【新文速递】2024年5月14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 1 篇，Mechanics of Materials 1 篇，Thin-Walled Structures 1 篇

International Journal of Solids and Structures

Quasi-static behavior of a pair of serially-connected Kresling Origami springs

Ravindra Masana, Mohammed F. Daqaq

doi:10.1016/j.ijsolstr.2024.112877

一对串联Kresling折纸弹簧的准静态行为

Many of the patterns seen in Origami are currently being explored as a platform for building functional engineering systems with versatile characteristics that cater to niche applications in various technological fields. One such pattern is the Kresling pattern, which can be used to construct mechanical springs with unconventional properties and rich translational-rotational restoring behavior. In this paper, we investigate, both theoretically and experimentally, the quasi-static behavior of a pair of serially-connected Kresling Origami springs under different end loading conditions. We show that, depending on the end loading of the spring, it can exhibit coupled/ decoupled motion; one, two, or three equilibria; fixed, quasi-zero, or variable stiffness; and symmetric/asymmetric restoring behavior. We also present a technique to predict the restoring behavior of the serially-connected springs by combining a simple truss model with the experimentally-identified restoring behavior of a single unit. The technique permits accurate prediction of the deformation path of any number of serially-connected springs. We believe that serially connected Kresling Origami Springs offer a pathway towards the design of axial and torsional springs with unique and versatile functionalities.

在Origami中看到的许多模式目前正在作为构建功能工程系统的平台进行探索，这些系统具有多种特性，可以满足各种技术领域的特定应用。其中一种模式是Kresling模式，它可以用来构建具有非常规性能和丰富的平移-旋转恢复行为的机械弹簧。本文从理论和实验两方面研究了一对串联的Kresling折纸弹簧在不同端部载荷条件下的准静态行为。我们表明，根据弹簧的末端载荷，它可以表现出耦合/解耦运动;一个、两个或三个平衡;固定的、准零的或可变的刚度;对称/不对称恢复行为。我们还提出了一种技术，通过结合一个简单的桁架模型和实验确定的单个单元的恢复行为来预测串联弹簧的恢复行为。该技术可以准确预测任意数量串联弹簧的变形路径。我们相信，连续连接的Kresling折纸弹簧为设计具有独特和多功能的轴向和扭转弹簧提供了一条途径。

Journal of the Mechanics and Physics of Solids

On the conditions for self-catapulting of freezing water droplets

Haimin Yao

doi:10.1016/j.jmps.2024.105685

关于冰冻水滴自弹射的条件

Despite the remarkable progress of anti-icing and deicing technologies in the past decades, it remains a grand challenge to dislodge freezing water from a solid surface without consuming external energy. Herein, we propose a strategy to dislodge freezing water from solid surfaces just by leveraging its volume expansion resulting from the phase change from water to ice. The implementation of this energy-saving strategy relies on a simple micropillar-based gadget on the surface, termed freezing-empowered droplet catapult (FEDC), whereby the work done by the volume expansion of a freezing droplet accreted on it can be harvested and stored as elastic energy, and subsequently released in due course to catapult the freezing droplet away from the surface. Mechanics-based modelling is carried out to reveal the necessary conditions of occurrence for the self-catapulting of freezing water droplets on an FEDC, yielding a phase map that manifests the necessary synergy among the characteristic dimensions and stiffness of the FEDC as well as the volume of the droplet in triggering its self-catapulting. Our study not only demonstrates the feasibility of an energy-saving strategy for shedding off freezing droplets from solid surfaces but also provides a quantitive guideline for the design of the gadget for implementation, paving the way to a new technology for controlling ice accretion on solid surfaces with zero consumption of external energy.

尽管在过去的几十年里，防冰和除冰技术取得了显著的进步，但在不消耗外部能量的情况下，将冰冻的水从固体表面移除仍然是一个巨大的挑战。在此，我们提出了一种策略，通过利用由水到冰的相变引起的体积膨胀，将冻结的水从固体表面移除。这种节能策略的实现依赖于表面上一个简单的基于微柱的装置，称为冷冻增强液滴弹射器(FEDC)，通过该装置，冷冻液滴在其上的体积膨胀所做的功可以被收集并储存为弹性能量，随后在适当的时候释放，将冷冻液滴弹射离表面。基于力学的建模揭示了冻结水滴在FEDC上自弹射发生的必要条件，得到了一个相位图，显示了FEDC的特征尺寸和刚度以及液滴体积在触发其自弹射时所必需的协同作用。我们的研究不仅证明了从固体表面脱落冷冻液滴的节能策略的可行性，而且为装置的设计提供了定量指导，为零消耗外部能量控制固体表面冰积聚的新技术铺平了道路。

Mechanics of Materials

A mathematical model to design pillar-shaped bioinspired mechanical sensors

A. Solis, L. Alonso

doi:10.1016/j.mechmat.2024.105031

设计柱状仿生机械传感器的数学模型

Soft robots and sensor/actuator systems are often based on bioinspired designs to leverage nature patterns. Specifically, pillar-shaped sensors are useful for human activity monitoring, locomotion of soft robots or treatment of cardiovascular diseases. If electric or magnetic particles are added in the manufacturing process, these structures can be tuned through remote fields to attain a specific mechanical behaviour. This promising technique has direct applications in high-impact fields such as bioengineering, soft robots or sensor designing. Filament-shaped smart sensors can send electrical signals when subjected to an external mechanical stimulus or provide a mechanical response when a remote and controllable field is applied broadening their possibilities of action. As the efficient design of these structures is highly challenging, developing a technical tool with a low computational cost to help throughout layout processes (i.e. inverse engineering) is pivotal. Theoretical modelling of the kinematics and dynamics of a wire-shaped structure under an external action is the first step to provide a methodology to help designing mechanical sensors in an efficient, understandable and low time-consuming way. The event of mechanical deformation after receiving the external stimulus and before sending the corresponding output signal is key in the conceptualisation process of smart sensors. This work intends to give insight into the dynamics of a deformable pillar-shaped sensor component under an external action without addressing or coupling its causes and, hence, provide the general mechanical framework to serve as basis for multiphysics formulations for pillar-shaped sensor design.

软机器人和传感器/执行器系统通常基于生物启发设计来利用自然模式。具体来说，柱状传感器可用于人体活动监测、软体机器人的运动或心血管疾病的治疗。如果在制造过程中加入电或磁颗粒，这些结构可以通过远程场进行调谐，以获得特定的机械行为。这项有前途的技术在生物工程、软机器人或传感器设计等高影响领域有直接的应用。灯丝形状的智能传感器可以在受到外部机械刺激时发送电信号，或者在应用远程可控场时提供机械响应，从而扩大其行动的可能性。由于这些结构的高效设计极具挑战性，因此开发一种具有低计算成本的技术工具来帮助整个布局过程(即逆向工程)至关重要。在外力作用下，线形结构的运动学和动力学的理论建模是提供一种有效、可理解和低耗时的方法来帮助设计机械传感器的第一步。在接收到外部刺激之后，在发送相应的输出信号之前，机械变形事件是智能传感器概念化过程中的关键。这项工作旨在深入了解在外部作用下可变形柱状传感器组件的动力学，而不解决或耦合其原因，因此，提供一般的机械框架，作为柱状传感器设计的多物理场公式的基础。

Thin-Walled Structures

Static behavior of stiffened CFST KK joints of offshore wind turbines under antisymmetric loading

Qiqi Li, Xuhong Zhou, Yuhang Wang, James B.P. Lim, Bin Wang, Shan Gao, Ran Deng

doi:10.1016/j.tws.2024.111998

海上风力机加劲CFST KK节点在反对称荷载作用下的静力性能

This study examines the static behavior of the critical joints of the new kind of offshore jacket foundations under antisymmetric loading by employing a combination of experiments, finite element analysis (FEA), and theoretical derivation. Three tests and 35 FEAs of stiffened concrete-filled steel tubular (CFST) KK joints are described. The introduction of a novel perfobond ring rib (PRB) as a stiffener, along with using a limiting fixture during loading to consider interactions among the four braces, are novelties of this research. Experiments compare the influence of stiffener rib forms (PRB and Perfobond Leister Ribs (PBL)) on the behavior of CFST KK joints, highlighting the superiority of PRB strengthening. However, the influence of the stiffener rib form on the stiffness of the CFST KK joints can be ignored. The properties of PRB-stiffened CFST KK joints are further investigated via validated FEA models, which introduce the modified Mohr-Coulomb (MMC) criterion to realize steel fracture damage. A parametric analysis is then undertaken to explore how variations in the joint's geometrical parameters, chord material strength, and thickness and quantity of the PRBs influence the punching shear capacity of PRB-stiffened CFST KK joints. Furthermore, a formula is presented for punching shear strength in PRB-stiffened CFST KK joints by employing the superposition method. Its predictions align well with both experimental and FEA results.

本文采用实验、有限元分析和理论推导相结合的方法，研究了一种新型海上导管基础临界节点在反对称荷载作用下的静力性能。介绍了钢管混凝土(CFST) KK节点的3次试验和35次有限元分析。本研究的新颖之处是引入了一种新型的环形肋(PRB)作为加强筋，以及在加载过程中使用限制夹具来考虑四个支撑之间的相互作用。试验比较了两种加筋肋形式(PRB和Perfobond Leister肋(PBL))对CFST KK节点性能的影响，突出了PRB加固的优越性。然而，加劲肋形式对节点刚度的影响可以忽略不计。采用改进的Mohr-Coulomb (MMC)准则对prb加筋的CFST KK节点进行了进一步的有限元分析。然后进行参数分析，探讨节点几何参数、弦材强度、prb厚度和数量的变化如何影响prb加筋CFST KK节点的冲剪能力。此外，采用叠加法推导了prb加筋钢管混凝土KK节点冲剪强度计算公式。它的预测与实验和有限元分析结果吻合得很好。

来源：复合材料力学仿真Composites FEM

【新文速递】2024年5月14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 Science and Technology 1 篇Composite StructuresSimultaneous modification and solidification of bamboo Fiber/Epoxy compositesShaohua Gu, Cuicui Wang, Wenfu Zhang, Ge Wang, Haitao Cheng, Lee M. Smithdoi:10.1016/j.compstruct.2024.118204竹纤维/环氧复合材料的同步改性与固化Bamboo fiber (BF) composite is a sustainable and environmentally friendly material. However, the traditional preparation process requires multiple modification processes, leading to changes in fiber properties, and often results in strength loss and energy waste. To address these issues, we report a novel tetrahydromethyl-1,3-isobenzofurandione epoxy system (MeTHPA-EP) that can simultaneously modify BF and solidify the matrix, resulting in a more efficient and sustainable composite material. In the BF/MeTHPA-EP forming process, BF acts as an “accelerator,” promoting the curing reaction and advancing the exothermic peak of the matrix by 10℃. Meanwhile, MeTHPA acts as a “bridge,” reducing the wettability of BF by 35–50% and decreasing the porosity to 1.02%. The combined effect of these two factors significantly strengthens BF as reinforcement, increasing matrix strength by 5.77 times and modulus by 5.82 times, exhibiting apparent ductile bulk failure. Furthermore, we conducted a comparison with the traditional isophorone diamine curing agent, verifying the superiority of the MeTHPA-EP system in reducing voids and enhancing interfacial stability. Our research expands the applicability of bamboo fiber as a reinforcing material, providing a cost-effective, environmentally friendly, and effective method for producing high-performance bamboo fiber composites.竹纤维复合材料是一种可持续发展的环保材料。然而，传统的制备工艺需要多次改性，导致纤维性能发生变化，往往造成强度损失和能量浪费。为了解决这些问题，我们报道了一种新的四氢甲基-1,3-异苯并呋喃二酮环氧树脂体系(MeTHPA-EP)，它可以同时改性BF和固化基体，从而产生更高效和可持续的复合材料。在BF/MeTHPA-EP成型过程中，BF起到“促进剂”的作用，促进固化反应，使基体放热峰提前10℃。同时，MeTHPA起到“桥梁”的作用，使BF的润湿性降低35-50%，孔隙率降至1.02%。这两种因素的共同作用显著增强了BF作为增强材料的强度，使基体强度提高了5.77倍，模量提高了5.82倍，呈现出明显的延性体破坏。此外，我们还与传统的异佛尔酮二胺固化剂进行了比较，验证了MeTHPA-EP体系在减少空隙和提高界面稳定性方面的优势。我们的研究拓展了竹纤维作为增强材料的适用性，为生产高性能竹纤维复合材料提供了一种经济、环保、有效的方法。Composites Part A: Applied Science and ManufacturingThe role of cavitation in the toughening of elastomer nanocomposites reinforced with graphene nanoplateletsConor T. O'Brien, Zheling Li, Mufeng Liu, J. Robert Innes, Suhao Li, Dimitrios G. Papageorgiou, Malte Storm, Timothy L. Burnett, Robert J. Youngdoi:10.1016/j.compositesa.2024.108269空化在石墨烯纳米片增强弹性体纳米复合材料增韧中的作用The toughening of different types of elastomers through the incorporation of graphene nanoplatelets (GNPs) has been investigated. Both the tear strength and tearing energy are increased significantly through a combination of mechanisms such as debonding, pull-out and cavitation. The processes that occur ahead of a tear/crack tip in natural rubber filled with GNPs have been monitored in situ using synchrotron-based X-ray computed tomography. The GNP particles are found to debond and form voids that grow under stress leading to considerable energy absorption. The mechanisms of cavitation and void growth are analysed theoretically and it is shown that voids need to be larger than ∼1 μm in size to grow in the triaxial tensile stress field ahead of the tear/crack tip. The high level of cavitation and void growth found for the elastomers filled with micron-sized GNP particles is suggested to be the reason why these nanocomposites have a high tear resistance.研究了石墨烯纳米片(GNPs)对不同类型弹性体的增韧作用。通过脱粘、拉出和空化等机制的结合，撕裂强度和撕裂能量都得到了显著的提高。利用基于同步加速器的x射线计算机断层扫描技术，对填充GNPs的天然橡胶在破裂/裂纹尖端之前发生的过程进行了现场监测。发现GNP颗粒脱落并形成在应力下生长的空洞，导致大量的能量吸收。从理论上分析了空化和孔洞扩展的机理，结果表明，在撕裂/裂纹尖端前的三轴拉伸应力场中，孔洞的尺寸必须大于1 μm。在微米级GNP颗粒填充的弹性体中发现了高水平的空化和空隙生长，这被认为是这些纳米复合材料具有高抗撕裂性的原因。Composites Science and TechnologyMetastructure Based Broadband Structural Stealth with Material-Structure-Function IntegrationYuhui Zhang, Huaiyu Dong, Chen Yu, Zhichen Wang, Yixing Huangdoi:10.1016/j.compscitech.2024.110661 基于元结构的材料-结构-功能集成宽带结构隐身Broadband microwave absorption is difficult to be realized in traditional coating form as multiple electromagnetic resonances are difficult to be generated even with dielectric-magnetic loss composites. Narrow absorption band confines the practical usage of the novel electromagnetic nano composites. Herein, the structural stealth concept is proposed to overcome the narrow-band absorption problem with the effect carrier of metastructure. The gradient honeycomb metastructure (GHM) was designed and optimized with module stack large mutation genetic algorithms. The structural design, fabrication, experimental verification and parameter adjustment were included in the closed loop with material-structure-function integration. Multiple resonance effects were introduced in the gradient designs. GHM achieved -10 dB absorption bandwidth in 1.92-17.6 GHz and three deep absorption peaks were introduced by three layers of electromagnetic resonant honeycomb. Broadband absorption in oblique incidence from 30° to grazing angle 85° was achieved to overcome the oblique absorption degeneration problems of traditional nano lossy composites. The structural mechanical performance was high with the maximum equivalent tensile strength of 108.6 MPa and the maximum flexural load of 0.873 kN. The results showed the importance of structural stealth with material-structure-function integration to design metastructure for broadband microwave absorption, which provided a promising approach to achieve broadband microwave absorption.传统的涂层形式难以实现宽带微波吸收，因为即使是介质损耗复合材料也难以产生多重电磁共振。窄小的吸收带限制了新型电磁纳米复合材料的实际应用。为此，提出了结构隐身的概念，克服了利用元结构效应载体的窄带吸收问题。采用模块堆叠大突变遗传算法对梯度蜂窝元结构进行了设计和优化。该系统的结构设计、制造、实验验证和参数调整均在材料-结构-功能一体化的闭环中完成。在梯度设计中引入了多重共振效应。GHM在1.92 ~ 17.6 GHz范围内实现了-10 dB的吸收带宽，并通过三层电磁谐振蜂窝引入了三个深吸收峰。克服了传统纳米有损复合材料的倾斜吸收退化问题，实现了从30°到85°的斜入射宽带吸收。结构力学性能高，最大等效抗拉强度为108.6 MPa，最大弯曲荷载为0.873 kN。结果表明，材料-结构-功能一体化的结构隐身对宽带微波吸收元结构设计的重要性，为实现宽带微波吸收提供了一条有前途的途径。来源：复合材料力学仿真Composites FEM