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【新文速递】2024年2月29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 2 篇,Journal of the Mechanics and Physics of Solids 1 篇,International Journal of Plasticity 2 篇,Thin-Walled Structures 6 篇

International Journal of Solids and Structures

Quasistatic strain fields in normally- and tangentially-loaded elastomeric rollers under impending slip

Nehemiah Mork, Milosz K. Rajchel, Michael Varenberg, Antonia Antoniou, Michael J. Leamy

doi:10.1016/j.ijsolstr.2024.112739

即将滑移时正常载荷和切向载荷弹性辊中的准静态应变场

Elastomeric rollers are important components in applications such as printing and roll-to-roll manufacturing. To gain insight into roller mechanics and provide a basis for further investigations into dynamic rolling problems where rolling instabilities may arise, we employ a specially-designed apparatus to obtain displacement and strain fields via digital image correlation (DIC) under applied loads. We test loading scenarios leading to impending slip of an elastomeric roller, mounted on a steel hub, and in contact with a glass (rigid) substrate. We first examine strain fields under normal loading and compare them with the closest analytical predictions. We then progress to analyzing the strain fields under combined normal and tangential loading. For each loading scenario, we discuss the displacement and strain fields of the roller sidewall and contact interface. We use a conceptual string model to explore how stick and slip zones develop within the contact area as well as how memory effects arise during cyclic loading. This memory effect is then verified experimentally using the DIC strain fields. Additionally, we demonstrate a means for identifying the stick zone area between the roller and substrate using the experimentally-obtained displacement fields. We believe the apparatus, and the ability to obtain experimental displacement and strain fields, will prove valuable in understanding roller mechanics and associated instabilities.

弹性辊是印刷和卷对卷制造等应用中的重要部件。为了深入了解辊筒力学,并为进一步研究可能出现轧制不稳定性的动态轧制问题奠定基础,我们采用了一种专门设计的仪器,通过数字图像相关(DIC)获取外加载荷下的位移和应变场。我们测试了导致安装在钢轮毂上的弹性轧辊即将滑移的加载情况,该轧辊与玻璃(刚性)基体接触。我们首先检查了正常加载下的应变场,并将其与最接近的分析预测进行了比较。然后,我们分析了法向和切向联合加载下的应变场。对于每种加载情况,我们都会讨论滚筒侧壁和接触界面的位移和应变场。我们使用概念弦模型来探讨接触区域内粘滞和滑移区是如何形成的,以及在循环加载过程中记忆效应是如何产生的。然后使用 DIC 应变场对这种记忆效应进行实验验证。此外,我们还展示了一种利用实验获得的位移场确定滚筒和基体之间粘滞区面积的方法。我们相信,该仪器以及获得实验位移和应变场的能力,将被证明在了解滚筒力学和相关不稳定性方面具有重要价值。


Intelligent design and buckling experiment of curvilinearly stiffened thin-walled structures

Peng Hao, Kunpeng Zhang, Dachuan Liu, Xiaobo Wang, Shaojun Feng, Bo Wang

doi:10.1016/j.ijsolstr.2024.112737

曲线加劲薄壁结构的智能设计和屈曲实验

Curvilinearly stiffened variable-stiffness structures offer excellent load-bearing capacities and design flexibility, particularly for thin-walled structures with cutouts. Nevertheless, the complex combination of numerous variables, buckling failure modes, and unclear load-carrying mechanisms present significant challenges to structural analysis and optimization. Hence, a unified characterization method for nonuniform layouts and variable thicknesses is proposed and an intelligent optimization framework based on structural image learning is established. Buckling experiments on two stiffened panels and a corresponding numerical analysis are performed to verify the effectiveness of the method under axial compressive loading. Results show that the curvilinearly stiffened panel exhibits a superior load-bearing capacity of 28.8% compared with an orthogonally stiffened panel. Specifically, the curvilinearly stiffened panel efficiently transfers axial loads to a broader region and avoids interruptions in the force transmission path by cutouts, thereby resulting in material and buckling failures simultaneously.

曲线加劲变刚度结构具有出色的承载能力和设计灵活性,尤其适用于带切口的薄壁结构。然而,众多变量的复杂组合、屈曲失效模式以及不明确的承载机制给结构分析和优化带来了巨大挑战。因此,我们提出了非均匀布局和可变厚度的统一表征方法,并建立了基于结构图像学习的智能优化框架。对两块加劲板进行了屈曲实验和相应的数值分析,以验证该方法在轴向压缩载荷下的有效性。结果表明,与正交加劲板相比,曲线加劲板的承载能力提高了 28.8%。具体来说,曲线加劲板可将轴向载荷有效地传递到更宽的区域,并避免了因切口而中断力传递路径,从而导致材料和屈曲同时失效。


Journal of the Mechanics and Physics of Solids

Third-order exceptional points and frozen modes in planar elastic laminates

Ariel Fishman, Guy Elbaz, T. Venkatesh Varma, Gal Shmuel

doi:10.1016/j.jmps.2024.105590

平面弹性层板中的三阶异常点和冻结模式

Exceptional points (EPs) are degeneracies of two or more natural modes of open systems, which lead to unusual wave phenomena. Despite the robustness against imperfections of spatial EPs, they are less studied relative to temporal EPs, particularly in elastodynamics. However, elastic waves exhibit features not found in sound and light, which have proven useful for forming spatial EPs. Here, we harness these features to tune the coalescence of three eigenmodes in the Bloch spectrum of planar elastic laminates. We show that these third-order EPs give rise to axially frozen modes: anomalous transmitted waves with zero axial group velocity and finite transmittance. These modes, which were first reported in optics and required three-dimensional laminates, are achieved here in a planar setting thanks to elastodynamics tensorial structure, and expand the toolbox for elastic wave shaping.

异常点(EPs)是开放系统中两种或两种以上自然模式的退化,会导致异常波现象。尽管空间异常点具有抗缺陷的鲁棒性,但相对于时间异常点,它们的研究较少,尤其是在弹性动力学中。然而,弹性波具有声和光所不具备的特征,这些特征已被证明有助于形成空间 EP。在这里,我们利用这些特征来调整平面弹性层板布洛赫频谱中三个特征模态的凝聚。我们的研究表明,这些三阶 EP 会产生轴向冻结模式:具有零轴向群速度和有限透射率的反常透射波。这些首次在光学领域报道的模式需要三维层压板才能实现,而在这里,由于采用了弹性力学张量结构,这些模式在平面环境中得以实现,并扩展了弹性波整形的工具箱。


International Journal of Plasticity

Uncovering origin of grain boundary resistance to irradiation damage in NiCoCr multi-principal element alloys

Fusheng Tan, Jia Li, Bin Liu, Peter K Liaw, Qihong Fang

doi:10.1016/j.ijplas.2024.103925

揭示镍钴铬多主元素合金晶界抗辐照损伤的起源

Multi-principal element alloys (MPEAs) demonstrate significant promise as structural materials for nuclear energy equipment owing to their exceptional mechanical properties and radiation-resistant performances. In these alloys, the grain boundary (GB) serves as a crucial microstructure that typically mitigates irradiation damage by absorbing the irradiation-induced defect. However, the micromechanisms governing the anti-irradiation performance of GBs in MPEAs remain unclear. In this study, we investigate the irradiation defect production during collision cascade in the model NiCoCr bicrystal system through atomic simulations, aiming to unveil the atomic-scale origin of the GB's ability to resist irradiation damage in MPEAs. The results reveal that GBs effectively serve as sinks for irradiation defects in NiCoCr. The sink efficiency depends on the GB energetic state, including GB excess energy and defect segregation energy, as well as the energetic difference between interstitial and vacancy segregation. Statistical analysis identifies a universally exponent function between the defect absorption rate at GB and GB energetic state. In NiCoCr, the GB-disorder-induced-entropy increase leads to a biased reduction in interstitial segregation energy, narrowing the gap between interstitial and vacancy segregation energies by approximately 11% compared to Ni. This improvement enhances the overall resistance of GBs to irradiation damage. Additionally, preferential segregation of Ni interstitial atoms is notably enhanced in NiCoCr, contributing to a high defect absorption rate at GBs. This study provides new insights into the resistance of GBs to irradiation defects in MPEAs and suggests GB engineering as an effective strategy for developing advanced alloys with enhanced radiation tolerance.

多主元素合金(MPEAs)具有优异的机械性能和抗辐射性能,因此有望成为核能设备的结构材料。在这些合金中,晶界(GB)是一种重要的微观结构,通常通过吸收辐照引起的缺陷来减轻辐照损伤。然而,中压电解合金中的晶界抗辐照性能的微观机制仍不清楚。在本研究中,我们通过原子模拟研究了模型镍钴铬双晶体系中碰撞级联过程中辐照缺陷的产生,旨在揭示 GB 在 MPEA 中抗辐照损伤能力的原子尺度起源。结果表明,国标有效地充当了镍钴铬中辐照缺陷的汇。汇效率取决于 GB 的能量状态,包括 GB 的过剩能和缺陷偏析能,以及间隙偏析和空位偏析之间的能量差异。统计分析确定了 GB 缺陷吸收率与 GB 能量状态之间的普遍指数函数。在镍铬中,GB-无序诱导熵的增加导致了间隙偏析能的偏向性降低,与镍相比,间隙偏析能与空位偏析能之间的差距缩小了约 11%。这种改善增强了 GB 对辐照损伤的整体抵抗力。此外,在镍钴铬中,镍间隙原子的优先偏析明显增强,从而导致了 GB 的高缺陷吸收率。这项研究为了解多孔介质协会中 GB 对辐照缺陷的抗性提供了新的视角,并建议将 GB 工程作为开发具有更强辐照耐受性的先进合金的有效策略。


ANISOTROPIC DUCTILE FRACTURE OF A STAINLESS STEEL UNDER BIAXIAL LOADING: EXPERIMENTS AND PREDICTIONS

Madhav Baral, Peter W. Ripley, Yanshan Lou, Yannis P. Korkolis

doi:10.1016/j.ijplas.2024.103927

不锈钢在双轴载荷作用下的各向异性韧性断裂:实验与预测

The anisotropic ductile fracture behavior of a stainless steel is investigated using a combination of experiments and analysis. The material is SS-304L, an austenitic, low-carbon stainless steel, received in the form of tubes of 2.38 mm dia. and 0.15 mm thickness. The tubes are inflated under volume control in a custom apparatus. At the same time, the axial force on the tubes is kept proportional to the pressure induced by the inflation. This leads to quasi-proportional stress paths in the meridional-hoop engineering stress space. A total of 15 discrete paths are successfully tested. Stereo-type Digital Image Correlation is used to measure the strains. In every case, the tubes develop a series of instabilities before bursting. The failure is oriented along the meridional or the hoop direction of the tube, depending on which stress is greater. A mild plastic anisotropy is detected in these experiments. Hence these results are then used for calibrating the anisotropic yield criterion Yld2004-3D. This is introduced in a finite element model of the experiments, which includes a thickness imperfection designed to capture the two failure orientations observed in the experiments. The numerical model using the Yld2004-3D criterion reproduces the experiments well, e.g., it captures the experimental stress-strain and induced strain paths better than von Mises. It is then used to probe the conditions at the onset of fracture (hybrid method). It is found that most paths lead to essentially proportional loading during deformation. A significant anisotropy in the fracture behavior is detected, with the meridional-stress-dominated paths being able to develop much higher strains than the hoop-dominated ones. These results are then captured by the DF2016 ductile fracture criterion, modified to use the anisotropic yield criterion Yld91. The proposed criterion is flexible enough to represent the fracture anisotropy very well, without being unnecessarily complex. The fracture forming limit curve (i.e., the fracture envelope in strain space) predicted by the DF2016/Yld91 model is also found to be very close to the experiments. The results and findings of this work help establish a framework to reliably design components and processes when significant fracture anisotropy is expected.

通过实验和分析相结合的方法研究了不锈钢的各向异性韧性断裂行为。材料是 SS-304L,一种奥氏体低碳不锈钢,以直径 2.38 毫米、厚度 0.15 毫米的管状形式接收。管子在一个定制设备中进行体积控制充气。同时,管子上的轴向力与充气产生的压力成正比。这就导致了经向环工程应力空间中的准比例应力路径。共成功测试了 15 条离散路径。采用立体型数字图像相关技术测量应变。在每种情况下,管道在爆裂前都会出现一系列不稳定现象。破损的方向沿着管子的经向或环向,取决于哪个应力更大。在这些实验中检测到了轻微的塑性各向异性。因此,这些结果被用于校准各向异性屈服准则 Yld2004-3D。这被引入到实验的有限元模型中,该模型包括一个厚度缺陷,旨在捕捉实验中观察到的两种破坏方向。使用 Yld2004-3D 准则的数值模型很好地再现了实验结果,例如,它比 von Mises 更好地捕捉了实验应力-应变和诱导应变路径。然后用它来探测断裂开始时的条件(混合方法)。研究发现,在变形过程中,大多数路径都会导致基本成比例的加载。在断裂行为中发现了明显的各向异性,以经向应力为主的路径能够产生比以箍筋为主的路径高得多的应变。DF2016 韧性断裂准则捕捉到了这些结果,并对其进行了修改,以使用各向异性屈服准则 Yld91。所提出的准则非常灵活,能够很好地代表断裂各向异性,同时又不会产生不必要的复杂性。DF2016/Yld91 模型预测的断裂成形极限曲线(即应变空间中的断裂包络)也与实验结果非常接近。这项工作的结果和发现有助于建立一个框架,在预计会出现明显断裂各向异性的情况下,可靠地设计部件和工艺。


Thin-Walled Structures

Experimental investigation on the self-healing properties of ester-exchanged vitrimeric CFRP laminate with microchannels

Yang Zhao, Zhongqi Wang, Menglin Zhao, Peng Jiang, Anyang Wang, Zhengping Chang

doi:10.1016/j.tws.2024.111755

带有微通道的酯交换玻璃纤维增强塑料层压板自愈合性能的实验研究

Epoxy vitrimer theoretically achieves an unlimited healing cycle drawing support from dynamic molecular chains. The healing conditions required for microvascular systems are variable and flexible. Current research has often focused on a single healing system, further exploration is needed for a dual heling system that combines the advantages of both. In this study, the effects of curing agent and catalyst content on the performances of vitrimer, as well as the healing parameters on the healing efficiency were studied. And then the vitrimeric CFRP (vCFRP) laminates with microchannels were prepared, and the three-point bending tests were implemented to characterize the healing efficiency of CFRP with a single and dual healing system. The results indicated that the cured vitrimer exhibited the best comprehensive performance when the molar ratio of reactants was 1:1:0.07. The healing temperature had the greatest impact on the healing efficiency of vitrimer, followed by the catalyst content and the healing pressure. The two healing systems could improve the mechanical properties of laminates, especially the healing efficiency of CFRP with dual healing system reached 134.5%. The healing agent in the microchannels could heal micro-damage, and the healability of the vitrimer could still be utilized after the healing agent was exhausted.

从理论上讲,环氧树脂三聚体可通过动态分子链的支持实现无限的愈合周期。微血管系统所需的愈合条件是多变和灵活的。目前的研究通常集中在单一愈合系统上,需要进一步探索一种结合了两种系统优点的双重愈合系统。在本研究中,研究了固化剂和催化剂含量对玻璃聚合物性能的影响,以及愈合参数对愈合效率的影响。然后制备了带有微通道的玻璃纤维增强塑料层压板(vCFRP),并通过三点弯曲试验来表征单一和双重愈合体系下 CFRP 的愈合效率。结果表明,当反应物的摩尔比为 1:1:0.07 时,固化的玻璃聚合物表现出最佳的综合性能。愈合温度对玻璃纤维增强塑料的愈合效率影响最大,其次是催化剂含量和愈合压力。两种愈合体系都能改善层压板的机械性能,尤其是采用双愈合体系的 CFRP 的愈合效率达到了 134.5%。微通道中的愈合剂可以愈合微损伤,而且在愈合剂耗尽后,玻璃聚合物的愈合能力仍可被利用。


A Nonlinear FE formulation for Elastic Buckling and Post-Buckling Analysis of Pre-stressed Stayed Columns with Bonded/Un-bonded Cable Stays

Fengping Zhang, Moon-Young Kim

doi:10.1016/j.tws.2024.111760

带粘结/无粘结拉索支撑的预应力支撑柱弹性屈曲和屈曲后分析的非线性有限元计算公式

This study intends to investigate elastic buckling and post-buckling behaviors of pre-stressed (PS) stayed columns with single and triple cross-arms using a nonlinear FEM. To achieve this, a two-node shear-rigid/shear-flexible beam element considering second-order effects and multi-node stay cable elements under bonded/un-bonded conditions with consistent consideration of their unstrained lengths are formulated using an energy method. After validity and accuracy of the present formulation under the bonded condition is demonstrated through comparison of analysis results by Abaqus, elastic buckling and post-buckling characteristics of two PS stayed column models with single and triple cross arms is rigorously examined, considering the stays under the bonded or un-bonded conditions.

本研究旨在使用非线性有限元模型研究单横臂和三横臂预应力(PS)留置柱的弹性屈曲和屈曲后行为。为此,我们使用能量法建立了一个考虑二阶效应的双节点剪刚性/剪柔性梁单元和粘结/非粘结条件下的多节点留索单元,并一致考虑了它们的非应变长度。通过比较 Abaqus 的分析结果,证明了本公式在粘结条件下的有效性和准确性,之后,考虑到粘结或非粘结条件下的留索,对两种具有单横臂和三横臂的 PS 留索柱模型的弹性屈曲和屈曲后特性进行了严格检验。


An Analytical Investigation on Nonlinear Vibrations and Stability of Timoshenko Pipes Conveying Two-Phase Flow

Mohammad Ali Sabahi, Ali Reza Saidi

doi:10.1016/j.tws.2024.111749

输送两相流的季莫申科管道的非线性振动和稳定性分析研究

The primary objective of this study is to conduct a comprehensive investigation on the nonlinear free vibration and stability analysis of the multilayer graphene reinforced pipe conveying liquid-gas two-phase flow based on the Timoshenko beam model. The Halpin-Tsai micromechanics model is employed which provides a means to evaluate and analyze the mechanical behavior and performance of the multilayer FG reinforced pipe. According to Von-Kármán strain relations and applying the Hamilton's principle, the governing equations of motion are derived. The Galerkin technique is operated to convert the partial differential equation (PDE) to the ordinary differential equation (ODE). The homotopy analysis method is employed to solve the fourth order nonlinear differential equation. Closed-form expressions for the nth nonlinear frequency and time history as well as the critical flow velocity based on the Timoshenko theory are achieved. The results demonstrate that neglecting the effects of rotary inertia and shear deformation may cause some errors by the increment of the initial amplitude. Furthermore, the critical flow velocity, depends not only on the mechanical and geometrical properties of the pipe but also on the initial mode shape excitation. The results indicate that by the increment of flow velocity, liquid density and slenderness ratio, the nonlinear frequency decreases, on the other hand, by the increment of the initial amplitude, the nonlinear frequency increases.

本研究的主要目的是基于季莫申科梁模型,对输送液气两相流的多层石墨烯增强管道的非线性自由振动和稳定性分析进行全面研究。所采用的 Halpin-Tsai 微力学模型为评估和分析多层石墨烯增强管道的力学行为和性能提供了一种方法。根据 Von-Kármán 应变关系并应用汉密尔顿原理,推导出了支配运动方程。利用 Galerkin 技术将偏微分方程 (PDE) 转换为常微分方程 (ODE)。同调分析法用于求解四阶非线性微分方程。根据季莫申科理论,得到了 n 次非线性频率和时间历程以及临界流速的闭式表达式。结果表明,忽略旋转惯性和剪切变形的影响可能会因初始振幅的增大而导致一些误差。此外,临界流速不仅取决于管道的机械和几何特性,还取决于初始模态振型。结果表明,随着流速、液体密度和细长比的增大,非线性频率会降低;而随着初始振幅的增大,非线性频率会升高。


Investigation on fatigue life of push-the-bit rotary steerable bottom hole assembly with random bit-rock interaction

Yanying Li, Yongping Yu, Daisen Zhao, Youhong Sun, Bailong Li, CW Lim

doi:10.1016/j.tws.2024.111752

对具有随机钻头-岩石相互作用的推钻头旋转转向底孔组件疲劳寿命的研究

Rotary steerable systems are critical for challenging boreholes in deep-sea oil and gas drilling, where fatigue failure is the normal form of damage. A procedure with deterministic excitation and random excitation is presented in this paper to reliably predict the fatigue life of the bottom hole assembly. The initial defects, the Coulomb friction model, frictional contact between the drill bit and rock, and the stochastic rock-cutting process are included in the model. Monte Carlo approach is used to obtain the Statistical characteristics of the stochastic model. Based on the program mentioned above, influences of some parameters, such as rotational speed, weight on bit, steering force, and random excitation on torsional vibration characteristics, are investigated. Moreover, the rain-flow counting method is applied to reveal the dependency relationship between fatigue life and torsional vibration. It is found that random excitation can exacerbate the torsional vibration phenomenon and even significantly reduce the fatigue life. Finally, compared with the deterministic system, the sensitivity index coefficient of the fatigue life in the random excitation model is about 0.8% - 2.2% higher. The research results can provide a theoretical basis for reducing tool failure in on-site deep-sea oil and gas drilling.

旋转转向系统对于深海石油和天然气钻探中具有挑战性的钻孔至关重要,疲劳失效是通常的损坏形式。本文提出了一种确定性激励和随机激励程序,用于可靠地预测孔底组件的疲劳寿命。模型中包括初始缺陷、库仑摩擦模型、钻头与岩石之间的摩擦接触以及随机切岩过程。采用蒙特卡罗方法获得随机模型的统计特征。根据上述程序,研究了一些参数,如转速、钻头重量、转向力和随机激励对扭转振动特性的影响。此外,还应用雨流计数法揭示了疲劳寿命与扭转振动之间的依存关系。结果发现,随机激励会加剧扭转振动现象,甚至会显著降低疲劳寿命。最后,与确定性系统相比,随机激励模型的疲劳寿命灵敏度指数系数高出约 0.8% - 2.2%。该研究成果可为减少现场深海油气钻井中的工具故障提供理论依据。


Band folding induced broadband vibration suppression of star-shaped metamaterials: theory and experiment

Zhenkun Guo, Jiaqi Wen, Yongjun Shen, Guobiao Hu, Guoqing Jiang

doi:10.1016/j.tws.2024.111756

星形超材料的带折叠诱导宽带振动抑制:理论与实验

Metamaterials with bandgap features can block wave propagation in specific frequency ranges and thus have wide applications for vibration mitigation and noise reduction. In this study, we renovated the design of star-shaped metamaterial (SSM) to make it capable of producing lower and wider vibration bandgaps. Unlike traditional periodic truss structures in the literature, the designed SSM structure breaks the spatial symmetry, opening the degenerate points formed by the band folding effect, thereby producing extra bandgaps for vibration suppression. First of all, a finite element (FE) model of the SSM is established, and its band structures and vibration transmittance are calculated. The preliminary result validated our hypothesis, demonstrating that the proposed SSM structure created additional bandgaps for suppressing low-frequency and broadband vibrations. Subsequently, the frequency response analyses are conducted using the spectral element method (SEM) and experimental test. The effects of the structural parameters on the bandgaps of the proposed SSM are studied. In addition, we further extended and generalized the band folding design concept. We showed that one can produce more bandgaps by designing high-order SSMs. In general, this study presents an approach for designing truss structures with improved vibration suppression performance.

具有带隙特性的超材料可以阻挡特定频率范围内的波传播,因此在减震和降噪方面有着广泛的应用。在本研究中,我们改进了星形超材料(SSM)的设计,使其能够产生更低更宽的振动带隙。与文献中传统的周期性桁架结构不同,所设计的 SSM 结构打破了空间对称性,打开了由带折叠效应形成的退化点,从而产生额外的带隙用于振动抑制。首先,我们建立了 SSM 的有限元(FE)模型,并计算了其带状结构和振动透过率。初步结果验证了我们的假设,表明拟议的 SSM 结构产生了抑制低频和宽带振动的额外带隙。随后,利用谱元法(SEM)和实验测试进行了频率响应分析。研究了结构参数对拟议 SSM 带隙的影响。此外,我们还进一步扩展和推广了带折叠设计概念。我们发现,通过设计高阶 SSM 可以产生更大的带隙。总之,本研究提出了一种设计具有更佳振动抑制性能的桁架结构的方法。


Multipass roll forming of variable-curvature elliptical panels using the angular function based on UOSDM

Xuemeng Li, Rui Wang, Hui Jiang, Kai Zhang, Shumei Lou, Chunjian Su, Jie Sun

doi:10.1016/j.tws.2024.111759

利用基于 UOSDM 的角度函数对变曲率椭圆板材进行多道滚压成形

Variable-curvature elliptical panels are widely used, however, their forming process is complex. This study investigated the influence of different bending-angle-distribution methods and process parameters on the bending deformation and springback of the panels. The universal optimized springback defect method (UOSDM) is proposed for mitigating springback to improve the forming quality. The results show that the springback angle of the plate increases with the decrease of thickness and yield strength. The maximum stress and plastic strain of the plate manufactured by UOSDM are 268.88 MPa and 0.303, which are smaller than those by other methods. The overall stress distribution is more uniform and defects are not easy to occur. This study intends to reveal the uneven deformation mechanism and precise plastic forming law of curved parts with variable curvature, improve the forming quality of sheet metal and realize the precision manufacturing of complex parts with variable curvature by roll forming.

变曲率椭圆板应用广泛,但其成型工艺复杂。本研究探讨了不同弯曲角度分布方法和工艺参数对板材弯曲变形和回弹的影响。提出了通用优化回弹缺陷法(UOSDM)来减轻回弹,从而提高成形质量。结果表明,板材的回弹角随厚度和屈服强度的降低而增大。UOSDM 制造的板材的最大应力和塑性应变分别为 268.88 MPa 和 0.303,小于其他方法。整体应力分布较为均匀,不易出现缺陷。本研究旨在揭示变曲率曲面零件的不均匀变形机理和精密塑性成形规律,提高板材的成形质量,实现滚压成形变曲率复杂零件的精密制造。



来源:复合材料力学仿真Composites FEM
ACTMechanicalSystemAbaqusDeform振动疲劳断裂碰撞非线性通用核能油气理论材料
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【新文速递】2024年2月29日复合材料SCI期刊最新文章

今日更新:Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 3 篇,Composites Science and Technology 1 篇Composites Part A: Applied Science and ManufacturingStochastic modelling of out-of-autoclave epoxy composite cure cycles under uncertaintyMolly Hall, Xuesen Zeng, Tristan Shelley, Peter Schubeldoi:10.1016/j.compositesa.2024.108110不确定情况下高压釜外环氧树脂复合材料固化周期的随机建模Thermoset polymers and composites are subject to several sources of uncertainty which can produce a range of cure outcomes. Recent research into stochastically modelled thermoset cure has indicated that accounting for raw material and process uncertainty can model this range of expected output parameters. However, the uncertainty quantification methods are highly test-intensive, and the results of the simulations have been validated with limited experimental data. This study proposes a simple approach to cure kinetics uncertainty quantification that can be applied to any cure kinetics model without the need for additional testing. Stochastic cure kinetics and temperature conditions for a popular out-of-autoclave carbon fibre/epoxy prepreg were used to produce output distribution functions for key cure events, and the results were validated using data from ten cure replicates. The quantified variation expected from the cure of this prepreg resulted in processing recommendations to ensure quality metrics are met during processing.热固性聚合物和复合材料受多种不确定因素的影响,会产生一系列固化结果。最近对热固性固化随机建模的研究表明,考虑到原材料和工艺的不确定性,可以对这一系列预期的输出参数进行建模。然而,不确定性量化方法需要大量测试,而且模拟结果只能通过有限的实验数据进行验证。本研究提出了一种简单的固化动力学不确定性量化方法,可用于任何固化动力学模型,无需额外测试。针对一种常用的高压釜外碳纤维/环氧树脂预浸料,采用随机固化动力学和温度条件来生成关键固化事件的输出分布函数,并利用十次固化重复的数据对结果进行了验证。对该预浸料固化过程中的预期变化进行量化后,提出了加工建议,以确保在加工过程中达到质量指标。Composites Part B: EngineeringStrain-rate dependent mixed-mode traction laws for glass fiber-epoxy interphase using molecular dynamics simulationsSanjib C. Chowdhury, John W. Gillespiedoi:10.1016/j.compositesb.2024.111351 利用分子动力学模拟玻璃纤维-环氧树脂间相的应变速率相关混合模式牵引定律In this paper, we establish a methodology to predict strain rate-dependent mixed-mode traction-separation responses (i.e., traction laws) for glass-epoxy composite interphase using molecular dynamics (MD) simulations. Glass-epoxy interphases with monolayer glycidoxypropyltrimethoxy silane are prepared by varying silane number density from 0.0 nm−2 to 3.9 nm−2 following the epoxy-amine diffusion and curing reactions. To established the effects of strain rate and mode-mixity on the interphase traction laws, the nano-meter size interphase domain is loaded in various mode-mixity (θ = 0° (Mode−II), 15°, 30°, 45°, 60°, and 90° (Mode−I)) with full range of strain rates from quasit-static to high strain rate (∼1e16/s) where a theoretical plateau strength limit is predicted. Following our previous work on Mode-I [Chowdhury et al., Composites Part B 237 (2022) 109877], mathematical model is developed for Mode-II as function of strain rate for different interphase structures (i.e., silane number density). The continuum equivalent bi-linear cohesive traction law is developed using the MD results to determine the mode-mixity quadratic functions and associated exponents for peak tractions, energy absorption, crack initiation and crack opening displacement from the mixed-mode simulations data. The MD predicted traction laws can be used to model interphase in micromechanics finite element analysis to bridge the length scale for the prediction of fiber-matrix debonding in composites.在本文中,我们建立了一种方法,利用分子动力学(MD)模拟来预测玻璃-环氧复合材料相间的应变速率依赖性混合模式牵引分离响应(即牵引定律)。在环氧胺扩散和固化反应之后,通过改变硅烷数量密度(从 0.0 nm-2 到 3.9 nm-2),制备了具有单层缩水甘油氧丙基三甲氧基硅烷的玻璃-环氧中间相。为了确定应变速率和模式混合度对相间牵引力规律的影响,在不同的模式混合度(θ = 0° (Mode-II)、15°、30°、45°、60°和 90° (Mode-I))和从准静态到高应变速率(∼1e16/s)的全范围应变速率下加载了纳米级相间域,并预测了理论上的高原强度极限。根据我们之前关于模式 I 的研究成果[Chowdhury 等人,Composites Part B 237 (2022) 109877],针对不同的相间结构(即硅烷数量密度),建立了模式 II 的数学模型,并将其作为应变速率的函数。利用 MD 结果开发了连续等效双线性内聚牵引定律,以从混合模式模拟数据中确定模式-混合二次函数以及峰值牵引、能量吸收、裂纹起始和裂纹张开位移的相关指数。MD 预测的牵引定律可用于在微观力学有限元分析中建立相间模型,从而弥合复合材料中纤维-基体脱粘预测的长度尺度。Abundant nucleation sites-available liquid crystal hydrogel mimics bone ECM mineralization to boost osteogenesisLin Li, Kun Liu, Yating Lin, Wei Wen, Shan Ding, Mingxian Liu, Changren Zhou, Binghong Luodoi:10.1016/j.compositesb.2024.111340 丰富的成核点--可用液晶水凝胶模拟骨 ECM 矿化,促进骨生成Bone extracellular matrix (ECM) is a unique organic-inorganic composite material derived from highly mineralized liquid crystal (LC) organic substrate. However, it remains a substantial challenge to design bone ECM-like LC materials with sufficient available nucleation sites to mimic the mineralization process of natural bone. Herein, we designed a bioinspired hydrogel with bone ECM-like LC organic substrate and inorganic phosphate mineralization nucleation sites for robust cell biomineralization and bone regeneration. Black phosphorus (BP) nanosheet was firstly loaded by bioactive layered double hydroxide (LDH) based on electrostatic attraction to improve the stability and photothermal performance of BP. Then, the LDH@BP was creatively added into chitin whisker/poly (ethylene glycol) diacrylate (CHW/PEGDA) LC hydrogel, abbreviated as LCgel, to fabricate LCgel/LDH@BP to highly mimic the mineralization microenvironment of bone ECM. The bone ECM-like LC topology of LCgel/LDH@BP is conducive to facilitating cell adhesion, proliferation and osteogenic differentiation. More importantly, the in-situ phosphate mineralization nucleation sites combined with mild hyperthermia induced by BP can further synergistically reinforce biomineralization of cells adhered on bone ECM-like LC substrate, thus substantially promoting cell biomineralization-mediated osteogenesis in vitro and in vivo. This study opens a new insight for the design of bioinspired hydrogel for cell biomineralization-mediated osteogenesis.骨细胞外基质(ECM)是一种独特的有机-无机复合材料,由高度矿化的液晶(LC)有机基质衍生而来。然而,设计具有足够可用成核位点的类骨 ECM LC 材料以模拟天然骨骼的矿化过程仍是一项巨大挑战。在此,我们设计了一种生物启发水凝胶,该水凝胶具有类似骨 ECM 的液晶有机基底和无机磷酸盐矿化成核位点,可促进细胞生物矿化和骨再生。黑磷(BP)纳米片首先被基于静电吸引的生物活性层状双氢氧化物(LDH)负载,以提高 BP 的稳定性和光热性能。然后,创造性地将 LDH@BP 添加到甲壳素晶须/聚(乙二醇)二丙烯酸酯(CHW/PEGDA)LC 水凝胶(简称 LCgel)中,制成 LCgel/LDH@BP,高度模拟骨 ECM 的矿化微环境。LCgel/LDH@BP 类似骨 ECM 的 LC 拓扑结构有利于促进细胞粘附、增殖和成骨分化。更重要的是,原位磷酸盐矿化成核点与 BP 诱导的轻度高热相结合,可进一步协同强化粘附在骨 ECM 类 LC 基底上的细胞的生物矿化,从而大大促进细胞生物矿化介导的体外和体内成骨过程。这项研究为设计用于细胞生物矿化介导的成骨的生物启发水凝胶提供了新的思路。Enhancing mechanical performance and high-temperature lubrication enabled by MoS2/WB2 nanolayered filmsZhenrong Gao, Weiming Nie, Haixin Wang, Siming Ren, Dali Du, ShiYu Du, Jinlong Lidoi:10.1016/j.compositesb.2024.111350利用 MoS2/WB2 纳米层薄膜提高机械性能和高温润滑性能Molybdenum disulfide (MoS2) films are widespread application in aerospace, nuclear, mechanical, and electronic fields owing to their unique structural characteristics and inherent interlayer slip. However, their utility is hindered by environmental susceptibility, particularly oxidation at elevated temperatures and in humid environments, limiting their effectiveness. Herein, we report a nanocomposite integrating MoS2 with WB2 by periodic alternating arrangement, synthesized using magnetron sputtering technology. This nanolayered architecture effectively harnesses the synergistic properties of both materials, imparting exceptional mechanical properties, superior environmental adaptability and efficient high-temperature lubrication. Methodical experiments and atomistic simulations reveal the incorporation of WB2 promotes preferential growth of MoS2 along the (002) plane, yielding an impressive hardness-to-elastic modulus ratio of approximately 0.10. The resultant films demonstrate notable achievements: a minimal friction coefficient of 0.056 and a specific wear rate of 1.88 × 10−7 mm3 N−1 m−1 in humid air. These findings are primarily stem from the synergistic interaction between MoS2 and metal-oxide nanoparticles at the sliding interface. Remarkably, even at 400 °C, the engineered MoS2/WB2 nanocomposite achieves low friction and wear under high contact stress, outperforming conventional MoS2-based materials. This innovative design, complemented by insights into the high-temperature friction mechanism, holds promise for advancing the development of robust and high-temperature-resistant lubricants.二硫化钼(MoS2)薄膜因其独特的结构特征和固有的层间滑移特性,被广泛应用于航空航天、核能、机械和电子领域。然而,由于其易受环境影响,特别是在高温和潮湿环境中易氧化,限制了其应用的有效性。在此,我们报告了一种利用磁控溅射技术通过周期性 交替排列将 MoS2 与 WB2 集成在一起的纳米复合材料。这种纳米层状结构有效地利用了两种材料的协同特性,赋予了它们优异的机械性能、卓越的环境适应性和高效的高温润滑性。循序渐进的实验和原子模拟显示,WB2 的加入促进了 MoS2 沿 (002) 平面的优先生长,从而产生了令人印象深刻的硬度-弹性模量比(约为 0.10)。由此产生的薄膜取得了显著的成就:最小摩擦系数为 0.056,在潮湿空气中的特定磨损率为 1.88 × 10-7 mm3 N-1 m-1。这些发现主要源于 MoS2 和金属氧化物纳米颗粒在滑动界面上的协同作用。值得注意的是,即使在 400 °C 温度下,工程 MoS2/WB2 纳米复合材料也能在高接触应力下实现低摩擦和低磨损,性能优于传统的 MoS2 材料。这种创新设计,加上对高温摩擦机理的深入了解,有望推动坚固耐用的耐高温润滑剂的开发。Composites Science and TechnologyUltrawide sensing-range, super durable and high-strength epoxy/carbon fiber composites sensor based on stress-induced structureMengman Weng, Zhao-xia Huang, Qing-wen Yuan, Zhi-hua Liu, Jin-ping Qudoi:10.1016/j.compscitech.2024.110522 基于应力诱导结构的超宽传感范围、超耐用、高强度环氧树脂/碳纤维复合材料传感器Nowadays, high-pressure sensors are broadly utilized in manufacturing and applications for ensuring safe production and preventing failures. However, present high-pressure sensors are mainly fabricated by high-strength metal and cement, which are too heavy or easy-corrosive to satisfy long-term usage. Polymer piezoresistive materials have great potential due to their stability and light weight, but achieving high strength and durability at the same time remains a serious challenge. In this work, a high-strength pressure sensor is fabricated by epoxy resin/carbon fiber (EP/CF) composite, where CF builds a conductive network as a reinforcing phase and EP provides a durable and light-weight base phase. The conductive mechanism based on stress-induced structure has been elucidated, and the performance of related sensors in various conditions is revealed. The lightweight(∼1.28 g/cm3) pressure sensor manifests a wide sensing response range from 22 kPa to 80 MPa. Moreover, the durability of this novel pressure sensor is verified by repeating loading and unloading at a high pressure of 10 MPa for more than 3500 cycles. Meanwhile, the high temperature and water resistance are furtherly confirmed, where EP/CF composites exhibits excellent cycling stability (10 MPa, >1000 cycles) after heating (100 °C) or soaking in water. Attributed to the comprehensive performance of high-strength, ultrawide detection range, durability and light weight, EP/CF composites are applied for road safety monitoring and deep-sea operation, showing wide application prospects in high-pressure monitoring field.如今,高压传感器被广泛应用于制造业和各种应用领域,以确保安全生产和防止故障发生。然而,目前的高压传感器主要由高强度金属和水泥制成,重量过重或易腐蚀,无法满足长期使用的要求。聚合物压阻材料因其稳定性和轻质性而具有巨大潜力,但同时实现高强度和耐用性仍是一项严峻挑战。本研究采用环氧树脂/碳纤维(EP/CF)复合材料制作了一种高强度压力传感器,其中碳纤维作为增强相构建了导电网络,而 EP 则提供了耐用且轻质的基相。该材料阐明了基于应力诱导结构的导电机制,并揭示了相关传感器在各种条件下的性能。这种轻型(1.28 克/立方厘米)压力传感器的传感响应范围从 22 千帕到 80 兆帕不等。此外,通过在 10 兆帕高压下重复加载和卸载超过 3500 次,验证了这种新型压力传感器的耐用性。同时,EP/CF 复合材料的耐高温和耐水性也得到了进一步证实,在加热(100 °C)或浸泡在水中后,EP/CF 复合材料表现出卓越的循环稳定性(10 兆帕,大于 1000 次循环)。EP/CF 复合材料具有高强度、超宽检测范围、耐久性和轻质等综合性能,可应用于道路安全监测和深海作业,在高压监测领域具有广阔的应用前景。来源:复合材料力学仿真Composites FEM

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