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【新文速递】2024年5月16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 2 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 10 篇

International Journal of Solids and Structures

Manufacturing sensitivity study of tensegrity structures using Monte Carlo simulations

Keyao Song, Fabrizio Scarpa, Mark Schenk

doi:10.1016/j.ijsolstr.2024.112878

用蒙特卡罗模拟研究张拉整体结构的制造灵敏度

The successful construction of a tensegrity structure requires not only design techniques but also a means to account for any manufacturing or assembly errors. As a tensegrity is prestressed and is often stabilised by its prestress, it requires a form-finding technique to determine the balanced configuration in the design phase; this property also makes it challenging for engineers to evaluate the effect of manufacturing imperfections on the self-equilibrated configuration. In this paper we investigate the sensitivity of tensegrity structures to manufacturing imperfections, using a stiffness-matrix-based form-finding technique in combination with the Monte Carlo simulation method to introduce manufacturing length errors. The effects at the structural level are captured, and two general relationships between the variance of the input manufacturing error and the output distribution of the member tensions, between the variance and the mean across all groups, are observed. By identifying the most sensitive member group, this work provides a design and analysis strategy when the natural length errors of members are considered for tensegrity structures.

张拉整体结构的成功建造不仅需要设计技术,还需要一种方法来解释任何制造或装配错误。由于张拉整体是预应力的,并且经常通过其预应力来稳定,因此需要一种寻形技术来确定设计阶段的平衡配置;这种特性也使得工程师很难评估制造缺陷对自平衡结构的影响。在本文中,我们研究了张拉整体结构对制造缺陷的敏感性,使用基于刚度矩阵的寻形技术结合蒙特卡罗模拟方法来引入制造长度误差。捕获了结构层面的影响,并观察了输入制造误差的方差与成员张力的输出分布之间的两种一般关系,以及所有组的方差和平均值之间的关系。通过确定最敏感的构件群,本工作为考虑张拉整体结构构件自然长度误差时的设计和分析提供了一种策略。


Journal of the Mechanics and Physics of Solids

Cavitation in elastomers: A review of the evidence against elasticity

Evan Breedlove, Chao Chen, David Lindeman, Oscar Lopez-Pamies

doi:10.1016/j.jmps.2024.105678

弹性体中的空化:反弹性证据的回顾

In spite of the growing body of evidence against it, the elasticity view of the phenomenon of cavitation in elastomers continues to be utilized in numerous studies. In this context, the main objective of this paper is to provide a comprehensive review of the existing evidence that settles that cavitation in elastomers is not a purely elastic phenomenon. To that end, a review is first given of the experimental observations of cavitation in elastomers — gathered since the 1930s until present times — as well as of its theoretical description as an elastic phenomenon — whose development started in the 1950s and was substantially completed by the 2010s. The latter is then confronted to the former to pinpoint the reasons why the elastic behavior of elastomers cannot possibly explain the experimental observations. The last part of the paper includes a brief summary of the current view of cavitation as a fracture phenomenon and an outlook for the field in that direction.

尽管有越来越多的证据反对它,弹性体中空化现象的弹性观点继续在许多研究中使用。在这种情况下,本文的主要目的是提供一个全面的审查现有的证据,解决弹性体中的空化不是一个纯粹的弹性现象。为此,本文首先回顾了弹性体中空化现象的实验观察结果——从20世纪30年代至今——以及它作为一种弹性现象的理论描述——其发展始于20世纪50年代,到2010年代基本完成。后者然后面对前者,以查明弹性体的弹性行为不可能解释实验观察的原因。论文的最后一部分简要总结了目前对空化作为一种裂缝现象的看法,并对该领域的发展方向进行了展望。


Mechanics of Materials

On the Interaction of Grain-scale and Hydride-scale Stresses in Hydrogen Enriched Zirconium Alloy Nuclear Cladding via combined Discrete Dislocation Plasticity and Crystal Plasticity Finite Element modelling

Christos Skamniotis, Daniel Long, Liu Yang, Mark Wenman, Daniel S. Balint

doi:10.1016/j.mechmat.2024.105033

基于离散位错塑性和晶体塑性联合有限元模型的富氢锆合金核覆层晶粒尺度和氢化物尺度应力相互作用研究

The interaction of Zircaloy fuel cladding components with coolant water in a nuclear reactor leads to embrittlement and potentially delayed hydride cracking (DHC). We explore rate controlling mechanisms for the detrimental DHC process via Discrete Dislocation Plasticity (DDP) modelling of an intragranular -hydride, informed by Crystal Plasticity Finite Element (CPFE) analysis of a notched Zircaloy-4 (Zr-4) polycrystal. It is believed that nano-hydride plasticity occurs under a background (polycrystalline) stress state that depends on the grain-scale stress re-distribution associated with plastic deformation at a notch. We find that depending on grain size the background stresses can enhance plasticity during hydride growth (cooling), enhancing the residual hydrostatic stresses on hydride dissolution (heating), which encourages local hydrogen accumulation and re-precipitation. This ‘memory effect’ can be enhanced further by obstacles preventing dislocations from gliding backwards and annihilating during dissolution, highlighting that the discrete nature of plasticity can play important role in the DHC process. Our analysis provides a stepping-stone to modelling interacting nano-hydrides and irradiation effects for supporting the design of better nuclear materials.

在核反应堆中,锆合金燃料包壳组件与冷却水的相互作用会导致脆化和潜在的延迟氢化物开裂(DHC)。我们通过对缺口锆-4 (Zr-4)多晶的晶体塑性有限元(CPFE)分析,通过对颗粒内氢化物的离散位错塑性(DDP)建模,探讨了有害DHC过程的速率控制机制。认为纳米氢化物塑性发生在背景(多晶)应力状态下,这取决于与缺口处塑性变形相关的晶粒级应力重新分布。研究发现,根据晶粒尺寸的不同,背景应力可以增强氢化物生长(冷却)过程中的塑性,增强氢化物溶解(加热)时的残余静水应力,从而促进局部氢的积累和再沉淀。这种“记忆效应”可以通过防止位错在溶解过程中向后滑动和湮灭的障碍进一步增强,强调可塑性的离散性在DHC过程中发挥重要作用。我们的分析为模拟相互作用的纳米氢化物和辐射效应提供了一个跳板,为更好的核材料的设计提供了支持。


Multi-method examination of contact mechanics in orthotropic layers under gravity

Erdal Öner, Ecren Uzun Yaylacı, Murat Yaylacı

doi:10.1016/j.mechmat.2024.105036

重力作用下正交各向异性地层接触力学的多方法检验

Analyzing the behavior of intelligent unconventional materials under diverse contact scenarios, in comparison to conventional materials, is a critical step in the initial design of engineering systems. This paper presents the development of analytical and numerical approaches for analyzing contact mechanics in a system comprising an orthotropic layer resting on a rigid foundation. Parametric analyses include the consideration of cylindrical and flat punch profiles. Analytical formulation utilizes integral transform methods to convert planar elasticity equations into a Cauchy-type singular integral equation of the second kind. A detailed description of the solution technique for the integral equation is provided, encompassing both the analytical formulation and the required discretization for obtaining the solution. Subsequently, a finite element approach (FEA) is employed to approximate contact bodies using a collection of finite elements, while contact boundaries are approximated by utilizing a set of polygons. Alternatively, the problem is addressed using the Multilayer Perceptron approach, a form of artificial neural network frequently applied in diverse machine learning applications, including scenarios involving contact problems. Finally, the resolution to the problem is achieved by employing the multilayer perceptron (MLP) method. The study yields determinations of contact stresses under the punch, the critical separation load resulting in the detachment of the orthotropic layer from the rigid foundation, and the corresponding separation distance. This analysis considers a range of dimensionless parameters and explored the behavior of diverse orthotropic materials. Comparisons between the results of the analytical method and computations from FEA and MLP reveal the exceptional accuracy attained by all three approaches. As the pioneer study employing three distinct approaches to examine continuous contact mechanics within an orthotropic layer under the influence of gravity, this research constitutes a valuable point of reference for upcoming scholars in the field.

与常规材料相比,分析智能非常规材料在不同接触场景下的行为是工程系统初始设计的关键步骤。本文介绍了分析刚性基础上的正交各向异性层系统接触力学的解析和数值方法的发展。参数分析包括圆柱型和平面型冲孔。解析式利用积分变换方法将平面弹性方程转化为第二类柯西型奇异积分方程。详细描述了积分方程的求解技术,包括解析公式和获得解所需的离散化。随后,采用有限元法(FEA)逼近接触体,利用一组有限元逼近接触边界,利用一组多边形逼近接触边界。或者,使用多层感知器方法解决问题,这是一种人工神经网络形式,经常应用于各种机器学习应用,包括涉及接触问题的场景。最后,采用多层感知器(MLP)方法实现了问题的求解。研究得出了冲头作用下的接触应力、导致正交各向异性层脱离刚性基础的临界分离载荷以及相应的分离距离。该分析考虑了一系列无量纲参数,并探讨了不同正交各向异性材料的行为。将分析方法的结果与FEA和MLP的计算结果进行比较,揭示了所有三种方法获得的卓越精度。作为采用三种不同方法研究重力影响下正交各向异性层内连续接触力学的先驱研究,本研究为该领域的新学者提供了有价值的参考点。


International Journal of Plasticity

Effect of Nb solutes on the Kolbe mechanism for microtwinning in Ni-based superalloys

Valery V. Borovikov, Mikhail I. Mendelev, Nikolai A. Zarkevich, Timothy M. Smith, John W. Lawson

doi:10.1016/j.ijplas.2024.104004

Nb溶质对ni基高温合金微孪晶Kolbe机制的影响

As the operating temperature of jet turbine engines increase, creep becomes the life-limiting property for turbine disks and blades. At intermediate temperatures, between 600-800°C, microtwinning contributes significantly to creep strain in these alloys. Therefore, understanding how microtwins form and grow is critical to improving the creep life of future Ni-base superalloy components. In addition, exploring the effect of different alloying elements, such as Nb and Ta, on the formation of microtwins is critical for future alloy development. Several mechanisms of microtwinning have been proposed among which the Kolbe mechanism, based on thermally activated reordering, is believed to be dominant. In this work we employ atomistic simulation to investigate the effects of Nb solutes on the Kolbe mechanism. The simulation demonstrates that Nb atoms significantly slow down the reordering processes, explaining the experimentally observed improvement in the creep resistance.

随着喷气涡轮发动机工作温度的升高,蠕变成为影响涡轮盘和叶片寿命的主要因素。在600-800℃的中间温度下,微孪晶对合金的蠕变应变有显著影响。因此,了解微孪晶是如何形成和成长的,对于提高未来镍基高温合金部件的蠕变寿命至关重要。此外,探索不同合金元素(如Nb和Ta)对微孪晶形成的影响对未来合金的发展至关重要。人们提出了几种微孪晶的机制,其中基于热激活重排序的Kolbe机制被认为是主要的机制。在这项工作中,我们采用原子模拟来研究Nb溶质对科尔贝机制的影响。模拟结果表明,Nb原子显著减缓了重排序过程,解释了实验观察到的抗蠕变性能的提高。


Thin-Walled Structures

Experimental and numerical study on the in-plane bending behaviour of FRP-strengthened steel tubular welded T-joints

R. Rashnooie, M. Zeinoddini, E. Ghafoori, M. Sharafi

doi:10.1016/j.tws.2024.112000

frp加固钢管t形接头面内弯曲性能的试验与数值研究

This study reports the first experimental study on the in-plane bending stress concentration factor (SCF) of steel tubular T-joints with fibre-reinforced-polymer (FRP) jacketing. Experimental results showed that the SCF of the FRP-strengthened specimens was reduced by up to 35%, thereby significantly improving the fatigue strength of the joints. A numerical model, validated with experimental data, was used to further investigate the SCF of FRP-strengthened joints with different geometric/mechanical properties. Nonlinear regression analysis was also performed using experimental and numerical data, and parametric formulas were proposed for the in-plane bending SCF of FRP-strengthened tubular steel joints.

本文首次对带纤维增强聚合物(FRP)护套的t形钢管接头进行了面内弯曲应力集中系数(SCF)的试验研究。试验结果表明,frp加固试件的SCF降低幅度高达35%,从而显著提高了接头的疲劳强度。采用数值模型,对不同几何/力学性能frp加固节点的SCF进行了进一步研究。利用实验数据和数值数据进行非线性回归分析,提出了frp加固钢管节点面内弯曲SCF的参数公式。


Vibrations and thermoelastic quality factors of hemispherical shells with fillets

Longkai Zheng, Shurui Wen, Guoxing Yi, Fengming Li

doi:10.1016/j.tws.2024.111996

带圆角的半球形壳的振动和热弹性质量因子

In engineering applications, hemispherical shell resonators are typically machined with fillets to reduce stress concentration and enhance structure strength. The fillets will inevitably affect the dynamic properties and the mechanical quality factor of hemispherical shell resonators, which has been seldom investigated before. In this paper, an effective analytical method is developed to explore the free vibration and thermoelastic damping (TED) characteristics of the hemispherical shell with fillets. The fillets are characterized by the variation in the thickness of the hemispherical shell during modelling. The first-order shear deformation theory (FSDT) is used to describe the theoretical formulas of the hemispherical shell with fillets. By employing the unified Jacobi polynomials and Fourier series as the assumed mode shape functions, the equation of motion of the structure is established by Hamilton's principle and the assumed mode method. The analytical model for thermoelastic quality factor (QTED) which is determined by TED is obtained by computing the dissipated energy and the maximum elastic potential energy of the hemispherical shell with fillets. The validity and accuracy of the present method are confirmed by comparing the present solutions with the published results and those obtained from the finite element method (FEM). The influences of fillets on the vibration behaviors and QTED characteristics of the hemispherical shells are analyzed in detail. The present model can be used to optimize the design of the fillets of the hemispherical shell resonators with high quality factors.

在工程应用中,半球形壳体谐振器通常采用圆角加工,以减少应力集中,提高结构强度。圆角不可避免地会影响半球壳谐振器的动态特性和机械品质因数,而这一点以前很少有人研究。本文开发了一种有效的分析方法来探讨带圆角半球壳的自由振动和热弹性阻尼(TED)特性。圆角的特征是半球形壳体在建模过程中的厚度变化。一阶剪切变形理论(FSDT)用于描述带圆角半球壳的理论公式。通过使用统一的雅可比多项式和傅里叶级数作为假定模态形状函数,利用汉密尔顿原理和假定模态法建立了结构的运动方程。通过计算带圆角半球壳体的耗散能量和最大弹性势能,得到了由 TED 确定的热弹性质量因子(QTED)的解析模型。通过将本求解结果与已公布的结果和有限元法(FEM)求解结果进行比较,证实了本方法的有效性和准确性。详细分析了圆角对半球形壳体振动行为和 QTED 特性的影响。本模型可用于优化具有高品质因数的半球壳谐振器的圆角设计。


Fatigue properties of SPS composite-steel panel prepared by ultrasound resistance spot welding

Andrzej Kubit, Hamed Aghajani Derazkola, Koen Faes, Marcin Korzeniowski

doi:10.1016/j.tws.2024.111992

超声电阻点焊SPS复合钢板疲劳性能研究

The aim of this work is to analyze the properties of spot joints of metal-plastic composites (Litecor) with DP 800 steel. The joints were made using ultrasound resistance spot welding technology. A metallographic analysis of the joints was carried out, and the basic areas of the weld structure were determined. The separation and decomposition of the polymer core was also illustrated, with no observed diffusion between the Litecor covers and the polypropylene core. Fatigue tests were the main goal of this work, therefore a fatigue curve was determined and the mechanisms of fatigue failure at various levels of fatigue load were analyzed. The tests were carried out at a frequency of 30 Hz, the cycle asymmetry coefficient was R = 0.1 and the limit number of cycles was 2 × 106 . Fatigue failure mechanisms specific to particular levels of fatigue load were demonstrated, which were: 2.2, 1.9, 1.5, 1.2, and 1 kN. For joints subjected to fatigue shear has been demonstrated that the boundary between low-cycle and high-cycle fatigue is located at a cyclic shear stress level of approximately 132 MPa. however, with the assumed limit number of fatigue cycles, the fatigue shear strength was 70.576 MPa. Macro- and microscopic fractographic analysis was carried out for joints after fatigue tests in order to demonstrate the mechanisms of failure at individual levels of cyclic load.

本工作的目的是分析金属-塑料复合材料(Litecor)与DP 800钢的点焊接头的性能。接头采用超声电阻点焊技术。对接头进行了金相分析,确定了焊缝组织的基本区域。还说明了聚合物芯的分离和分解,没有观察到Litecor覆盖层和聚丙烯芯之间的扩散。疲劳试验是这项工作的主要目的,因此确定了疲劳曲线,并分析了不同疲劳载荷下的疲劳破坏机制。试验频率为30 Hz,循环不对称系数R = 0.1,极限循环次数为2 × 106。特定水平的疲劳载荷的疲劳失效机制被证明,这是:2.2,1.9,1.5,1.2和1 kN。对于受疲劳剪切作用的节理,低周疲劳和高周疲劳的边界位于约132 MPa的循环剪切应力水平。在假定极限疲劳循环次数下,疲劳抗剪强度为70.576 MPa。对疲劳试验后的接头进行了宏观和微观断口分析,以证明在各个循环荷载水平下的破坏机制。


Calculation of natural frequencies of doubly curved laminated shells using a modified higher order zigzag theory

Md. Irquam Alam, Mihir Kumar Pandit, Arun Kumar Pradhan

doi:10.1016/j.tws.2024.112007

用改进的高阶之字形理论计算双弯曲层合壳的固有频率

In this study, the analysis of free vibrations for doubly curved laminated shells has been performed with modified higher order zigzag theory (MHOZT). This approach incorporates higher order displacement kinematics and considers both transverse normal and shear strains. The model assumes that the displacement fields within the plane are a combination of a global cubicly varying field and a locally zigzag linearly varying field. On the other hand, the out-of-plane displacement field varies quadratically with shell thickness coordinates. This formulation considers extended thickness criteria, ensuring the inclusion of the ratio of thickness to the radius of curvature (z/R) in strain displacement relations. Additionally, this model guarantees that there is no transverse shear stress at the extreme surfaces of the shell and that inter-laminar shear stress at interfaces is continuous. To implement this formulation effectively, a C° finite element is used. The outcomes are compared against a three-dimensional (3D) elasticity solution, as well as other pertinent results available in the literature. The suggested model accurately predicts the vibration characteristics of laminated shells, showing good agreement with the 3D elasticity solutions.

本研究采用修正的高阶之字形理论(MHOZT)对双曲面层叠壳体的自由振动进行了分析。这种方法采用了高阶位移运动学,并考虑了横向法向应变和剪切应变。该模型假定平面内的位移场是全局立方变化场和局部人字形线性变化场的组合。另一方面,平面外位移场随壳厚度坐标二次变化。该模型考虑了扩展的厚度标准,确保在应变位移关系中包含厚度与曲率半径之比 (z/R)。此外,该模型还确保在壳体的极端表面不存在横向剪应力,并且界面上的层间剪应力是连续的。为了有效地实现这一公式,我们使用了 C° 有限元。研究结果与三维(3D)弹性解决方案以及文献中的其他相关结果进行了比较。建议的模型准确预测了层叠壳体的振动特性,与三维弹性解法显示出良好的一致性。


Blast resistance performance and failure modes of prestressed thin-walled aqueducts subjected to underwater contact explosion

Tao Peng, Gaohui Wang, Wenbo Lu, Zheng Gao, Xinhao Pan, Yizhan Shu

doi:10.1016/j.tws.2024.111993

水下接触爆炸作用下预应力薄壁渡槽的抗爆性能及破坏模式

To solve the problem of regional water resource shortage, water diversion projects have been built around the world. As an essential lifeline project, the prestressed aqueduct is commonly used in cross-regional water transfer and diversion projects. However, the prestressed aqueduct is inclined to damage and collapse under explosion loading due to its thin structure. The main purpose of this paper is to investigate the nonlinear dynamic performance and failure modes of the large prestressed U-shaped thin shell aqueduct to underwater contact explosion. The prestress application approach is validated by theoretical calculations. The reliability of the analysis method of underwater contact explosion for reinforced concrete structures is verified by the underwater contact explosion test. Damage cracking process and nonlinear dynamic response characteristics of prestressed aqueducts to the underwater contact explosion with different explosive weights are performed. Blast resistance performances of prestressed aqueducts are discussed in terms of the crack length, residual displacement, and prestressing force loss. The influence of prestress level on the damage modes of the prestressed aqueduct under the blast loading is discussed. The results indicate that thin-walled U-shaped structures are extremely vulnerable to localized damage from underwater contact explosions. The blast-resistance performance of the U-shaped thin shell aqueduct can be significantly improved by applying prestress.

为了解决区域水资源短缺的问题,世界各地纷纷修建调水工程。预应力渡槽是跨区域调水引水工程中常用的一种重要的生命线工程。然而,预应力渡槽由于结构较薄,在爆炸荷载作用下容易发生破坏和倒塌。本文的主要目的是研究大型预应力u型薄壳渡槽在水下接触爆炸作用下的非线性动力性能和破坏模式。理论计算验证了预应力方法的有效性。通过水下接触爆炸试验,验证了钢筋混凝土结构水下接触爆炸分析方法的可靠性。研究了预应力渡槽在不同炸药重量水下接触爆炸作用下的损伤开裂过程和非线性动力响应特性。从裂缝长度、残余位移和预应力损失等方面讨论了预应力渡槽的抗爆性能。讨论了在爆炸荷载作用下,预应力水平对预应力渡槽损伤模式的影响。结果表明,薄壁u型结构极易受到水下接触爆炸的局部损伤。u型薄壳渡槽通过施加预应力可显著提高其抗爆性能。


Non-linear buckling analysis of thin-walled beams modelled with 7-parameter shell elements

Anh-Khoa Chau, Michael Brun, Pascal Ventura, Hamid Zahrouni, Michel Potier-Ferry

doi:10.1016/j.tws.2024.111994

7参数壳单元薄壁梁非线性屈曲分析

The non-linear quasi-static buckling of thin-walled beams with arbitrary cross-sections is studied by developing coupling strategies between the composing plates (web, flanges). The element adopted for modeling the plates is a 7-parameter shell element using the Enhanced Assumed Strain concept (Bütcher et al., 1994). Different nodal shell directors exist at the interface between plates for thin-walled beams with arbitrary cross-sections, requiring appropriate strategies. The coupling between plates first considers Lagrange multipliers at the interface, following the mortar method on the surface between the plates. Second a simplified pre-processing method is proposed by modifying the shell directors of the nodes close to the interface. In the case of the quasi-static buckling of thin-walled beams with L-shaped and I-shaped cross-sections, the two coupling strategies are thoroughly assessed by using three different solution procedures: Newton–Raphson, Newton-Riks and Asymptotic Numerical Method (ANM). The pre-processing method is simple and turns out to be robust and efficient.

研究了任意截面薄壁梁的非线性准静力屈曲问题,提出了组合板(腹板、翼缘)之间的耦合策略。钢板建模采用的单元是采用增强假设应变概念的7参数壳单元(b<s:1> tcher et al., 1994)。任意截面薄壁梁在板间界面处存在不同的节点壳方向,需要适当的策略。板间耦合首先考虑界面处的拉格朗日乘子,遵循板间表面的砂浆方法。其次,提出了一种简化的预处理方法,即修改靠近接口的节点的shell指示符。以l形和i形截面薄壁梁的准静力屈曲为例,采用牛顿-拉夫森、牛顿-瑞克和渐近数值方法(ANM)三种不同的求解方法,对两种耦合策略进行了全面的评估。该预处理方法简单,鲁棒性好,效率高。


Hygrothermal vibro-buckling of FG ceramic-steel porous consolidated conical-conical shells

Ali Heidari-Soureshjani, Mohammad Rajabi, Roohollah Talebitooti, Mostafa Talebitooti

doi:10.1016/j.tws.2024.112002

FG陶瓷-钢多孔固结锥形-锥形壳的湿热振动屈曲

The present research deals with buckling and vibration analysis of joined functionally graded porous (FGP) conical-conical shells under hygro-thermal environments for the first time. Three different types of porosity distributions are considered across the thickness of temperature-dependent ceramic-steel functional material. Obtaining initial hygro-thermal stress resultant through the static step based on the FSDT and benefitting it in the dynamic one makes this research distinguished from other researches in dealing with hygro-thermal conditions. After consolidating two conical segments by following continuity rules, GDQ approach is implemented to the complete set of motion, marginal and continuity equations. Firstly, the accuracy of the results is checked via some comparisons with prior researches. Additionally, the paper provides novel results in the favor of temperature and moisture rises, porosity models and coefficients on the frequency trends from room conditions to hygro-thermal buckling states.

本文首次对连接功能梯度多孔(FGP)锥形-锥形壳在湿热环境下的屈曲和振动进行了研究。考虑了三种不同类型的孔隙率分布在温度相关的陶瓷-钢功能材料的厚度。基于FSDT的静态步长得到初始湿热应力,并在动态步长中受益,这使得本研究区别于其他处理湿热条件的研究。在遵循连续性规则合并两个圆锥段后,对运动、边缘和连续性方程的完整集 合实施GDQ方法。首先,通过与已有研究的比较,验证了所得结果的准确性。此外,本文还提供了有利于温度和湿度上升的新结果,孔隙率模型和从室温到湿热屈曲状态的频率趋势系数。


Experimental study on interfacial bond-slip behavior of weathering steel and seawater sea-sand concrete in corrosive marine environments

Xuetong Li, Yuhan Lin, Canlin Zhang, Yu Chen, Wei Chen, Li Geng

doi:10.1016/j.tws.2024.112003

海洋腐蚀环境下耐候钢与海水海砂混凝土界面粘结滑移特性试验研究

To improve the durability of marine renewable energy infrastructures, this paper proposed a weathering steel reinforced seawater sea-sand concrete (WSRSSC) structure and investigated its interfacial bond-slip behavior. Forty specimens were designed and underwent simulated marine corrosion tests and push-out tests to explore the effect of various factors, including the corrosion time, shaped steel type, steel section form, seawater sea-sand concrete (SSC) strength, and stirrup spacing. The findings indicated that the ultimate bond stress and residual bond stress increase with higher SSC strength but decrease with greater stirrup spacing. The steel section form significantly affected the ultimate bond stress. With the increase in corrosion time, the ultimate bond stress of WSRSSC specimens first increased and then slowly decreased in the later stages. Weathering steel specimens demonstrated superior corrosion resistance and long-term performance compared to carbon steel specimens. Considering the bond formation mechanism and corrosion damage, the calculation model for the ultimate bond stress and residual bond stress of WSRSSC specimens was proposed. Furthermore, the four-stage bond-slip constitutive model between weathering steel and seawater sea-sand concrete was established, aligning with the bond characteristics of different corrosion degrees and contributing to the numerical simulation of WSRSSC structures in corrosive marine environments.

为了提高海洋可再生能源基础设施的耐久性,提出了一种耐候钢增强海水海砂混凝土(WSRSSC)结构,并对其界面粘结滑移行为进行了研究。设计了40个试件,进行了模拟海蚀试验和推出试验,探讨了腐蚀时间、型钢类型、型钢截面形式、海水海砂混凝土(SSC)强度、箍筋间距等因素对试件的影响。结果表明:粘结极限应力和残余应力随SSC强度的增大而增大,随箍筋间距的增大而减小;型钢截面形式对极限粘结应力有显著影响。随着腐蚀时间的延长,WSRSSC试样的极限粘结应力先增大后缓慢减小。与碳钢试样相比,耐候钢试样表现出优越的耐腐蚀性和长期性能。考虑粘结机制和腐蚀损伤,建立了WSRSSC试件的极限粘结应力和残余粘结应力计算模型。建立了耐候钢与海水海砂混凝土的四阶段粘结-滑移本构模型,符合不同腐蚀程度下的粘结特性,为海洋腐蚀环境下WSRSSC结构的数值模拟提供了依据。


Experimental investigation on the low-velocity impact responses of fibre metal laminates with various internal and external factors

Zheng-Qiang Cheng, Yi-Zhi Zhong, Wei Tan, Zhi-Wu Zhu, Jun-Jiang Xiong, Hu Liu

doi:10.1016/j.tws.2024.112004

不同内外因素下金属纤维层合板低速冲击响应的实验研究

This paper aims to investigate the low-velocity impact (LVI) failure mechanism of fibre metal laminates (FMLs), and systematically explore the effects of internal factors (layup sequence and laminate configuration) and external factors (impact energy and environmental temperature) on the LVI responses. The drop-weight impact tester was utilised to conduct LVI tests at -30 ℃, 25 ℃, and 80 ℃ on FML-2/1 and FML-3/2 laminates. These laminates were made of S-class high-strength glass fibre and 2024 aluminium-alloy sheet with unidirectional, angle-ply, cross-ply and quasi-isotropic layup sequences. The characteristic curves including contact force-time, contact force-deflection, absorbed energy-time, and strain-time near the dent on the impacted and non-impacted specimen surfaces were obtained respectively. Furthermore, the dent depth of the impacted surface of the FMLs was measured. FML's damage was detected by ultrasonic C-scan, and its longitudinal and transverse sections were scanned by X-ray computed tomography (CT). The findings suggest that the layup sequence has a significant effect on the LVI response of FML-2/1, but has no obvious influence on FML-3/2. Moreover, FML-3/2 exhibits greater impact resistance compared to FML-2/1. The severity of LVI damage increases with the increase of impact energy. Notably, compared to the cases at 25 ℃, the LVI failure mechanisms of FMLs undergo significant changes at -30 ℃. The elevated temperature of 80 ℃ significantly affects the LVI damage of FML-2/1, while it has no significant effect on FML-3/2.

本文旨在研究金属纤维层压板(FMLs)的低速冲击(LVI)破坏机理,系统探讨内部因素(铺层顺序和层压板构型)和外部因素(冲击能量和环境温度)对LVI响应的影响。采用落锤冲击试验机对FML-2/1和FML-3/2层压板在-30℃、25℃和80℃下进行LVI试验。这些层压板由s级高强玻璃纤维和2024铝合金板制成,具有单向、角铺层、交叉铺层和准各向同性铺层顺序。得到了冲击和非冲击试样表面凹痕附近的接触力-时间、接触力-挠度、吸收能量时间和应变时间特征曲线。此外,还测量了FMLs撞击表面的凹痕深度。超声c扫描检测FML损伤,x线CT扫描FML纵、横切面。结果表明,铺层顺序对FML-2/1的LVI反应有显著影响,但对FML-3/2无明显影响。此外,与FML-2/1相比,FML-3/2具有更强的抗冲击性。LVI损伤程度随冲击能量的增加而增加。值得注意的是,与25℃时相比,-30℃时FMLs的LVI破坏机制发生了显著变化。80℃的高温对FML-2/1的LVI损伤有显著影响,而对FML-3/2无显著影响。


Modeling Frequency Shifts in Small-Scale Beams with Multiple Eccentric Masses

Hossein Darban, Raimondo Luciano, Michał Basista

doi:10.1016/j.tws.2024.112005

具有多个偏心质量的小尺度梁的频移建模

Studying the dynamics of small-scale beams with attached particles is crucial for sensing applications in various fields, such as bioscience, material science, energy storage devices, and environmental monitoring. Here, a stress-driven nonlocal model is presented for the free transverse vibration of small-scale beams carrying multiple masses taking into account the eccentricity of the masses relative to the beam axis. The results show excellent agreement with the experimental and numerical data in the literature. New insights into the frequency shifts and mode shapes of the first four vibrational modes of stress-driven nonlocal beams with up to three attached particles are presented. The study investigates the inverse problem of detecting the location and mass of an attached particle based on natural frequency shifts. The knowledge acquired from the present study provides valuable guidance for the design and analysis of ultrasensitive mechanical mass sensors.

研究带有附着粒子的小尺度光束的动力学对于生物科学、材料科学、储能装置和环境监测等各个领域的传感应用至关重要。本文建立了考虑质量相对于梁轴偏心率的多质量小梁横向自由振动的应力驱动非局部模型。计算结果与文献中的实验和数值数据吻合良好。提出了应力驱动的非局部梁的前四个振动模态的频移和模态振型的新见解。研究了基于固有频移的附着粒子位置和质量检测的反问题。本研究为超灵敏机械质量传感器的设计和分析提供了有价值的指导。




来源:复合材料力学仿真Composites FEM
ACTMechanicalSystemMarcDeform振动疲劳复合材料非线性海洋焊接求解技术理论水工爆炸材料储能控制
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【新文速递】2024年5月22日固体力学SCI期刊最新文章

今日更新:Journal of the Mechanics and Physics of Solids 2 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 8 篇Journal of the Mechanics and Physics of SolidsEnergy transmission through and reflection from a layer of random compositeJ.R. Willisdoi:10.1016/j.jmps.2024.105689能量通过和反射一层随机复合材料An approximate solution to the title problem for a scalar model elastic medium is obtained via a variational formulation. The layer of random composite is a mixture of two materials both of which have the same elastic modulus but different densities while the adjoining homogeneous half-spaces may have any moduli and densities. No information on the composite is assumed, other than statistical uniformity with the one- and two-point probabilities assigned. With the additional assumption of an exponential two-point correlation function, the composite supports exactly two mean plane waves and the solution is correspondingly explicit. Particular attention is paid to the total fluxes of energy. The system is excited by a plane harmonic wave incident from the lower half-space. All of the disturbance so generated is random and can be split into a mean disturbance (which is independent of the sample of the random composite) plus a disturbance whose mean is zero. Both contribute to the mean flux of energy, which conforms to the requirement of conservation of energy, both exactly and in the variational approximation. The entire solution is studied without any approximation other than that in the variational formulation.通过变分公式,得到了标量模型弹性介质标题问题的近似解。随机复合材料层是弹性模量相同但密度不同的两种材料的混合物,而相邻的均匀半空间可以具有任意模量和密度。除了给定的一点和两点概率的统计一致性外,不假设有关该组合的任何信息。通过对指数两点相关函数的附加假设,该复合结构恰好支持两个平均平面波,其解相应显式。特别注意的是总能量通量。系统由下半空间入射的平面谐波激发。这样产生的所有干扰都是随机的,可以分成一个平均干扰(与随机组合的样本无关)加上一个平均值为零的干扰。两者都有助于平均能量通量,这符合能量守恒的要求,无论是在变分近似中还是在变分近似中。研究整个解时,除了变分公式外,没有任何近似。Willis dynamic homogenization method for acoustic metamaterials based on multiple scattering theoryZhanyu Li, Peixin Han, Gengkai Hudoi:10.1016/j.jmps.2024.105692基于多重散射理论的声学超材料Willis动态均匀化方法This paper presents a spatial dispersive Willis dynamic homogenization method for acoustic metamaterials based on multiple scattering theory, which is valid for each physical dimension – 1D, 2D and 3D, and valid for arbitrary inhomogeneities/scatterers – passive or active. The homogenization can be viewed as the monopole and dipole truncation of multiple scattering theory. With the help of layer-doubling scheme, both propagating and evanescent waves can be characterized by the homogenization theory. Further, besides effective field, the theory also considers inner field (often neglected by traditional homogenizations), making it possible to study interface problems with a higher precision than traditional methods. To validate the homogenization theory, a two dimensional acoustic metamaterial composed of a square lattice of C-shape resonators is carefully studied as an application. By the proposed method, we can predict not only effective properties of bulk materials, including real and complex band structures, but also properties of interfaces, including transmission/reflection properties of a layer and dispersion of interface waves. An experiment of interface waves supported by the metamaterials is also conducted, and the results of experiments, simulations and homogenization are all in good agreement. Interestingly, two essentially different evanescent modes of the interface wave are observed in the experiment, and they can be distinguished by the proposed homogenization method, but are undistinguishable via traditional homogenizations. Finally, a detailed discussion on the limitations and some opening questions of the homogenization theory is presented. And the physical restrictions for the case of a reciprocal, passive and lossless material are additionally given and discussed. Our method paves the way for designing Willis’ type metamaterials and further realizing more novel acoustic wave-control functions.本文提出了一种基于多重散射理论的声学超材料空间色散Willis动态均匀化方法,该方法适用于一维、二维和三维物理维度,适用于任意非均匀性/散射体(被动或主动)。均匀化可以看作是多重散射理论的单极子和偶极子截断。在双层方案的帮助下,传播波和倏逝波都可以用均匀化理论来表征。此外,除了有效场之外,该理论还考虑了内场(通常被传统的均质化方法所忽略),使得该理论能够以比传统方法更高的精度研究界面问题。为了验证均匀化理论,本文研究了一种由c形谐振器的方形晶格组成的二维声学超材料的应用。通过该方法,我们不仅可以预测块状材料的有效性质,包括真实带结构和复杂带结构,还可以预测界面性质,包括层的透射/反射性质和界面波的色散。并进行了超材料支撑界面波的实验,实验结果、模拟结果和均质化结果吻合较好。有趣的是,在实验中观察到两种本质上不同的界面波的消失模式,它们可以通过所提出的均匀化方法进行区分,而通过传统的均匀化方法则无法区分。最后,详细讨论了均质化理论的局限性和一些开放性问题。另外给出并讨论了互易、被动和无损材料的物理限制。我们的方法为设计威利斯型超材料和进一步实现更多新颖的声波控制功能铺平了道路。International Journal of PlasticityCalculating the grain size effect during strain hardening through a probabilistic analysis of the mean slip distance in polycrystals.Rafael Schouwenaarsdoi:10.1016/j.ijplas.2024.104012通过多晶平均滑移距离的概率分析计算应变硬化过程中的晶粒尺寸效应。Grain refinement is an important mechanism to produce stronger alloys. Strain hardening is an essential phenomenon in metal forming processes. The interaction between grain size and strain hardening is evident: a decrease in grain size (dg) causes an increase in ultimate tensile strength but a decrease in uniform elongation. The Kocks-Mecking (KM) model for strain hardening is based on the relationship between shear strain and the path length for dislocation slip. It provides good general estimates for stress-strain curves, and empirical modifications have been made to include dg. Here, the empirical approach is substituted by theoretical probability calculations, accounting for the fact that the grain size imposes a bound on the mean slip distance, while strain compatibility defines a relationship between grain boundary-dislocation interaction and bulk storage and annihilation. The resulting differential only uses the two parameters inherent to KM. Fitting to published tensile curves for Al, Cu, and Ni produces excellent results. The fitting parameters allow to predict the tensile strength as a function of dg to good approximation, for dg &gt; 1μm. Below this limit, fundamental changes in dislocation statistics impose the activation of grain boundary dislocation sources and may induce dislocation density gradients, which seem to determine the flow stress in the sub-μm range.晶粒细化是生产强度更高的合金的重要机制。应变硬化是金属成型过程中的一个基本现象。晶粒大小与应变硬化之间的相互作用是显而易见的:晶粒大小(dg)的减小会导致极限抗拉强度的增加,但均匀伸长率却会减小。应变硬化的 Kocks-Mecking (KM) 模型基于剪切应变与位错滑移路径长度之间的关系。该模型为应力-应变曲线提供了良好的一般估计,并根据经验进行了修改,将 dg 包括在内。在这里,理论概率计算取代了经验方法,并考虑到晶粒尺寸对平均滑移距离施加了约束,而应变相容性定义了晶界-位错相互作用与块体存储和湮灭之间的关系。由此产生的差分只使用 KM 固有的两个参数。对已公布的铝、铜和镍的拉伸曲线进行拟合,结果非常好。在 dg &gt; 1μm 的情况下,拟合参数可以很好地近似预测抗拉强度与 dg 的函数关系。在此极限以下,位错统计的基本变化会导致晶界位错源的激活,并可能引起位错密度梯度,这似乎决定了亚微米范围内的流动应力。Thin-Walled StructuresVibration Analysis of Graphene-Reinforced Porous Aluminum-Based Variable-Walled Thickness Sandwich Joined Conical-Conical Panel with Elastic Boundary Conditions Using Differential Quadrature MethodH. Li, W. Zhang, Y.F. Zhangdoi:10.1016/j.tws.2024.112016用微分正交法分析弹性边界条件下石墨烯增强多孔铝基变壁厚夹层连接锥形-锥形板的振动In this paper, a unified solution is proposed to investigate the vibration characteristics of the variable-walled thickness graphene-reinforced porous aluminum-based (GRPA) sandwich joined conical-conical panel (JCCP) with the arbitrary elastic support boundary conditions by using the differential quadrature method (DQM). The two surfaces of the sandwich JCCP are made of metallic aluminum and the central core layer is the GRPA. The core thickness of each conical plate varies linearly with its generatrix. Three types of the graphene distributions and two types of porosity distributions are considered along the core thickness direction. Based on the first-order shear deformation theory (FSDT), von-Karman strain displacement relationship, constitutive relationship and Hamiltonian principle, the partial differential governing equations of motion are obtained for the variable wall thickness GRPA sandwich JCCP. Using the DQM, the dynamic equation is discretized into the ordinary differential equation. The matrix of the characteristic equation is analyzed to solve the frequencies and mode shapes of the variable wall thickness GRPA sandwich JCCP. The effects of the spring stiffness, boundary conditions, graphene distributions, porosity distributions and geometric parameters on the vibration properties are studied for the variable wall thickness GRPA sandwich JCCP with two interesting elastic supported boundary conditions. At the same time, this article provides a useful approach for studying the arbitrary boundary coupled plate and shell structures with the variable wall thickness.本文采用微分正交法(DQM)对任意弹性支承边界条件下变壁厚石墨烯增强多孔铝基(GRPA)夹层连接锥形-锥形板(JCCP)的振动特性进行了统一求解。夹层JCCP的两个表面由金属铝制成,中央芯层为GRPA。每个锥形板的芯厚随其母线呈线性变化。沿岩心厚度方向考虑了三种类型的石墨烯分布和两种类型的孔隙度分布。基于一阶剪切变形理论(FSDT)、von-Karman应变位移关系、本构关系和哈密顿原理,得到变壁厚GRPA夹层JCCP的运动偏微分控制方程。利用DQM将动力学方程离散为常微分方程。分析了变壁厚GRPA夹层JCCP的特性方程矩阵,求解了变壁厚GRPA夹层JCCP的频率和振型。研究了弹性支承边界条件下变壁厚GRPA夹层JCCP的弹性刚度、边界条件、石墨烯分布、孔隙率分布和几何参数对其振动性能的影响。同时,本文也为研究变壁厚板壳结构的任意边界耦合提供了一种有用的方法。Fold defects mechanism of aluminum alloy thin-walled stiffened cylinders during flow formingYehui Meng, Zhongqi Yu, Yixi Zhaodoi:10.1016/j.tws.2024.112018铝合金薄壁加筋汽缸流动成形时褶皱缺陷机理Flow forming is an advanced technology for manufacturing integrally thin-walled cylinders with orthometric stiffeners (longitudinal stiffeners (LSs) and transverse stiffeners (TSs)), and fold is a typical defect in this process. To understand the forming mechanism of fold defects, a flow forming finite element (FE) model of a representative cylinder with orthometric stiffeners was established, based on physical experiments. Meanwhile, the influence of geometry and process parameters on fold defects was investigated. In order to eliminate fold defects, the influence of sensitive parameter coupling on fold defects was investigated. It was found that the gap between the stiffener and groove wall in the flow forming process is the primary factor for the formation of fold defects, which is larger at the cross-region than that at TS and LS, and forms a surface pit during the subsequent forming process. Finally, the surface pit develops into the fold defect under the compression of material circumferential flow. Parametric analysis shows that the roller attack angle, groove corner radius and rotation trajectory of roller are sensitive to the development of fold defects. By coupling any two sensitive parameters, fold defects can be further weakened. By utilizing all three of them simultaneously, it is possible to completely eliminate fold defects. The results provide methods and guidance for improving the quality of aluminum alloy cylinders with orthometric stiffeners during flow forming.流动成形是制造具有正交加强筋(纵向加强筋和横向加强筋)的整体薄壁圆柱体的先进工艺,而褶皱是该工艺的典型缺陷。为了解褶皱缺陷的形成机理,在物理实验的基础上,建立了具有代表性的带正交加强筋圆柱的流动成形有限元模型。同时,研究了几何形状和工艺参数对褶皱缺陷的影响。为了消除折痕缺陷,研究了敏感参数耦合对折痕缺陷的影响。研究发现,流动成形过程中加强筋与槽壁之间的间隙是形成褶皱缺陷的主要因素,其在交叉区域的缺陷大于TS和LS,并在后续成形过程中形成表面凹坑。最后,表面凹坑在材料周向流动的压缩下发展为褶皱缺陷。参数化分析表明,轧辊攻角、槽角半径和轧辊旋转轨迹对褶皱缺陷的发展较为敏感。通过耦合任意两个敏感参数,可以进一步削弱褶皱缺陷。通过同时使用这三种方法,可以完全消除褶皱缺陷。研究结果为提高带正交加强筋的铝合金圆柱流动成形质量提供了方法和指导。Stress localization investigation of additively manufactured GRCop-42 thin-wall structureSubhadip Sahoo, Mohammad M. Keleshteri, Jason R. Mayeur, Kavan Hazelidoi:10.1016/j.tws.2024.112022增材制造GRCop-42薄壁结构应力局部化研究A full-field crystal plasticity (CP) framework is presented for the GRCop-42 alloy to study microscopic mechanical behavior and local stress heterogeneities. The microstructures of additively manufactured (AM) materials are often unique relative to conventionally processed materials, and the local thermal histories drive these differences during the build process. These thermal histories depend on the process parameters (laser power, scan speed, and scan strategy) and the part geometry. Prior research has shown that the mechanical properties of thin-walled structures can vary significantly with wall thickness due to changes in the thermal boundary conditions during manufacturing. It is, therefore, desirable to perform CP simulations based on the phenomenological constitutive model to predict the local mechanical responses induced by microstructural heterogeneities. This work generates representative microstructures based on experimentally collected grain information (i.e., texture) for grain scale stress analysis, and the material constitutive parameters are calibrated using the experimental mechanical testing data. We specifically investigated the effect of crystallographic texture and grain morphologies on the size-dependent mechanical properties of AM GRCop-42. The selection of appropriate material properties for implementing an effective free surface boundary condition and the influence of adjacent buffer layers are also discussed. Analysis of local field results reveals a strong correlation between stress localization and the initial grain orientation. However, no significant relationship between the misorientation of the individual adjacent grains and the average misorientation is observed.提出了一种用于研究GRCop-42合金微观力学行为和局部应力非均质性的全场晶体塑性框架。与传统加工材料相比,增材制造(AM)材料的微观结构通常是独特的,而在构建过程中,局部热历史驱动了这些差异。这些热历史取决于工艺参数(激光功率、扫描速度和扫描策略)和零件几何形状。先前的研究表明,由于制造过程中热边界条件的变化,薄壁结构的力学性能会随着壁厚的变化而发生显著变化。因此,需要基于现象学本构模型进行CP模拟,以预测微观结构非均质性引起的局部力学响应。本工作基于实验收集的晶粒信息(即织构)生成具有代表性的微观组织,用于晶粒尺度应力分析,并利用实验力学测试数据校准材料本构参数。我们专门研究了晶体织构和晶粒形态对AM GRCop-42的尺寸相关力学性能的影响。为实现有效的自由表面边界条件选择合适的材料性能以及相邻缓冲层的影响也进行了讨论。局部实测结果分析表明,应力局部化与初始晶粒取向之间存在较强的相关性。然而,单个相邻晶粒的取向偏差与平均取向偏差之间没有显著的关系。Topology optimization of stiffened revolution shell structures using multi-regional anisotropic MFSE methodZhonghao Gao, Yan Li, Lili Fu, Kai Yang, Yangjun Luodoi:10.1016/j.tws.2024.112030基于多区域各向异性MFSE方法的加劲旋转壳结构拓扑优化Stiffened revolution shell structures, prevalent in thin-walled load-bearing components across engineering disciplines, pose challenges in optimizing structural load-bearing capacity while maintaining ease of manufacturability and regularity of the structure. This paper presents an innovative anisotropic correlation-based material field series expansion (MFSE) method for topology optimization of stiffened revolution shell structures with multi-region strategy. In contrast to classical continuum topology optimization methods, the proposed approach directly represents regular stiffeners and provides smooth structural boundary description, without external manufacturing constraints. Leveraging the unique characteristics of revolution shell structures, a single anisotropic material field depicts uniformly oriented regular straight stiffeners organized into clusters. Multiple clusters of stiffeners are derived from two fundamental orthogonal stiffener clusters and integrated into a unified topological configuration through an innovative superposition function. Throughout the optimization process, the number, location and size of the optimized stiffeners are entirely determined by the specific problem and optimization procedure without necessitating special initial guess. Moreover, customizing or optimizing the shape of stiffener clusters to accommodate diverse loading conditions can be achieved through predefined structural forms. Ultimately, several numerical examples are solved using a gradient-based optimization algorithm incorporating the provided design sensitivity analysis program, validating the effectiveness of the proposed method.在工程学科薄壁承重部件中普遍存在的加筋转壳结构,在保持结构易于制造性和规律性的同时,对优化结构承载能力提出了挑战。提出了一种新颖的基于各向异性相关的材料场序列展开(MFSE)方法,用于多区域加筋旋转壳结构拓扑优化。与传统的连续体拓扑优化方法相比,该方法直接表示规则加强筋,并提供平滑的结构边界描述,不受外部制造约束。利用旋转壳结构的独特特性,单一的各向异性材料场描绘了组织成簇的均匀定向规则直加强筋。从两个基本的正交加劲筋簇中衍生出多个加劲筋簇,并通过创新的叠加函数集成为统一的拓扑构型。在整个优化过程中,优化加强筋的数量、位置和尺寸完全由具体问题和优化程序决定,无需特别的初始猜测。此外,通过预定义的结构形式,可以定制或优化加强筋簇的形状,以适应不同的加载条件。最后,结合所提供的设计灵敏度分析程序,用基于梯度的优化算法求解了几个数值算例,验证了所提方法的有效性。Verification of Euler–Bernoulli beam theory model for wind blade structure analysisPratiwi Fudlailah, David H. Allen, Roger Cordesdoi:10.1016/j.tws.2024.111989欧拉-伯努利梁理论模型在风叶片结构分析中的验证This paper presents a computational tool for analyzing the structural response of wind turbine blades using the advanced Euler–Bernoulli Beam theory. The objective is to achieve efficient computation of blade structural response under aerodynamic loading without sacrificing computational accuracy. This study involves the development of a Python-based computer program as a numerical tool, which utilizes inputs such as blade geometry and aerodynamic loading from Blade Element Momentum theory. The program outputs axially varying moments of inertia, spatial deflections of the blade, and stress distributions within the blade. The numerical tool is verified by comparing the results with both analytical solutions and far more time-consuming commercial finite element solvers. One of the key contribution of this research is the application of the polygon algorithm, which efficiently calculates the moments of inertia of web-stiffened turbine blades along the blade length. It is shown herein that this algorithm significantly reduces computational time while maintaining numerical accuracy as compared to the results obtained from commercially available finite element codes. The study confirms that the advanced Euler–Bernoulli beam theory, when combined with the polygon algorithm, is capable of accurately predicting the structural response of cambered and twisted wind turbine blades during the initial design phase.本文提出了一种利用先进的欧拉-伯努利梁理论分析风力机叶片结构响应的计算工具。目的是在不牺牲计算精度的前提下,实现气动载荷下叶片结构响应的高效计算。本研究涉及开发基于python的计算机程序作为数值工具,该程序利用叶片几何形状和叶片单元动量理论的气动载荷等输入。该程序输出轴向变化的惯性矩、叶片的空间挠度和叶片内的应力分布。通过将结果与解析解和更耗时的商业有限元解进行比较,验证了数值工具的有效性。本研究的关键贡献之一是多边形算法的应用,该算法有效地计算了腹板加筋涡轮叶片沿叶片长度的转动惯量。本文表明,与商业上可用的有限元代码获得的结果相比,该算法在保持数值精度的同时显著减少了计算时间。研究证实,先进的欧拉-伯努利梁理论与多边形算法相结合,能够准确预测弯曲和扭曲风力发电机叶片在初始设计阶段的结构响应。Numerical investigation of joinability and forming quality improvement on self-piercing riveting process with varying sheet stack combinationsChao Wang, Zhanpeng Du, Aiguo Cheng, Zhicheng Hedoi:10.1016/j.tws.2024.112017不同板堆组合自穿孔铆接性能及成形质量改善的数值研究Reducing complexity and increasing efficiency of the self-piercing riveting (SPR) process in joining varying sheet stack combinations by reducing the required rivet-die combinations have attracted great attention in the automobile industry. In this paper, the SPR joinability and the joining ranges of material strength and thickness of three types of stack combinations (e.g., steel-aluminium (SA), aluminium-aluminium (AA), and aluminium-steel (AS)) are investigated. In particular, the forming quality improvement process is developed to solve the forming quality defects generated in the riveting process. Two-dimensional axisymmetric finite element (FE) models are developed for each stack combination to simulate the SPR process, and the effects of rivet hardness, die type, sheet material and sheet thickness on the SPR joinability are studied numerically. The results show that the SPR joinability decreases with the increase in the thickness ratio, and the SPR joinability approaches zero when the thickness ratio exceeds 1.47. The rivet H4 and rivet H6 with a flat die can achieve higher SPR joinability compared to rivet H1. Specifically, the rivet H4 is suitable for joining the AA stack, and the rivet H6 is suitable for joining the SA and AS stacks. The average undercut ratio increases with the increase in rivet hardness, while a decreasing tendency is observed with the increase in thickness ratio. The rivet stiffness and hardness can be adjusted to solve the forming quality parameter defects and overcome upsetting deformation defects. Switching the riveting direction for the large thickness ratios (1.47 and 2.08) has proven to be an effective method to achieve successful joining.通过减少铆钉与模具的组合,降低不同板层组合的自穿孔铆接的复杂性,提高其效率,已成为汽车工业关注的焦点。本文研究了钢-铝(SA)、铝-铝(AA)和铝-钢(AS)三种堆叠组合的SPR接合性以及材料强度和厚度的接合范围。特别针对铆接过程中产生的成形质量缺陷,开发了成形质量改进工艺。建立了各叠层组合的二维轴对称有限元模型,对SPR焊接过程进行了数值模拟,研究了铆钉硬度、模具类型、板材材料和板材厚度对SPR焊接性能的影响。结果表明:随着厚度比的增大,SPR的可焊性逐渐降低,当厚度比超过1.47时,SPR的可焊性趋于零;与铆钉H1相比,带平模的铆钉H4和铆钉H6可以获得更高的SPR接合性。具体来说,铆钉H4适用于连接AA堆栈,铆钉H6适用于连接SA和AS堆栈。平均凹边率随铆钉硬度的增大而增大,随厚度比的增大而减小。通过调整铆钉刚度和硬度,解决了成形质量参数缺陷,克服了镦粗变形缺陷。在大厚度比(1.47和2.08)时,改变铆接方向是实现成功连接的有效方法。Capture Dynamics and Driving method of Origami capture mechanism in OrbitGang Wang, Qihui Zhang, Xi Hu, Kun Wang, Fei Yang, Honghao Yuedoi:10.1016/j.tws.2024.112019折纸捕获机构在轨捕获动力学及驱动方法This article focuses on the dynamic problem of origami capture mechanism capturing space debris in orbit. It delves into the envelope characteristics of the origami capture mechanism, analyzing the motion laws of its axisymmetric folding state. Furthermore, it establishes a kinematic model for the axisymmetric envelope of the origami capture mechanism. A rigid body dynamic model of the origami capture mechanism and a generalized torque equation for the hinge at the crease were established based on the D-H parameter method and the Lagrange method. The enveloping process of the origami capture mechanism in the microgravity environment was simulated using ADAMS software, and the accuracy of the rigid body dynamics model of the origami capture mechanism and the generalized moment equation of the hinge at the crease was verified. Using Ls-Dyna software to simulate the capture process of space debris by force-driven and displacement-driven flexible origami capture mechanisms in microgravity environments, the results show that displacement-driven origami capture mechanisms can quickly capture space debris and are suitable for capturing large-sized space debris; The force-driven origami capture mechanism can quickly complete envelope capture of space debris, suitable for capturing small-sized space debris.研究了折纸捕获机构捕获在轨空间碎片的动力学问题。深入研究了折纸捕获机构的包络特性,分析了其轴对称折叠态的运动规律。建立了折纸捕获机构轴对称包络的运动学模型。基于D-H参数法和拉格朗日方法,建立了折纸捕获机构的刚体动力学模型和折痕处铰链的广义力矩方程。利用ADAMS软件对微重力环境下折纸捕获机构的包络过程进行了仿真,验证了折纸捕获机构刚体动力学模型和折痕处铰链广义力矩方程的准确性。利用Ls-Dyna软件模拟了在微重力环境下力驱动和位移驱动柔性折纸捕获机构对空间碎片的捕获过程,结果表明:位移驱动折纸捕获机构能够快速捕获空间碎片,适合于捕获大尺寸空间碎片;力驱动折纸捕获机构能快速完成空间碎片包络捕获,适用于小尺寸空间碎片的捕获。Stiffness and ultimate strength of multi-ring-stiffened tube-gusset X-joints with dual-function stiffenersSongzhao Qu, Jun Yuan, Quan Zhang, Qing Sundoi:10.1016/j.tws.2024.112021带双功能加强筋的多环加筋管扣板x型节点的刚度和极限强度Tube-gusset (TG) joints that use stiffener plates as connecting plates for the crossarm chord are the main method for joining chords to tower bodies of transmission steel pipe towers. These joints experience the highest compression loads of the entire transmission tower structure. This study presents experimental research, numerical simulations, and theoretical analysis on the TG joint with a five-ring stiffener, where the middle stiffener plate serves as a connecting plate (referred to as C-Stiffener). This study elucidates the failure mechanism and mechanical characteristics of the C-Stiffener, identifies the key factors influencing its local buckling under compression, and proposes a stiffness calculation method for this type of stiffener plate. A calculation approach for the ultimate bearing capacity of the C-Stiffener is established by utilising its stiffness-deformation curve and a calculation method for the ultimate bearing capacity of the five-ring-stiffened TG joint under axial compression loading is proposed. The findings of this study can provide guidance for the meticulous design of joints between the crossarms and bodies of steel pipe transmission towers, thereby ensuring the safety and stability of transmission lines.采用加劲板作为横臂弦连接板的管扣节接是传输钢管塔与塔体连接弦的主要方式。这些节点承受着整个输电塔结构中最高的压缩载荷。本文对中间加劲板作为连接板(简称c -加劲板)的五环加劲板TG接头进行了实验研究、数值模拟和理论分析。阐明了c型加劲板的破坏机理和力学特性,确定了影响c型加劲板受压局部屈曲的关键因素,提出了c型加劲板的刚度计算方法。利用c型加筋刚度-变形曲线建立了c型加筋极限承载力的计算方法,提出了轴压载荷下五环加筋TG节点极限承载力的计算方法。研究结果可为钢管输电塔横臂与塔身连接处的精细设计提供指导,从而保证输电线路的安全稳定。来源:复合材料力学仿真Composites FEM

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