【新文速递】2023年9月24日固体力学SCI期刊最新文章

Thin-Walled Structures

Analysis of force generated in composite egg-box structures during draping as a function of draping angle

Che Jia-le, Chang Seung-Hwan

doi:10.1016/j.tws.2023.111224

悬垂过程中复合蛋盒结构产生的力与悬垂角度的函数关系分析

To closely investigate the correlation between the structural shape and forces generated along yarns, draping simulation was performed using a non-orthogonal constitutive equation programmed by a VUMAT code and a composite lay-up model considering the draping angle (0°, 15°, 30°, 45°) and the actual thickness of the prepregs. Force generation at seven representative points (RP) along the two major axes (sidewall and saddle) of the unit cell structure was studied during draping. Representative deformations, including wrinkle generation, of the fabric prepregs during draping were correlated to the generated forces. To estimate the onset of wrinkle generation of the draped structure for any draping angle cases, the distortion energy which was calculated using the yarn force and shear angle of a simple square FE model was used. Moreover, draping experiments were conducted to verify the deformation characteristics estimated by finite element analysis.

为了仔细研究结构形状与沿纱线产生的力之间的相关性，使用由 VUMAT 代码编程的非正交构成方程和复合铺层模型（考虑了铺层角度（0°、15°、30°、45°）和预浸料的实际厚度）进行了悬垂模拟。在悬垂过程中，研究了沿单元格结构的两个主轴（侧壁和鞍部）的七个代表性点 (RP) 的力的产生情况。织物预浸料在悬垂过程中的代表性变形（包括皱纹的产生）与产生的力相关联。为了估算任何悬垂角度情况下悬垂结构皱纹产生的起始时间，使用了通过简单方形 FE 模型的纱线力和剪切角计算出的变形能量。此外，还进行了悬垂实验来验证有限元分析估计的变形特性。

Buckling simulation of eccentrically rotating nanocomposite sector plates in thermal environment using the 2D Chebyshev collocation method

Huang Yong, Peng Shengguang, Habibi Mohammad, Moradi Zohre

doi:10.1016/j.tws.2023.111203

利用二维切比雪夫配位法模拟热环境中偏心旋转纳米复合材料扇形板的屈曲模拟

The present paper investigates the inertial stability of a graphene platelet (GPL) reinforced nanocomposite sector plate eccentrically rotating with a constant angular velocity. The axis of spinning is perpendicular to the plate and parallel to the transverse direction of origin. It is considered at a distance and angle to the plate coordinate origin. A uniform thermal environment is considered that affects the plate response. The nanocomposite is regarded as a laminated plate in which the GPLs in each layer are orientated and dispersed equally and randomly. The volume fraction of particles varies from layer to layer based on functionally graded (FG) linear models suitable for studying the buckling phenomenon. The pre-buckling and stability paths are separated by utilizing the adjacent equilibrium criterion. Both paths are solved by implementing the Chebyshev Collocation (CC) technique. The consequences of geometrical parameters, nanocomposite characteristics, and eccentric angle and distance on the stability of the current system are investigated. It will be revealed that the eccentric distance, according to its angle, can significantly increase or decrease the critical speed of the fabrication.

本文研究了以恒定角速度偏心旋转的石墨烯微粒（GPL）增强纳米复合材料扇形板的惯性稳定性。旋转轴垂直于板，平行于原点的横向方向。旋转轴与板坐标原点的距离和角度被考虑在内。考虑了影响板响应的均匀热环境。纳米复合材料被视为层压板，每层中的 GPL 均等且随机地定向和分散。根据适合研究屈曲现象的功能分级（FG）线性模型，各层颗粒的体积分数各不相同。利用相邻平衡准则将预屈曲路径和稳定路径分开。这两条路径都是通过切比雪夫定位（CC）技术求解的。研究了几何参数、纳米复合材料特性、偏心角和偏心距对当前系统稳定性的影响。结果表明，偏心距（根据其角度）可显著提高或降低 制造的临界速度。

Strength Prediction of Built-up Radially Battened Columns in Torsional Buckling

Sun Hao-Jun, Wen Chen-Bao, Zhu Bo-Li, Guo Yan-Lin, Duan Jin-Song, Liu Zhen-Guo, Zhao Qiang

doi:10.1016/j.tws.2023.111205

扭转屈曲中内置径向压筋柱的强度预测

The built-up radially battened column (RBC) has found its promising application in public buildings due to its aesthetical form and good load-bearing capacity. Like the X-shaped column, torsional buckling may be the major failure mode of the RBC under axial compression. However, current specifications lack rational design methods for the torsional buckling strength prediction of this innovative column. This paper will focus on the torsional buckling behaviour of the RBC and propose its corresponding strength design formulas. At first, the key sectional properties of the radially continuous-web tube columns (RCTC) are derived theoretically and are proven to be consistent with the numerical calculation result. Then, a finite element model (FEM) using the shell element of RCTC is established, accordingly, the elastic torsional buckling behaviour of RCTCs is investigated, and an expression for accurately estimating the elastic torsional buckling load of RCTCs is proposed. Afterward, the FEM of built-up RBCs is established to conduct the elastic buckling analysis and elastoplastic bearing capacity prediction. The elastic torsional buckling load of built-up RBCs is predicted by modifying the expression for RCTCs via the number of battens and the proportion of the area of battens. A key design parameter, the normalized slenderness ratio, is also obtained. Finally, the strength design recommendation of the RBCs for torsional buckling is presented on the ground of numerous elastoplastic FEM results by changing the normalized slenderness ratio, and a limit RBCs’ dimension that can prevent the built-up RBC from the torsion buckling is further proposed. These results are expected to guide the design of the RBC and promote its application in engineering.

内置径向压缝柱（RBC）因其美观的外形和良好的承载能力，在公共建筑中有着广阔的应用前景。与 X 型柱一样，扭转屈曲可能是 RBC 在轴向压缩下的主要失效模式。然而，目前的规范缺乏合理的设计方法来预测这种创新柱子的扭转屈曲强度。本文将重点研究 RBC 的扭转屈曲行为，并提出相应的强度设计公式。首先，从理论上推导出径向连续波纹管柱（RCTC）的关键截面特性，并证明其与数值计算结果一致。然后，利用 RCTC 的壳单元建立了有限元模型（FEM），并据此研究了 RCTC 的弹性扭转屈曲行为，提出了精确估算 RCTC 弹性扭转屈曲载荷的表达式。随后，建立了内置 RBC 的有限元模型，以进行弹性屈曲分析和弹塑性承载力预测。通过修改 RCTC 的表达式，即通过压条数量和压条面积比例，来预测加固型 RBC 的弹性扭转屈曲载荷。此外，还获得了一个关键的设计参数，即归一化细长比。最后，在大量弹塑性有限元计算结果的基础上，通过改变归一化细长比，提出了 RBC 扭转屈曲的强度设计建议，并进一步提出了可防止已建 RBC 扭转屈曲的 RBC 限制尺寸。这些结果有望指导 RBC 的设计并促进其在工程中的应用。

Uncertain Vibration Characteristics of Bi-directional Functionally Graded Sandwich Nanoplate subjected to Dynamic Load

Pham Quoc-Hoa, Tran Trung Thanh, Nguyen Phu-Cuong

doi:10.1016/j.tws.2023.111206

承受动态载荷的双向功能分级三明治纳米板的不确定振动特性

In this paper, we present a novel approach that combines isogeometric analysis (IGA) with the higher-order shear deformation theory (HSDT) and Monte Carlo simulation (MCS). Our objective is to investigate uncertain vibration characteristics of bi-functionally graded sandwich (BFGSW) nanoplates under dynamic loading. The small-scale effect observed in nanostructures is achieved by employing the nonlocal elasticity theory. This theory allows for the consideration of the mechanical behavior that arises at the nanoscale level. Within the stochastic design approach, the state function for design conditions is commonly formulated by incorporating input random variables, assumed distribution functions, and the random responses obtained from computational models. This work primarily focuses on investigating vibrational characteristics of BFGSW nanoplates when the model parameters are considered as random quantities. The obtained results show that distribution characteristics of vibration of the BFGSW nanoplate depend significantly on the standard deviation of input parameters.

在本文中，我们提出了一种结合等距分析（IGA）、高阶剪切变形理论（HSDT）和蒙特卡罗模拟（MCS）的新方法。我们的目标是研究双功能分级夹层（BFGSW）纳米板在动态加载下的不确定振动特性。在纳米结构中观察到的小尺度效应是通过采用非局部弹性理论实现的。该理论允许考虑在纳米尺度上产生的机械行为。在随机设计方法中，设计条件的状态函数通常是通过输入随机变量、假定分布函数以及从计算模型中获得的随机响应来制定的。本研究主要侧重于研究将模型参数视为随机量时 BFGSW 纳米板的振动特性。研究结果表明，BFGSW 纳米板的振动分布特性与输入参数的标准偏差有很大关系。

Confinement-based direct design method for fibre reinforced polymer confined CFST short columns

Hassanein M.F., Hamed Asmaa Y., Cashell K.A., Shao Yong-Bo

doi:10.1016/j.tws.2023.111207

基于约束的纤维增强聚合物约束 CFST 短柱直接设计方法

The paper presents a detailed analysis of the behaviour of circular and square concrete filled steel tube (CFST) short columns strengthened externally with carbon or glass fibre reinforced polymer sheets (CFRP or GFRP, respectively). A thorough review of existing test information is presented and discussed, and the most salient parameters in terms of the overall strength are identified. There are a large number of influential and inter-related parameters which affect the load-carrying capacity, including the geometry, cross-sectional shape, type of steel, concrete strength, boundary and loading conditions, and type of FRP. It is shown that existing design approaches do not reliably predict the strength for the full range of possible parameters. Therefore, this paper proposes a new design model to calculate the axial compressive strength of FRP-confined concrete filled steel tubular (CFST) short columns with either a circular or square cross-section. The method accounts for the various complexities which affect the behaviour, yet presents a user-friendly, performance-based design expression. It is based on an evaluation of the lateral confining pressure provided by the both the FRP and the steel tube to the concrete core. This is employed in the confinement-based direct resistance calculations. The paper validates the approach by comparing its capacity predictions with a large database of experimental results and alternative design models available in the literature. The results show that the proposed model provides much accurate strength predictions with greater reliability for the full range of parameters examined, than existing methods.

本文详细分析了用碳纤维或玻璃纤维增强聚合物板（分别为 CFRP 或 GFRP）进行外部加固的圆形和方形混凝土填充钢管（CFST）短柱的行为。报告对现有测试信息进行了全面回顾和讨论，并确定了整体强度方面最突出的参数。对承载能力有影响且相互关联的参数很多，包括几何形状、截面形状、钢材类型、混凝土强度、边界和加载条件以及玻璃纤维增强塑料的类型。结果表明，现有的设计方法无法可靠地预测所有可能参数的强度。因此，本文提出了一种新的设计模型，用于计算圆形或方形截面的 FRP 密实混凝土填充钢管（CFST）短柱的轴向抗压强度。该方法考虑到了影响行为的各种复杂性，并提出了一种用户友好、基于性能的设计表达式。它基于对 FRP 和钢管为混凝土核心提供的侧向约束压力的评估。在基于约束的直接阻力计算中采用了这种方法。本文通过将该方法的承载力预测结果与大型数据库中的实验结果和文献中的替代设计模型进行比较，验证了该方法的有效性。结果表明，与现有方法相比，所提出的模型能提供更准确的强度预测，并且在所考察的全部参数范围内具有更高的可靠性。

Experimental study on seismic behavior of cover-plate connections between steel beams and high strength steel box columns

Jiang Sheng, Shi Gang, Zhang Naizhou, Zhao Huatian, Sun Teng

doi:10.1016/j.tws.2023.111208

钢梁与高强度箱形钢柱之间盖板连接的抗震性能试验研究

As one of the beam-to-column fully restrained connections that could shift the plastic hinges of the beam away from the face of the column, cover-plate reinforced connections are expected to be a practical choice for high strength steel frame seismic applications. Five cover-plate reinforced and one unreinforced welded flange-bolted web connection specimens combined with Q355 steel I-shaped beams and Q460 or Q690 steel box columns were designed according to Chinese codes and tested under cyclic loads at full scale. Failure modes, including local buckling of the beam, complete joint penetration (CJP) weld fracture, and column web fracture, were reported. The strength, stiffness, deformation, and energy dissipation features were analyzed. The four cover-plate connections met the AISC requirements for special moment frames (SMF) with maximum story drift angles greater than 0.06 rad and exhibited satisfactory seismic behavior. According to the test results, a limit on the ratio of the diaphragm plate to column plate thickness should be considered when the electroslag welding (ESW) process is used in high strength box columns. The strong panel zone designed with a panel zone resistance ratio (γpz) greater than 1.20 was recommended for box columns with steel strength no less than 690 MPa. Additionally, other design implications of the results were discussed.

盖板加固连接作为梁与柱之间的全约束连接之一，可使梁的塑性铰远离柱面，因此有望成为高强度钢框架抗震应用中的实用选择。根据中国规范设计了五个盖板加固和一个未加固的焊接翼缘-螺栓腹板连接试件，这些试件与 Q355 钢工字梁和 Q460 或 Q690 钢箱形柱组合在一起，并在循环荷载下进行了全尺寸测试。报告了包括梁的局部屈曲、完全焊透（CJP）焊缝断裂和柱腹板断裂在内的破坏模式。分析了强度、刚度、变形和耗能特征。四个盖板连接符合 AISC 对最大楼层漂移角大于 0.06 rad 的特殊力矩框架 (SMF) 的要求，并表现出令人满意的抗震性能。根据测试结果，在高强度箱形柱中使用电渣焊（ESW）工艺时，应考虑隔墙板与柱板厚度比的限制。设计的强板区的板区阻力比 (γpz) 大于 1.20 的强板区建议用于钢强度不小于 690 兆帕的箱形柱。此外，还讨论了结果对其他设计的影响。

Test and design of built-up cold-formed steel-lightweight concrete (CFS-LWC) composite beams

Rahnavard Rohola, Craveiro Hélder D., Simões Rui A., Laím Luís, Santiago Aldina

doi:10.1016/j.tws.2023.111211

内置冷弯型钢-轻质混凝土（CFS-LWC）组合梁的试验和设计

Cold-formed steel (CFS) products are extremely versatile and can be used in multiple applications. To further extend their applicability, this investigation assesses the structural behaviour of innovative built-up CFS-lightweight concrete (LWC) composite beams through experimental testing and numerical modelling. First, four full-scale CFS-LWC simply supported composite beams were tested. The specimens included two distinct configurations of the innovative CFS built-up composite beams. The tested CFS-LWC composite beams comprised a lightweight concrete slab supported by profiled metal decking, connected to a CFS built-up beam using bolted shear studs. Following EN 1994-1-1, the degree of shear connection attained in the specimens ranged from 21% to 57%. The test procedure, setup, and collected results are described in detail, including load-bearing capacity, deformation, flexural stiffness, and failure modes. Numerical simulations and calibration against the experimental data were then performed, and the CFS-LWC composite beams with different degrees of shear connections were investigated using the calibrated finite element model. The validity of the available design code for the innovative CFS-LWC composite beams was assessed by comparing experimental findings and analytical predictions using EN1994-1-1 (equilibrium and simplified methods) and AISC 360 methodologies. The results showed that the maximum bending resistance of the composite beam obtained from the equilibrium method of EN 1994-1-1 and AISC 360 was unconservative due to the overprediction of shear resistance for the bolted shear connectors. Consequently, a calibrated finite element modelling technique determined the bolted shear connectors’ shear resistance. Finally, the bending resistance design prediction of CFS-LWC composite beams following EN1994-1-1 and AISC 360 methodologies, incorporating the shear connector resistance obtained from simulations, was compared with experimental and numerical results from the parametric study. An excellent agreement was observed between experimental and numerical results with the design predictions according to EN 1994-1-1.

冷弯型钢（CFS）产品用途极为广泛，可用于多种应用领域。为了进一步扩大其应用范围，本研究通过实验测试和数值建模，评估了创新的内置 CFS-轻质混凝土（LWC）复合梁的结构行为。首先，对四根全尺寸 CFS-LWC 简支复合梁进行了测试。试样包括两种不同结构的创新 CFS 内置复合梁。测试的 CFS-LWC 复合梁由轻质混凝土板和异型金属装饰板组成，轻质混凝土板通过螺栓剪力螺柱与 CFS 内置梁连接。根据 EN 1994-1-1，试样达到的剪力连接程度从 21% 到 57% 不等。详细介绍了试验程序、设置和收集的结果，包括承载能力、变形、抗弯刚度和破坏模式。然后根据实验数据进行了数值模拟和校准，并使用校准后的有限元模型对不同剪切连接程度的 CFS-LWC 复合梁进行了研究。通过比较实验结果和使用 EN1994-1-1（平衡和简化方法）和 AISC 360 方法进行的分析预测，评估了创新 CFS-LWC 复合梁可用设计规范的有效性。结果表明，由于对螺栓剪力连接件的剪切阻力预测过高，EN 1994-1-1 和 AISC 360 的平衡法得出的复合梁最大弯曲阻力是不严谨的。因此，采用校准有限元建模技术确定了螺栓剪力连接件的抗剪性。最后，根据 EN1994-1-1 和 AISC 360 方法对 CFS-LWC 复合梁进行了抗弯设计预测，并将模拟获得的剪力连接件阻力与参数研究的实验和数值结果进行了比较。实验结果和数值结果与 EN 1994-1-1 的设计预测结果非常吻合。

Fire and post-fire performance of blind-bolted concrete-filled steel tubular joints with restrained steel beams: Experiment and simulation

Song Tian-Yi, Zhu Di, Zhou Hongyuan, Xiang Kai, Chen Zheng

doi:10.1016/j.tws.2023.111212

带约束钢梁的盲栓混凝土填充钢管连接的火灾和火灾后性能：实验与模拟

Blind-bolted connection is a type of new developed prefabricated beam-column connection, which can be used to connect the concrete filled steel tubular (CFST) columns and the steel beams easily. The static and dynamic performance of CFST column to steel beam joints with blind-bolted connections have been well explored, but limited research has been conducted to investigate the fire and post-fire performance of this type of composite joint. In this paper, a series of reversed T-shaped joint fire tests were conducted to investigate the fire and post-fire performance of blind-bolted CFST joints with axially restrained steel beams. The influence of restrained effect from adjacent members in the entire frame structure on the response of blind-bolted joints in and after fire could be reasonably considered by the reversed T-shaped joint fire test. The joint temperature, failure modes, beam and column displacements and temperature internal force development during the entire loading and fire stage were recorded and discussed. The test results indicated that the blind-bolted connections showed very good working performance in and after fire, and no bolt shank fracture or bolt pull-out failure was observed. Finite element analysis (FEA) models were established to simulate the fire and post-fire performance of blind-bolted CFST T-shaped joints with axially restrained steel beams, and the joint moment versus relative rotation angle relationship curves of the blind-bolted joints during the entire fire and loading process were extracted and discussed based on the FEA models. The results indicated that the joint negative moment generated by the axially restrained beam boundary in the heating and cooling phases could go up to around 1.4 times the joint negative moment at ambient temperature.

盲孔螺栓连接是一种新开发的预制梁柱连接方式，可用于方便地连接混凝土填充钢管（CFST）柱和钢梁。采用盲孔螺栓连接的 CFST 柱与钢梁连接的静态和动态性能已经得到了很好的探讨，但对这种复合连接的火灾和火灾后性能的研究还很有限。本文进行了一系列反向 T 形接头火灾试验，以研究盲螺栓连接 CFST 接头与轴向约束钢梁的火灾和火灾后性能。通过反向 T 型连接防火试验，可以合理地考虑整个框架结构中相邻构件的约束效应对盲栓连接在火灾中和火灾后响应的影响。试验记录并讨论了整个加载和火灾阶段的接头温度、破坏模式、梁柱位移和温度内力发展。试验结果表明，盲螺栓连接在火灾中和火灾后均表现出良好的工作性能，未发现螺栓柄断裂或螺栓拉出失效。建立了有限元分析（FEA）模型来模拟带有轴向约束钢梁的 CFST T 型盲栓塞接头的火灾和火灾后性能，并根据有限元分析模型提取和讨论了盲栓塞接头在整个火灾和加载过程中的接头力矩与相对旋转角的关系曲线。结果表明，轴向约束梁边界在加热和冷却阶段产生的接头负弯矩可达环境温度下接头负弯矩的 1.4 倍左右。

Effect of cell size and wall thickness on the compression performance of triply periodic minimal surface based AlSi10Mg lattice structures

Mishra Ashish Kumar, Chavan Hrushikesh, Kumar Arvind

doi:10.1016/j.tws.2023.111214

晶胞尺寸和壁厚对基于 AlSi10Mg 晶格结构的三重周期性最小表面的压缩性能的影响

Triply periodic minimal surface (TPMS) are mathematical surfaces with zero mean curvature and are spatially invariant. Recently, these surfaces are investigated for potential application in the manufacturing of cellular materials or lattice structures for a variety of purposes. However, designing such structures is a difficult task as the dedicated design platforms impose higher costs. Therefore, in this study, lattice structures have been designed using an in-house developed opensource tool for different cell sizes and cell wall thicknesses. The lattice structures have been additively manufactured through laser powder bed fusion (LPBF) and their design compliance and manufacturing defects have been investigated through optical micrography and SEM. The lattice structures have been subjected to quasistatic uniaxial compression test in as-manufactured and heat-treated conditions and the resulting compressive stress-strain curves have been analyzed in detail to draw a relationship between the two varying quantities and the mechanical properties of the lattice structure. The results show that there has been small but visible differences between the as-designed and as-manufactured lattice structures. The mechanical properties of lattice structures deteriorated with increasing cell size at constant wall thickness and improved with increasing cell wall thickness at constant unit cell size. The heat treatment procedures homogenized and increased plastic deformation while decreasing the strength and modulus values. Overall the study outlined a significant effect of cell geometry, size, and cell wall thickness on the mechanical properties of the TPMS lattice structures.

三周期极小曲面（TPMS）是平均曲率为零且空间不变的数学曲面。最近，这些表面被研究用于制造蜂窝材料或晶格结构的潜在用途。然而，设计此类结构是一项艰巨的任务，因为专用设计平台的成本较高。因此，在本研究中，我们使用内部开发的开源工具，针对不同的细胞尺寸和细胞壁厚度设计了晶格结构。晶格结构是通过激光粉末床熔融（LPBF）快速制造的，并通过光学显微摄影和扫描电镜对其设计合规性和制造缺陷进行了研究。在制造状态和热处理状态下，对晶格结构进行了等静态单轴压缩试验，并详细分析了由此产生的压缩应力-应变曲线，以得出这两个变化量与晶格结构机械性能之间的关系。结果表明，设计和制造的晶格结构之间存在微小但明显的差异。在壁厚不变的情况下，晶格结构的机械性能随着晶胞尺寸的增加而降低，而在单位晶胞尺寸不变的情况下，随着晶胞壁厚的增加而提高。热处理程序使塑性变形均匀化并增加，同时降低了强度和模量值。总之，该研究概述了晶胞几何形状、尺寸和晶胞壁厚对 TPMS 晶格结构机械性能的显著影响。

Dynamic-constrained multi-material topology optimization under heat flux and thermal–mechanical loading

Nguyen Minh-Ngoc, Kang Joowon, Shin Soomi, Lee Dongkyu

doi:10.1016/j.tws.2023.111218

热通量和热机械负载下的动态约束多材料拓扑优化

In practice, the structures are often simultaneously related to thermal and mechanical loads, which can lead to stability failure. Improving the stability of the structures is needed to keep them safe. This study aims to optimize vibration capacity in a thermal environment by using an extended solid isotropic material with penalization (SIMP). The effects of thermal and mechanical loadings are considered simultaneously with dynamic constraints as a first effort that includes heat fluxes around boundaries. The incorporation of heat flux boundary conditions is explored in the multi-physics optimization instead of uniform heating using multi-materials. The results show that the distribution of materials changes significantly when thermal properties are changed. The adjoint method is used to analyze the sensitivity of objective functions, and the method of moving asymptotes (MMA) is employed to update new design variables. The effectiveness and reliability of the proposed method are verified by some examples.

在实践中，结构往往同时受到热荷载和机械荷载的影响，从而导致稳定性失效。为了保证结构的安全，需要提高结构的稳定性。本研究的目的是通过使用带惩罚的扩展固体各向同性材料（SIMP）来优化热环境下的振动能力。首先考虑了热负荷和机械负荷的影响，同时考虑了动态约束，包括边界周围的热通量。在多物理场优化中，探索了热通量边界条件的融入，而不是使用多材料进行均匀加热。结果表明，当热属性发生变化时，材料的分布会发生显著变化。利用邻接法分析目标函数的敏感性，并采用移动渐近线法（MMA）更新新的设计变量。通过一些实例验证了所提方法的有效性和可靠性。

Buckling and post-buckling analysis of three-layer shallow arches with geometric imperfections and interlayer slip

Adam Christoph, Paulmichl Ivan, Furtmüller Thomas

doi:10.1016/j.tws.2023.111220

具有几何缺陷和层间滑移的三层浅拱的屈曲和屈曲后分析

In this paper, a semi-analytical solution is derived to capture the nonlinear stability and equilibria of shallow three-layered arches with flexible bond, which also accounts for the interlayer slip (i.e., the relative displacement between the layers). The member axis can have arbitrary geometric imperfections. With the equations presented, for the first time, the complete stable and unstable equilibrium paths can be predicted including multiple remote equilibria, which may occur in the presence of an imperfect member axis but cannot be determined with finite element simulations. Expressions for the direct prediction of critical loads for limit point buckling and bifurcation buckling are also provided, which may also be on the remote unconnected equilibrium paths. In several application examples, the effect of geometric imperfection and interlayer slip on the critical loads and nonlinear equilibria is revealed. Comparative finite element analyses with plane stress continuum elements demonstrate the accuracy and computational efficiency of the presented theory.

本文导出了一种半解析解，以捕捉具有柔性粘接的浅三层拱的非线性稳定性和平衡，该解还考虑了层间滑移（即层间的相对位移）。构件轴线可以有任意几何缺陷。利用所提出的方程，首次可以预测完整的稳定和不稳定平衡路径，包括多个远距离平衡，这可能发生在不完美的构件轴上，但无法通过有限元模拟确定。此外，还提供了直接预测极限点屈曲和分叉屈曲临界载荷的表达式，这些临界载荷也可能出现在远程非连接平衡路径上。在几个应用实例中，揭示了几何缺陷和层间滑移对临界载荷和非线性平衡的影响。与平面应力连续元素的有限元对比分析表明了所提出理论的准确性和计算效率。

A combined periodic acoustic black hole beams with wide vibration attenuation bands

Wan Zhiwei, Zhu Xiang, Li Tianyun, Han Yueyang, Guo Wenjie

doi:10.1016/j.tws.2023.111221

具有宽振动衰减带的组合式周期声学黑洞光束

An acoustic black hole (ABH) structure has a gradual impedance gradient due to the thickness of the section decreasing as a power law, which shows excellent wave gathering and energy dissipation effect. To enhance the vibration suppression ability, periodic ABHs are proposed recently. A virtual spring-energy method (VEM) is adopted to handle the periodic boundary condition of periodic ABHs. The accuracy of the method is verified through the finite element method. The band gap of infinite periodic ABH beam and vibration transmission of finite periodic ABH beam are analyzed. For finite periodic ABH beams, the size of cells affects the attenuation band of vibration transmission, and the number of cells affects the amplitude. There is a linear superposition characteristic between the attenuation amplitude and the number of cells. The effect of damping layer on beams with different cross sections is also discussed. Finally, a combined ABH beam with damping layers of different cell sizes is proposed to achieve wide transmission attenuation bands.

声学黑洞（ABH）结构因截面厚度呈幂律递减而形成渐变阻抗梯度，具有极佳的集波和消能效果。为了提高振动抑制能力，最近有人提出了周期性 ABH。采用虚拟弹簧能量法（VEM）来处理周期性 ABH 的周期性边界条件。通过有限元法验证了该方法的准确性。分析了无限周期 ABH 梁的带隙和有限周期 ABH 梁的振动传输。对于有限周期 ABH 梁，单元的大小会影响振动传输的衰减带，单元的数量会影响振幅。衰减振幅与单元数之间存在线性叠加特性。此外，还讨论了阻尼层对不同截面梁的影响。最后，提出了一种具有不同单元尺寸阻尼层的组合 ABH 梁，以实现宽传输衰减带。

Method of strain analysis of pipelines under landslides: an improved semi-analytical method for softening bending moment-curvature

Xu Zhang, Yuguang Cao, Ying Zhen, Chenyi Ren, Zhongzheng Wang, Dong Huang, Ke Jiang

doi:10.1016/j.tws.2023.111222

山体滑坡下管道应变分析方法：软化弯矩-曲率半分析改进方法

The accurate description of the elastic‒plastic stress‒strain of a pipeline is used to evaluate the risk that the pipeline will undergo failure during a landslide. This paper proposes a complete set of refined semi-analytical methods (SAMs) for pipeline elastic-plastic strain to accurately evaluate the safety of pipelines. First, a concise model for the calculation of landslide thrust is established based on the pipe-soil interaction mechanism as load boundaries of the SAMs. Secondly, the plastic softening bending moment-curvature relationship (BMCR) is derived to establish a difference equation for the deformation of the pipeline during the plastic stage based on the principle of internal force balance of the pipe section, and then the bending plastic strain is calculated accurately. Finally, the axial strain is fully calculated considering the interaction between axial force and bending of the pipeline. The comparison of the results of small-scale landslide tests, large-scale landslide tests, and SAM calculations shows that the improved SAM has good applicability, with 20% better accuracy than traditional methods. In conclusion, the SAM proposed in this paper can effectively guide the design and evaluation of the strain-based design pipeline.

准确描述管道的弹塑性应力应变可用于评估管道在滑坡过程中发生故障的风险。本文提出了一套完整的管道弹塑性应变精细半解析方法（SAM），以准确评估管道的安全性。首先，基于管道与土壤的相互作用机理，建立了简明的滑坡推力计算模型，作为 SAMs 的荷载边界。其次，根据管段内力平衡原理，推导出塑性软化弯矩-曲率关系（BMCR），建立了塑性阶段管道变形的差分方程，进而精确计算出弯曲塑性应变。最后，考虑到管道轴向力和弯曲之间的相互作用，全面计算了轴向应变。小型滑坡试验、大型滑坡试验和 SAM 计算结果的对比表明，改进后的 SAM 具有良好的适用性，精度比传统方法高 20%。总之，本文提出的 SAM 可以有效指导基于应变设计管道的设计和评估。

Cold-formed stainless steel elliptical hollow sections under combined biaxial bending and axial compression - Numerical modeling and design

YAO Ye, QUACH Wai-Meng, YOUNG Ben

doi:10.1016/j.tws.2023.111229

双轴弯曲和轴向压缩联合作用下的冷弯不锈钢椭圆空心型钢 - 数值建模与设计

This paper aims to investigate the cross-section response of cold-formed stainless steel (CFSS) elliptical hollow sections (EHS) under combined biaxial bending and axial compression. In the present study, an advanced finite element (FE) model was adopted to perform a comprehensive parametric study for CFSS EHS under combined biaxial bending and axial compression, with different stainless steel alloys, as well as a broad range of cross-section sizes, aspect ratios, loading eccentricities and angles. Numerical results obtained from the parametric study were compared with the design strengths calculated by the current design rules in European code EN 1993-1-4, American specification SEI/ASCE 8-02 and Australian/New Zealand standard AS/NZS 4673. In addition, the Continuous Strength Method (CSM) for CFSS circular hollow sections (CHS) under combined actions, was also evaluated for the design of CFSS EHS under combined actions. The comparisons revealed that the current design codes EN 1993-1-4, SEI/ASCE 8-02 and AS/NZS 4673 provided conservative and very scattered predictions for CFSS EHS under combined actions. The existing CSM can provide more accurate predictions than the current design codes (i.e., AS/NZS 4673, EN 1993-1-4 and SEI/ASCE-8), but a further improvement is needed. In the present study, a modified CSM is proposed for CFSS EHS under combined actions, which can achieve reliable and accurate design predictions.

本文旨在研究冷弯不锈钢（CFSS）椭圆空心截面（EHS）在双轴弯曲和轴向压缩联合作用下的截面响应。本研究采用先进的有限元（FE）模型，对不同不锈钢合金以及多种截面尺寸、长宽比、加载偏心率和角度的 CFSS EHS 在双轴弯曲和轴向压缩联合作用下的截面响应进行了全面的参数研究。将参数研究得出的数值结果与欧洲标准 EN 1993-1-4、美国标准 SEI/ASCE 8-02 和澳大利亚/新西兰标准 AS/NZS 4673 中的现行设计规则计算出的设计强度进行了比较。此外，还对 CFSS 圆形空心截面（CHS）在联合作用下的连续强度法（CSM）进行了评估，用于 CFSS EHS 在联合作用下的设计。比较结果表明，现行设计规范 EN 1993-1-4、SEI/ASCE 8-02 和 AS/NZS 4673 对 CFSS EHS 在联合作用下的预测较为保守，且非常分散。与现行设计规范（即 AS/NZS 4673、EN 1993-1-4 和 SEI/ASCE-8）相比，现有的 CSM 可以提供更准确的预测，但仍需进一步改进。本研究针对联合作用下的 CFSS EHS 提出了一种改进的 CSM，可实现可靠、准确的设计预测。