-纤维,其峰值强度位于戈斯成分,而镍-60钴则显示出均匀的α-纤维纹理。这两种合金在再结晶后还显示出旋转立方(Rt C)和旋转铜(Rt Cu)成分。除此之外,Ni-60Co 还显示出黄铜再结晶 (BR) 纹理成分。两种镍钴合金再结晶纹理的差异归因于微观结构中不同的异质变形特征以及从 Cu 型到 Bs 型变形纹理的过渡。再结晶微观结构主要由大量退火孪晶(Σ3)边界的形成所主导,同时也产生了许多新的取向,从而削弱了再结晶纹理。这些实验结果和所提出的机制被用作输入,利用并行化细胞自动机(CA)技术模拟合金中的再结晶微观结构和纹理。除平行退火孪生特征外,平行化 CA 模型通过模拟成功预测了再结晶纹理和显微组织的演变。Thin-Walled StructuresExperimental and PDDO-based meshfree numerical study on ductile fracture behavior of steel plateLiu Fan, Hu Yu-meng, Xu Yi-gang, Feng Guo-qingdoi:10.1016/j.tws.2023.111424钢板韧性断裂行为的实验和基于 PDDO 的无网格数值研究This paper presents a meshfree approach based on the coupling of peridynamic differential operator (PDDO) and continuum mechanics to predict the ductile fracture of the steel plates. The interpolation function of particles for a shell model is established by applying the PDDO in the 2D case. The weak form of the kinetic equations is derived by discretizing the motion variables. The Gurson-Tvergaard-Needleman (GTN) constitutive model is adopted to characterize the plasticity and ductile fracture behavior of material, in which the material parameters are determined by conducting uniaxial tensile tests and scanning electron microscope analysis. The ductile fracture test of the EH36 steel plate with a prefabricated crack is conducted to validate the proposed numerical approach. The results show that the established meshfree shell model is able to accurately simulate the bearing capacity, crack propagation rate, and ductile fracture characteristics of the structure.本文提出了一种基于周动态微分算子(PDDO)和连续介质力学耦合的无网格方法,用于预测钢板的韧性断裂。通过在二维情况下应用 PDDO,建立了壳模型的粒子插值函数。通过对运动变量进行离散化,得出了动力学方程的弱形式。采用 Gurson-Tvergaard-Needleman(GTN)构成模型来表征材料的塑性和韧性断裂行为,其中材料参数是通过单轴拉伸试验和扫描电子显微镜分析确定的。对带有预制裂纹的 EH36 钢板进行了韧性断裂试验,以验证所提出的数值方法。结果表明,所建立的无网格壳模型能够准确模拟结构的承载能力、裂纹扩展速率和延性断裂特征。Investigation on shear and fatigue performance of CFRP/aluminum alloy single-lap adhesive jointLiming Duan, Wei Liang, Yongai Hou, Dayong Wang, Junjia Cui, Guangyao Li, Hao Jiangdoi:10.1016/j.tws.2023.111421CFRP/ 铝合金单层粘接接头的剪切和疲劳性能研究The size parameter is quite significant for the performance of adhesive joint. In order to investigate the effect of size parameters on the mechanical property and failure behavior of CFRP/aluminum alloy adhesive single-lap joint, T300 CFRP laminate and AA5182 aluminum alloy sheet were bonded by Sika Power 497 structural adhesive under different size parameters. The quasi-static shear test and fatigue test were implemented, and the failure behavior and failure mechanism were analyzed. Results showed that the increase of aluminum alloy sheet thickness or bonding area length could effectively improve the bonding strength of adhesive joint, when the strength of the aluminum alloy sheet or the adhesive layer was insufficient. The shear failure modes of adhesive joint mainly included adhesive failure, base material failure and mixed failure. The fatigue failure modes of adhesive joint were mainly adhesive cohesion failure and adhesive adhesion failure. At low stress levels, the aluminum alloy sheet might fracture. In addition, this work can provide a scientific guidance for the engineering application of adhesive bonding technology.尺寸参数对粘合剂接头的性能影响很大。为了研究尺寸参数对 CFRP/ 铝合金粘接单搭接接头力学性能和失效行为的影响,采用西卡 Power 497 结构胶在不同尺寸参数下粘接了 T300 CFRP 层压板和 AA5182 铝合金板。进行了准静态剪切试验和疲劳试验,分析了失效行为和失效机理。结果表明,当铝合金板材或粘合剂层强度不足时,增加铝合金板材厚度或粘合区域长度可有效提高粘合接头的粘合强度。粘接接头的剪切失效模式主要包括粘接失效、基材失效和混合失效。胶接件的疲劳失效模式主要是胶粘剂内聚失效和胶粘剂粘合失效。在低应力水平下,铝合金板可能会断裂。此外,这项工作还能为粘合剂粘接技术的工程应用提供科学指导。来源:复合材料力学仿真Composites FEM

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