今日更新:International Journal of Solids and Structures 2 篇,International Journal of Plasticity 2 篇,Thin-Walled Structures 9 篇
Self-excited fluctuation of sliding velocity induced by LuGre friction in a minimal mechanical model
Balazs J. Bekesi, Gabor Csernak
doi:10.1016/j.ijsolstr.2025.113293
最小力学模型中LuGre摩擦引起的滑动速度自激波动
The paper explores various bifurcations that can occur due to the variation of the linear internal damping (bristle damping) term in the LuGre friction model. To capture the essence of the nonlinear effects associated with friction, we consider a minimal mechanical model: a block sliding on a horizontal surface, which is subjected to a constant external force and the LuGre friction force with a viscous damping term. Despite the simplicity of the mechanical model, six different bifurcation scenarios are identified, involving Hopf bifurcations. Due to the emerging limit cycles – that may undergo fold or homoclinic bifurcations, as well – the slipping velocity and the friction force fluctuate near the Stribeck characteristic at sufficiently large bristle damping values. This phenomenon can be considered as a self-excited counterpart of the well-known frictional lag phenomenon.
本文探讨了由于LuGre摩擦模型中线性内阻尼(鬃毛阻尼)项的变化而可能发生的各种分岔。为了捕捉与摩擦相关的非线性效应的本质,我们考虑了一个最小力学模型:在水平表面上滑动的块,它受到恒定的外力和带有粘性阻尼项的LuGre摩擦力。尽管力学模型很简单,但我们确定了六种不同的分岔情况,包括Hopf分岔。由于出现了极限环——也可能发生褶皱或同斜分叉——在足够大的刚毛阻尼值下,滑移速度和摩擦力在Stribeck特性附近波动。这种现象可以看作是众所周知的摩擦滞后现象的自激对应。
The determination of interfacial strength in Al/SiC long fibre composites
Luke J. Rollings, Samuel A. McDonald, M.J. Roy, Philip J. Withers
doi:10.1016/j.ijsolstr.2025.113335
Al/SiC长纤维复合材料界面强度的测定
The interfacial properties have been measured for a novel AA6061/SiC-C coated silicon carbide SM3256 monofilamentary fibre (Al/SiC f ) MMC with a variant of the single fibre test. In this test, fibre fragmentation is followed in situ using synchrotron X-ray diffraction to probe the axial fibre elastic strains as a function of applied loading, while X-ray radiography is used to follow the fracture sequence. In this way, the variation in axial fibre stress along the fibre is tracked and hence the variation in interfacial shear stress along the fibre inferred at stages of fibre fragmentation. Prior to loading, the fibre was in a state of axial compression ( ≈ 280 MPa) due to thermal residual stresses representative of cooling from 200 °C. During the fragmentation process, the variations in axial strain and interfacial stress show characteristic “stick–slip” behaviour, where the fibre interface must exceed a threshold stress ( τ deb = 94 ± 10 MPa), close to the shear strength of the matrix before debonding. Once debonded, the fibre slides at a frictional shear stress, τ fr , initially of around 40 MPa, but falling with increased sliding distance to around τ fr = 15 ± 5 MPa. Radiography taken during loading, and post-mortem, indicates that interfacial failure occurs at the fibre-coating interface, leaving coating material lining the pull-out within the matrix. The accumulation of coating damage may be responsible for the progressive decrease in sliding stress with increased sliding. These sliding stresses, are much lower than observed for comparable Ti/SiC composites, and would facilitate significant fibre-pull-out and fibre bridging under fatigue conditions.
采用单纤维测试的方法,对新型AA6061/SiC- c涂层碳化硅SM3256单丝纤维(Al/SiC f) MMC的界面性能进行了测试。在本试验中,使用同步加速器x射线衍射原位跟踪纤维断裂,探测纤维轴向弹性应变作为施加载荷的函数,同时使用x射线照相跟踪断裂顺序。这样,沿纤维轴向应力的变化被跟踪,从而在纤维碎裂阶段推断沿纤维界面剪切应力的变化。在加载之前,由于来自200°C冷却的热残余应力,纤维处于轴向压缩状态(≈280 MPa)。在破碎过程中,轴向应变和界面应力的变化表现出典型的“粘滑”行为,其中纤维界面必须超过阈值应力(τ deb = 94±10 MPa),接近基体的抗剪强度。一旦脱粘,纤维在摩擦剪切应力τ fr下滑动,最初约为40 MPa,但随着滑动距离的增加而下降,约为τ fr = 15±5 MPa。加载过程中拍摄的x射线照片和事后分析显示,纤维涂层界面发生了界面破坏,导致涂层材料衬里在基体内被拉出。涂层损伤的累积可能是导致滑动应力随滑动量的增加而逐渐减小的原因。这些滑动应力远低于同类Ti/SiC复合材料,并将促进疲劳条件下显著的纤维拉出和纤维桥接。
Strain Gradient-induced Size Effect of Nickel-Titanium Shape Memory Alloys
Jae-Hoon Choi, Hyemin Ryu, Ji-Young Kim, Kwang-Hyeok Lim, Gi-Dong Sim
doi:10.1016/j.ijplas.2025.104309
应变梯度诱导的镍钛形状记忆合金尺寸效应
This study investigates size effect in nickel-titanium (NiTi) shape memory alloys (SMAs), focusing on their elastic deformation and phase transformation behaviors. A series of experiments, including bulk-scale tension tests, micro-scale tension, compression, and cantilever bending tests, were conducted to observe the effect of specimen dimensions on SMA behavior. Micro-scale tension and compression tests unveiled a notable asymmetry in the stress-induced phase transformation, irrespective of specimen dimensions. Moreover, micro-cantilever bending tests, spanning a thickness range from 1.9 to 21.0 μm, revealed a significant increase in both the effective elastic modulus and phase transformation stress as the beam thickness decreased. A constitutive model has been developed to address the tension/compression asymmetry and size effect based on couple stress theory, and implemented in finite element analysis of beam structures. Finally, experimental results were compared with simulation outcomes, and the deformation mechanisms responsible for the size effect were discussed. The growing prominence of SMAs in micro/nano-scale applications highlights the necessity of understanding and accounting for size effects. Therefore, developing the capability to measure and simulate size effects is crucial for ensuring the effective utilization of SMAs in these scales.
本研究对镍钛(NiTi)形状记忆合金(SMA)的尺寸效应进行了探究,重点关注其弹性变形和相变行为。开展了一系列实验,包括宏观拉伸试验、微观拉伸、压缩和悬臂弯曲试验,以观察试样尺寸对形状记忆合金行为的影响。微观拉伸和压缩试验揭示了应力诱导相变的显著不对称性,且不受试样尺寸的影响。此外,厚度范围在 1.9 至 21.0 微米的微悬臂弯曲试验表明,随着梁厚的减小,有效弹性模量和相变应力均显著增加。基于偶应力理论,开发了一个能解决拉伸/压缩不对称性和尺寸效应的本构模型,并将其应用于梁结构的有限元分析。最后,将实验结果与模拟结果进行了比较,并讨论了导致尺寸效应的变形机制。形状记忆合金在微/纳米级应用中的日益突出地位凸显了理解并考虑尺寸效应的必要性。因此,开发测量和模拟尺寸效应的能力对于确保形状记忆合金在这些尺度上的有效利用至关重要。
A texture-dependent yield criterion based on Support Vector Classification
Jan Schmidt, Surya R. Kalidindi, Alexander Hartmaier
doi:10.1016/j.ijplas.2025.104311
基于支持向量分类的纹理相关屈服准则
Conventional yield criteria for anisotropic plasticity rely on linear transformations of the stress tensor to map the directional dependence of critical stress tensors at yield onset onto a unit sphere in stress space. These linear transformations are made material specific by a number of anisotropic parameters, which need to be determined by experimental procedures for each material. One drawback of this approach is that these anisotropic parameters cannot be explicitly expressed as functions of the crystallographic texture. Hence, any change in the texture of a material, as it occurs during cold deformation, requires a complete re-parametrization of the yield function. In this work, we present a data-oriented yield criterion based on Support Vector Classification (SVC) that is an explicit function of the crystallographic texture. This texture-dependency is achieved by including the coefficients of the general spherical harmonics (GSH) series expansion of the orientation distribution function (ODF) to the feature space of the machine learning model. The capabilities of the proposed yield criterion are demonstrated by training the model on a dataset containing micromechanical data from over 8000 distinct cubic-orthorhombic textures. The trained SVC combines the efficiency of classical phenomenological models with the flexibility of elaborate CP models. It provides a path to efficient hierarchical materials modeling as the anisotropy of the macroscopic yield onset is explicitly linked to the crystallographic texture.
传统的各向异性塑性屈服准则依赖于应力张量的线性变换,将屈服开始时临界应力张量的方向依赖性映射到应力空间的单位球上。这些线性变换是由许多各向异性参数决定的,这些参数需要通过每种材料的实验程序来确定。这种方法的一个缺点是,这些各向异性参数不能明确地表示为晶体织构的函数。因此,在冷变形过程中发生的材料织构的任何变化,都需要对屈服函数进行完全的重新参数化。在这项工作中,我们提出了一个基于支持向量分类(SVC)的面向数据的屈服标准,该标准是晶体织构的显式函数。这种纹理依赖性是通过将方向分布函数(ODF)的一般球面谐波(GSH)级数展开的系数包含到机器学习模型的特征空间中来实现的。它为有效的分层材料建模提供了一条途径,因为宏观屈服开始的各向异性与晶体织构明确地联系在一起。
Testing, simulation and design of built-up cold-formed steel-lightweight concrete (CFS-LWC) composite beams subjected to elevated temperatures
Rohola Rahnavard, Hélder D. Craveiro, Rui A. Simões, Luís Laím, Aldina Santiago, Leroy Gardner
doi:10.1016/j.tws.2025.113212
高温下冷弯钢-轻量混凝土(CFS-LWC)组合梁的试验、模拟和设计
Cold-formed steel (CFS) products are lightweight, structurally efficient and highly versatile, making them suitable for a wide range of construction applications. Although studies have been performed to analyse the flexural behaviour of CFS composite beams at room temperature, their performance at elevated temperatures has yet to be investigated; this is, therefore, the focus of the present study. Through experiments, the structural fire performance of innovative built-up CFS-lightweight concrete (LWC) composite beams is examined. Two full-scale fire tests on simply-supported CFS-LWC composite beams are presented. The test setup, test procedure and obtained results, including the temperature evolution, fire resistance time and failure modes, are described. A numerical modelling study is also presented through which additional insights into the observed structural behaviour are gained. Comparisons between the experimental results and those determined according to EN 1994-1-2 design provision are presented. The results showed that, despite the studied CFS-LWC composite sections being beyond the scope of the code, good predictions of fire resistance were obtained.
冷弯型钢(CFS)产品重量轻,结构高效,用途广泛,适用于各种建筑应用。虽然已经进行了研究来分析CFS复合梁在室温下的弯曲行为,但它们在高温下的性能尚未进行研究;因此,这是本研究的重点。通过试验,研究了新型组合梁的结构防火性能。介绍了两种简支CFS-LWC组合梁的全尺寸火灾试验。介绍了试验装置、试验步骤和试验结果,包括温度演变、耐火时间和失效模式。数值模拟研究也提出了通过观察到的结构行为获得额外的见解。并将试验结果与en1994 -1-2设计规定的结果进行了比较。结果表明,尽管所研究的CFS-LWC复合材料截面超出了规范的范围,但获得了较好的耐火性预测。
Tensile and shear performance of detachable tapered-head bolt inter-module connection of steel modular structure
Anling Zhang, Jiadi Liu, Zhihua Chen
doi:10.1016/j.tws.2025.113228
钢组合结构可拆卸锥头螺栓模间连接的抗拉剪切性能
The connections between modular units significantly impact the construction speed and load-bearing capacity of modular steel structures. However, most existing inter-module connections struggle to meet the installation requirements at central connections, often necessitating openings in the module columns, walls, or floor slabs to provide installation space. This leads to internal redecoration after the connections have been installed, reducing construction efficiency and increasing costs. The detachable tapered-head bolt connection is a new type of connection that enables rapid installation and removal of central connection in modular buildings. In this paper, the tensile and shear performance of the connection under static loading is investigated, and the failure mode, bearing capacity and load-displacement response of the connection are investigated. The results indicate that the tensile failure mode of the connection includes the pull-out of the tapered-head bolt or the fracture of weld seam of the upper corner base plate. The shear failure mode is characterized by the shearing of the bolt and bearing-yield failure in the upper corner base plate. It is obtained that the thickness of the upper corner base plate and side plate as well as the diameter of the tapered-head bolt are the key design parameters of the connection. It is recommended that the thickness of the side plate should not be greater than that of the baseplate, otherwise the material strength of the side plate will not be fully utilized and the economy of the connection design will be reduced. Furthermore, the simplified analytical model of tensile resistance of the connection is established, and the calculation formula for the tensile capacity of the connection is developed. Additionally, the study confirms that the shear capacity of the connection can be calculated using the method outlined in GB50017-2017. These research results provide a reliable design basis and reference for the engineering application of detachable tapered-head bolt inter-module connection.
模块化单元之间的连接方式对钢结构的施工速度和承载能力有重要影响。然而,大多数现有的模块间连接难以满足中央连接的安装要求,通常需要在模块柱、墙壁或楼板上开开口来提供安装空间。这导致在连接安装后进行内部重新装修,降低了施工效率并增加了成本。可拆卸锥形头螺栓连接是一种新型的连接方式,可以在模块化建筑中快速安装和拆卸中心连接。本文研究了静荷载作用下连接的拉剪性能,并对连接的破坏模式、承载能力和荷载-位移响应进行了研究。结果表明,接头的拉伸破坏形式包括锥头螺栓的拔出或上角底板焊缝的断裂。剪切破坏模式主要表现为锚杆的剪切和上部角底板的受力破坏。得出了上角底板和侧板的厚度以及锥头螺栓的直径是连接的关键设计参数。建议侧板的厚度不应大于底板的厚度,否则将不能充分利用侧板的材料强度,降低连接设计的经济性。建立了连接抗拉能力的简化解析模型,推导了连接抗拉能力的计算公式。此外,研究还证实了采用GB50017-2017中概述的方法计算节点抗剪承载力。研究结果为可拆卸锥头螺栓模块间连接的工程应用提供了可靠的设计依据和参考。
Defects in double-sided incremental forming of woven fabric prepreg: experimental and numerical analysis
Peng Xu, Xiaoqiang Li, XiaoBing Li, Yi Wang, Weizhao Zhang, Hongrui Dong, Quan Zhi
doi:10.1016/j.tws.2025.113229
机织物预浸料双面增量成形缺陷:实验与数值分析
Forming processes of fiber reinforced polymers have been widely investigated for decades, driven by the need for lightweight, high-performance components in industries such as aerospace and automotive. However, the traditional forming techniques for composites often depend on the use of dies, which can be expensive and time-consuming to produce, resulting in increased overall manufacturing costs and extended production timelines, particularly for small batch production and prototype manufacturing. In this study, a die-less forming method, namely double-sided incremental forming (DSIF), was firstly investigated for the forming of woven fabric prepregs. Key manufacturing parameters, including the auxiliary dummy sheets (material, thickness and combinations) and tool diameters as well as their influence on forming quality, were systematically investigated. The mechanisms underlying the formation of macroscopic defects, such as wrinkling and fabric breakage, were analyzed through both experimental and numerical approaches. Results showed that dummy sheet selection and tool diameter significantly impact the prepreg forming quality in DSIF and defect-free parts can be obtained through optimized parameters. Specially, the combination of a hard upper dummy sheet and soft lower dummy sheet helped mitigate deformation discrepancies between the sheets and reduced prepreg wrinkling, while larger tool diameters minimized yarn failure by alleviating the high local contact pressures on the prepreg. The study can provide insights for future research and highlights the potential of DSIF for industrial applications, enabling more efficient small batch production and prototype manufacturing of complex composite parts.
几十年来,由于航空航天和汽车等行业对轻质、高性能部件的需求,纤维增强聚合物的成型工艺得到了广泛的研究。然而,复合材料的传统成型技术通常依赖于模具的使用,这可能是昂贵和耗时的生产,导致整体制造成本增加和生产时间延长,特别是小批量生产和原型制造。本文首次研究了机织物预浸料的无模成形方法,即双面增量成形(DSIF)。系统研究了辅助假人板(材料、厚度、组合)、刀具直径等关键制造参数对成形质量的影响。通过实验和数值方法分析了起皱和织物断裂等宏观缺陷的形成机制。结果表明,虚拟板的选择和刀具直径对DSIF预浸成形质量有显著影响,通过优化参数可以获得无缺陷零件。特别是,硬的上假人片和软的下假人片的组合有助于减轻片间的变形差异,减少预浸料起皱,而更大的工具直径通过减轻预浸料的高局部接触压力来最大限度地减少纱线故障。该研究可以为未来的研究提供见解,并突出DSIF在工业应用中的潜力,实现更高效的小批量生产和复杂复合材料零件的原型制造。
Mechanical Properties of a Novel Mechanical Metamaterial with Multi-stable and Mono-stable Characteristics
Min Sun, Zhiwei Qiu, Qiang Chen, Hongshuai Lei, Xia Hua, Zheng Zhang, Yi Song, Shaofei Jiang, Diyong Huang, Haonan Fu
doi:10.1016/j.tws.2025.113230
一种具有多稳定和单稳定特性的新型机械超材料的力学性能
This study designed a novel mechanical metamaterial with multi-stable and mono-stable characteristics, fabricated using carbon fiber composite through a hot-pressing process. The mechanical properties of the designed mechanical metamaterial were obtained through quasi-static compression tests, and the effects of structural geometric parameters on its mechanical performance were analyzed. The finite element model of the mechanical metamaterial was established, and the comparison between the simulation and experiment results showed good agreement. A torque test platform was constructed to measure the torque for transitions between the multi-stable and mono-stable characteristics. The results indicate that transitioning from mono-stable to multi-stable characteristics requires a higher torque than transitioning from multi-stable to mono-stable characteristics. The designed mechanical metamaterial has both multi-stable and mono-stable characteristics, which have potential for a wide range of applications in the field of impact energy absorption as well as vibration attenuation.
本研究设计了一种具有多稳定和单稳定特性的新型机械超材料,采用碳纤维复合材料热压工艺制备。通过准静态压缩试验获得了所设计的力学超材料的力学性能,并分析了结构几何参数对其力学性能的影响。建立了机械超材料的有限元模型,仿真结果与实验结果吻合较好。搭建了转矩测试平台,用于测量多稳特性和单稳特性转换时的转矩。结果表明,从单稳定过渡到多稳定比从多稳定过渡到单稳定需要更高的转矩。所设计的机械超材料具有多稳定和单稳定两种特性,在冲击能量吸收和振动衰减领域具有广泛的应用潜力。
Experimental Study of Non-reinforced Thin-walled Concrete-filled Double Skin Steel Tubular Bridge Columns with Socket Connection
Jiang Yi, Fuxiang Zhu, Wenjing Xu
doi:10.1016/j.tws.2025.113231
无筋薄壁双皮钢管混凝土承插连接桥柱试验研究
A novel non-reinforced thin-walled concrete-filled double skin steel tubular (NRTW-CFDST) structure with a socket connection is proposed for bridge columns. The advantages of this column include the absence of reinforcement, elimination of formwork installation and removal, and ease of customization, making it ideal for the rapid construction of short-line bridge piers with individualized size and height. Through experiments and finite element simulation analysis, the bending capacity and seismic performance of connection joints are investigated, and design recommendations for the novel column are provided. Experimental results indicate that the failure mode of the column is characterized by concrete crushing due to bending at the plastic hinge, and the full hysteresis curves indicate its good seismic performance. Importantly, the joints remained undamaged, demonstrating a significant reserve of bending capacity. For optimal performance, it is recommended to use a socket depth of 1.0 D to 1.2 D (D is the column section width) and a 6 mm thick base end plate. This configuration ensures adequate bending stiffness of the pier structure and a reasonable failure location at the plastic hinge.
提出了一种新型无钢筋薄壁双皮钢管混凝土承插连接结构。该柱的优点包括无需加固,无需安装和拆卸模板,易于定制,非常适合快速建造具有个性化尺寸和高度的短线桥墩。通过试验和有限元模拟分析,对连接节点的抗弯能力和抗震性能进行了研究,提出了新型柱的设计建议。试验结果表明,该柱的破坏模式为塑性铰处弯曲导致混凝土破碎,其全滞回曲线表明其具有良好的抗震性能。重要的是,接头保持完好无损,显示出弯曲能力的显著储备。建议插座深度为1.0 D ~ 1.2 D (D为柱截面宽度),底座端板厚度为6mm,以获得最佳性能。这种结构保证了桥墩结构有足够的抗弯刚度和合理的塑性铰失效位置。
Nonlinear response of high-strength cold-formed steel built-up members subject to cyclic compression
Shin Rui Kho, Adeline LingYing Ng, Daniel TingWee Looi, Hieng-Ho Lau, Emad Gad, Krishanu Roy
doi:10.1016/j.tws.2025.113233
循环压缩作用下高强度冷弯型钢组合构件的非线性响应
Cold-formed steel (CFS) built-up sections have attracted attention for their enhanced strength and stability over single channels. While previous research has focused on the axial behaviour of CFS built-up sections under monotonic compression, studies on their cyclic performance are limited. Cyclic actions can affect the material properties and potentially cause early failure, making it crucial to understand the cyclic behaviours of CFS built-up sections. This research examined the cyclic responses of G550 high-strength CFS built-up compression members through experimental and numerical investigations. Different built-up sections, such as open-lipped built-up sections (OL series) and closed-unlipped built-up sections (CU series), composed of various section sizes and screw spacings, were studied. These proposed parameters assessed the influence of the member slenderness and section slenderness on the CFS built-up sections with thin-walled profiles. The results demonstrated that the cyclic actions have little influence on the structural performance of the CFS built-up sections at the pre-peak stage. At the post-peak stage, a faster degradation in strength and stiffness was observed for specimens with greater member slenderness and section slenderness. Moreover, the increase in section slenderness leads to higher axial ductility for the CU series but minimal influence on the OL series. Furthermore, a greater member slenderness leads to smaller energy dissipation capacity, especially for the specimens with smaller section slenderness. The OL series is recommended to be designed as a strength-control element that provides structural stability and integrity, such as primary columns. In contrast, the CU series can be used as the sacrificial element to dissipate energy, such as lateral bracing in the framing system, to minimise the risk of catastrophic collapse subject to extreme loadings such as typhoons or earthquakes.
冷弯型钢(CFS)组合型钢因其比单道型钢具有更高的强度和稳定性而备受关注。虽然以往的研究主要集中在CFS组合截面在单调压缩下的轴向行为,但对其循环性能的研究有限。循环作用会影响材料性能,并可能导致早期破坏,因此了解CFS组合截面的循环行为至关重要。本文通过试验和数值研究对G550高强CFS组合受压构件的循环响应进行了研究。研究了不同截面尺寸和螺杆间距组成的不同组合段,如开唇形组合段(OL系列)和闭非唇形组合段(CU系列)。所提出的参数评估了构件长细和截面长细对薄壁型CFS组合截面的影响。结果表明,在峰值前阶段,循环作用对CFS堆砌截面的结构性能影响不大。峰后阶段,构件长细比和截面长细比越大,试件的强度和刚度退化越快。此外,截面长细比的增加导致CU系列的轴向延性提高,但对OL系列的影响最小。构件长细比越大,耗能能力越小,截面长细比越小的试件耗能能力越小。OL系列建议设计为强度控制元件,提供结构稳定性和完整性,如主柱。相比之下,CU系列可以用作消耗能量的牺牲元件,例如框架系统中的横向支撑,以最大限度地减少在台风或地震等极端载荷下发生灾难性倒塌的风险。
Seismic Performance of Damaged Steel-Concrete Shear Wall with Prestressed Diagonal Bracing Repaired by CFRP Strips
Jian-Gui Qin, Jie Tian, Yi-Xin Mai, Kai Qian, Xiao-Fang Deng
doi:10.1016/j.tws.2025.113234
CFRP条修复预应力斜撑钢-混凝土剪力墙的抗震性能
To investigate the seismic performance of damaged steel-concrete shear wall with prestressed diagonal bracing repaired by Carbon Fiber Reinforced Polymer (CFRP) strips. Three steel-concrete shear walls with diagonal bracing seriously damaged by low reversed cyclic loading were repaired by replacing damaged concrete, repairing diagonal bracing, restoring buckled reinforcements, and wrapping walls with CFRP strips. The seismic performance of the repaired specimens was evaluated using the same quasi-static test as for the original specimens. The seismic performance including the failure modes, deformation capacity, bearing capacity, energy dissipation, stiffness degradation, and bearing capacity degradation of the repaired specimens were researched in the study. Experimental results show that the used repair schemes effectively restore specimens’ bearing capacity, ductility, and energy dissipation, as well as enhancing deformation capacity. Applying an "X"-shaped CFRP repair scheme which aligned with the direction of the bracing can effectively compensates for the reductions of stiffness and bearing capacity due to cyclic loading. Compared to shear wall with smooth steel tubes as diagonal bracing, those with threaded reinforcements create a stronger mechanical interlocking effect between the bracing and concrete. This enhanced synergy interaction increases the effective shear resistance section in the midsection of the wall panel, thereby forming a more efficient diagonal load transfer mechanism. Therefore, shear damage can be avoided in the middle of the wall limb. Additionally, the study presents the theoretical calculation model for the original and the repaired shear walls, and the comparison of the calculation results with test results demonstrates that the calculation model has high computational accuracy.
研究碳纤维增强聚合物(CFRP)条修复损伤钢-混凝土斜撑剪力墙的抗震性能。采用更换破损混凝土、修复斜撑、恢复屈曲钢筋、CFRP条包墙等方法修复低反循环荷载严重破坏的3面钢-混凝土斜撑剪力墙。修复后试件的抗震性能采用与原试件相同的准静力试验进行评估。对修复试件的破坏模式、变形能力、承载力、耗能、刚度退化和承载力退化等抗震性能进行了研究。试验结果表明,所采用的修复方案能有效地恢复试件的承载力、延性和耗能,提高试件的变形能力。采用与支撑方向一致的“X”形CFRP修复方案,可以有效补偿循环加载造成的刚度和承载能力的降低。与光滑钢管作为斜支撑的剪力墙相比,螺纹加固的剪力墙在支撑和混凝土之间产生了更强的机械联锁效应。这种增强的协同作用增加了墙板中部的有效抗剪截面,从而形成更有效的斜向荷载传递机制。因此,可以避免墙肢中部的剪切破坏。建立了原剪力墙和修复后剪力墙的理论计算模型,并将计算结果与试验结果进行了比较,表明该计算模型具有较高的计算精度。
Data orbits similarity conversion law of scaled-down model tests of ship structures under strong impact loads
Xiongliang Yao, Renjie Huang, Kun Zhao, Yongran Yin
doi:10.1016/j.tws.2025.113235
强冲击载荷下船舶结构缩比模型试验数据轨道相似转换规律
The model test under strong impact loads constitutes a transient, strongly nonlinear, and non-stationary physical process that exhibits extreme sensitivity to system parameters, boundary conditions, and initial conditions. A minor perturbation induces bifurcation and abrupt changes in system dynamics, resulting in output uncertainty for model tests and significant challenges in achieving similarity conversion between models and prototypes. In this paper, the second law of similarity is applied to construct data orbits of impact responses for characterizing kinematic system evolution, and a principle of topologically conjugate conversion for similar systems in phase space is proposed. Through phase space reconstruction methodology, the kinematic evolution patterns of acceleration responses in ship structures under strong impact loads are investigated, with mapping functions of acceleration response data orbits derived in phase space. A similarity equation for model-to-prototype conversion is established based on the topologically conjugate conversion principle. Theoretical analysis demonstrates the rationality of introducing prediction coefficients in distortion models, while fundamental conditions for achieving similarity conversion in nonlinear dynamical systems are formulated. Finally, the numerical results from the single-layer reinforced plate rack and cabin section show that the data orbits corresponding to the acceleration responses of the 1:2 scaled model and the prototype have the same symbol sequences in the phase space under satisfying the similarity conversion condition, which verifies the correctness of the similarity conversion of data orbits for the scaling model test of the ship structures under the strong impact loads.
强冲击载荷下的模型试验是一个瞬态的、强非线性的、非平稳的物理过程,对系统参数、边界条件和初始条件表现出极大的敏感性。一个微小的扰动就会引起系统动力学的分叉和突变,从而导致模型测试的输出不确定,并且在实现模型和原型之间的相似性转换方面面临重大挑战。本文利用相似第二定律构造碰撞响应的数据轨道来表征运动系统的演化,并提出了相空间相似系统的拓扑共轭转换原理。采用相空间重构方法,研究了船舶结构在强冲击载荷作用下加速度响应的运动演化规律,推导了加速度响应数据轨道在相空间中的映射函数。基于拓扑共轭转换原理,建立了模型到原型转换的相似方程。理论分析证明了在畸变模型中引入预测系数的合理性,给出了非线性动力系统实现相似转换的基本条件。最后,对单层加筋板架和舱室截面的数值计算结果表明,在满足相似转换条件下,1:2比例模型和原型的加速度响应对应的数据轨道在相空间具有相同的符号序列,验证了数据轨道相似转换用于船舶结构在强冲击载荷下的比例模型试验的正确性。
Nonlinear buckling and post-buckling of multilayered piezoelectric graded porous circular nanoplates considering of surface/interface effects
Qinglu Li, Xiaojie Niu, Zhaoyi Pan, Jinghua Zhang
doi:10.1016/j.tws.2025.113236
考虑表面/界面效应的多层压电梯度多孔圆形纳米板的非线性屈曲和后屈曲
The special characteristics of surfaces and interfaces significantly influence the durability and performance of materials. For the first time, this article introduces surface and interface effects into Kirchhoff thin plate theory to study the buckling and nonlinear post-buckling behavior of multilayer piezoelectric porous nanostructures. The bulk structure is a graded porous material and pores are embedded in the plate in two cosine forms of non-uniform porosity distribution with a pair of piezoelectric layers surface bonded on both sides of the bulk surface. Then, classical plate theory, combined with minimum potential energy principle, is utilized to derive the post-buckling governing equation coupling the piezoelectric effect. A shooting method is presented to obtain the buckling and post-buckling numerical solutions. The numerical results obtained reveal that the surface and interface effects, along with the applied potential, significantly influence the stability of multilayer piezoelectric graded porous circular nanoplates to varying extents.
表面和界面的特殊特性对材料的耐久性和性能有重要影响。本文首次将表面和界面效应引入Kirchhoff薄板理论,研究了多层压电多孔纳米结构的屈曲和非线性后屈曲行为。块体结构为梯度多孔材料,孔隙以非均匀孔隙分布的两种余弦形式嵌入板中,块体表面两侧表面粘接一对压电层。然后,利用经典板理论,结合最小势能原理,推导出耦合压电效应的后屈曲控制方程。提出了一种求解屈曲和后屈曲数值解的射击方法。数值结果表明,表面和界面效应以及外加电位对多层压电梯度多孔圆形纳米板的稳定性有不同程度的显著影响。