今日更新:International Journal of Solids and Structures 1 篇,Thin-Walled Structures 4 篇
In-situ measurements of contact evolution for fractal rough surfaces under normal compression
Shaoqi Huang, Deheng Wei, Wenwen Han, Hengxu Song, Siyang Song, Yixiang Gan, Chongpu Zhai, Minglong Xu
doi:10.1016/j.ijsolstr.2024.112841
法向压缩下分形粗糙表面接触演化的原位测量
The contact interface plays a key role in the overall functionality and stability of structures. Understanding the evolution of the contact interface over time and its dependency on materials and load is crucial for functional integrity and operational safety assessment. In this study, we employ in-situ three-dimensional X-ray computed tomography (3DXRCT) to examine the creep behavior of 3D-printed surfaces exhibiting various roughness under constant normal compression. We observe that the overall contact area enlargement during the contact creep decreases with roughness amplitude and fractal dimension. The variation of interfacial separation distance is found to increase with roughness amplitude and decrease with fractal dimension. Correlation analysis reveals that the microcontact size played a more important role than the asperity shape in determining the microcontact enlargement. By examining the calculated interfacial strains extracted from XRCT measurements, significant deformations are found to occur at the non-contacting zones, indicating strong asperity interactions. This study offers high-resolution experimental measurements and unravels the asperity micromechanics for contact creep on rough surfaces, providing insights into understanding and optimizing the performance of rough interfaces.
接触界面对结构的整体功能和稳定性起着关键作用。了解接触界面随时间的演变及其对材料和载荷的依赖对于功能完整性和操作安全性评估至关重要。在这项研究中,我们使用原位三维x射线计算机断层扫描(3DXRCT)来检查在恒定的法向压缩下具有不同粗糙度的3d打印表面的蠕变行为。在接触蠕变过程中,整体接触面积随粗糙度和分形维数的增加而减小。界面分离距离随粗糙度的增大而增大,随分形维数的减小而减小。相关分析表明,微接触尺寸对微接触增大的影响比凹凸不平形状更大。通过检查从XRCT测量中提取的计算界面应变,发现在非接触区域发生了显着变形,表明强烈的粗糙相互作用。本研究提供了高分辨率的实验测量,揭示了粗糙表面接触蠕变的粗糙微观力学,为理解和优化粗糙界面的性能提供了见解。
Fire test and simulation of circular steel tube confined steel-reinforced concrete columns
Fengqin Wang, Faqi Liu, Kang Hai Tan, Hua Yang, Kang Peng
doi:10.1016/j.tws.2024.111942
圆钢管约束钢筋混凝土柱的火灾试验与模拟
Steel tube confined steel-reinforced concrete (STCSRC) columns are novel steel-concrete composite columns where the steel tubes are disconnected at beam-column connections. Few researches have been conducted on the fire behaviour of STCSRC columns by now, though there are some relevant studies on the fire performance of steel-reinforced concrete-filled steel tubular (SR-CFST) columns. However, the mechanical behaviour of STCSRC columns under fire exposure differs from that of SR-CFST columns due to the discontinuous external steel tube. It is essential to carry out a study on the fire performance of STCSRC columns. The fire tests of four axially loaded STCSRC columns were carried out in this paper, and the failure mode, distribution of cross-sectional temperature, fire resistance, and lateral deflection were discussed. A finite element model was developed and validated with test results, and then a parametric analysis of the STCSRC stub and slender columns under fire exposure was performed. The load ratio, steel tube strength, the area ratio of steel tube to concrete, and slenderness ratio have an adverse effect on the fire resistance of STCSRC columns, whereas cross-sectional dimension, area ratio of steel section to concrete, and strength of steel section have a favourable impact. Concrete strength has a different influence on the fire resistance of STCSRC stub and slender columns. Finally, based on the specifications JGJ/T 471-2019 and EN 1994-1-2, simplified calculation methods for assessing the fire resistance of STCSRC columns were proposed.
钢管约束钢-钢筋混凝土柱是一种新型的钢-混凝土组合柱,在梁柱连接处将钢管断开。尽管对钢管混凝土(SR-CFST)柱的防火性能进行了相关研究,但目前对钢管混凝土柱的防火性能研究较少。然而,由于外部钢管的不连续,STCSRC柱在火灾暴露下的力学行为与SR-CFST柱不同。对STCSRC柱的防火性能进行研究是十分必要的。本文对4根轴向加载STCSRC柱进行了火灾试验,讨论了柱的破坏模式、截面温度分布、耐火性能和侧向挠度。建立了有限元模型,并与试验结果进行了验证,对STCSRC短柱和细长柱在火灾下进行了参数化分析。荷载比、钢管强度、钢管与混凝土面积比和长细比对STCSRC柱的耐火性能有不利影响,而截面尺寸、钢截面与混凝土面积比和钢截面强度有有利影响。混凝土强度对STCSRC短柱和细长柱的耐火性能有不同的影响。最后,根据JGJ/T 471-2019和EN 1994-1-2规范,提出了STCSRC柱耐火评定的简化计算方法。
B-Spline Subdomain Method for static calculations of Double-Curved Arch structures
Zhang Youhua, Yuan Bo, Shi Minjie, XU Zijie, Zheng Shiyu
doi:10.1016/j.tws.2024.111931
双曲拱结构静力计算的b样条子域法
A static computational study of a new type of Doubly-Curved Arch (DCA) structure using the Spline Subdomain Method (SSM) has been conducted and a new subdomain and generalized model for the static analysis of compression DCA structures have been developed. The equations for the numerical calculations by SSM are derived. The model is based on the SSM for the subdomain division of DCA. For the discretization of the flat shell subdomain, two sets of uniformly distributed spline nodes are used along the neighboring edges of the rectangular projection of the shallow shell subdomain. The linear combination of the product of these two specially designed cubic B-spline interpolation functions is the displacement field. This model generates its overall structural stiffness matrix and load vector of the DCA by direct assembly following the discretization of the spline in the shallow shell subdomain. This method is characterized by high modeling efficiency, low computational cost, and a wide range of applications for the analysis of irregular shell structures. Abaqus software is used to verify the performance of the suggested method through numerical examples. The findings demonstrate that non-regular DCA structures subjected to static compression can have their mechanical properties analyzed using the suggested method.
采用样条子域法对一种新型双曲拱结构进行了静力计算研究,建立了一种新的双曲拱压缩结构静力分析的子域和广义模型。推导了用SSM进行数值计算的方程。该模型是基于SSM的DCA子域划分模型。对于平壳子域的离散化,在浅壳子域矩形投影的相邻边缘上使用了两组均匀分布的样条节点。这两个特别设计的三次b样条插值函数的乘积的线性组合就是位移场。该模型在浅壳子域对样条曲线进行离散化后,通过直接装配的方式生成DCA的整体结构刚度矩阵和载荷向量。该方法具有建模效率高、计算成本低的特点,在不规则壳结构分析中具有广泛的应用前景。利用Abaqus软件,通过数值算例验证了所提方法的有效性。研究结果表明,非规则DCA结构在静压缩作用下的力学性能可以用该方法进行分析。
A FINITE STRAIN THEORY FOR INCOMPRESSIBLE RUBBER-LIKE CIRCULAR ARCHES WITH AN APPLICATION
R. Faruk Yükseler
doi:10.1016/j.tws.2024.111939
不可压缩类橡胶圆拱的有限应变理论及其应用
A theory for incompressible rubber-like circular arches, undergoing finite strains and rotations, with an application to the stability of Mooney-Rivlin, doubly fixed, thin beams having initially small circular imperfections under uniformly distributed radial loads, is presented. The essence of considering transverse normal strain is emphasized for an incompressible rubber-like material. The effects of the thickness, initial curvature, and perturbation terms of the pseudo strain components on the buckling loads and central deflections are investigated. The thresholds of buckling are observed to depend on the values of the curvature of the initially imperfect beam for the chosen nonlinear material.
提出了一种不可压缩的橡胶类圆拱理论,在有限应变和旋转作用下,应用于均匀分布径向载荷下具有初始小圆缺陷的Mooney-Rivlin双固定薄梁的稳定性。强调了不可压缩类橡胶材料考虑横向法向应变的本质。研究了拟应变分量的厚度、初始曲率和扰动项对屈曲载荷和中心挠度的影响。观察到屈曲的阈值取决于所选非线性材料的初始不完美梁的曲率值。
Modeling and vibro-acoustic behavior analysis of a plate-cavity coupling system equipped with a nonlinear energy sink
Yilin Chen, Jingtao Du, Yuhao Zhao, Yang Liu
doi:10.1016/j.tws.2024.111940
含非线性能量汇的板腔耦合系统建模及振声特性分析
This study establishes a three-dimensional model of a local NES-plate-acoustic cavity coupling system and investigates the nonlinear vibro-acoustic response of the NES-equipped plate coupled with the acoustic cavity and the control effect of the NES on the plate-cavity coupling system. Using the energy method to construct the governing equation of the coupled system, the vibro-acoustic behavior of the system is solved by the harmonic average approach and numerical integration method. The correctness of the results is proved through the comparison with the reference and mutual verification between different methods. On this basis, the control effect of NES on the vibration response and sound pressure response of the plate-cavity coupling system is investigated. It is found that NES exhibits a good control effect on the higher plate-controlled (PC) modal response peak, while showing a limited control effect on the lower PC modal response peak and the cavity-controlled (CC) modal peak. Due to the installation of the NES, various complex dynamic behaviors are generated in the unstable response area of the plate and cavity. At this time, the vibration state of sound pressure in the cavity is consistent with the vibration state of the plate, but the frequency distribution is different. The targeted energy transfer (TET) phenomenon between the NES and plate occurs at some frequencies. Furthermore, the nonlinear stiffness and concentrated mass of NES have a great influence on the response of the coupled system, and the damping effect of NES plays a major role in higher-order resonance response. When the damping and nonlinear stiffness are constant, an optimal value for the mass of NES exists to minimize the peak response. Finally, the comparison of vibro-acoustic characteristics of the plate-cavity coupling system equipped with the NES and TMD are investigated.
本文建立了局域NES-板-声腔耦合系统的三维模型,研究了安装NES的板与声腔耦合的非线性振声响应,以及NES对板-腔耦合系统的控制效果。利用能量法建立耦合系统的控制方程,采用谐波平均法和数值积分法求解系统的振声特性。通过与参考文献的比较和不同方法之间的相互验证,证明了结果的正确性。在此基础上,研究了NES对板腔耦合系统振动响应和声压响应的控制效果。研究发现,NES对较高的板控(PC)模态响应峰具有良好的控制效果,而对较低的板控(PC)模态响应峰和腔控(CC)模态响应峰的控制效果有限。由于NES的安装,在板腔的不稳定响应区产生了各种复杂的动力行为。此时腔内声压的振动状态与板的振动状态一致,但频率分布不同。靶能量传递(TET)现象在某些频率下发生。此外,网元的非线性刚度和集中质量对耦合系统的响应有很大影响,网元的阻尼效应在高阶共振响应中起主要作用。当阻尼和非线性刚度一定时,存在一个能使峰值响应最小的最优质量值。最后,比较了安装了NES和TMD的板腔耦合系统的振声特性。