International Journal of Mechanical Sciences最新文献

Nonlinear dynamic behavior of a rotor-bearing system considering time-varying misalignment 考虑时变偏心的转子轴承系统的非线性动态行为

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2024-10-11 DOI: 10.1016/j.ijmecsci.2024.109772

The dynamic response of rotating systems supported by hydrodynamic bearings considering the journal deformation-induced misalignment has been investigated in recent years. However, most of the previous work studied misaligned angles as fixed configurations, ignoring the variation of misalignment due to the time-varying journal deformation. In this study, a numerical method is proposed to predict the dynamic response of a rotor-bearing system considering time-dependent misalignment. As journal deformation is recognized as a significant factor leading to misalignment, a flexible rotor is considered to determine the misalignment state. The finite element method is employed to calculate the dynamic deformation of the rotor and, hereby, the misaligned angles and film thickness. Subsequently, the pressure distributions of the oil film are calculated using the finite difference method to update the bearing force. The transient lubrication performance and the vibration response of the rotor are discussed based on the numerical computation. In particular, the difference in the oil whip phenomenon is compared between the aligned and misaligned conditions. The results show that the journal orientation varies with time considering the journal deflection. The discussion about the oil whip shows that the misalignment has a significant impact on the stability of the system. In addition, the transient lubrication properties are considerably influenced by the rotation speed and external loading since they affect the magnitude of the resonance vibration and the oil whip.

近年来，考虑到轴颈变形引起的不对中，对流体动力轴承支撑的旋转系统的动态响应进行了研究。然而，之前的大部分研究都是将不对中角作为固定配置进行研究，忽略了轴颈变形随时间变化引起的不对中变化。本研究提出了一种数值方法，用于预测转子轴承系统在考虑随时间变化的不对中情况下的动态响应。由于轴颈变形被认为是导致不对中的重要因素，因此考虑采用柔性转子来确定不对中状态。采用有限元法计算转子的动态变形，并据此计算错位角度和薄膜厚度。随后，使用有限差分法计算油膜的压力分布，以更新轴承力。根据数值计算结果，讨论了转子的瞬态润滑性能和振动响应。特别是比较了对准和错位条件下油鞭现象的差异。结果表明，考虑到轴颈挠度，轴颈方向随时间变化。对油鞭现象的讨论表明，不对中对系统的稳定性有重大影响。此外，瞬态润滑特性受转速和外部负载的影响很大，因为它们会影响共振振动和油鞭的大小。

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引用次数: 0

Energy absorption of the kirigami-inspired pyramid foldcore sandwich structures under low-velocity impact 受桐木启发的金字塔折叠芯夹层结构在低速冲击下的能量吸收

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2024-10-09 DOI: 10.1016/j.ijmecsci.2024.109774

Foldcore sandwich structures offer a promising alternative to conventional honeycomb sandwiches in the field of lightweight structures, demonstrating significant potential as efficient energy absorption devices. The dynamic behavior of foldcore sandwich structures is crucial in response to low-velocity impacts in various engineering scenarios such as bird strikes, airdrops, and vehicle collisions. This study investigates the dynamic responses of a kirigami-inspired pyramid foldcore sandwich subjected to low-velocity impacts, which has previously exhibited remarkable energy absorption efficiency under quasi-static compression. Through a combination of experimental investigations and numerical simulations under impact conditions, it is observed that the pyramid foldcore initially undergoes pronounced localized deformation which results in a sensitivity to the loading rate and causes the high initial peak stress. Different from the mechanism observed under quasi-static compression, additional stationary plastic hinges on the facets are triggered during the post-buckling stage, thereby slightly enhancing the overall energy absorption. Moreover, the multi-layer pyramid foldcores with graded geometries are proposed, characterized by varying height and wall thickness for each layer. The graded pyramid foldcores significantly reduce the initial peak stress while maintaining energy absorption efficiency. In comparison with the conventional square honeycomb and Miura-ori foldcore under the impact velocity of 10 m/s, the uniformity ratio of the graded pyramid foldcore decreases by 70.9 % and 80.5 %, while the specific energy absorption improves by 0.97 % and 138.37 %, respectively. To summarize, the graded pyramid foldcore shows outstanding energy absorption efficiency, indicating its potential as a high-performance sandwich structure for impact applications.

在轻质结构领域，折芯夹层结构为传统蜂窝夹层结构提供了一种前景广阔的替代品，显示出作为高效能量吸收装置的巨大潜力。在鸟击、空投和车辆碰撞等各种工程场景中，折叠芯夹层结构在应对低速冲击时的动态行为至关重要。本研究探讨了受桐木启发的金字塔折叠芯夹层结构在受到低速冲击时的动态响应。通过结合冲击条件下的实验研究和数值模拟，可以观察到金字塔折叠芯最初会发生明显的局部变形，这导致了对加载速率的敏感性，并造成了较高的初始峰值应力。与在准静态压缩条件下观察到的机理不同，在折叠后阶段，面上的额外静止塑性铰链被触发，从而略微增强了整体能量吸收。此外，还提出了具有分级几何形状的多层金字塔折叠结构，其特点是每层的高度和壁厚各不相同。分级金字塔折叠结构在保持能量吸收效率的同时，显著降低了初始峰值应力。在 10 米/秒的冲击速度下，与传统的方形蜂窝和三浦织折芯相比，分级金字塔折芯的均匀度比分别降低了 70.9 % 和 80.5 %，而比能量吸收分别提高了 0.97 % 和 138.37 %。总之，分级金字塔折叠芯材显示出卓越的能量吸收效率，表明其具有作为冲击应用领域高性能夹层结构的潜力。

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引用次数: 0

Modeling the coupled bubble-arc-droplet evolution in underwater flux-cored arc welding 水下药芯焊丝电弧焊中气泡-电弧-液滴耦合演变建模

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2024-10-09 DOI: 10.1016/j.ijmecsci.2024.109754

For the numerical simulation of underwater wet flux-cored arc welding, the most crucial issue is to investigate the intense interactions between the underwater bubble, arc plasma, and molten metal. However, it is a great challenge to couple them into a single numerical model. In this study, a 3D three-phase flow model is originally established, which successfully couples the dynamic bubble, arc, and droplet. A modified Lee model is employed to realize spontaneous phase transition from liquid water to bubble gas. According to the simulation results, the bubble evolution is divided into four main stages, and two bubble separation modes are recognized. It is found that, both the changing pressure field around the bubble and the varying flow direction of surrounding water contribute to the unique bubble evolution patterns. As for the droplet, its violent up-and-down oscillation at the wire tip is mainly caused by the opposite gas drag forces, which are produced by the turbulent gas flow inside the bubbles. The upward gas drag force can even make the neck of the droplet disappear. With different droplet detaching angles, two predominant droplet transfer modes are numerically produced; when the angle reaches 147°, the droplet is pushed away and becomes a spatter. Furthermore, the underwater arc is found to be subjected to compressions from both the radial direction due to bubble necking and the axial direction due to droplet growth. The arc temperature and velocity vary significantly not only during the whole droplet transfer period, but also within each bubble evolution cycle. To verify the reliability of the model, underwater welding experiments and visual sensing are conducted. The simulated results match well with the experimental ones, with an 8% error in the droplet transfer period and only a 1.4% error in the bubble evolution cycle.

对于水下湿药芯电弧焊的数值模拟，最关键的问题是研究水下气泡、电弧等离子体和熔融金属之间的强烈相互作用。然而，将它们耦合到一个单一的数值模型中是一个巨大的挑战。本研究最初建立了三维三相流模型，成功地将动态气泡、电弧和熔滴耦合在一起。采用改进的 Lee 模型实现了从液态水到气泡气体的自发相变。根据模拟结果，气泡演化分为四个主要阶段，并确认了两种气泡分离模式。研究发现，气泡周围压力场的变化和周围水流方向的变化都促成了独特的气泡演化模式。至于液滴，其在金属丝顶端的剧烈上下摆动主要是由气泡内部湍流气体产生的相反气体阻力造成的。向上的气体阻力甚至可以使液滴的颈部消失。在不同的液滴分离角度下，数值上产生了两种主要的液滴转移模式；当角度达到 147°时，液滴被推开，变成飞溅物。此外，还发现水下电弧受到来自径向和轴向的挤压，径向挤压的原因是气泡缩颈，轴向挤压的原因是液滴增长。电弧的温度和速度不仅在整个液滴传输期间变化很大，而且在每个气泡演化周期内变化也很大。为了验证模型的可靠性，进行了水下焊接实验和视觉感应。模拟结果与实验结果非常吻合，在液滴传输期间误差为 8%，而在气泡演化周期中误差仅为 1.4%。

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引用次数: 0

A GAN-based stepwise full-field mechanical prediction model for architected metamaterials 基于 GAN 的结构超材料逐步全场力学预测模型

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2024-10-08 DOI: 10.1016/j.ijmecsci.2024.109771

The exploration of mechanical metamaterials, characterized by unique unit cells with significant macroscopic mechanical properties, is of crucial importance. Traditional methods relying on bioinspired structures lack broad design space and controllability to some extent, especially when practical requirements have no biological counterparts. Hence, there is a pressing need to advance methodologies for the expansive design of unit cells, catering to diverse practical demands. Inspired by architected material, a latent design paradigm gains prominence for its extensive possibilities and unique distribution. However, wide design space faces challenges in accurately assessing the deformation history and stress states of diverse units, requiring validation through experiments or simulations, and imposing efficiency constraints on design. Using patterns generated by a mimetic corrosion algorithm and computational simulations, a GAN-based machine learning surrogate model is constructed to predict the history of deformation and stress fields of architected unit cells with accuracy and efficiency, in which a stepwise mapping strategy is proposed to augment comprehension of mechanical information in image processing. In distinct cases covering both explored domains and several unexplored domains, the model achieves effective predictions, demonstrating the robustness and adaptability of the model in extrapolating predictions of both time domain and design space. The proposed method demonstrates efficacy, stability, and generalizability, pioneering a solution for the mechanical history prediction of architected metamaterials in a sparse data setting, thereby overcoming the limitations of the training set.

机械超材料的特征是具有显著宏观机械特性的独特单元，探索这种材料至关重要。依赖生物启发结构的传统方法在一定程度上缺乏广阔的设计空间和可控性，尤其是在实际需求没有生物对应物的情况下。因此，迫切需要推进单元单元的扩展设计方法，以满足不同的实际需求。受建筑材料的启发，潜在设计范式因其广泛的可能性和独特的分布而备受瞩目。然而，宽广的设计空间在准确评估不同单元的变形历史和应力状态方面面临挑战，需要通过实验或模拟进行验证，并对设计施加效率限制。利用模仿腐蚀算法和计算模拟生成的模式，构建了基于 GAN 的机器学习代理模型，以准确高效地预测建筑单元的变形历史和应力场，其中提出了逐步映射策略，以增强图像处理中对机械信息的理解。在涵盖已探索领域和若干未探索领域的不同案例中，该模型实现了有效预测，证明了该模型在推断时域和设计空间预测方面的稳健性和适应性。所提出的方法证明了其有效性、稳定性和通用性，开创了在稀疏数据环境中预测架构超材料力学历史的解决方案，从而克服了训练集的局限性。

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引用次数: 0

Backward motion suppression in space-constrained piezoelectric pipeline robots 空间受限压电管道机器人的后向运动抑制

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2024-10-05 DOI: 10.1016/j.ijmecsci.2024.109746

In response to the current challenges of detecting micro pipelines, a micro pipeline robot based on the principle of piezoelectric inertia stick-slip drive was proposed in this paper, which can be effectively applied to the detection and maintenance of micro pipelines. However, during the analysis of the robot's displacement trajectory, it was observed that using inertial drive could cause the backward motion of the robot. This may adversely affect the accuracy and stability of the robot's operation within the micro pipelines. Therefore, a novel control method is derived from the original pipeline robot structure. By affixing piezoelectric sheets to the driving feet of the robot to adjust their deformation and subsequently employing collaborative control of piezoelectric sheets and piezoelectric stacks to regulate friction between the driving feet and the pipe wall, the backward motion of the robot was effectively mitigated. Compared to existing backward motion suppression methods, the approach proposed in this paper has a minimal impact on the actuator's size, allowing for flexible adaptation to various space-constrained applications, while also offering the advantage of a simple control strategy. After determining the structure and working principle, deformation analysis of the driving foot and dynamic simulation analysis of the driving system were conducted. These analyses provide insights into the relationship between mechanical and electrical parameters and output performance within the driving system, thereby validating the feasibility of the control method. Subsequently, a prototype was fabricated, and its output performance was tested. Results demonstrate that this control method can effectively suppress inertial backward motion, achieving a suppression rate close to 100 %. This research presents a novel idea and methodology for mitigating the backward motion of piezoelectric inertial stick-slip actuators with driving foot structures.

针对当前微型管道检测面临的挑战，本文提出了一种基于压电惯性粘滑驱动原理的微型管道机器人，可有效应用于微型管道的检测和维护。然而，在对机器人位移轨迹进行分析时发现，使用惯性驱动会导致机器人向后运动。这可能会对机器人在微型管道内运行的精度和稳定性造成不利影响。因此，在原有管道机器人结构的基础上衍生出一种新的控制方法。通过在机器人的驱动脚上粘贴压电片来调节其变形，然后利用压电片和压电叠层的协同控制来调节驱动脚与管壁之间的摩擦，从而有效地减缓了机器人的后退运动。与现有的后向运动抑制方法相比，本文提出的方法对致动器的尺寸影响极小，可灵活适应各种空间受限的应用，同时还具有控制策略简单的优势。在确定了结构和工作原理后，对驱动脚进行了变形分析，并对驱动系统进行了动态模拟分析。这些分析深入揭示了驱动系统内机械和电气参数与输出性能之间的关系，从而验证了控制方法的可行性。随后，制作了一个原型，并对其输出性能进行了测试。结果表明，这种控制方法能有效抑制惯性后退运动，抑制率接近 100%。本研究提出了一种新颖的思路和方法，用于减轻具有驱动脚结构的压电惯性粘滑致动器的后向运动。

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引用次数: 0

Mechanical performance and prediction of a novel reinforced octagonal honeycomb 新型强化八角蜂窝的机械性能和预测

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2024-10-05 DOI: 10.1016/j.ijmecsci.2024.109758

Honeycomb structures are widely used in various engineering applications due to their lightweight and excellent energy absorption capabilities. Materials with two plateau stress regions exhibit unique advantages in multi-stage energy dissipation and multi-task applications. This paper presents a reinforced octagonal honeycomb structure (ROHC) inspired by the topology of an octagonal tensegrity structures. The paper demonstrates the phenomenon of two plateau deformation stages through the 3D printing of ROHC specimens and finite element simulation. By adjusting three geometric parameters of ROHC (angle α, length ratio r, and thickness t of internal reinforcement), the paper obtains the influence laws on the first and second plateau stress and strain, and proves the controllability of two-stage mechanical performance of ROHC. Based on deep learning technology, a performance prediction model for ROHC's two-stage mechanical performance is proposed, with the MSE and R values confirming the accuracy of the prediction model. Based on the prediction model, a rapid reverse design method is proposed, capable of designing structures with expected two-stage mechanical performance, with errors <7.25 %. The proposed honeycomb structure with predictable and reversible design has significant research value in fields with multi-stage energy absorption and crash protection requirements.

蜂窝结构因其轻质和出色的能量吸收能力而被广泛应用于各种工程领域。具有两个高原应力区的材料在多级能量消耗和多任务应用方面具有独特的优势。本文介绍了一种受八角形张弦结构拓扑学启发的增强八角形蜂窝结构（ROHC）。本文通过三维打印 ROHC 试样和有限元模拟，展示了两个高原变形阶段的现象。通过调整 ROHC 的三个几何参数（角度 α、长度比 r 和内加强筋厚度 t），论文得到了第一和第二高原应力和应变的影响规律，证明了 ROHC 两阶段力学性能的可控性。基于深度学习技术，提出了 ROHC 两阶段力学性能预测模型，其 MSE 值和 R 值证实了预测模型的准确性。基于预测模型，提出了一种快速逆向设计方法，能够设计出具有预期两阶段力学性能的结构，误差<7.25 %。所提出的具有可预测性和可逆设计的蜂窝结构在具有多级能量吸收和碰撞保护要求的领域具有重要的研究价值。

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引用次数: 0

Influence of weft yarn distribution on 3D woven composites under impact loading 冲击载荷下纬纱分布对三维编织复合材料的影响

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2024-10-05 DOI: 10.1016/j.ijmecsci.2024.109762

This paper provides new insights into the impact resistance of 3D woven composites from a weft yarn distribution perspective. Two 3D through-thickness angle interlock (3D ATT) woven composites with aligned and misaligned weft yarn distributions were prepared for investigation. And a macro-meso combination model based on a bottom-up multi-scale framework was constructed to elucidate the damage evolution and dynamic response mechanisms of the composites during impact. The results show that the misaligned structure has superior impact resistance, more dispersed damage distribution, and less permanent damage at similar area density. The synergistic effect of finely dispersed resin pockets and misaligned yarns helped to retard the damage evolution, thereby improving the performance. The multi-scale simulation framework proved to be an effective tool for analyzing the mechanical properties of 3D woven composites, with misaligned weft yarns playing a critical role in stress and damage distribution. This research will aid in the design and application of 3D woven composites in impact resistant fields such as bird impact, ballistic impact, and explosions.

本文从纬纱分布的角度为三维编织复合材料的抗冲击性提供了新的见解。本文制备了两种纬纱分布对齐和错位的三维通厚角联锁（3D ATT）编织复合材料进行研究。并构建了一个基于自下而上多尺度框架的宏观-微观组合模型，以阐明复合材料在冲击过程中的损伤演变和动态响应机制。结果表明，错位结构具有更优越的抗冲击性能、更分散的损伤分布以及在相似面积密度下更小的永久损伤。精细分散的树脂袋和错位纱线的协同效应有助于延缓损伤演变，从而提高性能。事实证明，多尺度模拟框架是分析三维编织复合材料机械性能的有效工具，其中错位纬纱在应力和损伤分布中起着关键作用。这项研究将有助于三维编织复合材料在抗冲击领域的设计和应用，如鸟类撞击、弹道撞击和爆炸。

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引用次数: 0

On the thermo-visco-elastic behaviour of neat and aged PPS composites 纯 PPS 复合材料和老化 PPS 复合材料的热粘弹性行为

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2024-10-04 DOI: 10.1016/j.ijmecsci.2024.109761

Reinforced PPS thermoplastics exposed to variations in temperature and humidity are subject to aging and interface degradation. These phenomena can lead to ruptures due to the interphase weakening. In this study, a micromechanical model based on the equivalent inclusion model is implemented using the viscoelastic behaviours of the neat and aged grades identified by spectrometric analyses. The presented coated inclusion model allows to extract the viscoelastic behavior of the interphase in the dry-as-molded composite and in the aged composite by inverse method conducted for viscoelastic behavior. The presence of the interphase testifies to the degradation of the thermomechanical properties in the vicinity of the reinforcements. In the aged composite, the interphase also undergoes an aging phenomenon. Thus, the model compares the behavior of the interphase in the dry-as-molded and aged grades of the composite and separates the effects linked to the degradation of adhesion of the fibers from the effects linked to specific hydroscopic aging.

增强型 PPS 热塑性塑料在温度和湿度变化的环境中会出现老化和界面降解现象。这些现象会导致相间削弱而发生断裂。在本研究中，利用光谱分析确定的未老化和老化牌号的粘弹性行为，建立了基于等效包覆模型的微观力学模型。所提出的涂层夹杂物模型可以通过粘弹性行为反演法提取干模复合材料和老化复合材料中夹杂物的粘弹性行为。夹层的存在证明了增强材料附近的热力学特性发生了退化。在老化的复合材料中，中间相也会出现老化现象。因此，该模型比较了干模和老化等级的复合材料中夹层的行为，并将与纤维粘附性退化相关的影响与特定水镜老化相关的影响区分开来。

引用次数: 0

Shear Band Formation with Split Hopkinson Bar Experiments 利用分体式霍普金森棒实验形成剪切带

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2024-10-04 DOI: 10.1016/j.ijmecsci.2024.109749

The essence of dynamic failure is closely linked to dramatic shear deformations which often lead to the formation of adiabatic shear bands (ASB). Under high loading velocities and the subsequent rapid temperature increase, the localization of shear strain is crucial in view of safety issues of systems in mechanical and aircraft engineering, especially with respect to fast rotating components and diverse crash scenarios. In this research, we perform high speed impact tests at the split Hopkinson pressure bar (SHPB) setup and use particular hat-shaped specimen geometries that resemble the stresses and failure conditions at the component level.

In the first step, we specify a notched specimen geometry using finite element (FE) simulations to ensure pure shear. Further, quasi-static compressive tests and a series of impact tests at high strain rates of

1 0^{3} - 1 0^{4} s^{- 1}

are conducted on specimens manufactured from a fine-grain structural steel with the properties of S355. Optical microscopy and electron backscatter diffraction (EBSD) of the sheared zones unveil significant localization to maximal shear strains of about 0.9 accompanied by grain refinement by factors 5 to 14. The displacements across the surface of the specimens are captured with subset-based local digital image correlation (DIC) during the impact time, and serve as an objective to validate a viscoplastic constitutive relationship. More precisely, the deformation distribution is accurately reproduced by the widely recognized Johnson-Cook (JC) model, which features an enhanced description of damage evolution. Thus, combining experimental and characterization techniques, continuum mechanics and reasonable optimization strategies for the identification of model parameters provides an efficient approach for comprehensive insights into the strain localization behaviour and its impact on the mechanical performance of S355 under extreme strain rates and deformations.

动态失效的本质与剧烈的剪切变形密切相关，而剧烈的剪切变形往往会导致绝热剪切带（ASB）的形成。在高加载速度和随后的快速升温条件下，剪切应变的定位对机械和飞机工程系统的安全问题至关重要，特别是在快速旋转部件和各种碰撞情况下。在这项研究中，我们在分体式霍普金森压力棒（SHPB）装置上进行了高速冲击试验，并使用了特殊的帽形试样几何形状，这些试样几何形状与部件层面的应力和失效条件相似。第一步，我们使用有限元（FE）模拟来指定凹槽试样几何形状，以确保纯剪切力。此外，我们还在具有 S355 性能的细晶粒结构钢制成的试样上进行了准静态压缩试验和一系列 103-104s-1 高应变率冲击试验。剪切区的光学显微镜和电子反向散射衍射（EBSD）揭示了最大剪切应变约为 0.9 的显著局部化，同时伴随着 5 至 14 倍的晶粒细化。在冲击过程中，利用基于子集的局部数字图像相关性（DIC）捕获了试样表面的位移，并以此为目标验证了粘塑性构成关系。更准确地说，变形分布是由广受认可的约翰逊-库克（JC）模型精确再现的，该模型增强了对损伤演变的描述。因此，结合实验和表征技术、连续介质力学和合理的优化策略来确定模型参数，是全面了解 S355 在极端应变速率和变形条件下的应变局部化行为及其对机械性能影响的有效方法。

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引用次数: 0

Transformative elastic metamaterials: Temperature-induced passband-to-bandgap conversion 变革性弹性超材料：温度诱导的通带-带隙转换

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2024-10-04 DOI: 10.1016/j.ijmecsci.2024.109767

Elastic metamaterials favor the wide bandgap generation, but their formation mechanisms impose certain constraints on the achievable locations and widths. To overcome this limitation, this study proposes an innovative method that optimizes specific passbands and subsequently transforms them into bandgaps through an external stimulus. As an illustration, two meta-beams with different third passbands are optimized. In addition, to examine the formation and transformation mechanisms of the optimized passbands, this study develops several meta-beam models, incorporating force neutralizers, moment neutralizers, and their hybrid combinations, which are modally equivalent to the optimized unit cells. Samples for the two optimized meta-beams are fabricated using a three-dimensional printing technique. The experimental measurements are conducted at both room temperature and elevated temperatures, and the results confirm that when the temperature increases to approximately 60 °C, the optimized third passbands transform into bandgaps. Furthermore, repeated thermal loading cycles substantiate the reversibility of this transformation, demonstrating a promising application potential of the proposed method to tunable broadband meta-beam designs.

弹性超材料有利于产生宽带隙，但其形成机制对可实现的位置和宽度有一定的限制。为了克服这一限制，本研究提出了一种创新方法，即优化特定通带，然后通过外部刺激将其转化为带隙。举例来说，两个元波束的第三通带不同，但都得到了优化。此外，为了研究优化通带的形成和转化机制，本研究开发了几种元梁模型，包括力中和器、力矩中和器及其混合组合，它们在模态上与优化单元等效。两个优化元梁的样品是用三维打印技术制作的。实验测量在室温和高温下进行，结果证实，当温度升高到约 60 ℃ 时，优化的第三通带会转化为带隙。此外，反复的热加载循环证实了这种转变的可逆性，证明了所提出的方法在可调谐宽带元光束设计中具有广阔的应用前景。

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引用次数: 0