【新文速递】2024年9月19日固体力学SCI期刊最新文章

今日更新：International Journal of Solids and Structures 1 篇，Journal of the Mechanics and Physics of Solids 1 篇，Mechanics of Materials 1 篇，International Journal of Plasticity 1 篇，Thin-Walled Structures 5 篇International Journal of Solids and StructuresStability discussion and application study of pseudo-corner modelsTianyin Zhang, Xianhong Handoi:10.1016/j.ijsolstr.2024.113136伪角模型的稳定性讨论及应用研究Accurate plastic flow modelling under complex working conditions is crucial for metal deformation simulations. Recently, some advanced pseudo-corner models have been developed to describe corner effects and analyze strain localization problems. The present work consists of three parts. The first part discusses the intrinsic stability of the pseudo-corner model class, which forms the premise of application analysis. The second part applies the pseudo-corner models and the associated flow rule (AFR) to buckling onset estimation, plastic post-buckling analysis and shear band analysis. The experimental conditions are strictly reproduced and the optimal model parameters are determined. The results reveal that the pseudo-corner models and AFR are indistinguishable in the buckling onset estimation. AFR overestimates the post-buckling strength of circular tubes under axial compression, and cannot reproduce the shear band development during sheet bending; while the pseudo-corner models have better prediction performance in both scenarios. The results also suggest that the parameter values of pseudo-corner models are apparently inconsistent in the above two types of problems. Then in the third part, two representative influencing factors including strain gradient plasticity and initial imperfections are discussed, and this inconsistency is finally attributed to the shortwave surface defect which however is usually neglected by previous studies.复杂工况下精确的塑性流动建模是金属变形模拟的关键。近年来，人们发展了一些先进的伪转角模型来描述转角效应和分析应变局部化问题。本文的工作由三个部分组成。第一部分讨论了伪角模型类的固有稳定性，这是应用分析的前提。第二部分将拟角点模型和关联流动规则（AFR）应用于屈曲起始估计、塑性后屈曲分析和剪切带分析。严格再现了实验条件，确定了最优模型参数。结果表明，伪转角模型和AFR在屈曲起始估计中是不可区分的。AFR过高估计了轴压作用下圆管的屈曲后强度，不能再现板弯曲过程中剪切带的发展；而伪角点模型在两种情况下都具有更好的预测性能。结果还表明，在上述两类问题中，伪角模型的参数值明显不一致。然后在第三部分，讨论了应变梯度塑性和初始缺陷这两个具有代表性的影响因素，并最终将这种不一致归因于短波表面缺陷，而短波表面缺陷在以往的研究中往往被忽视。Journal of the Mechanics and Physics of SolidsThermodynamic potentials for viscoelastic compositesMartín I. Idiartdoi:10.1016/j.jmps.2024.105936粘弹性复合材料的热力学势Explicit expressions for the free-energy and dissipation densities of viscoelastic composites at fixed temperature are proposed. The composites are comprised of an arbitrary number of distinct constituents exhibiting linear Maxwellian rheologies and distributed randomly at a length scale that is much smaller than that over which applied loads vary significantly. Central to their derivation is the recognition that any viscous deformation field can be additively decomposed into an irrotational field and a solenoidal field in such a way that variational approximations available for elastic potentials become applicative to viscoelastic potentials. The thermodynamic potentials conform to a generalized standard model with a finite number of effective internal variables with explicit physical meaning. Specific approximations of the Hashin–Shtrikman and the Self-Consistent types are worked out in detail. Under particular circumstances, these approximations may turn out exact. Macroscopic stress–strain relations and intraphase statistics of the stress field up to second order are also provided.给出了粘弹性复合材料在固定温度下的自由能和耗散密度的显式表达式。复合材料由任意数量的不同组分组成，表现出线性麦克斯韦流变性，并随机分布在长度尺度上，该尺度远小于施加载荷显著变化的长度尺度。其推导的核心是认识到任何粘性变形场都可以加性地分解为无旋场和螺线线场，从而使可用于弹性势的变分近似适用于粘弹性势。热力学势符合具有有限数量的具有明确物理意义的有效内变量的广义标准模型。详细计算了Hashin-Shtrikman和自洽型的具体近似。在特殊情况下，这些近似值可能是精确的。给出了宏观应力-应变关系和二级应力场的相内统计。Mechanics of MaterialsLocal measurement on oedometric compression tests: Time and temperature ageing effects on a fluorosiliconeClémence Logeais, Cristian Ovalle, Lucien Laiarinandrasanadoi:10.1016/j.mechmat.2024.105193计量压缩试验的局部测量：氟硅树脂的时间和温度老化效应O-ring durability is a key issue for engineering structures that require sealing over a long service life. Rubber-like materials are used for this type of component because of the assumption of incompressibility, i.e. a high bulk modulus K . However, this assumption has been called into question in the literature, particularly for elastomers under high hydrostatic pressures. This work examines the compressibility of rubber-like materials, with a particular focus on fluorosilicone elastomers (FVMQ). A method of confined compression using a transparent crucible is presented, which allows local measurement of the displacement field. This technique provides a better understanding of the analysis of oedometric compression data and a reliable way to determine the K value. Furthermore, this approach allows following the evolution of K over time with accelerated ageing. Three ageing temperatures - 200, 220 and 250 °C - were tested up to 34, 15 and 1 weeks respectively. For the three ageing temperatures, the FVMQ results show a decrease in K values with ageing. In particular, at 250 °C, a turning point was observed after 72 h of ageing. These results highlight the influence of ageing on the compressibility of the FVMQ and the presence of two different ageing mechanisms affecting the K evolution.对于需要长寿命密封的工程结构来说，o型圈的耐久性是一个关键问题。类橡胶材料被用于这种类型的组件，因为假设不可压缩，即高体积模量K。然而，这一假设在文献中受到质疑，特别是在高静水压力下的弹性体。这项工作考察了橡胶类材料的可压缩性，特别关注氟硅弹性体（FVMQ）。提出了一种利用透明坩埚进行密闭压缩的方法，可以对位移场进行局部测量。该技术提供了一个更好的理解的分析测量压缩数据和一个可靠的方法来确定K值。此外，这种方法允许跟随K随着时间的推移而加速老化的演变。三种老化温度- 200,220和250°C -分别测试了34,15和1周。对于3种老化温度，FVMQ结果表明，K值随老化而减小。特别是，在250°C时，72 h后观察到一个转折点。这些结果强调了老化对FVMQ可压缩性的影响，以及两种不同的老化机制影响K演化的存在。International Journal of PlasticitySignificantly enhanced mechanical properties of NiCoV medium-entropy alloy via precipitation engineeringJunyang He, Weijin Cai, Na Li, Li Wang, Zhangwei Wang, Shuai Dai, Zhifeng Lei, Zhenggang Wu, Min Song, Zhaoping Ludoi:10.1016/j.ijplas.2024.104180 通过沉淀工程使NiCoV中熵合金的力学性能得到显著提高Precipitation engineering is one of the most effective means to enhance the strength of an alloy, which essentially requires precipitates with certain deformability, fine size, and uniform distribution. However, for multicomponent alloy systems, the chemical complexity poses significant difficulties in applying this strengthening method due to the diversity and brittleness of the potential precipitate phases. In this work, we demonstrated the precipitation engineering in a chemically complex prototype alloy NiCoV. Specifically, formation of detrimental σ, μ and Heusler phases was avoided by reducing the V content, and a two-step short-term annealing was designed to trigger homogeneous κ nucleation while inhibiting its rapid coarsening. It is found that both grain and phase boundaries can trap V atoms, which not only pins these interfaces but also hinders the V partitioning needed for κ growth. Consequently, we achieved an ultrafine κ/γ architecture in the NiCoV0.9 alloy, which surprisingly exhibited an ultrahigh yield strength of 1.6 GPa and a total work-hardening amount of 219 MPa. Our analysis indicates that the hetero-deformation induced (HDI) stress is mainly responsible for the high strength, while the coherent nature of phase boundaries and decent deformability of κ alleviate stress concentration, giving rise to the pronounced work-hardening. Our work highlights the importance of suitable phase selection and delicate substructure tailoring in precipitation engineering, with key findings also useful for enhancing overall mechanical properties in other multicomponent alloys.析出工程是提高合金强度的最有效手段之一，其本质是要求析出物具有一定的变形能力、尺寸细小、分布均匀。然而，对于多组分合金体系，由于潜在析出相的多样性和脆性，化学复杂性给应用这种强化方法带来了很大的困难。在这项工作中，我们展示了化学复杂合金NiCoV原型的沉淀工程。具体来说，通过降低V含量可以避免有害的σ、μ和Heusler相的形成，并设计了两步短期退火来触发均匀的κ成核，同时抑制其快速粗化。发现晶界和相界都可以捕获V原子，这不仅固定了这些界面，而且阻碍了κ生长所需的V分配。因此，我们在NiCoV0.9合金中实现了超细κ/γ结构，令人惊讶的是，该合金具有1.6 GPa的超高屈服强度和219 MPa的总加工硬化量。分析表明，高强度的主要原因是异质变形诱导应力（HDI），而相界的共格性和κ的良好变形性缓解了应力集中，导致加工硬化。我们的工作强调了在沉淀工程中适当的相选择和精细的子结构剪裁的重要性，其关键发现也有助于提高其他多组分合金的整体机械性能。Thin-Walled StructuresA Crashworthiness Design Framework based on Temporal-Spatial Feature Extraction and Multi-Target Sequential ModelingHechen Wei, HaiHua Wang, Ziming Wen, Yong Peng, Hu Wang, Fengchun Sundoi:10.1016/j.tws.2024.112694 基于时空特征提取和多目标序列建模的飞机耐撞设计框架Temporal-spatial crashworthiness design remains a challenging issue in engineering applications. Metamodeling techniques have been widely used to improve design efficiency by reducing the need for extensive experiments or simulations. However, these methods often fail to capture the essential information of temporal and spatial during the dynamical procedure. In this study, a novel multi-target modeling and optimization framework is introduced to overcome these limitations. This framework utilizes autocorrelation functions to identify key temporal-spatial segments, ensuring that the most influential factors are captured, and then builds a metamodel using multi-target regression techniques and partial autocorrelation functions, effectively capturing the complex relationships among different time steps. An adaptive sampling strategy is also employed to generate additional training data according to the objective functions, thereby enhancing the accuracy and robustness of the metamodels. These improvements enable a more accurate and interpretable integration of temporal-spatial information compared to popular methods. The effectiveness of the proposed framework is demonstrated through its successful implementation in optimizing crashworthiness across diverse scenarios: a cylindrical tube, a multi-cell energy-absorbing structure, and a B-pillar designed to withstand side impacts. The results show that the proposed method provides reliable predictions for subsequent optimization tasks and has the potential to address complex crashworthiness design challenges by comprehensively considering temporal-spatial information.时空耐撞性设计在工程应用中一直是一个具有挑战性的问题。元建模技术已被广泛用于通过减少对大量实验或模拟的需要来提高设计效率。然而，这些方法往往不能捕捉到动态过程中重要的时空信息。在本研究中，引入了一种新的多目标建模和优化框架来克服这些局限性。该框架利用自相关函数识别关键的时空片段，确保捕获最重要的影响因素，然后利用多目标回归技术和部分自相关函数构建元模型，有效捕获不同时间步长之间的复杂关系。采用自适应采样策略，根据目标函数生成额外的训练数据，从而提高元模型的准确性和鲁棒性。与流行的方法相比，这些改进使时空信息的整合更加准确和可解释。所提出的框架的有效性通过其在不同场景下的成功实施来证明：圆柱管、多单元吸能结构和b柱设计以承受侧面冲击。结果表明，该方法为后续优化任务提供了可靠的预测，并具有通过综合考虑时空信息来解决复杂耐撞设计挑战的潜力。Microstructure and mechanical properties of WE43 magnesium alloy fabricated by wire-arc additive manufacturingFukang Chen, Xiaoyu Cai, Bolun Dong, Sanbao Lindoi:10.1016/j.tws.2024.112699 线弧增材制造WE43镁合金的组织与力学性能Wire-arc additive manufacturing (WAAM) is emerging as a revolutionary method for fabricating heat-resistant WE43 magnesium alloy (WE43-Mg) components and multiple other Mg alloys. In this study, we successfully utilized cold metal transfer WAAM technology to fabricate high quality single-pass thin-walled WE43-Mg structures. The results show that the microstructure is mainly composed of equiaxed grains, and Mg14Nd2(Y,Gd) is the main second phase distributed along the grain boundaries. The relative density of the sample reaches 99.96%, and the main defects are oxide inclusions. The room temperature yield strength, ultimate tensile strength and elongation are 147.0 MPa, 221.9 MPa and 7.2%, respectively, with anisotropy rates of 1.9%, 2.2% and 3.7%. High-temperature tensile tests conducted at 250°C showed a slight increase in ultimate tensile strength and a significant increase in elongation from 7.2% to 16.8%, representing a 133% improvement. Under these conditions, the proportion of substructure increased significantly, and the proportion of low-angle grain boundaries rose from 3.2% to 69%. The stress-strain curves exhibited pronounced serrated flow behavior, which can be attributed to the interaction between solute atoms and dislocations.电弧增材制造（WAAM）是一种革命性的方法，用于制造耐热WE43镁合金（WE43-Mg）部件和多种其他镁合金。在这项研究中，我们成功地利用冷金属转移WAAM技术制造了高质量的单道薄壁WE43-Mg结构。结果表明：显微组织以等轴晶为主，沿晶界分布的第二相主要为Mg14Nd2(Y,Gd)；样品的相对密度达到99.96%，主要缺陷为氧化物夹杂。室温屈服强度、极限抗拉强度和延伸率分别为147.0 MPa、221.9 MPa和7.2%，各向异性率分别为1.9%、2.2%和3.7%。在250℃下进行的高温拉伸试验表明，极限拉伸强度略有提高，伸长率从7.2%显著提高到16.8%，提高了133%。在此条件下，亚结构的比例显著增加，低角度晶界的比例从3.2%上升到69%。应力应变曲线表现出明显的锯齿状流动特征，这可归因于溶质原子与位错的相互作用。The metastructures actuated by rotational motion with quasi-zero stiffness, negative stiffness, and bistabilityDiankun Pan, Shuangfen Tan, Zhimin Zhang, Wenbing Lidoi:10.1016/j.tws.2024.112700转动驱动的元结构具有准零刚度、负刚度和双稳性In this paper, a mechanical metastructure actuated by rotational motion is proposed, which consists of several cosine beams and two supporting frames, with its mechanical properties tuned by the remaining shape of the beam concerning the size of the inner frame. The finite element method combining the experiments is adopted to explore the effect of geometric parameters and identify the variation of mechanical properties with the size of the inner frame, exhibiting different features including positive stiffness, quasi-zero stiffness, negative stiffness, and bistability. An angle difference describing the geometric relationship between the beam and the inner frame is employed to relate the mechanical properties. For the maximized angle difference, the quasi-zero stiffness is obtained and the bistability is easy to capture when the angle difference is around zero. Next, the quasi-zero stiffness feature and bistability are investigated in parametric analysis concerning the shape of the beam and offset distance, respectively, and the double-layer structures with two-step quasi-zero stiffness feature or multistability are designed to expand the design space of the proposed structure. The metastructure in this work provides a new option for designing multistable structures with rotational deformation freedom and developing torsional vibration isolators.本文提出了一种由旋转运动驱动的力学元结构，该结构由若干余弦梁和两个支撑框架组成，其力学性能由梁的剩余形状与内框架的大小有关。采用有限元法结合实验，探讨几何参数的影响，识别力学性能随内框架尺寸的变化，表现出正刚度、准零刚度、负刚度和双稳性的不同特征。采用描述梁与内框架之间几何关系的角差来描述其力学性能。对于最大的角差，获得准零刚度，当角差在零附近时容易捕获双稳性。其次，在参数化分析中分别研究了梁的形状和偏移距离的准零刚度特征和双稳定性特征，并设计了具有两步准零刚度特征或多重稳定性的双层结构，以扩大结构的设计空间。本文研究的元结构为设计具有旋转变形自由的多稳定结构和研制扭振隔振器提供了新的选择。Impact Resistance Performance of 3D Woven TZ800H Plates with Different Textile ArchitectureQingbo Guo, Yachen Xie, Mengqi Yuan, Hong Zhang, Tao Wang, Guangyan Huangdoi:10.1016/j.tws.2024.112701不同纺织结构的三维编织TZ800H板的抗冲击性能Two typical methods commonly used to improve the mechanical properties and impact resistance properties of 3D woven composites are studied, namely weave pattern and layered architectures. The mechanical property and impact resistance performance were studied by utilizing the quasi-static compressive test, split Hopkinson pressure bar (SHPB) test and ballistic impact test. The compressive responses in warp and weft directions with different strain rates 0.001, 500 and 1300 s-1 were presented and analysed, providing strain rate influence on the material strength of different 3D woven composites. The impact resistance performance including damage mode, ballistic limit and specific energy absorption of three structures were discussed through impact tests. The results reveal that as the strain rate increases, the compressive strength and Young's modulus in both directions of 3D woven composites exhibit a significant increase. The compressive strength and modulus in the warp direction of the composites can be enhanced by using shallow interlocking of the warp tow or layered architectures. However, the two methods degrade the failure strain and weaken the strain rate strengthening effect of compressive strength in the weft direction, resulting in a significant decrease in the average strain energy density. For the ballistic impact case, the crimp of warp tows would decrease its load-bearing capacity, while resisting matrix crack growth under the ballistic impact. The significant reduction in the average strain energy density in the weft direction leads to a decrease in ballistic limit and specific energy absorption capacity under ballistic impact.研究了提高三维编织复合材料力学性能和抗冲击性能的两种典型方法，即编织模式和分层结构。通过准静态压缩试验、劈裂霍普金森压杆（SHPB）试验和弹道冲击试验，研究了复合材料的力学性能和抗冲击性能。分析了不同应变率（0.001、500和1300 s-1）下经纬方向的压缩响应，给出了应变率对不同三维机织复合材料强度的影响。通过冲击试验，讨论了三种结构的抗冲击性能，包括损伤模式、弹道极限和比能吸收。结果表明：随着应变速率的增大，三维编织复合材料的抗压强度和双向杨氏模量均有显著提高；采用经纱束的浅互锁或分层结构可以提高复合材料经纱方向的抗压强度和模量。但两种方法在纬向均降低了破坏应变，减弱了抗压强度的应变率强化效果，导致平均应变能密度显著降低。在弹道冲击情况下，翘曲束的卷曲会降低其承载能力，但会抵抗弹道冲击下基体裂纹的扩展。纬向平均应变能密度的显著降低导致了弹道极限和弹道冲击下的比能吸收能力的降低。Nonlinear deflection and thermal post-buckling analysis of sector annular poroelastic composite nanodisks using mathematical simulation and machine learning algorithmZhijun Xu, Yang Han, Mohammed El-Meligy, Khalil El Hindi, Hamed Safarpourdoi:10.1016/j.tws.2024.112702基于数学模拟和机器学习算法的扇形环形孔弹性复合材料纳米盘非线性挠曲和热后屈曲分析Poroelastic nanodisks offer mechanical engineers enhanced control over material properties, enabling precise tuning of mechanical responses for advanced applications in sensors, actuators, and nano-mechanical systems. This study presents a comprehensive analysis of thermally-affected multi-directional functionally graded sector annular nanodisks, focusing on their thermal-post buckling and nonlinear deflection behaviors. Utilizing a refined quasi-3D logarithmic theory (RQLT), the study incorporates the effects of Von-Karman nonlinearity to accurately capture the large deflection responses of these advanced nanostructures under thermal loading. The material properties of the nanodisks are graded in multiple directions, enhancing their ability to withstand thermal stresses and maintain structural integrity. To solve the complex governing equations derived from the RQLT, a nonlinear discrete-singular convolution (DSC) solution procedure is employed. This novel numerical technique allows for precise computation of the nonlinear deformation and stability characteristics of the nanodisks, providing insights into their behavior under various thermal conditions. The nonlinear DSC method's ability to handle singularities and discontinuities makes it particularly suitable for this type of advanced analysis. After obtaining the mathematics simulation data, a machine learning algorithm is used to test, train, and validate the results for future analysis of the mentioned problem with low computational cost. The results demonstrate the critical influence of thermal gradients and material gradation on the post-buckling and nonlinear deflection responses of sector annular nanodisks. The interplay between thermal effects and material properties highlights the necessity for incorporating multi-directional functionally graded materials in the design of high-performance nanostructures. This study's findings are pivotal for the development of next-generation nanodisks used in thermal environments, offering a robust analytical and computational framework for their assessment and optimization.多孔弹性纳米盘为机械工程师提供了对材料性能的更好控制，能够精确调整传感器、致动器和纳米机械系统中先进应用的机械响应。本研究对热影响的多向功能梯度扇形环形纳米片进行了综合分析，重点研究了其热后屈曲和非线性挠曲行为。利用一种精细的准三维对数理论（RQLT），该研究结合了Von-Karman非线性效应，以准确捕捉这些先进纳米结构在热载荷下的大挠度响应。纳米片的材料性能在多个方向上进行了分级，增强了它们承受热应力和保持结构完整性的能力。为了求解由RQLT导出的复杂控制方程，采用了非线性离散-奇异卷积（DSC）求解过程。这种新颖的数值技术可以精确计算纳米片的非线性变形和稳定性特征，从而深入了解它们在各种热条件下的行为。非线性DSC方法处理奇点和不连续的能力使其特别适合于这种类型的高级分析。在获得数学模拟数据后，使用机器学习算法对结果进行测试、训练和验证，从而以较低的计算成本对上述问题进行后续分析。结果表明，热梯度和材料梯度对扇形环形纳米片的后屈曲和非线性挠曲响应有重要影响。热效应与材料性能之间的相互作用凸显了在高性能纳米结构设计中引入多向功能梯度材料的必要性。这项研究的发现对于在热环境中使用的下一代纳米盘的开发至关重要，为它们的评估和优化提供了一个强大的分析和计算框架。来源：复合材料力学仿真Composites FEM