
今日更新:International Journal of Solids and Structures 3 篇,Journal of the Mechanics and Physics of Solids 1 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 7 篇
Strain-rate-independent elasticity and strain-rate-sensitive plasticity in metallic glass stochastic network nanostructure
Yuhang Zhang, Xiuming Liu, Yiqun Hu, Suhang Ding
doi:10.1016/j.ijsolstr.2025.113742
金属玻璃随机网络纳米结构的应变率无关弹性和应变率敏感塑性
Metallic materials with nanoscale voids have emerged as a novel class of structural and functional materials due to their unique properties. This study employs molecular dynamics simulations to investigate the strain-rate-dependent mechanical behaviors of Cu50Zr50 metallic glass stochastic network nanostructure (MGSNN) under uniaxial tension and compression over the strain rates from 5 × 106 to 5 × 109 s–1. It is found that the MGSNN exhibits strain-rate-independent elasticity and prominent strain-rate-sensitive plasticity. The Young’s modulus remains nearly constant, whereas the yield strength and ultimate tensile strength (UTS) significantly increase with increasing strain rate. This phenomenon originates from intrinsic deformation mechanis ms: elastic response is governed by bond stretching that is inherently strain-rate-independent, whereas plastic deformation involves shear transformation zone activation and extension, which requires strain energy release and is strongly strain-rate-dependent. At higher strain rates, the release of energy is more difficult, and thus, the activation and appreciation of plastic events are restricted. As a result, the yield strength, yield strain, and UTS are enhanced at higher strain rates. The sequential yielding, necking, and breakage of individual nanowires are hindered at higher strain rates, resulting in the delayed global fracture of the MGSNN. A modified Gibson-Ashby relation comprising the strain rate effect precisely predicts the yield strength. The findings provide fundamental insights into the deformation mechanis ms of amorphous porous nanostructures and establish guidelines for designing metallic glass nanofoams with tailored mechanical properties for structural and functional applications.
具有纳米级空隙的金属材料由于其独特的性能而成为一类新型的结构和功能材料。本文采用分子动力学模拟方法研究了Cu50Zr50金属玻璃随机网络纳米结构(MGSNN)在应变速率为5 × 106 ~ 5 × 109 s-1的单轴拉伸和压缩条件下随应变速率变化的力学行为。结果表明,MGSNN具有应变率无关的弹性和显著的应变率敏感塑性。杨氏模量几乎保持不变,而屈服强度和极限抗拉强度(UTS)随着应变速率的增加而显著增加。这种现象源于固有的变形机制:弹性响应由固有的应变速率无关的键拉伸控制,而塑性变形涉及剪切转变区的激活和扩展,这需要应变能释放,并且与应变速率密切相关。在较高的应变速率下,能量的释放更加困难,因此,塑性事件的激活和欣赏受到限制。因此,在较高的应变速率下,屈服强度、屈服应变和UTS都得到了提高。在较高的应变速率下,单个纳米线的顺序屈服、颈缩和断裂受到阻碍,导致MGSNN的整体断裂延迟。包含应变率效应的修正Gibson-Ashby关系式可以准确地预测屈服强度。这些发现为非晶多孔纳米结构的变形机制提供了基本的见解,并为设计具有结构和功能应用的定制机械性能的金属玻璃纳米泡沫提供了指导。
Stochastic identification of transversally isotropic elastic tensor generated from a micromechanics model for equi-biaxially stretched polymer
Luc Chevalier, Yun-Mei Luo
doi:10.1016/j.ijsolstr.2025.113743
等双轴拉伸聚合物微力学模型中横向各向同性弹性张量的随机识别
The paper focusses on the probabilistic study of transversally isotropic (TI) elastic tensors properties generated by fast equi-biaxial (EB) stretching of polyethylene terephthalate (PET) sheets. The transformation from an initially isotropic amorphous sheet to an anisotropic stretched plate is a complex process, and the resulting elastic properties exhibit variations that depend on the processing conditions. The experimental variations observed on the parameters of the micromechanical model are identified and probability density functions (PDF) are built. A Monte-Carlo simulation is conducted to generate a stochastic TI elastic tensor. The PDF of the stochastic elastic tensor, reflecting the TI symmetry class, is identified an alytically. The Markov chain Monte Carlo (MCMC) generation of this last is compared to the results of the Monte-Carlo simulation obtained from the micromechanical model. The observed differences are an alyzed and discussed.
本文主要研究了快速等双轴(EB)拉伸聚对苯二甲酸乙二醇酯(PET)片材所产生的横向各向同性(TI)弹性张量特性的概率性。从最初的各向同性非晶片到各向异性拉伸板的转变是一个复杂的过程,并且由此产生的弹性性能表现出依赖于加工条件的变化。识别了实验观测到的细观力学模型参数的变化,建立了概率密度函数。通过蒙特卡罗模拟生成随机TI弹性张量。对反映TI对称类的随机弹性张量的PDF进行了解析识别。最后将马尔可夫链蒙特卡罗(MCMC)生成的结果与从微观力学模型中获得的蒙特卡罗模拟结果进行了比较。对观察到的差异进行了分析和讨论。
Dual tunability in flexural and torsional bandgaps for pipe systems using perforated auxetic rings
Yutong Yuan, Hui Wang
doi:10.1016/j.ijsolstr.2025.113747
管道系统的弯曲和扭转带隙的双重可调性
The mid-low frequency vibration of pipes caused by external excitations or internal fluid flow significantly impacts their functionality and service life. For this aim, a novel pipe-vibration-isolation design is proposed, featuring a periodic arrangement of meta-rings bonded to the pipe’s surface along the axial direction to form a combined structure. Each meta-ring incorporates orthogonally aligned peanut-shaped holes in both radial and circumferential directions. First, a simplified combined pipe model with solid rings is solved by theoretical ana lysis to explore its bandgap characteristics and validate the established finite element model. Then, the superiority of the peanut-shaped perforation in generating lower-frequency bandgap is demonstrated by comparing to the rectangular and elliptical perforations and the solid cases. Thirdly, the vibration-isolation capacity of the combined pipe is numerically investigated in time- and frequency-domains, and the effects of the design parameters of the meta-ring on the bandgap characteristics of the combined pipe are discussed. The main findings include: (1) the dual tunability for the flexural and torsional waves is realized by the proposed meta-ring design; (2) the local resonance induced by the coupling of meta-rings and pipe creates significant mid-frequency bandgaps; (3) the bandgap of the combined pipe considerably depend on meta-ring’s material and geometrical dimensions. Particularly, bandgap frequencies can drop below 20 Hz when silicone rubber is used.
由于外部激励或内部流体流动引起的管道中低频振动严重影响管道的功能和使用寿命。为此,提出了一种新型的管道隔振设计,其特点是在管道表面沿轴向周期性地布置元环,形成一个组合结构。每个元环在径向和周向上都包含正交排列的花生形孔。首先,通过理论分析求解了带实体环的简化组合管模型,探索了其带隙特性,并验证了所建立的有限元模型。然后,通过与矩形、椭圆形穿孔和固体情况的比较,证明了花生形穿孔在产生低频带隙方面的优越性。在时域和频域上对组合管的隔振能力进行了数值研究,并讨论了元环设计参数对组合管带隙特性的影响。主要研究结果包括:(1)通过提出的元环设计实现了弯扭波的双重可调谐;(2)元环与管道耦合引起的局部共振产生显著的中频带隙;(3)组合管的带隙与元环的材料和几何尺寸有很大的关系。特别是,当使用硅橡胶时,带隙频率可以降至20 Hz以下。
Effects of multiscale substructures on the effective behavior and field statistics of porous materials
Shuvrangsu Das
doi:10.1016/j.jmps.2025.106411
多尺度子结构对多孔材料有效行为和场统计的影响
This work investigates the effects of multiscale substructure on the mechanical response of porous materials. First, we consider porous materials consisting of two populations of cylindrical pores embedded in an incompressible anisotropic viscous matrix and obtain ana lytical estimates for the overall response and field statistics under plane-strain loading in transverse plane. We demonstrate that the effective bulk viscosity of three-scale porous materials is lower compared to that of two-scale porous materials, whereas the effective shear viscosity remains unaffected. However, the stress and strain-rate fields become substantially more heterogeneous because of the multiscale substructure, with the enhancement increasing with the anisotropy of the viscous matrix, the total pore volume fraction, and the relative volume fraction of large and s mall pores. Next, we consider porous polycrystals in which the pores of two populations are distributed in a polycrystalline material composed of anisotropic viscous grains. Depending on the relative sizes of the pores to the grains, three types of porous polycrystals are considered: porous polycrystals containing intergranular pores and voids; porous polycrystals with porous grains and intergranular pores; and porous polycrystals with porous grains and voids. As before, the overall deviatoric response remains largely independent of the relative sizes of pores and grains, but the polycrystals containing porous grains show a softer dilatational response than the other two types of porous polycrystals. Moreover, the polycrystals consisting of intragranular pores exhibit substantially more heterogeneity of the stress and strain-rate fields, compared to polycrystals containing only voids or intergranular pores. While this work focuses on multiscale porous viscous materials, the framework to derive the overall response and field statistics is quite general and, with an appropriate linearization scheme, it can be extended to multiscale porous viscoplastic materials. In this work, however, we considered porous materials with anisotropic viscous phases and focused on uncovering the effects of multiscale substructures, which are found to significantly influence the field statistics of porous materials with strongly anisotropic phases.
本文研究了多尺度子结构对多孔材料力学响应的影响。首先,我们考虑了由嵌套在不可压缩各向异性粘性矩阵中的两类圆柱孔组成的多孔材料,并获得了横向平面应变加载下的总体响应和场统计的解析估计。我们证明了三尺度多孔材料的有效体积粘度比两尺度多孔材料低,而有效剪切粘度不受影响。但由于多尺度子结构的存在,应力场和应变率场的非均质性明显增强,且随黏性基质的各向异性、总孔隙体积分数、大小孔隙相对体积分数的增加而增强。接下来,我们考虑多孔多晶,其中两个种群的孔隙分布在由各向异性粘性颗粒组成的多晶材料中。根据孔隙与晶粒的相对大小,可以考虑三种类型的多孔多晶:含有晶间孔隙和空隙的多孔多晶;具有多孔颗粒和粒间孔隙的多孔多晶;以及带有多孔颗粒和空隙的多孔多晶。与之前一样,总体偏差响应在很大程度上与孔隙和晶粒的相对大小无关,但含有多孔颗粒的多晶比其他两种类型的多孔多晶表现出更柔和的膨胀响应。此外,与只含有孔洞或粒间孔洞的多晶相比,由粒内孔洞组成的多晶表现出更强的应力和应变率场的非均质性。虽然本研究的重点是多尺度多孔粘塑性材料,但推导整体响应和场统计的框架是相当通用的,通过适当的线性化方案,可以将其扩展到多尺度多孔粘塑性材料。然而,在这项工作中,我们考虑了具有各向异性黏性相的多孔材料,并重点揭示了多尺度子结构的影响,发现多尺度子结构对具有强各向异性相的多孔材料的场统计有显著影响。
Theoretical and numerical investigations of dislocation evolution and anisotropic plasticity in UO2
Mengke Cai, Tenglong Cong, Yinan Cui, Yang Li, Zhifang Qiu, Zhipeng Sun, Hanyang Gu
doi:10.1016/j.ijplas.2025.104538
UO2中位错演化及各向异性塑性的理论与数值研究
Uranium dioxide (UO2), the most widely used nuclear fuel, exhibits complex plasticity and highly anisotropic mechanical properties. Under high burnup conditions, the rim region is formed with tangled dislocation networks in UO2, involving the propagation and interaction of dislocations in multiple slip systems, leading to distinct behaviors compared to the traditional metals. In this work, we proposed an atomic-informed dislocation mobility law corresponding to both {100} and {110} slip systems, with all parameters calibrated from experiments. By employing this newly developed mobility law as well as a thermally activated cross-slip model, we carried out three-dimensional discrete dislocation dynamics (DDD) simulations to explore the anisotropic plastic responses of UO2 across a wide range of temperatures from 900K to 1900K. The temperature dependence of critical resolved shear stress of {100} and {110} slip systems has been successfully reproduced by our simulations, which agrees well with experimental data. A strong orientation and temperature dependent yield strength has been observed from the single crystal UO2 tensile tests, which agrees well with experiments. Notably, the experimentally observed yield stress drop of UO2 is reproduced in our DDD simulations, rooted in the slip system transition from the {110} (hard) to {100} (easy) slip systems. To highlight the interplay of dislocations in different slip systems, a dislocation density evolution model was established, incorporating dislocation multiplication, annihilation, cross-slip, and junction formation mechanis ms. This model not only accurately predicts the dislocation density evolution for both {100} and {110} slip systems, but also reveals the underlying mechanis m for the aforementioned slip transition behaviors. In conjunction with the dislocation mobility law, a dislocation-based crystal plasticity model was developed which can accurately predict the macroscopic mechanical response of single crystal UO2 under different temperatures and strain rates. These insights are expected to shed light on understanding the mechanical anisotropy of UO2 under high irradiation dose and complex loading conditions.
二氧化铀(UO2)是应用最广泛的核燃料,具有复杂的塑性和高度各向异性的力学性能。在高燃耗条件下,UO2在边缘区域形成缠结位错网络,涉及多滑移体系中位错的传播和相互作用,导致与传统金属不同的行为。在这项工作中,我们提出了一个与{100}和{110}滑移系统相对应的原子信息位错迁移率定律,所有参数都是从实验中校准的。利用这一迁移率定律和热激活交叉滑移模型,我们进行了三维离散位错动力学(DDD)模拟,探讨了UO2在900K至1900K范围内的各向异性塑性响应。模拟结果成功地再现了{100}和{110}滑移系统临界分解剪应力的温度依赖性,与实验数据吻合较好。从UO2单晶拉伸试验中观察到很强的取向和温度依赖性屈服强度,这与实验结果吻合得很好。值得注意的是,实验观察到的UO2屈服应力下降在我们的DDD模拟中得到了再现,这是由于滑移系统从{110}(硬)到{100}(易)滑移系统的转变。为了突出位错在不同滑移体系中的相互作用,建立了位错密度演化模型,包括位错增殖、湮灭、交叉滑移和结形成机制。该模型不仅准确地预测了{100}和{110}滑移体系的位错密度演变,而且揭示了上述滑移转变行为的潜在机制。结合位错迁移率规律,建立了基于位错的晶体塑性模型,该模型可以准确预测不同温度和应变速率下UO2单晶的宏观力学响应。这些发现将有助于理解UO2在高辐照剂量和复杂载荷条件下的力学各向异性。
Flexural performance tests and bearing capacity calculation method for steel–UHPC–steel composite beams incorporating longitudinal and transverse diaphragms
Xin Wang, Muyu Liu, Qi Li, Tengfei Wang
doi:10.1016/j.tws.2025.114179
纵向和横向隔板钢- uhpc -钢组合梁抗弯性能试验及承载力计算方法
To enhance the load-bearing capacity and impact resistance of steel–concrete–steel composite structures (SCSCSs), this study investigated replacing conventional concrete with ultra-high-performance concrete (UHPC). A novel steel–UHPC–steel composite structure (SUSCS), featuring a steel shell compartmentalized by longitudinal and transverse diaphragms, was proposed. This configuration, however, results in a discontinuous UHPC distribution. Existing methods for calculating the flexural capacity of SUSCSs do not account for the effects of compartmentalization. To investigate the mechanis m and effect of installing longitudinal and transverse diaphragms on the flexural capacity of SUSCSs, eight steel–UHPC–steel composite beam (SUSCB) designs were an alyzed through theoretical calculations, beam tests, and finite element simulations. The failure mechanis ms, damage characteristics, and crack propagation patterns of SUSCBs with diaphragms were investigated. Based on these an alyses, finite element models were developed, novel schematic diagrams for calculating flexural capacity were proposed, and a method incorporating the effects of longitudinal and transverse diaphragms was established. Results show that installation of longitudinal diaphragms increased the flexural capacity of SUSCBs by 34.1%, while transverse diaphragms reduced it by 7.1%. The theoretically calculated flexural capacities closely matched experimental values, with an average error of only 3%. These findings provide a robust a nalytical basis for the design and construction of SUSCSs.
为了提高钢-混凝土-钢组合结构(SCSCSs)的承载能力和抗冲击能力,研究了用超高性能混凝土(UHPC)替代传统混凝土的方法。提出了一种新型钢- uhpc -钢复合结构(SUSCS),其钢壳由纵向和横向隔板分隔。然而,这种配置导致UHPC分布不连续。现有的计算suscs抗弯能力的方法没有考虑到分区的影响。为了研究安装纵向隔板和横向隔板对SUSCB抗弯承载力的影响机理和影响,通过理论计算、梁试验和有限元模拟分析了8种钢- uhpc -钢组合梁(SUSCB)设计。研究了带隔板suscb的破坏机理、损伤特征和裂纹扩展模式。在此基础上,建立了有限元模型,提出了新的抗弯承载力计算原理图,并建立了考虑纵横隔板影响的抗弯承载力计算方法。结果表明,安装纵向隔板可使suscb的抗弯承载力提高34.1%,横向隔板可使suscb的抗弯承载力降低7.1%。理论计算的抗弯承载力与实验值接近,平均误差仅为3%。这些发现为suscs的设计和建造提供了强有力的分析基础。
A universal parametric nonlinear model order reduction method for complex shell structures
Yipeng Liu, Wei Fan, Tengfei Yuan, Shengjun Zeng, Hui Ren
doi:10.1016/j.tws.2025.114185
复杂壳结构的通用参数非线性模型降阶方法
To address constructing nonlinear reduced-order models for perforated shell structures with complex geometries, this paper proposes a universal nonlinear model reduction technique. Utilizing conformal mapping that preserves inherent modal properties, the technique establishes reduction bases for such structures in the mapped plane. The proposed method employs boundary first flattening (BFF) to map non-planar shells to planar domains for global parameterization of complex shells. Within the mapped parametric plane, higher-order elements are employed for high-accuracy computation of parametric modes and modal derivatives, establishing parametric nonlinear reduced-order models for non-planar shells. By exploiting the decoupling of in-plane and out-of-plane deformations in planar structures, the static condensation method (SCM) is employed within the parametric plane to further reduce degrees of freedom (DoFs). The optimal static condensation method (OSCM), which is directly applicable to complex non-planar shells, is developed without the need for additional mathematical modes. The approach is applicable to modal reduction of arbitrarily complex non-planar shells. With computational accuracy maintained, a significant reduction in system DoFs is achieved, providing a solution for real-time a nalysis and control of complex multibody systems.
为解决复杂几何孔壳结构非线性降阶模型的构造问题,提出了一种通用的非线性模型降阶技术。利用保角映射保留固有模态属性,该技术在映射平面上建立了这种结构的还原基。该方法采用边界优先平坦化(BFF)将非平面壳映射到平面域,实现复杂壳的全局参数化。在映射的参数平面内,采用高阶元进行参数模态和模态导数的高精度计算,建立非平面壳的参数化非线性降阶模型。利用平面结构面内、面外变形的解耦特性,在参数平面内采用静凝聚法进一步降低结构的自由度。在不需要附加数学模型的情况下,建立了直接适用于复杂非平面壳结构的最优静态凝结法。该方法适用于任意复杂非平面壳的模态简化。在保证计算精度的前提下,实现了系统自由度的显著降低,为复杂多体系统的实时分析和控制提供了一种解决方案。
Nonlinear internal resonance in graphene platelet-reinforced metal foam plates: Straight-side quadrilateral geometry effects
Zhong-Shi Ma, Gui-Lin She, M.A. Eltaher
doi:10.1016/j.tws.2025.114186
石墨烯平板增强金属泡沫板的非线性内部共振:直边四边形几何效应
This research a nalyzes nonlinear dynamics in straight-edged quadrilateral graphene platelet-reinforced metal foam (GPLRMF) plates of arbitrary shape, focusing on the unique case of 1:3 internal resonance. The equivalent mechanical properties of GPLRMF composite materials were evaluated using the mixture rule and Halpin-Tsai model. Based on the first-order shear deformation theory (FSDT) and von Kármán geometric nonlinearity assumption, the lateral vibration control equation for quadrilateral plates was derived through Hamilton's principle, accounting for in-plane displacement, rotational inertia, and shear deformation effects. The generalized differential quadrature method (GDQM) was used to discretize the control equations and boundary conditions in space, followed by the numerical Galerkin method to transform them into Duffing-type nonlinear equations. Subsequently, the modulation equations for 1:3 internal resonance in polar and Cartesian coordinate systems were established using the multiscale method. By employing the Runge-Kutta algorithm and nonlinear equation solver, the study traced the nonlinear dynamic solutions and steady-state equilibrium solutions, and constructed the bifurcation characteristic diagram accordingly. Finally, the influence mechanis ms of the damping coefficient, external excitation amplitude, detuning parameters, and material parameters on the 1:3 internal resonance nonlinear dynamic behavior were ana lyzed. The results demonstrate that systematically varying the vertex angles (βL, βR ) of a quadrilateral plate adjusts structural asymmetry and stiffness, thereby shifting resonance peaks and expanding the multi-valued solution region. Furthermore, an optimal frequency detuning parameter enhances inter-modal energy transfer efficiency.
本研究分析了任意形状的直边四边形石墨烯片状增强金属泡沫(GPLRMF)板的非线性动力学,重点研究了1:3内部共振的独特情况。采用混合规则和Halpin-Tsai模型对GPLRMF复合材料的等效力学性能进行了评价。基于一阶剪切变形理论(FSDT)和von Kármán几何非线性假设,利用Hamilton原理推导了考虑面内位移、转动惯量和剪切变形影响的四边形板横向振动控制方程。采用广义微分正交法(GDQM)对控制方程和边界条件进行空间离散化,然后采用数值Galerkin方法将其转化为duffing型非线性方程。随后,利用多尺度方法建立了在极坐标系和直角坐标系下1:3内共振的调制方程。采用龙格-库塔算法和非线性方程求解器,对非线性动力解和稳态平衡解进行了跟踪,并据此构造了分岔特征图。最后,分析了阻尼系数、外激励幅值、失谐参数和材料参数对1:3内共振非线性动力特性的影响机理。结果表明,系统地改变顶点角(βL, βR )调整结构的不对称性和刚度,从而移动共振峰,扩大多值解区域。此外,最优频率失谐参数提高了模态间能量传递效率。
Reinforced structural design, additive manufacturing and crashworthiness of continuous fiber reinforced composite Negative Poisson’s Ratio (NPR) honeycomb
Hongyong Jiang, Shuheng Xiao, Yuan Yang, Qinglei Sun, Tiancai Xie, Yiru Ren, Zhihui Liu
doi:10.1016/j.tws.2025.114190
连续纤维增强复合材料负泊松比(NPR)蜂窝的增强结构设计、增材制造及耐撞性
In this work, the reinforced design, continuous fiber 3D-printing and crashworthiness of composite Negative Poisson’s Ratio (NPR) honeycombs are investigated. Two types of NPR honeycombs are designed, including design-I with a double-layer configuration, and design-II incorporating inclined reinforcement rods. Single-stroke continuous fibers 3D-printing paths are strategically planned to align with the unique geometry of complex samples, thereby minimizing fiber dragging and ensuring structural continuity. The process parameters, including line width and layer thickness, are studied to reduce manufacturing defects. Effects of feature sizes on the crashworthiness of samples are studied. The trends in printing defects, such as fiber dragging and fiber-free areas, are characterized and revealed. Crushing tests and simulations are conducted to evaluate the mechanical and failure behaviors, indicating similar experimental and simulated data. It is found that the design-II has higher energy absorption (+113.9%) and specific energy absorption (SEA) (+68.9%) compared to unreinforced NPR honeycombs, and its maximum load and SEA increase with decreasing feature angle. Microscopic observations illustrate that the primary failure modes of samples are fiber splitting, matrix cracking, interlayer delamination, fiber buckling, at different regions/corners. Finally, the reinforcement mechanis m is revealed that the inclined reinforcement rod can not only suppresses the premature inward folding deformation but also form a secondary contact bearing latterly, inducing progressive failure modes. This work offers a theoretical foundation for the design and manufacturing of composite energy-absorbing structures.
本文对复合材料负泊松比(NPR)蜂窝的增强设计、连续纤维3d打印和耐撞性进行了研究。设计了两种类型的NPR蜂窝,其中设计i采用双层结构,设计ii采用倾斜钢筋。单冲程连续纤维3d打印路径被战略性地规划为与复杂样品的独特几何形状对齐,从而最大限度地减少纤维拖拽并确保结构连续性。研究了工艺参数,包括线宽和层厚,以减少制造缺陷。研究了特征尺寸对样本耐撞性的影响。分析并揭示了纤维拖拽和无纤维区等印刷缺陷的发展趋势。进行了破碎试验和模拟,以评估其力学和破坏行为,结果表明实验和模拟数据相似。结果表明,与未加筋的蜂窝式结构相比,设计型蜂窝式结构具有更高的能量吸收(+113.9%)和比能量吸收(+68.9%),且其最大载荷和比能量吸收随特征角的减小而增大。微观观察表明,试样在不同区域/角落的主要破坏模式为纤维断裂、基体开裂、层间分层和纤维屈曲。最后,揭示了倾斜钢筋杆的加固机理:倾斜钢筋杆不仅能抑制过早向内折叠变形,而且后期还会形成二次接触轴承,诱发渐进式破坏模式。为复合材料吸能结构的设计和制造提供了理论依据。
Moment-resisting capacity of a fully bolted assembled inter-module connection for staggered modular steel constructions
Jian Tang, Yang Liu, Zhihua Chen, Huaqiao Wang
doi:10.1016/j.tws.2025.114177
交错模组钢结构全螺栓组合模间连接的抗弯矩能力
Modular steel constructions (MSCs), as an innovative, environmentally friendly, and highly assembled form of construction, are characterized by 'multi-beam' and 'multi-column'. This configuration characteristic enhances construction efficiency but leads to a significant increase in the amount of steel used. To further optimize the modular structure system, a multi-story staggered modular structure system is developed, with a spaced arrangement of modular units, and accordingly, a fully bolted assembled inter-module connection is proposed in this study. The static performance of the substructure, including failure modes, load-displacement curves, and strain distribution, was experimentally investigated through three full-scale monotonic static loading tests. Particular emphasis was placed on examining the effects of connection reinforcement parameters, specifically the thickness of corner fittings and types of stiffening plates. The test results demonstrated that the maximum bearing capacity was increased by 11.7% by adding beam flange cover plates. Furthermore, when the thickness of corner fittings was increased to 10 mm, a significant enhancement of 39.3% in the maximum bearing capacity was achieved, accompanied by optimal ductility. A refined finite element model (FEM) was subsequently developed and validated against test results. The failure modes were found to be in good agreement with test observations, with errors in initial stiffness and yield bearing capacity maintained below 4%. Through parametric ana lysis, the influences of gap between double beams, diameter of the bolts, and thickness of corner fitting on the substructure's static performance were systematically investigated. Based on the FEM results, corresponding design recommendations were proposed. In addition, the theoretical formula for the yield moment of connection was derived based on the elastic theory, and the absolute error is within 7% between the theoretical value and the test and FEM values. The research results can provide a basis for the design of the staggered modular structure system.
模块化钢结构(MSCs)是一种创新的、环保的、高度组装的建筑形式,其特点是“多梁”和“多柱”。这种结构特点提高了施工效率,但导致钢材使用量的显著增加。为进一步优化模块化结构体系,设计了多层交错模块化结构体系,模块单元间隔布置,并据此提出了全螺栓拼装的模块间连接方式。通过三次全尺寸单调静载试验,研究了子结构的静力性能,包括破坏模式、荷载-位移曲线和应变分布。特别强调的是检查连接加固参数的影响,特别是拐角配件的厚度和加强板的类型。试验结果表明,添加梁缘盖板可使梁的最大承载能力提高11.7%。当角件厚度增加到10 mm时,最大承载能力显著提高39.3%,同时延性最佳。随后建立了一个精细化的有限元模型,并根据试验结果进行了验证。破坏模式与试验结果吻合较好,初始刚度和屈服承载力误差均保持在4%以下。通过参数分析,系统地研究了双梁间距、螺栓直径、角件厚度对子结构静力性能的影响。根据有限元分析结果,提出了相应的设计建议。此外,基于弹性理论推导了连接屈服弯矩的理论计算公式,理论值与试验值和有限元值的绝对误差在7%以内。研究结果可为交错模块化结构体系的设计提供依据。
Enhancing fracture resistance of AM parts via the Concurrent Channel Reinforcement method: A Study of manufacturing parameters and loading conditions
Hadi Sadeghian, Majid R. Ayatollahi, Nima Razavi
doi:10.1016/j.tws.2025.114178
通过并发通道加固方法提高增材制造零件的抗断裂能力:制造参数和加载条件的研究
In recent years, researchers have proposed various reinforcing methods to promote the mechanical properties of Fused Filament Fabrication (FFF) parts. Among these strengthening techniques, the Concurrent Channel Reinforcement (CCR) method, recently introduced, offers promise in enhancing the fracture strengths of FFF specimens; however, different aspects of this technique remain unexplored. In this context, this study aims to answer how the CCR technique performs under different printing parameters and loading conditions, considering that these factors can significantly affect both the polymer matrix properties and the reinforcement effectiveness. To this end, a comprehensive experimental and numerical investigation is conducted to evaluate the fracture resistance of Polylactic Acid (PLA) parts reinforced with AISI 430 stainless steel macro-fibers. Pre-cracked Single Edge Notch Tension (SENT) and Semi-Circular Bend (SCB) specimens with raster angles of ±45°, 0°, and 90° are printed and subjected to tension- and tension-bending-dominated loading conditions, with a comparison of experimental results with respect to those of corresponding control counterparts. During these experimental tests, specimens are monitored by the Digital Image Correlation (DIC) technique to measure Notch Opening Distance (NOD) values in addition to their fracture strengths. A Finite Element (FE) an alysis is then performed, aiming to comparatively assess the stresses induced in the polymer matrices and the interfacial bonding at fiber/matrix interfaces across different cases. Ultimately, detailed fractography of the fracture surfaces of the reinforced parts is conducted to study the failure mechanis ms and their alteration among the studied cases. Findings reveal that the incorporation of less than 0.63% fiber volume fraction leads to declining NOD values, with significant improvements of fracture loads up to 42% in SENT and 21% in SCB specimens compared to control counterparts. This is while strain energy values of these specimens, absorbed prior to the final failure, are substantially enhanced utmost by 1685% and 1424% relative to the control specimens, respectively. The reported results confirm the potency of the CCR technique in simultaneously enhancing fracture strengths of varied FFF structures and postponing their final failure, both of which can lead to a wider utilization of these structures in load-bearing applications.
近年来,研究人员提出了各种增强方法来提高熔丝制造(FFF)零件的力学性能。在这些强化技术中,最近引入的并发通道强化(CCR)方法为提高FFF试件的断裂强度提供了希望;然而,这项技术的不同方面仍未被探索。在此背景下,本研究旨在回答CCR技术在不同打印参数和加载条件下的表现,因为这些因素会显著影响聚合物基体性能和增强效果。为此,对AISI 430不锈钢宏纤维增强聚乳酸(PLA)零件的抗断裂性能进行了综合试验和数值研究。打印出光栅角为±45°、0°和90°的预裂单边缘缺口拉伸(SENT)和半圆弯曲(SCB)试样,并对其进行拉伸和拉伸弯曲主导的加载条件,并将实验结果与相应对照的实验结果进行比较。在这些实验测试中,试样通过数字图像相关(DIC)技术进行监测,以测量缺口开启距离(NOD)值以及断裂强度。然后进行了有限元分析,旨在比较评估不同情况下聚合物基体中诱导的应力和纤维/基体界面的界面结合。最后,对强化件的断口进行了详细的断口形貌分析,研究了强化件的破坏机制及其变化。研究结果表明,纤维体积分数低于0.63%会导致NOD值下降,与对照组相比,SENT试件的断裂载荷显著提高42%,SCB试件的断裂载荷显著提高21%。与此同时,这些试样在最终破坏前吸收的应变能值,相对于对照试样,分别大幅提高了1685%和1424%。报道的结果证实了CCR技术在同时提高各种FFF结构的断裂强度和推迟其最终破坏方面的效力,这两者都可以导致这些结构在承载应用中的更广泛应用。
High-frequency vibration ana lysis of honeycomb plate based on EFEA: numerical calculation, experiment and damping loss factor identification
Yuchen Qiu, Xiuyan Cheng, Jili Rong
doi:10.1016/j.tws.2025.114183
基于EFEA的蜂窝板高频振动分析:数值计算、实验及阻尼损失因子辨识
To address the demand for high-frequency vibration response ana lysis of aluminum honeycomb sandwich plates, this study conducts an in-depth investigation through a combination of numerical simulations and experimental testing, and propose a novel method for identifying the damping loss factor of aluminum honeycomb sandwich plates. Equivalent parameters of the aluminum honeycomb sandwich plate were calculated based on equivalent plate theory and honeycomb plate theory. Three EFEA models were established: a plate-equivalent EFEA model, an orthotropic EFEA model, and an average-wavenumber-equivalent EFEA model. The accuracy of these models was validated by comparing numerical results with an alytical solutions. Subsequently, a finite difference method was employed to develop a theoretical framework for energy density testing corresponding to the three EFEA models. The validity of this testing theory was confirmed by numerical verification. Furthermore, guided by the principle of minimizing the error between experimental and numerical results, a damping loss factor identification method for aluminum honeycomb sandwich plates was proposed. The method was further refined by introducing a comprehensive influence factor. The results demonstrate that, the orthotropic EFEA model accurately and effectively captures the high-frequency vibration response of aluminum honeycomb sandwich plates in both numerical simulations and experimental tests. Additionally, the proposed method identifies the damping loss factor of the structure more effectively when incorporating a comprehensive influence factor.
针对铝蜂窝夹层板高频振动响应分析的需求,本研究通过数值模拟与实验测试相结合的方法进行了深入研究,提出了一种确定铝蜂窝夹层板阻尼损失因子的新方法。基于等效板理论和蜂窝板理论,计算了铝蜂窝夹层板的等效参数。建立了板等效EFEA模型、正交各向异性EFEA模型和平均波数等效EFEA模型。通过数值结果与解析解的比较,验证了模型的准确性。随后,采用有限差分法建立了三种EFEA模型对应的能量密度测试理论框架。通过数值验证,验证了该测试理论的有效性。在此基础上,以实验与数值误差最小为原则,提出了一种铝蜂窝夹层板阻尼损失因子辨识方法。通过引入综合影响因子,进一步完善了该方法。数值模拟和试验结果表明,正交各向异性有限元模型准确有效地捕捉了铝蜂窝夹层板的高频振动响应。此外,该方法在纳入综合影响因子时,可以更有效地识别结构的阻尼损失因子。