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【新文速递】2024年11月25日固体力学SCI期刊最新文章

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今日更新:International Journal of Solids and Structures 1 篇,Journal of the Mechanics and Physics of Solids 3 篇,International Journal of Plasticity 2 篇,Thin-Walled Structures 4 篇

International Journal of Solids and Structures

Characterizing and modeling the wide strain rate range behavior of air-filled open-cell polymeric foam

Xinghao Wang, Zhibo Du, Jiarui Zhang, Yue Kang, Chenxu Liu, Tian Ma, Zhanli Liu

doi:10.1016/j.ijsolstr.2024.113155

充气开孔聚合物泡沫的宽应变速率范围特性表征与建模

Air-filled open-cell polymeric foams are widely used for absorbing impact energy under various strain rates. Modeling their compression behavior under large deformation across a wide strain rate range remains a challenge, as the air pressure is dominated by viscous effect or inertial effect at different strain rates. In this study, the compression response of air-filled open-cell polyurethane (PU) foam is characterized across a wide strain rate range from 0.0001 s−1 to 5000 s−1. The plateau stress and energy absorption properties of the foam exhibit a power-law dependency on strain rate, showing lower rate sensitivity at quasi-static rates and increased sensitivity at high strain rates. To describe the observed rate sensitivity variation, the effect of airflow resistance is quantitatively modeled and a visco-hyperelastic constitutive model considering air pressure is developed. It shows that at high strain rates, the air pressure can constitute up to 30 % of the energy absorption contribution while it is relatively negligible at quasi-static strain rates, which significantly amplifies the difference in rate sensitivity between quasi-static and high strain rates. Furthermore, a simplified semi-empirical formula is proposed to rapidly estimate the air pressure in open-cell foams at high strain rates. This formula demonstrates the mechanical response transition from open-cell to closed-cell foams with increasing strain rates. This study is meaningful for understanding the dynamic response and the energy absorption capabilities of air or fluid filled open-cell foam.

充气开孔泡沫塑料被广泛用于吸收不同应变速率下的冲击能。由于在不同应变率下,空气压力主要受粘性效应或惯性效应的影响,因此在大变形、宽应变率范围内对其压缩行为进行建模仍然是一个挑战。在这项研究中,充气开孔聚氨酯(PU)泡沫的压缩响应特征是在0.0001 s−1到5000 s−1的宽应变率范围内。泡沫的平台应力和能量吸收性能与应变速率呈幂律关系,在准静态速率下表现出较低的速率敏感性,在高应变速率下表现出较高的灵敏度。为了描述观测到的速率敏感性变化,对气流阻力的影响进行了定量建模,并建立了考虑气压的粘-超弹性本构模型。结果表明,在高应变率下,空气压力可占能量吸收贡献的30% %,而在准静态应变率下,空气压力相对可以忽略不计,这显著放大了准静态应变率与高应变率之间的速率灵敏度差异。此外,提出了一种简化的半经验公式来快速估计高应变率下开孔泡沫内的空气压力。该公式显示了随应变速率的增加,从开孔泡沫到闭孔泡沫的力学响应转变。本研究对了解空气或流体填充开孔泡沫的动态响应和吸能能力具有重要意义。


Journal of the Mechanics and Physics of Solids

Modeling direct and converse flexoelectricity in soft dielectric rods with application to the follower load

Pushkar Mishra, Prakhar Gupta

doi:10.1016/j.jmps.2024.105956

软介质杆的正、反挠性电建模,并应用于从动器负载

Dielectric rods have been employed in various electromechanical applications, including energy harvesters and sensors. This paper develops a general framework to model large deformations in dielectric rods, considering both direct and converse flexoelectric effects. Initially, we derive the governing differential equations for a three-dimensional dielectric continuum solid to model large deformations, incorporating converse flexoelectricity. Then, we derive the equilibrium equations for the flexoelectric strain-gradient special Cosserat rod. Subsequently, we establish its constitutive relations and identify the corresponding work conjugates. To solve these governing differential equations numerically, we implement a quaternion-based numerical approach and obtain flexoelectricity-based solutions corresponding to the follower load. Moreover using these constitutive relations, we have also obtained nonlinear analytical solutions for bending under the follower load that show an excellent agreement with our numerical results. Bending under the follower load is also compared with the transverse load to understand the electric field generation. Unlike, under the application of the transverse load, where the electric field increases monotonically, for the follower load, the electric field gradually switches its sign. The role of direct and converse flexoelectric coefficients has also been examined, and several interesting conclusions have been drawn. Finally, we analyze the effect of mechanical and electrical length scale parameters. The electromechanical response from the follower load can be utilized to fabricate flexoelectric sensors for nanoelectromechanical systems.

介电棒已用于各种机电应用,包括能量采集器和传感器。本文发展了一个通用的框架来模拟在介质棒的大变形,同时考虑了直接和反向挠曲电效应。首先,我们推导了三维介质连续体的控制微分方程来模拟大变形,包括反向挠性电。在此基础上,推导了挠曲电应变梯度特殊Cosserat棒的平衡方程。然后,建立了它的本构关系,并确定了相应的功共轭。为了对这些控制微分方程进行数值求解,我们实现了基于四元数的数值方法,并得到了对应于从动器负载的基于柔性电的解。此外,利用这些本构关系,我们还得到了从动件载荷作用下弯曲的非线性解析解,与数值结果非常吻合。并将从动载荷下的弯曲与横向载荷进行了比较,以了解电场的产生情况。与横向负载作用下电场单调增大不同,随动负载作用下电场逐渐变换符号。本文还研究了正挠曲电系数和反挠曲电系数的作用,得出了几个有趣的结论。最后,分析了机械和电气长度尺度参数的影响。从动件负载的机电响应可用于制造纳米机电系统的柔性电传感器。


Modeling spider silk supercontraction as a hydration-driven solid-solid phase transition

Vincenzo Fazio, Giuseppe Florio, Nicola Maria Pugno, Giuseppe Puglisi

doi:10.1016/j.jmps.2024.105959

蜘蛛丝超收缩模型为水合作用驱动的固-固相变

Spider silks have attracted significant interest due to their exceptional mechanical properties, which include a unique combination of high strength, ultimate strain, and toughness. A notable characteristic of spider silk, still debated from both mechanical and functional viewpoints, is supercontraction–a pronounced contraction of up to half its original length when an unconstrained silk thread is exposed to a wet environment. We propose a predictive model for the hygro-thermo-mechanical behavior of spider silks, conceptualizing this phenomenon as a solid–solid phase transition, similar to the glass transition in rubber, but driven by humidity. As wetting increases, the system undergoes a transition, at the network scale, from a hard, highly crystalline, dry state–where the material behavior is governed by stiff chains elongated along the fiber axis–to a soft, amorphous, wet state, regulated by a rubber-like response. We model these states using a two-well free energy function dependent on molecular stretch, with transition energy modulated by humidity. Based on the methods of Statistical Mechanics, we deduce that supercontraction can be interpreted as a solid–solid phase transition. We elucidate the important role of thermal fluctuations. In particular, the decrease of the critical humidity needed for supercontraction as temperature grows results as an effect of entropic stabilization of the softer rubbery phase. Our model quantitatively predicts the observed experimental behavior, capturing the temperature dependence of humidity-induced supercontraction effects and related cooperative properties.

蜘蛛丝由于其特殊的机械性能而引起了极大的兴趣,其中包括高强度,极限应变和韧性的独特组合。蜘蛛丝的一个显著特征是超收缩——当一根不受约束的丝线暴露在潮湿的环境中时,它会明显收缩到原来长度的一半,这在机械和功能上都存在争议。我们提出了蜘蛛丝的湿-热-机械行为的预测模型,将这种现象概念化为固体-固体相变,类似于橡胶中的玻璃相变,但由湿度驱动。随着润湿度的增加,系统在网络尺度上经历了一个转变,从坚硬的、高度结晶的干燥状态(材料的行为由沿着纤维轴拉长的硬链控制)到柔软的、无定形的、潮湿状态(由橡胶样的响应调节)。我们使用依赖于分子拉伸的双阱自由能函数来模拟这些状态,过渡能由湿度调节。根据统计力学的方法,我们推导出超收缩可以解释为一种固-固相变。我们阐明了热波动的重要作用。特别是,随着温度的升高,超收缩所需的临界湿度降低,这是软橡胶相熵稳定的结果。我们的模型定量地预测了观察到的实验行为,捕捉了湿度诱导的超收缩效应和相关的协同特性的温度依赖性。


Multi-scale modeling of hydrogel-based concrete formed under the ambient environment and the extremely harsh environment of Mars

Ning Liu, Tianju Xue, Jishen Qiu

doi:10.1016/j.jmps.2024.105969

在环境和火星极端恶劣环境下形成的水凝胶混凝土的多尺度建模

Hydrogel-based concretes (HBCs) are an emerging class of load-bearing composite materials consisting of inert particles joined together by micro-hydrogel joints. As HBCs can harden via sol-gel process and H2O phase changes under a freezing temperature and vacuum, they are suitable for future exterritorial constructions. Previous studies have demonstrated that the internal microstructure of the hydrogel joints in HBC varies significantly with curing temperature and air pressure, leading to variations in their mechanical properties. In this study, we present a new multi-scale model that quantitatively predicts the mechanical properties of HBC formed under different curing environments including Martian atmosphere. On the micro-scale, four representative joint microstructures are studied, including tubular, foamy, honeycomb, and tube-cased-foam joints. We experimentally studied and analytically derived the constitutive relationship between the joint force and displacement. Particularly, we determined the process of hydrogel skin peeling from the particle's surface of tubular joints based on force and energy equilibrium. On the macro-scale, we simplified the constitutive joint relationships in a linear parallel bond model (LPM) and employed them to quantify interparticle relationships in a discrete element method (DEM)-based HBC model. The Weibull distribution is used to consider the variation of tensile and shear strengths of the hydrogel joints in the DEM. The modeling results are not only validated with the experimentally acquired compressive stress-strain curves of HBC, but also accurately predict the combined influence of mix design and curing conditions on the mechanical properties.

水凝胶基混凝土(hbc)是一类新兴的承重复合材料,由惰性颗粒通过微水凝胶接缝连接在一起。由于HBCs可以在冷冻温度和真空条件下通过溶胶-凝胶过程和H2O相变硬化,因此适合未来的域外构建。已有研究表明,HBC中水凝胶接头的内部微观结构随着养护温度和空气压力的变化而发生显著变化,从而导致其力学性能的变化。在这项研究中,我们提出了一个新的多尺度模型,可以定量预测在不同固化环境下形成的HBC的力学性能,包括火星大气。在微观尺度上,研究了管状、泡沫状、蜂窝状和管套泡沫状四种具有代表性的节理微观结构。实验研究和解析推导了关节力与位移的本构关系。特别地,我们基于力和能量平衡确定了水凝胶皮从管状接头颗粒表面剥离的过程。在宏观尺度上,我们简化了线性平行键模型(LPM)中的本构结合部关系,并利用它们在基于离散元法(DEM)的HBC模型中量化质点间关系。采用Weibull分布来考虑水凝胶节理在DEM中的抗拉强度和抗剪强度变化。建模结果不仅与实验得到的HBC压应力-应变曲线相吻合,而且准确预测了配合比设计和养护条件对HBC力学性能的综合影响。


International Journal of Plasticity

Multiscale computational analysis of crack initiation at the grain boundaries in hydrogen-charged bi-crystalline alpha-iron

Yipeng Peng, Thanh Phan, Haibo Zhai, Liming Xiong, Xiang Zhang

doi:10.1016/j.ijplas.2024.104182

含氢双晶α -铁晶界裂纹萌生的多尺度计算分析

This paper presents a mesoscale concurrent atomistic–continuum (CAC) simulation of crack initiation at the atomically structured grain boundaries (GBs) in bi-crystalline BCC iron (α-Fe) charged with hydrogen (H). By retaining the atomistic GB structure evolution together with the long-range dislocation-mediated plastic flow away from the GB in one model at a fraction of the cost of full molecular dynamics (MD), CAC enables us to probe the interplay between the atomic-level H diffusion, the nanoscale GB cavitation, crack initiation, growth, as well as the dislocation activities far away from the GB. Our several main findings are: (i) a tensile strain normal to the GB plane largely promotes the H diffusion towards the GB. (ii) the plasticity-induced clustering of H atoms (PICH) is identified as an intermediate process in between the H-enhanced localized plasticity (HELP) and H-enhanced de-cohesion (HEDE). (iii) PICH significantly amplifies the local stress concentration at the GB and decreases its cohesive strengths, and (iv) the GBs with different atomic structures fail differently. In detail, the H-charged Σ3 GB fails through micro-twinning assisted void nucleation and coalescence, while the H-charged Σ9 GB fails through crack initiation and growth accompanied by dislocation emission. Compared with nanoscale molecular dynamics (MD) simulations, the mesoscale CAC models get one step closer to the experimentally measurable length scales and thus predict reasonably lower GB cohesive strengths. This research addresses one key aspect of how H impacts the GB cohesive strengths in α-Fe. It offers insights into the multiscale processes of hydrogen embrittlement (HE). Our findings highlight the importance of using concurrent multiscale models, such as a combination of CAC, crystal plasticity finite element (CPFE), and cohesive zone finite element method (CZFEM), to understand HE. This will, in turn, support the development of new strategies for mitigating HE in a variety of engineering infrastructures.

本文提出了一种介观并行原子-连续体(CAC)模拟方法,用于研究双晶BCC铁(α-Fe)在氢(H)负载条件下的晶界(GB)处裂纹的萌生。通过在保持原子级GB结构演化的同时,在一个模型中利用长程位错介导的塑性流动远离GB,从而以分子动力学(MD)模拟成本的一小部分,CAC使我们能够探究原子级H扩散、纳米级GB空洞、裂纹萌生、生长以及远离GB的位错活动之间的相互作用。我们的主要发现如下:(i)垂直于GB平面的拉伸应变极大地促进了H向GB的扩散。(ii)由塑性诱导的H原子簇集(PICH)被识别为H增强局部塑性(HELP)和H增强解粘(HEDE)之间的中间过程。(iii)PICH显著放大了GB处的局部应力集中,降低了其粘结强度,(iv)具有不同原子结构的GB以不同的方式失效。具体来说,H-带电的Σ3 GB通过微孪生辅助空洞成核和合并而失效,而H-带电的Σ9 GB则通过伴随位错发射的裂纹起始和扩展而失效。与纳米尺度分子动力学(MD)模拟相比,介观尺度CAC模型更接近可实验测量的长度尺度,因此预测的GB粘结强度更合理。这项研究解决了H如何影响α-Fe GB粘结强度的一个关键方面。它为理解氢致脆化(HE)的多尺度过程提供了见解。我们的发现强调了使用并行多尺度模型(如CAC、晶体塑性有限元(CPFE)和粘结区有限元法(CZFEM)的组合)的重要性,以理解HE。这将反过来支持开发各种工程基础设施中氢致脆化(HE)的新策略。


Hydrostatic pressure-mediated grain boundary smoothing and plastic deformability in high-entropy alloys

Zhipeng Zhang, Yao Tang, Qishan Huang, Haofei Zhou

doi:10.1016/j.ijplas.2024.104185

高熵合金中静压介导的晶界平滑和塑性变形性能

In the presence of intrinsic lattice distortion and local concentration waves, high-entropy alloys (HEAs) possess unique microstructures, deformation patterns of dislocations and grain boundaries (GBs), and superior mechanical properties. In contrast to traditional crystalline metals, GBs in HEAs have been revealed to exhibit spontaneous roughening behavior, which reduces their migration ability and weakens the plastic deformability of HEAs. In addition, hydrostatic pressure (HP) treatment can modify the microstructure and deformability of GBs in HEAs, leading to enhanced strength and ductility in HEAs. In the present work, we aim to investigate the effect of HP on GB structural evolution in HEAs and reveal the HP-induced enhancement of plastic deformability via molecular dynamics (MD) simulations. Using a FeNiCrCoCu alloy as an example, we have demonstrated that the initially rough GBs in the HEA samples undergo a smoothing mechanism under the application of HP. The GB smoothing mechanism depends not only on the initial GB misorientation and microstructure, but also on the temperature and GB segregation. For the <110>(113) GB, the GB roughness is featured by individual GB segments connected by atomic-scale disconnections. Under HP, the disconnections glide along the GB plane and annihilate with neighboring disconnections, reducing the roughness of the GB. For <110>(112), <110>(114), <110>(116) and <110>(223) GBs, atomic rearrangements take place in local GB segments under HP, resulting in structural adjustment and GB smoothing. These HP-induced GB smoothing mechanisms can increase the plastic deformability of GBs under shear loading. Our findings deepen the understanding of GB plasticity in HEAs and provide insights into GB engineering through HP treatment.

在本征晶格畸变和局部浓度波存在的情况下,高熵合金(HEAs)具有独特的显微组织、位错和晶界变形模式以及优异的力学性能。与传统的结晶金属相比,GBs在HEAs中表现出自发的粗化行为,这降低了它们的迁移能力,削弱了HEAs的塑性变形能力。静水压力(HP)处理可以改变HEAs中GBs的微观组织和变形能力,从而提高HEAs的强度和延展性。在目前的工作中,我们的目的是研究HP对HEAs中GB结构演变的影响,并通过分子动力学(MD)模拟揭示HP诱导的塑性变形能力增强。以FeNiCrCoCu合金为例,我们证明了HEA样品中最初粗糙的gb在HP的作用下发生了平滑机制。GB平滑机制不仅取决于初始的GB错取向和微观结构,还与温度和GB偏析有关。对于<110>(113)GB, GB粗糙度的特征是由原子尺度断开连接的单个GB段。在高压下,断开沿GB平面滑动并与相邻断开湮灭,降低了GB的粗糙度。对于<110>(112)、<110>(114)、<110>(116)和<110>(223)GB, HP作用下的局部GB段发生原子重排,导致结构调整和GB平滑。这些hp诱导的光滑机制可以提高GB在剪切载荷下的塑性变形能力。我们的发现加深了对HEAs中GB塑性的理解,并通过HP处理为GB工程提供了见解。


Thin-Walled Structures

Parameter optimisation of piezoelectric vibration absorber in composite cylindrical shells: A multi-modal approach to mitigate stochastic vibration

Yucai Zhong, Rihuan Yu, Kai Zhou, Zhenguo Zhang

doi:10.1016/j.tws.2024.112713

复合材料圆柱壳压电吸振器参数优化:一种多模态方法来减轻随机振动

This paper investigates the stochastic vibration mitigation of composite cylindrical shells using multi-modal piezoelectric vibration absorbers (PVAs). A novel semi-analytical method is proposed to analyse the stochastic vibration characteristics of composite cylindrical shells equipped with PVAs. The vibration behavior under stochastic excitations is determined using the modified Ritz method and the pseudo excitation method (PEM). Compared to the finite element method (FEM), the proposed model greatly enhances efficiency by eliminating the need for repeated modelling and meshing, thereby facilitating the optimization of PVAs. The effects of piezoelectric patch layout and circuit parameters on PVA performance are examined in detail using the proposed electro-mechanical model. Additionally, a multi-modal PVA design procedure, combining the semi-analytical model with a surrogate model-based optimisation algorithm, is presented. The superior stochastic vibration suppression performance of the multi-modal PVA is demonstrated by comparing the dynamic responses of the composite cylindrical shell without PVA, with single-modal PVA, and with multi-modal PVA. The proposed optimisation procedure offers a valuable approach for the design of multi-modal PVAs for stochastic vibration control of cylindrical structures.

研究了多模态压电吸振器对复合材料圆柱壳随机减振的影响。提出了一种新的半解析方法来分析聚乙烯醇复合材料圆柱壳的随机振动特性。采用改进的里兹法和伪激励法确定了随机激励下的振动特性。与有限元法(FEM)相比,该模型消除了重复建模和网格划分的需要,大大提高了效率,从而便于pva的优化。利用所建立的机电模型,详细分析了压电片布局和电路参数对PVA性能的影响。此外,提出了一种多模态PVA设计程序,将半解析模型与基于代理模型的优化算法相结合。通过对比无PVA、单模态PVA和多模态PVA复合材料圆柱壳的动力响应,证明了多模态PVA优越的随机抑制振动性能。所提出的优化方法为圆柱结构随机振动控制的多模态pva设计提供了一种有价值的方法。


Experimental and Numerical Study of Hysteresis Behaviour of Innovative Hybrid Steel-Timber Shear Wall System

Mojtaba Gorji Azandariani, Ali Parvari, Arvin Yaghmouri, Mehdi Vajdian

doi:10.1016/j.tws.2024.112743

新型钢-木混合剪力墙体系滞回特性试验与数值研究

This research presents hybrid steel-timber shear walls (HSTSWs) as an environmentally friendly and structurally efficient system. The HSTSW system provides quick and easy interchangeability of the timber components, making it adjustable and adaptable to different design needs throughout the building's lifecycle. Additionally, the incorporation of timber elements into the steel frame contributes to lateral resistance while offering an eco-friendly alternative to materials such as steel and concrete. This research includes experimental studies and numerical simulations using finite element analysis to investigate and comprehensively compare the hysteresis behavior of HSTSW and SPSW. The hysteresis behavior, ultimate load, failure modes, energy dissipation mechanisms, ultimate displacement, weight-related characteristics, and efficiency of load-carrying capacity are analyzed for both HSTSW and SPSW specimens. Comparative results with SPSW indicate that HSTSW exhibit a slightly higher ultimate load-carrying capacity and significantly greater ultimate deformation capacity. The cyclic behavior and failure modes of both systems are detailed, emphasizing the trade-off between strength and ductility in HSTSWs. Stiffness, ductility, absorbed energy, and equivalent viscous damping ratio are assessed, revealing that HSTSW absorb more energy with higher specific absorbed energy and exhibit comparable damping behavior to SPSW. Additionally, numerical modeling is employed to simulate the response of SPSW and HSTSW, and a validation process is conducted to compare numerical and experimental outcomes.

本研究提出了钢-木混合剪力墙(HSTSWs)作为一种环保和结构高效的系统。HSTSW系统提供了木材组件的快速和容易的互换性,使其在整个建筑生命周期中可调节和适应不同的设计需求。此外,将木材元素结合到钢框架中有助于抵抗横向阻力,同时提供了钢和混凝土等材料的环保替代品。本研究包括实验研究和数值模拟,利用有限元分析对HSTSW和SPSW的迟滞行为进行研究和全面比较。分析了HSTSW和SPSW试件的滞回特性、极限荷载、破坏模式、能量耗散机制、极限位移、重量相关特性和承载力效率。与SPSW的对比结果表明,HSTSW的极限承载能力略高于SPSW,极限变形能力显著高于SPSW。详细介绍了两种系统的循环行为和破坏模式,强调了HSTSWs强度和延性之间的权衡。通过刚度、延性、吸收能量和等效粘性阻尼比的评估,发现HSTSW吸收更多的能量,比吸收能量更高,并且具有与SPSW相当的阻尼行为。此外,采用数值模拟方法对SPSW和HSTSW的响应进行了模拟,并对数值结果和实验结果进行了对比验证。


Mechanical behavior of reinforced Al2O3 lattice structures: Effects of structural parameters from experiments and simulations

Ke Zhong, Zhiguo Wang, Jin Cui, Xuehua Yu, Mingtao Zhang, Zhenfeng He, Yuhui Zhao, Jibin Zhao

doi:10.1016/j.tws.2024.112753

增强Al2O3晶格结构的力学行为:结构参数对实验和模拟的影响

The pressure hull is one of the core components of autonomous underwater vehicles (AUVs), necessitating a new structural material with improved mechanical and lightweight properties. For this purpose, a novel type of reinforced lattice structure (RLS) that integrates Al2O3 lattice structures (ALSs) with phenol-formaldehyde (PF) resin was designed and fabricated via stereolithography (SL)-based additive manufacturing and infiltration processes. The responses of the RLSs with different structural configurations, relative densities, and unit cell sizes under compressive loading were systematically characterized. Additionally, numerical simulations were conducted to further predict and study the mechanical behavior of the RLSs using Johnson-Holmquist-II (JH-2) model. The results revealed that the mechanical properties of the RLSs from superior to inferior were simple cubic (SC), body-centered cubic (BCC), Gyroid, octet truss (Oct), and SchwarzP (Sch). As the relative density and the unit cell size increased, the mechanical properties of the RLSs increased. Furthermore, the results of the numerical simulations closely aligned with the experimental results, which provided an in-depth analysis of internal damage and crack propagation in the RLSs under compression. A comparison of the mechanical properties also demonstrated that RLSs exhibit superior compressive strength and energy absorption performance than traditional ALSs do. After this investigation, this type of RLS is anticipated to facilitate lightweighting of AUVs, advancing the development of deep-sea scientific research.

耐压壳体是自主水下航行器(auv)的核心部件之一,因此需要一种具有改进机械性能和轻量化性能的新型结构材料。为此,通过基于立体光刻(SL)的增材制造和渗透工艺,设计并制造了一种新型的增强晶格结构(RLS),该结构将Al2O3晶格结构(ALSs)与酚醛(PF)树脂相结合。系统表征了不同结构构型、相对密度和晶胞尺寸的rls在压缩载荷作用下的响应。此外,采用Johnson-Holmquist-II (JH-2)模型进行了数值模拟,进一步预测和研究了rls的力学行为。结果表明,rls的力学性能由高到低依次为简单立方(SC)、体心立方(BCC)、陀螺(Gyroid)、八元桁架(Oct)和SchwarzP (Sch)。随着相对密度和晶胞尺寸的增大,rls的力学性能增大。数值模拟结果与实验结果吻合较好,深入分析了rls在压缩作用下的内部损伤和裂纹扩展过程。力学性能的比较也表明,rls具有比传统als更好的抗压强度和能量吸收性能。通过本次研究,这种类型的RLS有望促进auv的轻量化,推动深海科学研究的发展。


Macro/micro failure mechanism of transparent armour subjected to multiple impacts of 7.62mm bullets

Yubo Gao, Liutong Shi, Zhihao Li, Zhe Jia, Yanxin Ge

doi:10.1016/j.tws.2024.112754

7.62mm子弹多重冲击下透明装甲宏微观破坏机理

Transparent armor is widely used in military and civilian impact protection fields due to its excellent light transmittance and ballistic performance. This work focused on the macro/micro failure mechanisms of transparent armor for vehicles subjected to multiple impacts. Results showed that the penetration depth after the first impact by a 7.62 mm bullet is about 14 mm, regardless of the impact position. Based on the cavity expansion theory, the penetration depth under multiple projectile impacts was predicted, relating it to the distance between the impact points, the distance from the projectile hole to the edge of the target plate, and the damage radius caused by the first impact. In the thickness direction, observation of the glass layer damage modes revealed that the interlayer adhesive could hinder the propagation of vertical cracks between different glass layers, with delamination primarily caused by insufficient shear strength. In the in-plane direction, the size of the fractured glass gradually increases outward from the impact point because circumferential cracks can prevent the propagation of radial cracks. Finally, the micro failure analysis of glass fragments showed that the radial cracks are dominated by numerous irregular microcracks and river-like textures, while the circumferential cracks consist of the mirror region, mist region, hackle region, and river-like texture region.

透明装甲以其优异的透光性和弹道性能,广泛应用于军用和民用防撞领域。本文主要研究了车辆透明装甲在多重冲击下的宏观/微观失效机制。结果表明,无论在何种位置,7.62 mm子弹第一次撞击后的侵彻深度约为14 mm。基于空腔膨胀理论,预测了弹丸在多次冲击下的侵彻深度,并将其与弹丸点之间的距离、弹丸孔到靶板边缘的距离以及第一次冲击造成的损伤半径联系起来。在厚度方向上,对玻璃层损伤模式的观察表明,层间胶粘剂会阻碍不同玻璃层之间垂直裂纹的扩展,导致分层的主要原因是剪切强度不足。在平面方向上,破碎玻璃的尺寸从撞击点向外逐渐增大,因为周向裂纹可以阻止径向裂纹的扩展。最后,玻璃碎片的微观破坏分析表明,径向裂纹以大量不规则微裂纹和河状织构为主,而周向裂纹则由镜像区、雾区、毛刺区和河状织构区组成。



来源:复合材料力学仿真Composites FEM
MeshingACTMechanicalAdditiveSystem振动复合材料非线性电路通用建筑增材离散元裂纹电场参数优化理论材料
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首次发布时间:2024-11-27
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【新文速递】2024年11月25日复合材料SCI期刊最新文章

今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 9 篇,Composites Science and Technology 1 篇Composite StructuresStiffness degradation of woven roving GFRP due to shear and compression fatigue damageAkihiko Sato, Yasuo Kitane, Kunitomo Sugiura, Yoshinao Goidoi:10.1016/j.compstruct.2024.118725机织粗纱玻璃钢剪切和压缩疲劳损伤引起的刚度退化Woven roving GFRP is widely used in the structural members of GFRP bridges which are subject to compression or shear stress. However, it is not revealed well about fatigue strength and stiffness degradation under these loading conditions. This study aims to clarify the fatigue strength and residual stiffness of woven roving GFRP under in-plane shear and compression cyclic loading. The specimens were tested at 45 degrees to the fiber direction in the cyclic tensile test, while the compression fatigue test was adjusted to prevent buckling. It is revealed that the in-plane fatigue limit corresponds to the principal strain of about 3700×10^-6. The compression fatigue limit was 40% of the static compression strength. In-plane shear fatigue damage is predominantly due to matrix cracks, and the stiffness degradation appears in Region I, II, and III. The shear stiffness decreased by 20% before the fatigue failure. On the other hand, in the compression fatigue test, matrix cracks hardly occur, and delamination is dominant. The stiffness degradation of Region I is very limited in compression, and stiffness decreased about 10% before the fatigue failure. Moreover, theoretical models are proposed to express the residual stiffness, and they agree well with the experimental value.编织粗纱GFRP广泛应用于GFRP桥梁的受压或受剪应力的结构构件中。然而,在这些载荷条件下,材料的疲劳强度和刚度退化情况并没有得到很好的揭示。本研究旨在阐明纺纱玻璃钢在面内剪切和压缩循环荷载作用下的疲劳强度和剩余刚度。在循环拉伸试验中,试样在与纤维方向45度的方向上进行试验,压缩疲劳试验中为了防止屈曲进行了调整。结果表明,面内疲劳极限对应的主应变约为3700×10^-6. 压缩疲劳极限为静压强度的40%。面内剪切疲劳损伤以基体裂纹为主,在I区、II区和III区出现刚度退化。在疲劳破坏前,剪切刚度降低了20%。另一方面,在压缩疲劳试验中,基体裂纹几乎不发生,以脱层为主。I区在压缩条件下刚度退化非常有限,在疲劳破坏前刚度下降约10%。建立了剩余刚度的理论模型,与试验值吻合较好。Composites Part A: Applied Science and ManufacturingStructural and material double mechanical enhancement of HAp scaffolds promote bone defect regenerationXingyu Gui, Boqing Zhang, Yuxiang Qin, Haoyuan Lei, Xiuwen Xia, Yiyang Li, Haoxiang Lei, Xuerui Zhou, Yanfei Tan, Zhihong Dong, Qi You, Changchun Zhou, Yujiang Fandoi:10.1016/j.compositesa.2024.108600羟基磷灰石支架的结构和材料双力学增强促进骨缺损的再生Critical bone defects caused by trauma, bone tumors, and infections are still challenges in clinical surgery. Digital light processing printing of hydroxyapatite (HAp) scaffolds can fabricate high-resolution personalized bone repair scaffolds. However, creating load-bearing bone regeneration HAp scaffolds with satisfactory mechanical property remain challenging. This study investigated the enhancement of the HAp scaffold mechanical properties from both structural and material perspectives. Structurally, the diamond structure model was optimized to Triply Periodic Minimal Surface structures, increasing the compressive strength of scaffolds from 2.2 to 7.2 MPa. Material-wise, ZnO was incorporated as second-phase particle, improved the compressive strength of HAp scaffolds from 7.2 to 13.7 MPa. Additionally, the incorporation of zinc ions enhanced the bioactivity of the HAp scaffolds. Animal mechanical testing revealed that the enhanced scaffolds effectively supported load-bearing. The HAp/ZnO-TPMS scaffolds exhibited excellent mechanical properties and promoted cellular osteogenic differentiation, showing potential for clinical development and application.外伤、骨肿瘤、感染引起的严重骨缺损仍是临床外科的难题。羟基磷灰石(HAp)支架的数字光处理打印可以制备高分辨率的个性化骨修复支架。然而,制造具有令人满意力学性能的承重骨再生HAp支架仍然具有挑战性。本研究从结构和材料两方面对HAp支架力学性能的增强进行了研究。在结构上,将金刚石结构模型优化为三周期最小表面结构,将支架抗压强度从2.2提高到7.2 MPa。在材料方面,ZnO作为第二相颗粒加入,使HAp支架的抗压强度从7.2提高到13.7 MPa。此外,锌离子的掺入增强了羟基磷灰石支架的生物活性。动物力学试验表明,增强后的支架能有效地支撑承重。HAp/ZnO-TPMS支架具有优异的力学性能,促进细胞成骨分化,具有临床开发和应用潜力。Composites Part B: EngineeringDual hetero-structured Ti composites by manipulating self-assembled powder embedded with nano-reinforcementsShuhui Feng, Yuanfei Han, Cheng Du, Huaqiang Liu, Fu Chen, Jianwen Le, Kang Wang, Guangfa Huang, Weijie Ludoi:10.1016/j.compositesb.2024.111999 利用自组装粉末嵌入纳米增强材料制备双异质结构Ti复合材料Traditional discontinuously micro-reinforced titanium matrix composites (DRTMCs) produced by casting or forging, are usually confronted with the strength-ductility trade-off dilemma. Their micro-scale reinforcements easily cause incompatible deformation and stress localization. Novel self-assembled composite powder embedding nano-reinforcements paired with additive manufacturing technology has great potential to address this dilemma. Here, we report a special dual-heterogeneous structure with micro-scale networks and grain size gradients. It bespoke exciting strength-ductility synergy and excellent uniform elongation surpassing the as-deposited Ti6Al4V alloy by 32%, while manifesting a steadier strain hardening behavior. Primarily, alternating basal and pyramidal slips together with substantial pyramidal &lt;c+a&gt; slips induced by hetero-interfaces significantly improved the uniform deformation ability. Then geometrically necessary dislocation (GNDs) and long-range back stress induced by strain inhomogeneity remarkably enhanced the strain hardening ability. This work firstly determined the most preferred orientation relationship (OR) (58.91°/ ) between TiBw and the adjoining α-Ti in as-deposited composites. These interfaces show higher interface strength (16.42 GPa) than those with the most preferred OR of 0°/ in as-forged TMCs, making more contributions to promoting the load bearing capacity of TiBw. It provided scientific guidance for in-situ synthesizing heterogeneous structures with attractive mechanical properties in Ti composites.传统的非连续微增强钛基复合材料(DRTMCs)是通过铸造或锻造生产的,通常面临着强度与塑性的权衡困境。它们的微尺度增强容易造成不相容变形和应力局部化。新型自组装复合材料粉末包埋纳米增强材料与增材制造技术相结合,有望解决这一难题。在这里,我们报告了一种特殊的双非均质结构,具有微尺度网络和晶粒尺寸梯度。它具有令人兴奋的强度-塑性协同作用和优异的均匀伸长率,比沉积态Ti6Al4V合金高出32%,同时表现出更稳定的应变硬化行为。主要是基底和锥体交替滑移以及异质界面引起的大量锥体&lt;c+a&gt;滑移显著提高了均匀变形能力。应变不均匀性引起的几何必要位错(GNDs)和长程背应力显著增强了材料的应变硬化能力。本文首先确定了沉积态复合材料中TiBw与相邻α-Ti的最优取向关系(OR)(58.91°/)。这些界面的界面强度(16.42 GPa)高于锻造tmc中最优OR为0°/的界面强度,对提高TiBw的承载能力有更大的贡献。为原位合成具有良好力学性能的Ti复合材料的异相结构提供了科学指导。Multifunctional Manganese-Based Nanogels Catalyze Immune Energy Metabolism to Promote Bone RepairZiyan Huang, Xinzhao Jiang, Lichen Zhang, Wei Wang, Ziang Li, Yiyang Huang, Yichang Xu, Liang Zhou, Jie Wu, Jincheng Tang, Kun Xi, Yu Feng, Liang Chendoi:10.1016/j.compositesb.2024.112005多功能锰基纳米凝胶催化免疫能量代谢促进骨修复Tissue regeneration during bone defect repair is regulated by the energy metabolism of macrophages. Abnormal energy metabolism can negatively affect bone repair in pathological conditions. A promising strategy involves developing biomaterials that regulate macrophage energy metabolism to coordinate immune response and bone regeneration. In this study, hollow mesoporous MnO2, known for its excellent reactive oxygen species (ROS) scavenging and drug-loading abilities, was loaded with dexamethasone. This was followed by electrostatic self-assembly using chitosan coating to create nanogels (Alg-MD@CS). In vitro experiments showed that the nanogel effectively scavenged excess ROS, restored mitochondrial function, and reduced the levels of inflammatory factors. It downregulated glycolysis by inhibiting the ERK/HIF-1α/GLUT1 pathway, facilitating the M1-to-M2 phenotype switch to promote an anti-inflammatory and pro-regenerative ecological environment. In vivo experiments confirmed these findings. The nanogel reduced ROS levels in rats, reshaped the local immune microenvironment, and promoted bone regeneration. In summary, we developed a multifunctional nanogel for bone defect repair and demonstrated the significance and feasibility of reverse reprogramming by regulating the energy metabolism of macrophages during bone regeneration.骨缺损修复过程中的组织再生受巨噬细胞能量代谢的调控。在病理状态下,异常的能量代谢会对骨修复产生负面影响。一个有希望的策略是开发调节巨噬细胞能量代谢的生物材料,以协调免疫反应和骨再生。在本研究中,以其优异的活性氧(ROS)清除能力和载药能力而闻名的中空介孔MnO2被装载地塞 米松。接下来是静电自组装,使用壳聚糖涂层来制造纳米凝胶(Alg-MD@CS)。体外实验表明,纳米凝胶能有效清除过量的活性氧,恢复线粒体功能,降低炎症因子水平。它通过抑制ERK/HIF-1α/GLUT1通路下调糖酵解,促进m1 - m2表型转换,促进抗炎和促再生的生态环境。体内实验证实了这些发现。纳米凝胶可降低大鼠体内ROS水平,重塑局部免疫微环境,促进骨再生。综上所述,我们开发了一种用于骨缺损修复的多功能纳米凝胶,并证明了通过调节骨再生过程中巨噬细胞的能量代谢进行反向重编程的意义和可行性。Fabrication of polypropylene/carbon fiber/carbon black composite foam bonded with continuous carbon fiber reinforced polypropylene prepregs via high-pressure foam injection moldingDongxu Tian, Junji Hou, Jinkai Liang, Jingbo Chendoi:10.1016/j.compositesb.2024.112006 聚丙烯/碳纤维/炭黑复合泡沫与连续碳纤维增强聚丙烯预浸料粘合的高压泡沫注塑成型The fabrication of polymer composite foams with several functions offers various advantages. Herein, we reported a highly efficient and mass-produced method for preparing polypropylene/carbon fiber/carbon black (PP/CF/CB) composite foams bonded with continuous CF reinforced PP prepregs. CFs were uniformly dispersed in PP via melt blending, but some agglomerations of CBs were observed owing to their little size. Compared with pure PP, the introduction of CB improved the thermal stability and flame retardance of composites. Owing to the homogeneity of polymer between composites and prepregs, they were well bonded by injection molding. The tensile strength of the samples bonded with prepregs was improved by 158.3–257.7% for different filler contents. As CF and CB played the role of heterogeneous nucleation, and the high-pressure foam injection molding could easily tailor cellular structure by adjusting the holding time and mold temperature, composite foams bonded with two prepregs and with desired cells were successfully prepared. The injected foams with two prepregs had an enhanced electromagnetic interference shielding performance, which was 65.4 dB when the content was 10 wt% and 15 wt% for CF and CB, respectively. This work provides a universal approach for efficient and large-scale preparation of lightweight and multifunctional polymer composite foams.具有多种功能的高分子复合泡沫材料的制备具有多种优点。本文报道了一种高效、批量生产的聚丙烯/碳纤维/炭黑(PP/CF/CB)复合泡沫材料与连续CF增强PP预浸料粘合的方法。熔体共混使碳纤维均匀地分散在PP中,但由于碳纤维的体积小,出现了团聚现象。与纯PP相比,CB的引入提高了复合材料的热稳定性和阻燃性。由于复合材料和预浸料之间聚合物的均匀性,通过注射成型可以很好地结合。不同填料含量下,预浸料粘结试样的拉伸强度可提高158.3 ~ 257.7%。由于CF和CB发挥了非均相成核的作用,并且高压泡沫注塑成型可以通过调整保温时间和模具温度来方便地定制胞孔结构,因此成功制备了两种预浸料结合并具有所需胞孔的复合泡沫。两种预浸料的注入泡沫具有较好的电磁干扰屏蔽性能,当CF和CB含量分别为10 wt%和15 wt%时,屏蔽效果分别为65.4 dB。本研究为高效大规模制备轻质多功能聚合物复合泡沫材料提供了一种通用方法。Investigation of two sandwich-structured nanohybrid coating derived from graphene oxide/carbon nanotube on interfacial adhesion and fracture toughness of carbon fiber compositesQing Wu, Yating Li, Jun Chang, Dan Jin, Bolin Xiao, Renjie Yao, Jianfeng Zhudoi:10.1016/j.compositesb.2024.112007 氧化石墨烯/碳纳米管两种三明治结构纳米杂化涂层对碳纤维复合材料界面附着力和断裂韧性的影响Designing stronger interphase towards solving the long-standing dilemma of interfacial delamination is critical for stable application of carbon fiber composites. Herein, nano-scale sandwich-structured coatings, where carbon nanotubes (CNTs) were uniformly anchored on both sides of graphene oxide (GO) layer (abbreviated as C/GO/C) and its reverse, that is double GO layers encapsulated CNT network (G/CNT/G in short), were reported around fiber periphery via vacuum filtration method. The effects of surface structure differences on interfacial shear strength (IFSS) and fracture toughness were compared in epoxy matrix. Impressively, composite incorporating G/CNT/G modified fiber delivered prominent IFSS and interfacial fracture toughness of 114.6 MPa and 137.0 J/m2, 105.7% and 279.5% increases over control fiber composite. This strategy was also superior to C/GO/C and other reported GO and CNT related works. The main factors for maximal IFSS offered by G/CNT/G are that two GO panels enrich active sites to tightly bridge fiber and epoxy, as well as its layered feature and large surface area provide a stable “skeleton” at interphase for stress transfer. Additionally, the G/CNT/G “skeleton” is closer to sandwich structure of iris leaf, in which the porous CNT intermediate network creates larger deformation and adsorb more energy, leading to peak interfacial fracture toughness.设计更强的界面相以解决长期存在的界面分层问题是碳纤维复合材料稳定应用的关键。本文通过真空过滤的方法,在纤维外围制备了纳米尺度的三明治结构涂层,其中碳纳米管(CNTs)均匀地固定在氧化石墨烯(GO)层(简称C/GO/C)的两侧,其反面是双氧化石墨烯层封装的碳纳米管网络(简称G/CNT/G)。比较了环氧基表面结构差异对界面抗剪强度和断裂韧性的影响。G/CNT/G改性纤维复合材料具有显著的IFSS和界面断裂韧性,分别为114.6 MPa和137.0 J/m2,比对照纤维复合材料提高了105.7%和279.5%。该策略也优于C/GO/C和其他已报道的GO和CNT相关研究。G/CNT/G提供最大IFSS的主要因素是两个氧化石墨烯面板丰富的活性位点紧密桥接纤维和环氧树脂,其分层特性和大表面积在界面提供稳定的“骨架”,用于应力传递。此外,G/CNT/G“骨架”更接近于虹膜叶片的夹层结构,其中多孔的CNT中间网络产生更大的变形和吸附更多的能量,导致界面断裂韧性达到峰值。Mechanical properties of carbon fiber composites with various wear characteristics during knitting processZhaoling Sun, Peixiao Zheng, Chaoyu Chen, Zhijia Dong, Fengxiang Chen, Pibo Madoi:10.1016/j.compositesb.2024.112010不同磨损特性的碳纤维复合材料在针织过程中的力学性能The inherent brittleness of carbon fiber (CF) presents a significant challenge during the knitting process, as the yarn is prone to breakage under bending stress, resulting in the occurrence of hairiness that directly impacts the mechanical properties of the composites. Therefore, it is imperative to examine the frictional and wear characteristics of CF bundles in order to minimize potential damage incurred during the weaving process and enhance the overall properties of composites. This study initially modified the CF through flexible coating with polydimethylsiloxane (PDMS), followed by preparing a knitted preform. Subsequently, an investigation was conducted to assess the impact of contact area and sinking depth on CF damage. Furthermore, the finite element method was employed to simulate stress distribution during the loop formation of CF. Finally, the impact of CF wear on the mechanical characteristics of the composite was examined. After heat treatment and low damage treatment, the tensile strength and bending strength of CF@PDMS/TD-C increased by 16.7% and 23.64%, respectively. The energy absorption performance was measured at 17.79 J, 27.84 J, 37.77 J, and 42.34 J for impact energies of 20 J, 30 J, 40 J, and 50 J, respectively. These findings establish an experimental and theoretical foundation for mitigating damage during the weaving process.碳纤维(CF)固有的脆性在编织过程中提出了一个重大挑战,纱线在弯曲应力下容易断裂,导致毛羽的产生,直接影响复合材料的力学性能。因此,研究碳纤维束的摩擦磨损特性,以减少编织过程中潜在的损伤,提高复合材料的整体性能是十分必要的。本研究首先通过聚二甲基硅氧烷(PDMS)柔性涂层对CF进行改性,然后制备针织预成型。随后,对接触面积和下沉深度对CF损伤的影响进行了研究。在此基础上,采用有限元方法模拟了碳纤维环成形过程中的应力分布。最后,研究了碳纤维磨损对复合材料力学特性的影响。经过热处理和低损伤处理后,CF@PDMS/TD-C的抗拉强度和抗弯强度分别提高了16.7%和23.64%。在冲击能量为20 J、30 J、40 J和50 J时,分别测量了17.79 J、27.84 J、37.77 J和42.34 J的吸能性能。这些研究结果为减轻织造过程中的损伤提供了实验和理论基础。Boosted Triboelectric Performance in Stretchable Nanogenerators via 2D MXene-Driven Electron Accumulation and LiNbO₃-Assisted Charge TransferBiswajit Mahanty, Sujoy Kumar Ghosh, Dong-Weon Leedoi:10.1016/j.compositesb.2024.111995通过二维mxene驱动的电子积累和LiNbO 3辅助的电荷转移提高可拉伸纳米发电机的摩擦电性能The development of piezoelectrically enhanced triboelectric hybrid nanogenerators (PET-HNGs) has garnered considerable attention for their potential in energy harvesting. However, their performance in stretchable applications across diverse environments, such as air and water, remains limited due to the lack of high-performance, stretchable material compositions and a comprehensive understanding of the charge transfer mechanism involved. To address these challenges, we have designed a high-performance, stretchable nano-/micro-composite film by embedding 2D MXene nanosheets and piezoelectric LiNbO3 microparticles into an Ecoflex polymer matrix. Quantum mechanical calculations revealed that MXene nanosheets significantly increase electron density near the Fermi level, while LiNbO3 microparticles enhance electron transfer during contact electrification with polydimethylsiloxane (PDMS). This synergistic effect resulted in a substantial enhancement of the triboelectric energy harvesting performance, with the composite film exhibiting a 355% increase in voltage, a 324% increase in current, and a 100% boost in power output density compared to systems using pure Ecoflex based TENGs. The fabricated PET-HNG demonstrated remarkable output metrics, including a voltage of 455 V, current of 140 μA, power output density of 15.6 W m-2, and an energy conversion efficiency of 78.5%, all while maintaining exceptional performance stability even under mechanical stretching.This stretchable nanogenerator shows great potential as a self-powered wearable sensor for real-time biomechanical monitoring in various environments, including air and underwater. This innovation paves the way for the development of next-generation wearable electronics and energy harvesting devices.压电增强摩擦电混合纳米发电机(PET-HNGs)因其在能量收集方面的潜力而受到广泛关注。然而,由于缺乏高性能、可拉伸的材料成分和对所涉及的电荷转移机制的全面理解,它们在不同环境(如空气和水)的可拉伸应用中的性能仍然有限。为了解决这些挑战,我们通过将2D MXene纳米片和压电LiNbO3微粒嵌入Ecoflex聚合物基质中,设计了一种高性能、可拉伸的纳米/微复合薄膜。量子力学计算表明,MXene纳米片显著提高了费米能级附近的电子密度,而LiNbO3微粒子在与聚二甲基硅氧烷(PDMS)接触带电过程中增强了电子转移。这种协同效应大大提高了摩擦电能量收集性能,与使用纯Ecoflex的teng系统相比,复合薄膜的电压提高了355%,电流增加了324%,输出功率密度提高了100%。制备的PET-HNG具有优异的输出性能,电压为455 V,电流为140 μA,输出功率密度为15.6 W m-2,能量转换效率为78.5%,即使在机械拉伸下也能保持优异的性能稳定性。这种可拉伸的纳米发电机显示出巨大的潜力,可以作为一种自供电的可穿戴传感器,在各种环境中进行实时生物力学监测,包括空气和水下。这一创新为下一代可穿戴电子设备和能量收集设备的发展铺平了道路。Ultratough Nacre-inspired Soybean Protein Isolate/Graphene Nanocomposite with Flame-retardant, Thermal Conductivity and RecyclableTao Liu, Zheng Liu, Weidong Gu, Jieyu Zhang, Shanshan Gong, Jianzhang Lidoi:10.1016/j.compositesb.2024.111998 具有阻燃性、导热性和可回收性的超韧大豆分离蛋白/石墨烯纳米复合材料Bioplastics synthesized from soybean protein isolate (SPI) and graphite are promising alternatives but often suffer from their inability of mass production, high-cost, poor mechanical robustness, and even flammability. Herein, the scalable production of nacre-like nanocomposite by using the ball-milling spray method of graphene/SPI materials is demonstrated. The dynamic non-covalent was employed to facilitate the toughening effect of inorganic nano-fillers, while simultaneously utilizing dynamic covalent supramolecular interactions to realize plasticizer reinforcement materials. The dissipation of stress is facilitated through a combination of covalent and non-covalent interactions, thereby enhancing the interface interaction and resulting in materials with superior mechanical properties. The interfacial interaction between the SPI and the nano-reinforce confer exceptional mechanical properties to the bioplastic, achieving an excellent tensile strength 11.01 ± 0.81 MPa and fracture toughness14.52 ± 0.71 MJ/m3, which are 3.4 and 3.5 times, respectively, those of neat SPI. The recycling for highly reinforced nacre-mimetic SPI-based nanocomposites is critically enabled by the dynamic bond and improves the sustainability of bioinspired nanocomposites in cyclic economy. In addition, the SPI composite has exceptional flame retardancy, thermal conductivity, and electromagnetic shielding properties. This study provides new insights into the design of reliable and environmentally friendly biomaterials, which is significant for the development of sustainable development resources.以大豆分离蛋白(SPI)和石墨为原料合成生物塑料是一种很有前途的替代材料,但往往存在无法批量生产、成本高、机械坚固性差、甚至易燃性差的问题。本文演示了利用石墨烯/SPI材料的球磨喷涂方法可大规模生产类纳米复合材料。利用动态非共价来促进无机纳米填料的增韧效果,同时利用动态共价超分子相互作用来实现增塑剂增强材料。通过共价和非共价相互作用的结合,促进应力的消散,从而增强界面相互作用,从而使材料具有优越的力学性能。SPI与纳米增强剂的界面相互作用使生物塑料具有优异的力学性能,抗拉强度为11.01±0.81 MPa,断裂韧性为14.52±0.71 MJ/m3,分别是纯SPI的3.4倍和3.5倍。高增强纳米复合材料的循环利用是动态键的关键,提高了生物纳米复合材料在循环经济中的可持续性。此外,SPI复合材料具有优异的阻燃性、导热性和电磁屏蔽性能。本研究为设计可靠、环保的生物材料提供了新的思路,对可持续发展资源的开发具有重要意义。Additive Manufacturing of Continuous Carbon Fiber/Epoxy Composites with Structured Core-Shell Towpreg: Methods, Characterization, and MechanicsKaiyue Deng, Md Habib Ullah Khan, Soyeon Park, Dae Han Sung, Kelvin Fudoi:10.1016/j.compositesb.2024.112001碳纤维/环氧树脂复合材料的增材制造:方法、表征和力学Continuous carbon fiber thermoset composites are acclaimed for their exceptional structural integrity, environmental durability, and extended service life, yet their additive manufacturing (AM) has been relatively underexplored. This study investigates the mechanical performances of 3D-printed continuous carbon fiber/epoxy composites fabricated using the Tow-Preg Cladding (TPC) method. This novel approach integrates in-situ epoxy impregnation, dual-cure cladding, and tow-preg deposition to enhance the producibility of such composites via AM. The resulting composite showcases a fiber volume fraction exceeding 50%, offering remarkable mechanical properties. We report a tensile strength of 1295.72 MPa, a compressive strength of 544.13 MPa, a flexural strength of 659.30 MPa, and an interlaminar shear strength of 50.87 MPa. Furthermore, the tensile strength and modulus achieved 41.5% and 58.1% of the values predicted by a modified rule of mixture equation, indicating competitive performance among various AM systems for continuous fiber composites. By addressing challenges in uniform fiber distribution and optimizing composite morphology, this research marks a significant advancement in AM for thermally curable thermoset composites. The comparative analysis of diverse AM techniques positions our TPC approach as a promising solution in the field, potentially transforming future high-performance composite fabrication.连续碳纤维热固性复合材料因其卓越的结构完整性、环境耐久性和延长的使用寿命而备受赞誉,但其增材制造(AM)的探索相对不足。本文研究了采用TPC (Tow-Preg覆层)法制备的3d打印连续碳纤维/环氧复合材料的力学性能。这种新颖的方法集成了原位环氧浸渍、双固化包层和双预浸沉积,以提高增材制造复合材料的可生产性。所得复合材料的纤维体积分数超过50%,具有卓越的机械性能。我们报告的抗拉强度为1295.72 MPa,抗压强度为544.13 MPa,抗折强度为659.30 MPa,层间剪切强度为50.87 MPa。此外,拉伸强度和模量分别达到了修正混合方程规则预测值的41.5%和58.1%,表明了各种增材制造系统在连续纤维复合材料中的竞争力。通过解决纤维均匀分布和优化复合材料形态的挑战,该研究标志着增材制造在热固化热固性复合材料方面取得了重大进展。通过对各种增材制造技术的比较分析,我们的TPC方法在该领域是一种很有前途的解决方案,有可能改变未来的高性能复合材料制造。Flame-retardant and thermal insulating biomass aerogel with super-elasticityTing Wang, Cheng Xu Xu, Ning Yu, Wen-Li An, Wei luo, Hai-Bo Zhao, Fu-Rong Zeng, Ming-Jun Chendoi:10.1016/j.compositesb.2024.112004 超弹性阻燃保温生物质气凝胶Biomass aerogels possessing both resilience and flame retardance exhibit great potential as alternatives to fossil-based thermal insulators. Nevertheless, the functional applications of elastic biomass aerogels are impeded by their poor resilience persistence, especially at low temperatures. Herein, a synergetic strategy was proposed for designing biomass aerogels with exceptional elasticity across a broad temperature range (from 150 °C to −78 °C), by strategically manipulating their microstructure and implementing a chemically cross-linked network. The resultant aerogels suffered from slight plastic deformation of only 6.1 % even after 1000 loading-unloading cycles at a strain of 60 %, manifesting super-elastic performance. Additionally, the structure and resilience of aerogel can be well maintained even under frigid temperatures (−78 °C). Because firmly cross-linked networks and loosely packed microstructures with elongated cell walls were constructed to minimize plastic deformation and bending stress, thereby suppressing structural destruction. Furthermore, the resulting biomass aerogel exhibited a remarkable combination of advantageous properties including lightweight, flame retardance (limiting oxygen index of 29 %), thermal insulation (32.8 mW m−1 K−1) and infrared stealth. This research offers new insights into the design of elastic biomass aerogels with exceptional overall performance.具有弹性和阻燃性的生物质气凝胶作为化石基绝热材料的替代品显示出巨大的潜力。然而,弹性生物质气凝胶的功能应用受到其弹性持久性差的阻碍,特别是在低温下。本文提出了一种协同策略,通过战略性地操纵其微观结构并实现化学交联网络,设计出在宽温度范围(从150°C到- 78°C)内具有优异弹性的生物质气凝胶。在60%的应变下,即使经过1000次加载-卸载循环,气凝胶也仅发生6.1%的轻微塑性变形,表现出超弹性性能。此外,即使在低温(- 78°C)下,气凝胶的结构和弹性也能很好地保持。因为构建牢固的交联网络和具有细长细胞壁的松散排列的微结构可以最大限度地减少塑性变形和弯曲应力,从而抑制结构破坏。此外,所得到的生物质气凝胶具有轻质、阻燃(极限氧指数为29%)、绝热(32.8 mW m−1 K−1)和红外隐身等优点。该研究为具有优异综合性能的弹性生物质气凝胶的设计提供了新的见解。Composites Science and TechnologyEnhancement of radar-infrared stealth performance of EPDM-based composites through the asymmetric sandwich structural constructionZikang Han, Rong Chen, Jiang Li, Shaoyun Guodoi:10.1016/j.compscitech.2024.110981非对称夹层结构增强epdm基复合材料雷达红外隐身性能The development of radar-infrared-compatible stealth materials is crucial for the weaponry stealth field. However, reconciling the mechanistic contradiction between radar and infrared stealth remains a challenge. In this study, an asymmetrical sandwich structure composite was developed, with an absorbing layer situated in the middle and low emissivity layers on either side. The structure and properties of the functional layers were optimized: In the absorbing layer, ethylene propylene diene monomer/carbon nanotubes/silica (EPDM/CNTs/SiO2) was foamed to enhance its microwave absorption and thermal insulation properties. In the low emissivity layers, the orientation of the flake aluminum powders was adjusted to reduce the infrared emissivity to as low as 0.236 and 0.183 at 3∼5 and 8∼14μm, respectively. As a result, the composite achieved an effective absorption bandwidth of 7.26 GHz and maintained an equilibrium temperature of 29.4 °C after being placed on a 60 °C hot stage, demonstrating excellent infrared stealth performance. Additionally, the composite has a suitable density (0.77 g/cm3) and thickness (3.58 mm). Considering its broad bandwidth, low emissivity, lightness, and softness, the sandwich structure composite is suitable for compatible stealth applications.雷达-红外兼容隐身材料的研制是武器隐身领域的关键。然而,协调雷达隐身与红外隐身之间的机理矛盾仍然是一个挑战。本研究开发了一种非对称夹层结构复合材料,吸收层位于中间,两侧为低发射率层。对功能层的结构和性能进行了优化:在吸波层中,采用乙丙二烯单体/碳纳米管/二氧化硅(EPDM/CNTs/SiO2)进行发泡,增强其微波吸收和保温性能;在低发射率层中,调整片状铝粉的取向,使其在3 ~ 5 μm和8 ~ 14μm处的红外发射率分别降至0.236和0.183。结果表明,该复合材料放置在60℃高温台上后,有效吸收带宽为7.26 GHz,平衡温度为29.4℃,具有优异的红外隐身性能。此外,该复合材料具有合适的密度(0.77 g/cm3)和厚度(3.58 mm)。该复合材料具有宽带宽、低发射率、轻、柔软等特点,适合兼容隐身应用。来源:复合材料力学仿真Composites FEM

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