Extreme Mechanics Letters最新文献_第7页

Clot treatment via spinning-induced fibrin microstructure densification and clot volume reduction 通过纺丝诱导的纤维蛋白微观结构致密化和凝块体积减小治疗凝块

IF 4.3 3区工程技术 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Extreme Mechanics Letters

Pub Date : 2025-09-01 Epub Date: 2025-07-21 DOI: 10.1016/j.eml.2025.102391

Yilong Chang , Guansheng Li , Jay Sim , George Em Karniadakis , Ruike Renee Zhao

Blood clots, composed of red blood cells (RBCs) embedded within a fibrin network, can cause life-threatening conditions such as strokes and heart attacks. However, conventional thrombectomy techniques, such as aspiration or stent retrievers, often struggle with large or tough clots, limiting their clinical efficacy. The recently developed milli-spinner thrombectomy offers a breakthrough approach that fundamentally departs from these traditional methods. Instead of extracting the clot intact, the milli-spinner mechanically shrinks the clot by densifying its microstructure through the combined action of compression and shear forces, achieving up to 95 % volume reduction. This novel clot debulking strategy enables more effective clot removal and holds strong potential for significantly improved clinical outcomes in thrombectomy procedures. To uncover the underlying mechanisms and optimize performance, we combine in vitro experiments with dissipative particle dynamics (DPD) simulations for multiscale analysis of clot volume reduction and microstructural densification under integrated compression and shear. Experiments quantify macroscopic clot volume reduction under controlled loading, while simulations reveal microscale fibrin network densification and RBC release. This systematic study provides a quantitative understanding of how different loading modes alter clot microstructure across clot types. These findings lay the foundation for the rational design of next-generation thrombectomy systems, capable of mechanically reconfiguring clot microstructure in situ, offering enhanced efficacy and broader clinical applicability.

血凝块是由嵌在纤维蛋白网络中的红血球（rbc）组成的，可导致危及生命的疾病，如中风和心脏病发作。然而，传统的取栓技术，如抽吸或支架回收，往往与大的或坚硬的血栓作斗争，限制了它们的临床疗效。最近开发的微旋血栓切除术提供了一种突破性的方法，从根本上脱离了这些传统方法。与完整提取凝块不同的是，微纺丝机通过压缩和剪切力的共同作用使其微观结构致密化，从而使凝块机械收缩，体积减少高达95% %。这种新颖的凝块减容策略能够更有效地去除凝块，并具有显著改善血栓切除术临床结果的强大潜力。为了揭示潜在的机制并优化性能，我们将体外实验与耗散粒子动力学（DPD）模拟相结合，对综合压缩和剪切作用下的凝块体积缩小和微观结构致密化进行了多尺度分析。实验量化了控制负荷下宏观的血块体积减少，而模拟揭示了微观尺度的纤维蛋白网络致密化和红细胞释放。这个系统的研究提供了一个定量的了解不同的加载模式如何改变凝块的微观结构跨越凝块类型。这些发现为下一代取栓系统的合理设计奠定了基础，该系统能够在原位机械地重新配置凝块微观结构，从而提高疗效和更广泛的临床适用性。

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引用次数: 0

Non-local elastic lattices with PT-symmetry and time modulation: From perfect trapping to the wave boomerang effect 具有pt对称和时间调制的非局部弹性晶格：从完美的俘获到波回旋效应

IF 4.3 3区工程技术 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Extreme Mechanics Letters

Pub Date : 2025-09-01 Epub Date: 2025-07-25 DOI: 10.1016/j.eml.2025.102383

Emanuele Riva

Wave motion is fundamentally constrained by the dispersion properties of the medium, often making it challenging — or even impossible — to guide wave packets along desired trajectories, particularly when wave inversion is required. The paper illustrates how one-dimensional (1D) and two-dimensional (2D) non-Hermitian elastic lattices with time-varying non-local feedback interactions offer unprecedented wave guidance. By relaxing the constraint of Hermiticity while preserving

PT

-symmetry of the nonlocal interactions, it is herein built a framework where the dispersion transitions from positive to negative group velocity, passing through an intermediate regime characterized by a perfectly flat band across all momenta. This effect, realized within the unbroken

PT

-symmetric phase, is further enhanced by the time modulation of lattice parameters, thereby unlocking functionalities such as perfect trapping, where a wave packet is intentionally stopped, and the wave boomerang effect, where the wave packet is reversed or guided back to its initial position. The framework presented in this paper unlocks opportunities that extend beyond wave guidance, including information processing through dispersion engineering in elastic media.

波的运动基本上受到介质色散特性的限制，这使得引导波包沿着期望的轨迹变得具有挑战性，甚至是不可能的，特别是当需要进行波的反演时。本文阐述了具有时变非局部反馈相互作用的一维（1D）和二维（2D）非厄米弹性晶格如何提供前所未有的波导。在保持非局域相互作用pt对称性的同时，通过放宽hermite约束，本文建立了一个色散从正群速度向负群速度转变的框架，该框架通过一个中间区域，其特征是在所有动量上都有一个完美的平坦带。这种效应是在完整的pt对称相位中实现的，通过晶格参数的时间调制进一步增强，从而解锁诸如完美捕获（波包被故意停止）和波回旋效应（波包被逆转或引导回其初始位置）等功能。本文提出的框架揭示了超越波导的机会，包括通过弹性介质中的色散工程进行信息处理。

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引用次数: 0

Conditional stability in metamaterials: Experiments, modeling, and 3D design 超材料的条件稳定性：实验、建模和3D设计

IF 4.5 3区工程技术 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Extreme Mechanics Letters

Pub Date : 2025-09-01 Epub Date: 2025-08-07 DOI: 10.1016/j.eml.2025.102393

G. Risso , L. Pesaresi , A.S. Meeussen , K. Bertoldi

The mechanical properties of metamaterials are typically governed by their architecture in the undeformed configuration, which limits their adaptability. Recent work has shown that interactions between structural components with strongly nonlinear responses can reshape the system’s energy landscape. For instance, a structure composed of four von Mises trusses coupled through an elastic matrix exhibits conditional stability: stability along one principal direction can be tuned on demand by modifying the metamaterial’s topological state along the orthogonal direction. Here, we systematically investigate the mechanical response of such conditionally stable structures through a combination of experiments, Finite Element simulations, and analytical modeling. Building on these insights, we propose a strategy to extend conditional stability to a three-dimensional architecture, demonstrating its potential for reprogrammable energy absorption.

超材料的力学性能通常由其未变形的结构决定，这限制了它们的适应性。最近的研究表明，具有强烈非线性响应的结构部件之间的相互作用可以重塑系统的能量景观。例如，由四个von Mises桁架通过弹性矩阵耦合组成的结构表现出条件稳定性：沿着一个主方向的稳定性可以根据需要通过修改沿着正交方向的超材料拓扑状态来调整。在这里，我们通过实验、有限元模拟和分析建模相结合，系统地研究了这种条件稳定结构的力学响应。基于这些见解，我们提出了一种将条件稳定性扩展到三维结构的策略，展示了其可重新编程能量吸收的潜力。

引用次数: 0

Multiscale structure-mechanical property relationship and data-driven design of ultra-high temperature ceramics: A review 超高温陶瓷的多尺度结构-力学性能关系与数据驱动设计综述

IF 4.3 3区工程技术 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Extreme Mechanics Letters

Pub Date : 2025-09-01 Epub Date: 2025-07-24 DOI: 10.1016/j.eml.2025.102392

Xiaoqian Gao , Li Chen , Runkai Liu , Jing Wan , Huasong Qin , Yilun Liu

Ultra-high temperature ceramics (UHTCs) exhibit exceptional melting points, superior oxidation resistance, and outstanding ablation performance, positioning them as indispensable materials for extreme-environment applications. However, their inherent brittleness, high density, limited elasticity, and poor fatigue resistance restrict broader implementation. This review presents a rigorous, multiscale examination of interrelationships between UHTC structural characteristics and mechanical behaviors, addressing critical knowledge gaps in failure mechanisms and state-of-the-art design of strengthening and toughening strategies. The analysis commences with crystal-chemical principles and progresses through salient microstructural and mesostructural characteristics, followed by an exploration of thermally induced deformation and structural evolution at elevated temperatures. The dominated factors in mechanical degradation and corresponding strengthening and toughening mechanisms across nanoscale, microscale, and mesoscale levels are systematically dissected. Furthermore, we highlight recent advances in high-throughput screening within materials genome engineering and the integration of machine learning (ML) for rapid property prediction and structural optimization of UHTCs. Finally, prospective multiscale design strategies are proposed to synergistically optimize the balance of strength and toughness in UHTCs.

超高温陶瓷（UHTCs）具有卓越的熔点，卓越的抗氧化性和出色的烧蚀性能，使其成为极端环境应用中不可或缺的材料。然而，它们固有的脆性、高密度、有限弹性和较差的抗疲劳性限制了它们的广泛应用。本文对UHTC结构特征和力学行为之间的相互关系进行了严格的、多尺度的研究，解决了失效机制和最先进的强化和增韧策略设计方面的关键知识空白。分析从晶体化学原理开始，通过突出的微观结构和细观结构特征进行进展，随后探索高温下的热致变形和结构演变。在纳米尺度、微尺度和中尺度水平上系统剖析了机械降解的主要因素和相应的强化和增韧机制。此外，我们强调了材料基因组工程中高通量筛选的最新进展，以及机器学习（ML）的集成，用于UHTCs的快速性能预测和结构优化。最后，提出了未来的多尺度设计策略，以协同优化UHTCs的强度和韧性平衡。

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引用次数: 0

Band gap analysis and prediction for phononic metamaterials with different spiral shapes based on transfer learning 基于迁移学习的不同螺旋形状声子超材料带隙分析与预测

IF 4.3 3区工程技术 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Extreme Mechanics Letters

Pub Date : 2025-09-01 Epub Date: 2025-07-22 DOI: 10.1016/j.eml.2025.102379

Majid Kheybari, Hongyi Xu

This study presents a comprehensive computational investigation of band gap characteristics in spiral-based phononic metamaterials, including Archimedean, Octagon, Hexagon, and Square spiral configurations. It offers a quantitative understanding of the similarities in Bloch wave properties across these spiral types and demonstrates the feasibility of using data from known spiral patterns to facilitate the property prediction of new types. Based on the spiral datasets that vary in the number of turns, cutting width, and inner radius, we observed strong correlations in band gap counts among patterns (e.g., Rotated Octagon and Octagon, Archimedean and Rotated Octagon), indicating similar behaviors in band gap occurrence across different geometries. It was also found that the rotation of geometric shapes had a minor impact on band gap counts. However, we observed that the distribution of band gap width varies significantly across different types of spirals, with weak correlations. Furthermore, we demonstrate that transfer learning (TL) enhances prediction accuracy for new spiral types compared to traditional neural network approaches. TL model demonstrated superior performance, effectively capturing complex band gap details and improving overall prediction accuracy, without requiring extensive training data.

本研究对基于螺旋的声子超材料的带隙特性进行了全面的计算研究，包括阿基米德、八边形、六边形和方形螺旋结构。它提供了对这些螺旋型布洛赫波性质相似性的定量理解，并证明了利用已知螺旋型数据促进新类型性质预测的可行性。基于旋转次数、切割宽度和内半径不同的螺旋数据集，我们观察到带隙数量在模式（例如，旋转八边形和八边形，阿基米德和旋转八边形）之间具有很强的相关性，表明不同几何形状的带隙发生相似的行为。还发现几何形状的旋转对带隙数的影响较小。然而，我们观察到带隙宽度的分布在不同类型的螺旋中有显著差异，具有弱相关性。此外，我们证明了与传统的神经网络方法相比，迁移学习（TL）提高了对新螺旋类型的预测精度。TL模型表现出优异的性能，在不需要大量训练数据的情况下，有效地捕获了复杂的带隙细节，提高了整体预测精度。

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引用次数: 0

Peeling a rigid sphere from a stretched rubber substrate 从拉伸的橡胶基材上剥下坚硬的球体

IF 4.5 3区工程技术 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Extreme Mechanics Letters

Pub Date : 2025-09-01 Epub Date: 2025-07-26 DOI: 10.1016/j.eml.2025.102381

Christopher W. Barney , Yue (Luna) Zheng

Polymer coatings are an important technology where pre-stresses can develop during draping, drying, and cooling. This paper aims to quantify the impact that these stresses have on the indentation response. Spherical probe indentation is performed on a stretched and unstretched substrate where the evolution of the contact area is monitored. Consistent with previous works, it is found that the contact area becomes elliptical on stretched substrates. Further, it is observed that this ellipse dynamically evolves during the indentation and peel process. This change in contact area upon stretching is found to increase the apparent stiffness and decrease the adhesive response.

聚合物涂层是一项重要的技术，可以在悬垂、干燥和冷却过程中产生预应力。本文旨在量化这些应力对压痕响应的影响。在拉伸和未拉伸的基板上执行球形探头压痕，其中监测接触区域的演变。与以往的工作一致，发现在拉伸基底上接触面积变为椭圆形。此外，还观察到该椭圆在压痕和剥离过程中动态演变。发现拉伸时接触面积的变化增加了表观刚度，降低了粘接响应。

引用次数: 0

Inverse design of mechanical metamaterials balancing manufacturability and compactness: A case study on lattice cells 平衡可制造性和紧凑性的机械超材料的反设计：以晶格单元为例

IF 4.3 3区工程技术 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Extreme Mechanics Letters

Pub Date : 2025-09-01 Epub Date: 2025-07-25 DOI: 10.1016/j.eml.2025.102395

Jiacheng Xue, Hanmeng Bao, Tengfei Liu, Lingling Wu, Xiaoyong Tian, Dichen Li

Mechanical metamaterials are artificially engineered structures designed to exhibit unique and extraordinary mechanical properties. In recent years, machine learning has provided a more efficient and systematic approach, enabling inverse design of mechanical metamaterials, which allow for a broader exploration of material properties and support the integration of multifunctionality, significantly speeding up the design process. Despite the many advantages of inverse design, metamaterials often involve a trade-off between competing performance metrics-such as manufacturability and structural compactness. Furthermore, these trade-offs should be dynamically adjusted based on different additive manufacturing conditions. To address this, we proposed a regressional and conditional generative adversarial network based multi-objective (RCGAN-MO) architecture, which simultaneously handles the inverse design and adjustable multi-objective optimization of mechanical metamaterials. The RCGAN-MO includes two trained neural networks: a generator and a predictor, along with a weighted multi-objective optimizer. As a case study, the RCGAN-MO architecture is applied to the inverse design of the relative compressive elastic modulus for a metamaterial, and metamaterials with different weight vector values in the multi-objective optimizer are achieved through 3D printed prototypes. This approach achieves high accuracy and could adjust the importance of manufacturability and compactness, offering a flexible, scalable solution for engineering metamaterials tailored to practical application demands.

机械超材料是人工设计的结构，旨在表现出独特和非凡的机械性能。近年来，机器学习提供了一种更有效、更系统的方法，使机械超材料的逆设计成为可能，从而可以更广泛地探索材料特性，并支持多功能的集成，大大加快了设计过程。尽管逆向设计有许多优点，但超材料通常涉及到竞争性能指标之间的权衡，例如可制造性和结构紧凑性。此外，这些权衡应根据不同的增材制造条件进行动态调整。为了解决这一问题，我们提出了一种基于回归和条件生成对抗网络的多目标（RCGAN-MO）架构，该架构同时处理机械超材料的逆设计和可调多目标优化。RCGAN-MO包括两个经过训练的神经网络：一个生成器和一个预测器，以及一个加权多目标优化器。将RCGAN-MO体系结构应用于某超材料的相对压缩弹性模量反设计中，通过3D打印原型实现了多目标优化器中具有不同权重向量值的超材料。该方法实现了高精度，可以调整可制造性和紧凑性的重要性，为工程超材料提供了一个灵活的、可扩展的解决方案，以满足实际应用需求。

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引用次数: 0

Hard-to-soft part ratios in natural crawlers inform hybrid robotic design 自然履带的软硬零件比为混合动力机器人的设计提供了依据

IF 4.5 3区工程技术 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Extreme Mechanics Letters

Pub Date : 2025-09-01 Epub Date: 2025-07-25 DOI: 10.1016/j.eml.2025.102394

Jiayi Lei , Changhong Linghu , Min Pan , K. Jimmy Hsia

Most robots to date consist of either entirely hard parts or entirely soft parts. Nature, however, achieves a balance between hard and soft components, offering both adaptability and strength for adequate load-carrying capacity and locomotion in diverse environments. Inspired by nature, hybrid robotic designs, combining the flexibility of soft robots with the control and load-bearing capacity of hard robots, are being pursued. However, a proper range of the Hard-to-Soft Part Ratio (H2S-R) for the desirable performance of hybrid robots remains unclear. With a focus on crawlers, this study comprehensively compiles the H2S-R in crawling animals of four locomotion mechanisms: two-anchor, peristaltic, undulatory, and multi-legged crawling, and analyzes the trends and scaling in their performances. Results show distinct ranges of H2S-R in natural crawlers: 0.0005–0.003 for two-anchor crawlers, 0.08–0.09 for peristaltic, 0.02–0.08 for undulatory, and 1.0–2.4 for multi-legged. Within these ranges, except for the undulatory locomotion, increasing the H2S-R generally enhances their normalized crawling speed measured in body-lengths per second. Data for natural crawlers also show different ranges of normalized speeds as well as distinct scaling laws for different mechanisms. Comparisons with the performance of natural crawlers indicate that robotic crawlers have yet to achieve their full potential in crawling speed. This study provides guidelines for designing bio-inspired hybrid robots with potential applications in search and rescue, environmental monitoring, space exploration, and medical robotics.

迄今为止，大多数机器人要么完全由硬部件组成，要么完全由软部件组成。然而，大自然在硬构件和软构件之间取得了平衡，在不同的环境中提供了足够的承载能力和运动能力的适应性和强度。受大自然的启发，混合机器人的设计，将软机器人的灵活性与硬机器人的控制和承载能力相结合，正在被追求。然而，对于混合机器人理想性能的软硬零件比（H2S-R）的适当范围仍不清楚。本研究以爬行动物为研究对象，全面梳理了双锚爬行、蠕动爬行、波动爬行和多足爬行四种运动机制下爬行动物的H2S-R，并分析了其表现的趋势和尺度。结果表明，自然爬行动物的H2S-R含量范围明显不同：双锚爬行动物为0.0005-0.003，蠕动爬行动物为0.08-0.09，波动爬行动物为0.02-0.08，多足爬行动物为1.0-2.4。在这些范围内，除了波动运动外，增加H2S-R通常会提高它们的标准化爬行速度（以体长/秒为单位）。自然爬行器的数据也显示出不同的归一化速度范围以及不同机制的不同标度规律。与自然爬行器的性能比较表明，机器人爬行器尚未充分发挥其爬行速度的潜力。该研究为仿生混合机器人的设计提供了指导，这些机器人在搜救、环境监测、空间探索和医疗机器人等领域具有潜在的应用前景。

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引用次数: 0

Front cover CO1 前盖CO1

IF 4.5 3区工程技术 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Extreme Mechanics Letters

Pub Date : 2025-09-01 Epub Date: 2025-09-09 DOI: 10.1016/S2352-4316(25)00112-9

引用次数: 0

Modeling the dynamics of sub-millisecond electroadhesive engagement and release times 亚毫秒级电粘合剂接合和释放时间的动力学建模

IF 4.3 3区工程技术 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Extreme Mechanics Letters

Pub Date : 2025-09-01 Epub Date: 2025-07-22 DOI: 10.1016/j.eml.2025.102382

Ahad M. Rauf, Sean Follmer

Electroadhesive clutches are electrically controllable switchable adhesives commonly used in soft robots and haptic user interfaces. They can form strong bonds to a wide variety of surfaces at low power consumption. However, electroadhesive clutches in the literature engage to and release from substrates several orders of magnitude slower than a traditional electrostatic model would predict. Large release times, in particular, can limit electroadhesion’s usefulness in high-bandwidth applications. We develop a novel electromechanical model for electroadhesion, factoring in polarization dynamics, the drive circuitry’s rise and fall times, and contact mechanics between the dielectric and substrate. We show in simulation and experimentally how different design parameters affect the engagement and release times of centimeter-scale electroadhesive clutches to metallic substrates, and we find that the model accurately captures the magnitude and trends of our experimental results. In particular, we find that higher drive frequencies, narrower substrate aspect ratios, and faster drive circuitry output stages enable significantly faster release times. The fastest clutches have engagement times less than

15 μ

s and release times less than

875 μ

s, which are 10

\times

and 17.1

\times

faster, respectively, than the best times found in prior literature on centimeter-scale electroadhesive clutches.

电胶离合器是一种可电控的可切换粘合剂，通常用于软机器人和触觉用户界面。它们可以在低功耗下与各种各样的表面形成牢固的键合。然而，文献中的电粘合离合器与基材的接合和释放速度比传统静电模型预测的要慢几个数量级。特别是大的释放时间会限制电粘附在高带宽应用中的实用性。我们开发了一种新的电粘附的机电模型，考虑了极化动力学、驱动电路的上升和下降时间以及介电介质和衬底之间的接触力学。我们在模拟和实验中展示了不同的设计参数如何影响厘米级电粘合离合器与金属基板的接合和释放时间，我们发现该模型准确地捕捉了我们的实验结果的幅度和趋势。特别是，我们发现更高的驱动频率，更窄的衬底宽高比和更快的驱动电路输出级可以显著加快释放时间。最快的离合器啮合时间小于15μs，释放时间小于875μs，分别比现有文献中厘米级电粘合离合器的最佳啮合时间快10倍和17.1倍。

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引用次数: 0