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【新文速递】2024年6月11日固体力学SCI期刊最新文章

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今日更新:Journal of the Mechanics and Physics of Solids 1 篇,International Journal of Plasticity 3 篇,Thin-Walled Structures 6 篇

Journal of the Mechanics and Physics of Solids

Mechanics of magnetic-shape memory polymers

Lu Lu, Shuai Wu, Ruike Renee Zhao

doi:10.1016/j.jmps.2024.105742

磁形记忆聚合物的力学

Magnetic-shape memory polymers (M-SMPs) can not only undergo rapid and reversible deformation in response to magnetic actuation but also lock the actuated shape upon cooling, which has great potential in applications such as soft robotics, active metamaterials, and shape-morphing systems. In this work, we develop a constitutive model for M-SMPs with finite deformation. The constitutive model considers the Helmholtz free energy contributed by the thermally responsive shape memory polymers and the magnetically responsive particles, leading to a magneto-thermomechanical framework. It is shown that the developed model can capture the thermomechanical as well as magneto-elastic responses of M-SMPs at different temperatures. Simplified beam models for M-SMPs are presented to show the material's versatile functionalities including fast and reversible deformation, selective/sequential actuation, and shape-locking. We envision that the constitutive framework and the simplified beam models presented in this work can serve as useful tools to guide the rational design of M-SMP-based functional structures and devices.

磁形状记忆聚合物(M-SMPs)不仅可以在磁驱动下发生快速可逆的变形,而且在冷却后可以锁定被驱动的形状,在软机器人、活性超材料和形状变形系统等应用中具有很大的潜力。在这项工作中,我们建立了具有有限变形的m - smp的本构模型。本构模型考虑了热响应形状记忆聚合物和磁响应粒子所贡献的亥姆霍兹自由能,从而得到了一个磁-热-机械框架。结果表明,所建立的模型能够捕捉到M-SMPs在不同温度下的热力学响应和磁弹性响应。本文提出了m - smp的简化梁模型,以展示材料的多种功能,包括快速和可逆变形,选择/顺序驱动和形状锁定。我们设想本构框架和本工作中提出的简化梁模型可以作为有用的工具来指导基于m - smp的功能结构和器件的合理设计。


International Journal of Plasticity

A comprehensive analysis of cermet design and thermal cyclic stability via elasto-viscoplastic crystal plasticity modeling

Glenn R. Peterson, Youngung Jeong, Carlos N. Tomé, Michael D. Sangid

doi:10.1016/j.ijplas.2024.104032

基于弹粘塑性晶体塑性建模的金属陶瓷设计与热循环稳定性综合分析

Ceramic-metal composites, or cermets, exhibit beneficial properties resulting in their use in many industrial applications. One challenge with cermets is mismatches in the coefficient of thermal expansion (CTE) values between the ceramic and metal phases that lead to residual stresses after processing, plasticity in the metal phase, internal stresses, and instability after thermal cycling. In order to make predictions of these properties to inform the design of cermets, we employ an incremental elasto-viscoplastic, self-consistent formulation to calculate the thermal, elastic, and plastic strains in two-phase polycrystalline cermet materials. This framework is extended to include temperature dependent properties, which are called implicitly within the temperature-dependent, incremental elasto-viscoplastic, self-consistent (TE-VPSC) model. Temperature-induced cooling and thermal cycling simulations are conducted using the TE-VPSC framework to study the residual stresses and plastic strains in the metal phases. Two materials are discussed in detail exhibiting stark differences based on the CTE between their ceramic and metal phases, WC/57-vol% Cu (exhibiting a pronounced CTE mismatch) and Y2O3/27-vol% Nb (exhibiting a negligible CTE mismatch). The model demonstrates high residual stresses in the Cu phase during processing and reverse plasticity leading to recovery of plastic strain during thermal cycling of the WC/Cu cermet. Moreover, the model demonstrates relatively low residual stresses and plasticity in Y2O3/Nb and a thermal stability point of 1251°C, below which no plasticity develops in the cermet. We employ the TE-VPSC model as a design tool for cermets to systematically investigate the effects of process-induced microstructure variations (volume fraction, grain aspect ratio, and crystallographic texture are investigated) and compositional differences (19 compositions are explored) on the residual stress, degree of plasticity in the metal phase, and thermal stability point. The computational efficiency of the TE-VPSC framework makes it a desktop design tool that can be used to quantify the impact of changing composition, processing, and thermo-mechanical loading on the performance of the cermet, which can help reduce the number of time intensive and costly high temperature experiments.

陶瓷-金属复合材料,或陶瓷,表现出有益的特性,导致它们在许多工业应用中的使用。陶瓷的一个挑战是陶瓷和金属相之间的热膨胀系数(CTE)值不匹配,导致加工后的残余应力、金属相的塑性、内应力和热循环后的不稳定性。为了预测这些特性,为陶瓷的设计提供信息,我们采用增量弹粘塑性、自一致公式来计算两相多晶陶瓷材料的热、弹性和塑性应变。该框架扩展到包括温度相关的特性,这些特性在温度相关的增量弹粘塑性自一致(TE-VPSC)模型中被隐式调用。利用TE-VPSC框架进行了温度诱导冷却和热循环模拟,研究了金属相的残余应力和塑性应变。详细讨论了基于陶瓷相和金属相之间CTE差异的两种材料,WC/57 vol% Cu(表现出明显的CTE错配)和y2o3 /27 vol% Nb(表现出可以忽略不计的CTE错配)。该模型表明,WC/Cu陶瓷在加工过程中Cu相存在较高的残余应力,在热循环过程中出现反向塑性,导致塑性应变恢复。此外,该模型还表明,Y2O3/Nb的残余应力和塑性相对较低,热稳定性点为1251℃,低于1251℃,陶瓷不发生塑性。我们采用TE-VPSC模型作为陶瓷的设计工具,系统地研究了工艺诱导的微观结构变化(研究了体积分数、晶粒长径比和晶体织构)和成分差异(研究了19种成分)对金属相残余应力、塑性程度和热稳定性点的影响。TE-VPSC框架的计算效率使其成为桌面设计工具,可用于量化改变成分,加工和热机械载荷对金属陶瓷性能的影响,这有助于减少时间密集和昂贵的高温实验次数。


A predictive mesoscale model for continuous dynamic recrystallization

Franz Miller Branco Ferraz, Ricardo Henrique Buzolin, Stefan Ebenbauer, Thomas Leitner, Alfred Krumphals, Maria Cecilia Poletti

doi:10.1016/j.ijplas.2024.104022

连续动态再结晶的预测中尺度模式

Thermomechanical processing of titanium alloys often requires complex routes to achieve the desired final microstructure. Recent advancements in modeling and simulation tools have facilitated the optimization of these processing routes. However, existing models often fail to accurately predict microstructural changes at large deformations. In this study, we refine the physical principles of an existing mean-field model and propose a calibration method that uses experimental results under isothermal conditions, accounting for the actual local deformation within the workpiece. This new approach improves the predictability of microstructural changes due to continuous dynamic recrystallization during torsion and compression experiments. Additionally, we integrate the model into the commercial FEM-based DEFORMTM 2D software to predict the local microstructure evolution within hot torsion specimens thermomechanically treated by resistive heating. Validation using non-isothermal deformation tests demonstrates that the model provides realistic simulations at high strain rates, where adiabatic heat modifies temperature, flow stress and microstructure. This study demonstrates the intrinsic correlation between microstructure, flow behavior, and workpiece geometry, considering the impact of deformation history in thermomechanical processes.

钛合金的热机械加工通常需要复杂的工艺路线才能达到理想的最终显微组织。建模和仿真工具的最新进展促进了这些加工路线的优化。然而,现有的模型往往不能准确预测大变形时的微观结构变化。在这项研究中,我们完善了现有的平均场模型的物理原理,并提出了一种校准方法,该方法使用等温条件下的实验结果,考虑了工件内部的实际局部变形。这种新方法提高了在扭转和压缩实验中由于连续动态再结晶而导致的微观结构变化的可预测性。此外,我们将该模型集成到基于商用有限元的DEFORMTM 2D软件中,以预测经电阻加热热处理的热扭转试样的局部微观结构演变。使用非等温变形试验验证表明,该模型在高应变速率下提供了真实的模拟,其中绝热改变温度,流动应力和微观结构。考虑到热机械过程中变形历史的影响,本研究证明了微观结构、流动行为和工件几何形状之间的内在相关性。


Monotonic tensile and cyclic deformation of a Ni-based single crystal superalloy with anisotropic microstructural rafting patterns at high temperature: Experiment and constitutive modelling

Y.S. Fan, L. Tan, X.G. Yang, W.Q. Huang, D.Q. Shi

doi:10.1016/j.ijplas.2024.104031

ni基单晶高温合金各向异性显微组织泛起模式的单调拉伸和循环变形:实验和本构模型

Monotonic tensile and cyclic deformation behaviours are investigated under different microstructural rafting states of a SC Ni-based superalloy, with emphasis on the influences of the rafting extent, type and loading orientation. The deformed microstructures and the dislocation configurations are characterized to give a micro-based understanding on the varying of deformation behaviours due to rafting. It is found that the decreases in the initial yield point and cyclic stress amplitude are only related to the rafting extent. Nevertheless, the rafting type (namely, the plate-like and needle-like morphology) has an undeniable contribution to the shape of hysteresis loops, where the plate-like rafting morphology results in more significant Bauschinger effect than needle-like rafting morphology. The variation of monotonic and cyclic deformation induced by rafting shares affinity with the alteration of internal stress and the movement of dislocations. Afterwards, a microstructure-sensitive constitutive model with two-phase flow rules has been developed. The effect of rafting on the monotonic and cyclic stress-strain responses is captured by introduce a series of microscopic mechanisms and a micromechanics-based back stress model that considers the morphology and size of the γ'/γ two-phase structures. The developed model is used to simulate the macroscopic stress-strain responses of the SC Ni-based superalloy under different rafting states. Model predictions are in good agreement with tests, capturing the reduction of cyclic stress amplitudes and the change in hysteresis loops. Finally, the impacts of the two-phase flow rules and the micromechanics-based back stress on the simulation capability have been discussed.

研究了SC镍基高温合金在不同微观组织漂流状态下的单调拉伸和循环变形行为,重点研究了漂流程度、漂流类型和加载方向的影响。对变形的显微组织和位错构型进行了表征,以从微观角度理解漂流引起的变形行为的变化。研究发现,初始屈服点和循环应力幅值的减小只与漂流程度有关。然而,漂流类型(即板状和针状形态)对迟滞回路的形状有不可否认的贡献,其中板状漂流形态比针状漂流形态产生更显著的鲍辛格效应。漂流引起的单调和循环变形的变化与内应力的变化和位错的运动密切相关。随后,建立了具有两相流规律的微结构敏感本构模型。通过引入一系列微观机制和考虑γ′/γ两相结构形态和尺寸的基于微观力学的背应力模型,捕获了漂流对单调和循环应力-应变响应的影响。利用所建立的模型模拟了SC镍基高温合金在不同流变状态下的宏观应力应变响应。模型预测与试验结果很好地吻合,捕捉到循环应力幅值的减小和迟滞回路的变化。最后,讨论了两相流规律和基于细观力学的背应力对模拟能力的影响。


Thin-Walled Structures

An extension of composite bending strain κMITC3+ scheme in analysis of shell structures reinforced with rib stiffeners

Son H. Nguyen, Tiendung Vu, Quoc Hoa Pham, Trung Nguyen-Thoi

doi:10.1016/j.tws.2024.112062

复合弯曲应变 κMITC3+ 方案在分析用肋加劲件加固的壳体结构中的应用扩展

In this paper, the composite bending strain κMITC3+ approach is extended for analysing the shell structural domain in the rib-stiffened shell problems. Developed to achieve enhanced performance and emphasize a softer bending behaviour, this novel element employs a polynomial projection technique to construct an assumed composite bending strain field. This technique originates from the Hu-Washizu three-filed principle and the orthogonality condition. In the membrane component context, an improved Allman-like triangular element is utilized to remove the spurious energy mode commonly associated with the classical Allman's theory. To address the shear locking phenomenon within Timoshenko's beam model for the rib stiffeners, a selective/reduced integration approach is adopted. This involves using a standard two-point Gaussian rule for accurate bending strain computation and a one-point Gaussian rule for shear strain computation. The numerical examples showcased in our study unequivocally highlight the distinct superiority of the κMITC3+ element.

本文将复合弯曲应变κMITC3+方法推广到肋加筋壳结构域分析中。为了实现增强的性能并强调更柔和的弯曲行为,这种新型元件采用多项式投影技术来构建假设的复合材料弯曲应变场。该技术源于胡-和三场原理和正交性条件。在膜元件的背景下,一个改进的Allman类三角单元被用来去除通常与经典Allman理论相关联的虚假能量模式。为了解决Timoshenko肋加劲梁模型中的剪切锁定现象,采用了选择性/减少积分方法。这包括使用标准的两点高斯规则进行精确的弯曲应变计算,使用一点高斯规则进行剪切应变计算。在我们的研究中所展示的数值例子明确地强调了κMITC3+元素的明显优势。


Experimental and numerical analysis of joints and thin-walled steel beams fabricated through resistance spot welding and hot-dip galvanizing

Judyta Niemiro-Maźniak, Piotr Lacki

doi:10.1016/j.tws.2024.112105

电阻点焊和热镀锌薄壁钢梁接头和薄壁钢梁的试验与数值分析

The study conducted a numerical and experimental analysis of lap joints and thin-walled beams made of DC01 steel. The beams consisted of webs formed by two flat bars, which were connected to flanges using cold-formed angles through advanced resistance spot welding (RSW) technology. The beams varied in geometry and mass. Load capacity evaluation was performed on the beams using a test stand consisting a testing machine and additional bending tooling. Prior to testing, some of the beams underwent hot-dip galvanization to create a bimetallic structure. The application of hot-dip galvanization resulted in the filling of free spaces between the welded sheets of the beams, leading to increased load-bearing capacity and stiffness in the galvanized beams compared to the non-galvanized ones. The galvanized beams tested during the experimental study exhibited a bending load capacity that was 59-83% higher than that of the non-galvanized beams. The RSW lap joints were subjected to a uniaxial tensile test using digital image correlation and tracking (DIC). Three variants of joints were analyzed, differing in the number and arrangement of welds. The results obtained from the experimental tests were then compared with those from numerical analyses conducted in the ADINA software, utilizing the Finite Element Method (FEM). The initiation of cracks in the lap joints occured at the location of maximum plastic deformation, determined experimentally and confirmed by numerical simulations. The strength of the joint was influenced by the number and arrangement of welds in the joint. The use of 3D solid models to analyze RSW lap joints and resistance welded beams allowed for more accurate results in the weld area. The paper also presented the possibilities of using the designed beams.

对DC01型钢搭接薄壁梁进行了数值和试验分析。梁由两根扁钢组成的腹板组成,通过先进的电阻点焊(RSW)技术通过冷弯角连接到法兰上。这些梁的几何形状和质量各不相同。使用由试验机和附加弯曲工具组成的试验台对梁进行负载能力评估。在测试之前,一些横梁经过热浸镀锌以形成双金属结构。热镀锌的应用导致在梁的焊接板之间填充自由空间,导致与未镀锌的梁相比,镀锌梁的承载能力和刚度增加。在试验研究中,镀锌梁的弯曲承载力比未镀锌梁高59-83%。采用数字图像相关与跟踪(DIC)技术对RSW搭接接头进行了单轴拉伸试验。分析了三种不同的接头形式,它们的焊缝数量和排列方式不同。然后利用有限元法(FEM)将实验测试结果与ADINA软件中进行的数值分析结果进行比较。搭接节点的裂纹萌生发生在最大塑性变形的位置,这一点得到了实验和数值模拟的证实。接头的强度受焊缝数量和焊缝排列的影响。使用3D实体模型来分析RSW搭接和电阻焊梁,可以在焊接区域获得更准确的结果。文中还介绍了使用设计梁的可能性。


Isogeometric method for buckling prediction and post-buckling analysis of variable stiffness composite underwater pressure shell

Hao Miao, Peng Jiao, Huangyang Xu, Xinshuang Li, Zhiping Chen

doi:10.1016/j.tws.2024.112085

变刚度复合材料水下耐压壳屈曲预测及后屈曲分析等几何方法

Composite cylindrical pressure hulls are thin-walled structures widely used for autonomous underwater vehicles. Buckling failure is one of the most important failure modes for these shells under external pressure. In existing buckling studies of cylindrical pressure hulls, FEM is the most popular analysis method but not efficient enough when dealing with structures with complex material distributions such as the variable stiffness composite shells. Motivated by this, an isogeometric method for buckling prediction and post-buckling analysis of variable stiffness composite underwater pressure shell is proposed in this article. In this method, based on Reissner-Mindlin shell formulas undergoing large deformation, a buckling analysis framework in IGA forms is established. Then a modified arc-length method is proposed based on kinematics used in the shell formulas, and is used to overcome the inaccuracy caused by the 2 degrees of freedom node rotation in the prediction step of arc-length method. In addition, the influence of bifurcation is considered, which may seriously affect the precision of buckling behavior simulation when the limit point is close to a bifurcation point. The computational accuracy of this framework has been validated in a series of constant stiffness composite shell cases involving buckling load prediction and post-buckling behavior simulation. For variable stiffness composite hull cases, this framework achieves the same precision as FEM with fewer elements. Therefore, the proposed framework provides an efficient way for the buckling design of underwater variable stiffness composite pressure hulls.

复合圆柱形耐压壳体是一种广泛应用于自主水下航行器的薄壁结构。屈曲破坏是此类壳体在外压作用下最主要的破坏形式之一。在现有的圆柱耐压壳屈曲研究中,有限元法是最常用的分析方法,但对于变刚度复合壳等材料分布复杂的结构,有限元法的分析效率较低。基于此,本文提出了变刚度复合材料水下耐压壳体屈曲预测及后屈曲分析的等几何方法。该方法基于大变形时的Reissner-Mindlin壳公式,建立了IGA形式的屈曲分析框架。在此基础上,提出了一种改进的弧长法,克服了弧长法预测步骤中2自由度节点旋转带来的误差。此外,还考虑了分岔的影响,当极限点接近分岔点时,可能会严重影响屈曲行为模拟的精度。通过一系列等刚度复合材料壳体的屈曲载荷预测和后屈曲行为模拟,验证了该框架的计算精度。对于变刚度复合壳体,该框架在单元数较少的情况下达到了与有限元相同的精度。因此,该框架为水下变刚度复合耐压壳体屈曲设计提供了一种有效的方法。


Bandgap characteristics of a hybrid multi-resonator elastic metamaterial with negative stiffness mechanism and its application to mitigate seismic response of building structures

Wen Zhou, Haoran Zuo, Kaiming Bi, Hong Hao, Wensu Chen

doi:10.1016/j.tws.2024.112079

具有负刚度机制的混合多谐振腔弹性超材料带隙特性及其在减轻建筑结构地震反应中的应用

Seismic metamaterials have attracted extensive attention due to their unique ability to attenuate the transmission of elastic waves in their frequency bandgaps. However, generating a metamaterial with a low-frequency and wide bandgap remains challenging. Previous studies have shown that negative stiffness mechanisms can lower the frequency range of bandgaps while employing a multi-resonator technique can broaden the width of bandgaps. In this study, by combining these two techniques, a negative stiffness enhanced multi-resonator elastic metamaterial (NMEM) is first proposed. The feasibility of NMEM is validated by comparing the theoretical dispersion relation and the transmission spectra of a finite cell model. The results demonstrate that low-frequency and wide bandgaps can be realized by NMEM. To further widen the bandgap, a hybrid NMEM is proposed by connecting multiple types of cells in series. The proposed hybrid NMEM consists of two types of cells, one with a single resonator and another with two resonators, which merge individual bandgaps into a continuous and wider bandgap. The proposed hybrid NMEM is then adopted as a meta-basement for a case building to demonstrate its effectiveness in mitigating seismic responses. The results show that the seismic responses of the building with the hybrid meta-basement are considerably reduced than those of the building with the conventional basement. However, the hybrid meta-basement may lead to larger structural displacement response when the dominant frequency of ground motion is outside the designed bandgap.

地震超材料由于其独特的衰减弹性波在其频带隙中的传输的能力而引起了广泛的关注。然而,产生具有低频和宽带隙的超材料仍然具有挑战性。以往的研究表明,负刚度机制可以降低带隙的频率范围,而采用多谐振器技术可以拓宽带隙的宽度。在这项研究中,结合这两种技术,首次提出了一种负刚度增强多谐振腔弹性超材料(NMEM)。通过比较理论色散关系和有限单元模型的透射光谱,验证了NMEM的可行性。结果表明,NMEM可以实现低频率和宽带隙。为了进一步扩大带隙,提出了将多种类型的电池串联在一起的混合NMEM。所提出的混合NMEM由两种类型的单元组成,一种具有单个谐振器,另一种具有两个谐振器,它们将单个带隙合并成连续的更宽的带隙。然后采用所提出的混合NMEM作为案例构建的元基础,以证明其在减轻地震反应方面的有效性。结果表明,与普通地下室相比,混合地下室结构的地震反应明显降低。然而,当地震动主频率在设计带隙之外时,混合基底可能导致较大的结构位移响应。


Process defect analysis and visual detection of aluminum/copper cable joints with magnetic pulse crimping

Hao Jiang, Weixingyu Zhou, Ming Lai, Shaoluo Wang, Xiao Liu, Guangyao Li, Junjia Cui

doi:10.1016/j.tws.2024.112110

磁脉冲压接铝/铜电缆接头工艺缺陷分析与视觉检测

Magnetic pulse crimping (MPC) has been demonstrated to enhance the electrical and mechanical performance of the aluminum/copper cable joints compared to traditional mechanical crimping. However, little attention has been given to the impact of defects during the manufacture on the performance. This paper uses MPC technology to connect joints and investigates the influence of various defects (including scratches, skew, length inadequate, wire broken, and depth inadequate), on the electrical and mechanical performance of the joints. The results indicated that the defects lead to significant changes performance of joints. Compared to the normal joint, skew, length inadequate, wire broken, and depth inadequate contributed to decreased tightness and the strength of the joints, resulting in an increase in the average resistance by 518.8%, 1133.2%, 1533.8%, and 1377.9%. Simultaneously, average loads of joints decrease by 16.4%, 23.5%, 28.8%, and 91.3%, respectively. Scratches have no discernible impact on performance. To address these defects systematically, a hierarchical defect detection approach was proposed. Faster R-CNN was employed to search three distinct regions: a large region (L), a middle region (M), and a small region (S), each associated with different defects that proved to impact performance via previous experiments. A COCO metric of 84.85% was achieved. Four ResNet models were then utilized to classify defects within these regions. ResNet50 exhibited the best overall performance: 95% accuracy for L, 100% for M, and 87% for S.

与传统的机械压接相比,磁脉冲压接(MPC)已被证明可以提高铝/铜电缆接头的电气和机械性能。然而,制造过程中缺陷对性能的影响却很少得到重视。本文采用MPC技术连接接头,研究了各种缺陷(包括划伤、歪斜、长度不足、断线、深度不足)对接头电气性能和力学性能的影响。结果表明,缺陷导致接头性能发生明显变化。与正常接头相比,歪斜、长度不足、断丝和深度不足导致接头的密封性和强度下降,导致平均阻力增加518.8%、1133.2%、1533.8%和1377.9%。同时,节点平均荷载分别降低16.4%、23.5%、28.8%和91.3%。划痕对性能没有明显的影响。为了系统地解决这些缺陷,提出了一种分层缺陷检测方法。使用更快的R-CNN搜索三个不同的区域:大区域(L),中间区域(M)和小区域(S),每个区域都与不同的缺陷相关,这些缺陷在先前的实验中被证明会影响性能。COCO指标达到84.85%。然后利用四个ResNet模型对这些区域内的缺陷进行分类。ResNet50表现出最好的总体性能:L的准确率为95%,M的准确率为100%,S的准确率为87%。


A Novel Crimped Composite Spline Joint for Pultruded FRP Tubes: Conceptual Design and Tensile Properties

Dong-Dong Zhang, Chen-Xi Lv

doi:10.1016/j.tws.2024.112112

一种新型压接复合花键接头:概念设计及拉伸性能

Creating an effective composite joint between fiber-reinforced polymers (FRPs) and metallic profiles poses a significant challenge for heavy-loaded and lightweight emergency truss bridges. A novel crimped composite spline joint (CCSJ) was developed to achieve satisfactory engineering performance. Comparative tensile tests were conducted to evaluate the tensile properties and load-carrying mechanism of the CCSJ in comparison to those of joints without splines. Finite element (FE) analysis considering the crimping process and tensile loading was simultaneously executed and calibrated by experiments. Parametric simulation was supplemented to explore the key factors influencing the ultimate bearing capacity. The results indicated that the novel CCSJ features a simple preparation process, high connection efficiency, and large bearing capacity. A 60×6 mm hybrid FRP tube can withstand a maximum tensile load of 804 kN, achieving a connection efficiency of 61.3% without the need for any secondary processing of the FRP tube. The CCSJ demonstrates a significantly higher connection efficiency of approximately 20% compared to joints without splines. The ability of the CCSJ to effectively transfer significant axial loads through the interfacial friction effect is attributed to the increase in the interfacial contact area and preloading radial pressure resulting from the incorporation of pre-crimping splines. A typical failure mode involves interfacial slippage, resulting in satisfactory ductile behavior. The ultimate bearing capacity of the CCSJ is positively correlated with the crimping variables, friction coefficient, spline length, and number of splines. The FE model demonstrates sufficient accuracy in predicting the key behavioral indicators of the composite joint.

在纤维增强聚合物(frp)和金属型材之间建立有效的复合接头对重载和轻型应急桁架桥梁提出了重大挑战。为了获得满意的工程性能,研制了一种新型的卷曲复合花键接头。进行了对比拉伸试验,以评估CCSJ的拉伸性能和承载机制,并与无样条接头进行了比较。同时进行了考虑压接过程和拉伸载荷的有限元分析,并进行了实验标定。补充参数化模拟,探索影响极限承载力的关键因素。结果表明,新型CCSJ具有制备工艺简单、连接效率高、承载能力大等特点。60×6 mm复合FRP管可承受最大拉伸载荷804 kN,连接效率达61.3%,无需对FRP管进行二次加工。与没有花键的接头相比,CCSJ的连接效率显着提高了约20%。CCSJ通过界面摩擦效应有效传递显著轴向载荷的能力归因于预卷曲花键的加入导致的界面接触面积和预加载径向压力的增加。典型的破坏模式包括界面滑移,导致令人满意的延性行为。CCSJ的极限承载能力与卷曲变量、摩擦系数、样条长度和样条数呈正相关。有限元模型对复合材料接头关键行为指标的预测具有足够的准确性。



来源:复合材料力学仿真Composites FEM
ACTMechanicalSystemMAGNETDeform复合材料建筑焊接裂纹BIM理论材料机器人试验电气
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首次发布时间:2024-11-20
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【新文速递】2024年11月5日固体力学SCI期刊最新文章

今日更新:Journal of the Mechanics and Physics of Solids 1 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 1 篇Journal of the Mechanics and Physics of SolidsRegularization of softening plasticity with the cumulative plastic strain-rate gradientG. Bacquaert, J. Bleyer, C. Maurinidoi:10.1016/j.jmps.2024.105923软化塑性与累积塑性应变率梯度的正则化We propose a novel variational framework to regularize softening plasticity problems. Specifically, we modify the plastic dissipation potential term by adding a contribution depending on the cumulative plastic strain-rate gradient. We formulate the evolution of the so-obtained strain-rate gradient plasticity model with an incremental variational principle. The time-discretized evolution equations are deduced from the corresponding first-order optimality conditions. To investigate the model, the problem of a bar in traction is studied. Analytical solutions are explicitly derived, and characterized by exponential localization profiles. Contrary to other regularization strategies, no spurious spreading of the plastic localization band is observed. A first numerical implementation in 1D and 2D plane strain conditions is proposed based on conic programming solvers and validated against the analytical predictions. Numerical results on plane strain von Mises plasticity show that the proposed framework leads to mesh-independent results and efficient control of plastic localization bands.我们提出了一个新的变分框架来正则化软化塑性问题。具体来说,我们通过增加一个依赖于累积塑性应变率梯度的贡献来修改塑性耗散势项。用增量变分原理推导了应变率梯度塑性模型的演化过程。由相应的一阶最优性条件推导出时间离散演化方程。为了验证该模型,研究了牵引杆的问题。解析解被明确地导出,并以指数局域化曲线表征。与其他正则化策略相反,没有观察到塑性局部化带的虚假扩展。提出了基于二次规划求解的一维和二维平面应变条件下的第一个数值实现,并与分析预测进行了验证。平面应变von Mises塑性的数值结果表明,该框架具有网格无关性和塑性局部化带的有效控制。International Journal of PlasticityDeformation mechanism of a metastable medium entropy alloy strengthened by the synergy of heterostructure design and cryo-pre-strainingShilei Liu, Haitao Gao, Daixiu Wei, Charlie Kong, L.S.R. Kumara, M.W. Fu, Hailiang Yudoi:10.1016/j.ijplas.2024.104162异质结构设计与低温预应变协同强化亚稳介质熵合金的变形机制Face-centered cubic (FCC) medium entropy alloys (MEAs) have received considerable attention due to their impressive mechanical properties and responses. However, their practical application is limited by their modest yield strengths. The potential enhancement of the mechanical properties of single-phase MEAs was explored in this study through a synergistic approach combining heterogeneous structure design with subsequent cryo-pre-straining. A heterogeneous lamella structure was produced in a single-phase Fe55Mn20Cr15Ni10 MEA via two-step rolling and annealing. Cryo-pre-straining at varying degrees (6, 12, 21, and 36%) introduced hexagonal close-packed (HCP) phase, high-density dislocations, twins, and stacking faults, leveraging the reduced stacking fault energy at cryogenic temperatures. This process enhanced the alloy's yield strength from 353 MPa to 1.2 GPa (compared to the baseline uniform coarse-grained structure), while maintaining an acceptable total elongation of 8.4%. The impact of cryo-pre-straining on the microstructure and mechanical properties of the MEA was assessed using in-situ synchrotron X-ray diffraction analysis. Cryo-pre-straining (36%) achieved a higher dislocation density (6.1 × 1015 m−2) compared to room-temperature straining (2.5 × 1015 m−2). The stress contribution from HCP-martensite and the evolution of dislocation density during loading were quantified, along with observations of negative stacking fault probability and strain-induced HCP→FCC reverse transformation in cryo-pre-strained samples under loading conditions. Furthermore, the contributions of regulated microstructures to the enhancement of yield strength were quantitatively assessed.面心立方(FCC)介质熵合金(MEAs)由于其优异的力学性能和响应特性而受到广泛关注。然而,它们的实际应用受到其适度屈服强度的限制。本研究通过非均相结构设计与后续低温预应变相结合的协同方法,探讨了单相MEAs力学性能的潜在增强。通过两步轧制和退火,在单相Fe55Mn20Cr15Ni10 MEA中形成了非均匀片层结构。不同程度的低温预应变(6、12、21和36%)引入了六方密排(HCP)相、高密度位错、孪晶和层错,利用了低温下层错能的降低。该工艺将合金的屈服强度从353 MPa提高到1.2 GPa(与基线均匀粗晶组织相比),同时保持可接受的8.4%的总伸长率。采用原位同步x射线衍射分析方法研究了低温预应变对MEA微观结构和力学性能的影响。与室温拉伸(2.5 × 1015 m−2)相比,低温预拉伸(36%)获得了更高的位错密度(6.1 × 1015 m−2)。定量分析了加载过程中HCP-马氏体的应力贡献和位错密度的演变,并观察了加载条件下低温预应变样品的负层错概率和应变诱导的HCP→FCC反转变。此外,定量评价了调控微观结构对提高屈服强度的贡献。Thin-Walled StructuresA 3D shell model for static and free vibration analysis of multilayered magneto-elastic structuresS. Brischetto, D. Cesaredoi:10.1016/j.tws.2024.112620多层磁弹性结构静力和自由振动分析的三维壳模型In this paper, an exact 3D coupled magneto-elastic shell model for static and free vibration analysis of multilayered piezomagnetic smart structures is presented. The introduction of the mixed curvilinear orthogonal reference system (α,β,z) allows investigations of plates, cylindrical shells, cylinders and spherical shells as actuators or sensors and also in free vibration conditions. The present exact 3D coupled shell model is composed of four second-order differential equations whose primary variables are the three displacements u, v and w and the magnetic potential ψ. Displacements, stresses, strains, magnetic potential, magnetic induction and circular frequency values are computed to understand the behaviour of piezomagnetic smart structures. The resolution method adopted for the present 3D magneto-elastic problem is based on harmonic forms in α and β in-plane directions and the exponential matrix method in the z direction. Simply supported one-layered/multilayered structures with 0° or 90° orthotropic angles have been analyzed. The results section is divided into a first part related to the validation of the proposed 3D model and a second part where new benchmark cases are presented and discussed. Different lamination schemes, load boundary conditions, geometries and materials are studied. Magneto-elastic coupling, thickness and material layer effects are discussed for thin and thick structures. The main novelty of the present exact 3D coupled magneto-elastic shell model stands in the ability to analyze several geometries and multilayered configurations embedding piezomagnetic materials under the action of different boundary loads via a general mathematical formulation.本文提出了一种用于静态和自由振动分析的多层压电磁智能结构的精确三维耦合磁弹性壳体模型。引入混合曲线正交参考系(α,β,z)允许研究作为致动器或传感器的板、圆柱壳体、圆柱体和球形壳体,以及自由振动条件下的情况。该精确的三维耦合壳体模型由四个二阶微分方程组成,主要变量为三个位移u、v和w以及磁场位势ψ。计算位移、应力、应变、磁场位势、磁场感应和圆频率值以了解压电磁智能结构的行为。该问题的求解方法基于α和β平面方向的谐波形式和z方向的指数矩阵方法。分析了0°或90°各向异性角度的单层/多层结构。结果部分分为两部分,第一部分与所提出的三维模型的验证有关,第二部分则展示了新的基准案例并对其进行了讨论。研究了不同的层压方案、载荷边界条件、几何形状和材料。讨论了薄结构和厚结构中的磁弹性耦合、厚度和材料层效应。当前精确的三维耦合磁弹性壳体模型的主要创新之处在于,可以通过通用的数学公式分析在不同边界载荷作用下嵌入压电磁材料的多种几何形状和多层配置。来源:复合材料力学仿真Composites FEM

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