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【新文速递】2024年11月13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 1 篇,Thin-Walled Structures 1 篇

Journal of the Mechanics and Physics of Solids

Time-dependent constitutive behaviors of a dynamically crosslinked glycerogel governed by bond kinetics and chain diffusion

Ji Lin, Md. Tariful Islam Mredha, Rumesh Rangana Manimel Wadu, Chuanqian Shi, Rui Xiao, Insu Jeon, Jin Qian

doi:10.1016/j.jmps.2024.105951

由键动力学和链扩散控制的动态交联甘油凝胶的时间相关本构行为

Soft materials featuring dynamic networks represent a burgeoning frontier in materials science, offering multifaceted applications spanning soft robotics, biomaterials, and flexible electronics. Unraveling the time-dependent constitutive behavior of these materials, rooted in dynamic networks, stands as a pivotal pursuit for engineering advancements. Herein, we fabricate a tough and extreme-temperature-tolerant glycerogel with a polymer network crosslinked by metal-coordination crosslinkers and conduct a thorough analysis of its intricate mechanical responses across monotonic loading, relaxation, creep, and cyclic tests. We then develop a physically grounded constitutive model integrating the dynamics of crosslinker association/dissociation and polymer chain diffusion, furnishing a holistic framework to elucidate their interplay. We employ a statistical description, using density functions of chains in terms of end-to-end vectors, to characterize network reconfiguration. The evolution of chain density under external load, mediated by crosslinker kinetics and chain diffusion in a viscous medium, leads to intriguing variations in elastic energy and stress responses. Through meticulous experimental validation and numerical simulations, we demonstrate the efficacy of the model in forecasting the mechanical behavior of dynamic polymer networks under diverse loading scenarios, encompassing strain rate effects, stress relaxation, Mullins effect, and self-recovery phenomena. Our findings provide valuable insights into the design and optimization of dynamic network-based materials for diverse applications in biomedical and engineering fields.

具有动态网络特征的软材料代表了材料科学的新兴前沿,提供了涵盖软机器人、生物材料和柔性电子的多方面应用。揭示这些材料的时间依赖本构行为,根植于动态网络,是工程进步的关键追求。在此,我们制造了一种坚韧和耐极端温度的甘油凝胶,其聚合物网络由金属配位交联剂交联,并通过单调加载、松弛、蠕变和循环测试对其复杂的力学响应进行了彻底的分析。然后,我们开发了一个基于物理的本构模型,该模型集成了交联剂结合/解离和聚合物链扩散的动力学,提供了一个整体框架来阐明它们的相互作用。我们采用统计描述,使用链的密度函数在端到端矢量,以表征网络重构。外载荷下链密度的演变,由交联剂动力学和链在粘性介质中的扩散介导,导致弹性能量和应力响应的有趣变化。通过细致的实验验证和数值模拟,我们证明了该模型在预测动态聚合物网络在不同加载场景下的力学行为方面的有效性,包括应变率效应、应力松弛、Mullins效应和自恢复现象。我们的发现为动态网络材料的设计和优化在生物医学和工程领域的各种应用提供了有价值的见解。


International Journal of Plasticity

A novel cobweb-like sub-grain structured Al-Cu-Mg alloy with high strength-plasticity synergy

Yufeng Song, Qin Zhang, Heng Li, Xudong Yuan, Yuqiang Chen, Dingding Lu, Wenhui Liu

doi:10.1016/j.ijplas.2024.104178

一种具有高强塑性协同作用的网状亚晶Al-Cu-Mg合金

Al-Cu-Mg alloys, as the most widely used lightweight structural materials, have been recognized as promising candidates in the transportation field for a low-carbon economy. However, the tensile strength and plasticity of alloys cannot be simultaneously improved to satisfy the requirements of continuously upgraded transportation vehicles. In this work, inspired by high-tensile strength and high plasticity of cobweb structure, a novel cobweb-like sub-grain structure was developed in Al-Cu-Mg alloys by a successive solution, high-strain-rate rolling (4.4 s-1), cryogenic treatment (–196°C) and aging process (SRCA). Notably, the tensile strength and plasticity of this alloy were superior to those reported in the current study. An ultrahigh Vickers hardness and tensile strength value of 206.2 Hv and 619.6 MPa, which were 39.8% and 31.8% higher than those of traditional T6 heat-treated Al-Cu-Mg alloys, were obtained after SRCA. Meanwhile, an increase in the elongation of this alloy from 4.31% to 8.23% (increase of 90.9%) was also achieved. More importantly, the high strength-plasticity (“double high”) Al-Cu-Mg alloy was attributed to a cobweb-like sub-grain structure, which was proposed for the first time by utilizing reverse thinking to enhance plasticity through elevating dislocations, due to the formation of high-density dislocations from high-strain-rate rolling and rearrangement effect of dislocations from cryogenic treatment. Furthermore, the strength-plasticity mechanism was verified using in-situ tensile electron back scatter diffraction (EBSD), molecular dynamics (MD) simulations, and crystal plasticity (CP) models. The results indicated that the cobweb-like sub-grain structure, resembling countless walls, formed barriers that hindered dislocation migration towards high-angle grain boundaries (HAGBs) and absorbed them, thereby reducing the occurrence of stress concentration zones, i.e., the dislocation absorption and stress-strain sharing mechanisms. Additionally, the strengthening mechanism was associated with synergistic strengthening by multiscale microstructures, including micron-sized grains, micron-sized high-density dislocation lattices, and nanosized Al2CuMg phases, which were activated by successive deformation processes. Consequently, the concept of biomimetic structure design, which may serve as an effective method for achieving structural materials with high strength-plasticity synergy, can be extended to transportation fields, such as railway tracks and body structure design.

铝铜镁合金作为应用最广泛的轻质结构材料,在低碳经济的交通运输领域具有广阔的应用前景。然而,合金的抗拉强度和塑性不能同时提高,以满足不断升级的运输车辆的要求。本研究以蛛网组织的高抗拉强度和高塑性为灵感,通过连续固溶、高应变速率轧制(4.4 s-1)、低温处理(-196°C)和时效处理(SRCA),在Al-Cu-Mg合金中形成了一种新型的蛛网状亚晶组织。值得注意的是,该合金的抗拉强度和塑性优于目前报道的。经SRCA处理的Al-Cu-Mg合金的维氏硬度和抗拉强度分别为206.2 Hv和619.6 MPa,分别比传统的T6热处理Al-Cu-Mg合金高39.8%和31.8%。同时,合金的伸长率也从4.31%提高到8.23%,提高了90.9%。更重要的是,Al-Cu-Mg合金的高强度塑性(“双高”)归因于蛛网状亚晶结构,这是首次利用逆向思维通过提高位错来提高塑性,这是由于高应变速率轧制形成高密度位错和低温处理产生的位错重排效应。此外,利用原位拉伸电子背散射衍射(EBSD)、分子动力学(MD)模拟和晶体塑性(CP)模型验证了强度-塑性机理。结果表明:网状亚晶结构如同无数壁,形成屏障,阻碍位错向高角晶界迁移并吸收它们,从而减少了应力集中区的发生,即位错吸收和应力-应变分担机制。此外,强化机制与多尺度微观结构的协同强化有关,包括微米尺寸的晶粒、微米尺寸的高密度位错晶格和纳米尺寸的Al2CuMg相,这些微观结构在连续变形过程中被激活。因此,仿生结构设计的概念可以扩展到交通运输领域,如铁路轨道和车身结构设计,作为实现结构材料高强度-塑性协同的有效方法。


Thin-Walled Structures

Experimental and analytical investigation on the shear behaviour of a demountable interlocking connection applied in precast floor diaphragms

Peng CHEN, Jiachen GUO, Tak-Ming CHAN

doi:10.1016/j.tws.2024.112696

应用于预制楼板隔板的可拆卸联锁连接抗剪性能的试验与分析研究

Traditional web connections in precast floor diaphragms adopt cast-in-situ or field welding techniques, which pose significant challenges for the disassembly and reuse of floor slabs. This paper introduces an innovative demountable interlocking web connection that relies on neither traditional welding nor bolting methods, with greatly improved assembly and disassembly efficiencies. Besides, multiple shear connectors can be installed in one go to reduce installation time compared with bolted connection. To assess the in-plane interaction behaviour between shear connectors and embedded steel plates, as well as to evaluate the reusability of this new web connection, a comprehensive experimental investigation was conducted through monotonic loading tests. Results indicated that the proposed web connection exhibited excellent force transmission capabilities, and effectively transferred shear forces through the deformation of the shear connectors. By using faceplates made of high-strength steel, the shear damage was efficiently limited to the connectors, which can be easily demounted and reinstalled to allow the slab to be reused. Additionally, the results also showed that increasing the number of shear keys did not impair the normalised shear resistance per connector but could greatly improve the installation efficiency. Finite element analysis was carried out to further investigate the parameters that influence the connection performance of the proposed web connection. Design recommendations were proposed based on parametric results to predict the in-plane shear resistance of this innovative demountable interlocking web connection.

传统的预制楼板腹板连接采用现浇或现场焊接技术,这对楼板的拆卸和再利用构成了重大挑战。本文介绍了一种新型的可拆卸联锁腹板连接,它既不依赖传统的焊接方法,也不依赖传统的螺栓连接方法,大大提高了装配和拆卸效率。此外,与螺栓连接相比,多个剪切连接件可一次安装,缩短了安装时间。为了评估剪切连接件与预埋钢板之间的平面内相互作用行为,以及评估这种新型腹板连接的可重用性,通过单调加载试验进行了全面的试验研究。结果表明:所提出的腹板连接具有良好的传力能力,可通过剪力连接件的变形有效传递剪力。通过使用由高强度钢制成的面板,有效地将剪切损伤限制在连接器上,连接器可以很容易地拆卸和重新安装,从而使面板可以重复使用。此外,结果还表明,增加剪切键的数量不会影响每个连接器的正态抗剪能力,但可以大大提高安装效率。通过有限元分析,进一步研究了影响网络连接性能的参数。基于参数化结果提出了设计建议,以预测这种创新的可拆卸联锁腹板连接的面内抗剪能力。



来源:复合材料力学仿真Composites FEM
ACTMechanicalInspireDeform电子ADS焊接化机材料机器人分子动力学多尺度仿生控制试验螺栓装配
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首次发布时间:2024-11-21
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【新文速递】2024年8月16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 3 篇International Journal of Solids and StructuresThe stick-slip bending behavior of the multilevel helical structures: A 3D thin rod model with frictional contactYuchen Han, Jingshan Hao, Huadong Yong, Youhe Zhoudoi:10.1016/j.ijsolstr.2024.113005多层螺旋结构粘滑弯曲行为:含摩擦接触的三维细杆模型The multilevel helical structures in various engineering and natural fields offer excellent deformation flexibility and load bearing capabilities. Understanding the interplay between the local frictional contact and the geometric characteristics of the helical structure under complex external loads has attracted considerable interest. In this work, the effect of local frictional contact behaviors on the bending in multilevel helical structures is investigated by using a combination of theoretical modeling, finite element (FE) simulations, and experiments. In the case of pure bending, the kinematic parameters of the bent multi-stage helix are derived concisely by the idea of the kinematic analogy. The bending stiffness of the multi-stage helix is further obtained. In the case of the combined tension/torsion and bending, the 3D thin rod model incorporating Coulomb’s friction is established to describe the mechanical responses. It is found that the relationship between equivalent bending stiffness and the laying angle exhibits nonlinearity. A comparison with the classical Papailiou model reveals that, for helical structures at large laying angles, the influence of friction is primarily determined by the internal force in the tangential direction, which is the core assumption of the Papailiou model. However, in the case of small laying angles, the helical twisting characteristics and the contribution of the internal forces and moments in the other two directions (normal and binormal directions) to the friction cannot be ignored. Subsequently, a multilevel frictional contact transmission formulation is proposed according to the force action–reaction principle. Based on the above formulation, the non-simplified thin rod equations with Coulomb’s friction are extended to describe the multilevel stick-slip bending behaviors of the second stage cable (3*3). The dissipation capacity of helical structures is evaluated quantitatively under the hysteretic bending. Finally, the theoretical model is verified by FE simulations and experimental results. This work provides insights for unveiling the intrinsic relationship between the nonlinear bending and local frictional contact behaviors in the multilevel helical structures.多层螺旋结构在各种工程和自然领域中具有优异的变形灵活性和承载能力。复杂外载荷作用下螺旋结构的局部摩擦接触与几何特性之间的相互作用引起了人们的广泛关注。本文采用理论建模、有限元模拟和实验相结合的方法,研究了局部摩擦接触行为对多层螺旋结构弯曲的影响。在纯弯曲情况下,利用运动学类比的思想,简明地导出了弯曲多级螺旋的运动学参数。进一步得到了多级螺旋的弯曲刚度。在拉伸/扭转和弯曲复合作用下,建立了考虑库仑摩擦的细杆三维力学响应模型。结果表明,等效抗弯刚度与铺设角呈非线性关系。与经典Papailiou模型的对比表明,对于大铺放角的螺旋结构,摩擦的影响主要由切向内力决定,这是Papailiou模型的核心假设。然而,在铺设角较小的情况下,螺旋扭转特性以及其他两个方向(法向和法向)的内力和弯矩对摩擦的贡献是不可忽视的。随后,根据力-反作用原理,提出了多级摩擦接触传动公式。在此基础上,将含库仑摩擦的非简化细杆方程推广到描述二级索(3*3)的多级粘滑弯曲行为。对螺旋结构在滞回弯曲作用下的耗散能力进行了定量评价。最后,通过有限元仿真和实验结果对理论模型进行了验证。这项工作为揭示多层螺旋结构中非线性弯曲和局部摩擦接触行为之间的内在关系提供了见解。Journal of the Mechanics and Physics of SolidsEnhancement of adhesion strength in viscoelastic unsteady contactsC. Mandriota, N. Menga, G. Carbonedoi:10.1016/j.jmps.2024.105826粘弹性非定常接触中粘接强度的增强We present a general energy approach to study the unsteady adhesive contact of viscoelastic materials. Under the assumption of infinitely short-range adhesive interactions, we exploit the principle of virtual work to generalize Griffith’s local energy balance at contact edges to the case of a non-conservative (viscoelastic) material, subjected to a generic contact time–history. We apply the proposed energy balance criterion to study the approach-retraction motion of a rigid sphere in contact with a viscoelastic half-space. A strong interplay between adhesion and viscoelastic hysteretic losses is reported as the adhesion strength can strongly increase, depending on the loading history. Two different mechanisms govern the pull-off force increase during either approach-retraction cycles and approach – full relaxation – retraction tests. In the former case, hysteretic losses occurring close to the circular perimeter of the contact play the major role, significantly enhancing the energy release rate required change the contact size. In the latter case, instead, the pull-off enhancement depends on the glassy response of the whole material which, triggered by the fast retraction after relaxation, leads to a sort of ‘frozen’ state and flat-punch-like detachment mechanism (i.e., constant contact area). In this case, the JKR theory of adhesive contact cannot be invoked to relate the observed pull-off force to the effective adhesion energy, i.e. the energy release rate G , and strongly overestimates it. Therefore, a rigorous mathematical procedure is also proposed to correctly calculate the energy release rate in viscoelastic dissipative contacts.提出了一种研究粘弹性材料非定常粘接接触的通用能量方法。在无限短距离粘接相互作用的假设下,我们利用虚功原理将Griffith在接触边缘的局部能量平衡推广到非保守(粘弹性)材料的情况下,受到一般接触时程的影响。应用所提出的能量平衡准则,研究了刚性球体与粘弹性半空间接触时的接近-收缩运动。粘连和粘弹性滞回损失之间有很强的相互作用,据报道,粘连强度会随着加载历史的变化而显著增加。在接近-收放循环和接近-完全放松-收放测试中,有两种不同的机制控制着拉离力的增加。在前一种情况下,发生在接触圆周附近的滞回损耗起主要作用,显著提高了改变接触尺寸所需的能量释放率。在后一种情况下,拉脱增强取决于整个材料的玻璃响应,这种响应是由弛豫后的快速缩回触发的,导致一种“冻结”状态和平冲孔式分离机制(即恒定的接触面积)。在这种情况下,不能援引JKR黏着接触理论将观察到的拉脱力与有效黏着能即能量释放率G联系起来,并且严重高估了它。因此,还提出了一种严格的数学方法来正确计算粘弹性耗散接触的能量释放率。Mechanics of MaterialsMulti-scale FE analysis of coupled load-moisture mechanical behavior of saturated asphalt pavements considering transversely isotropic permeabilityMingyang Gong, Xin Sui, Zhen Leng, Binbin Yindoi:10.1016/j.mechmat.2024.105116考虑横向各向同性渗透率的饱和沥青路面荷载-水分耦合力学特性多尺度有限元分析Assessing the collective impacts of external loading and void pressure on the mechanical behavior of porous media presents a significant challenge due to its inherent heterogeneity and complex multi-physical field coupling mechanisms. This study addresses this challenge by developing a novel multiscale hydraulic-mechanical modeling framework to investigate the structural response of water-saturated asphalt pavement under sequential coupling hydro-mechanical loading. The framework comprises three key components. Firstly, incorporating an upscaling homogenization approach to establish the linkage of material properties between different scales; secondly, developing a downscaling transfer procedure to transfer the structural response across scales for insight into its multiphysics mechanisms; and finally, proposing a new sequential coupling algorithm in multiscale simulations for comprehensive multi-field coupling calculations. The primary outcomes of this study demonstrate that AC-graded pavements are susceptible to "down-top" cracks under hydro-mechanical loading, while OGFC-graded pavements have the potential to develop both "top-down" and "down-top" cracks. In AC-graded pavements, increasing the hydraulic head reduces stress concentrations, while in OGFC-graded pavements, changes in the permeability coefficient have a lesser impact on mechanical response. At the mesoscopic level, tensile stress concentrations in the asphalt mortar decrease significantly at higher temperatures. Furthermore, the OGFC-graded RVE model exhibits higher tensile stresses in the asphalt mortar compared to the AC-graded RVE model.由于多孔介质固有的非均质性和复杂的多物理场耦合机制,评估外部载荷和空隙压力对多孔介质力学行为的集体影响是一项重大挑战。本研究通过开发一种新颖的多尺度水力力学建模框架来研究水饱和沥青路面在顺序耦合水力力学载荷下的结构响应,从而解决了这一挑战。该框架包括三个关键部分。首先,采用上尺度均质化方法,建立不同尺度间材料性能的联系;其次,开发一个降尺度转移程序,以跨尺度转移结构响应,以深入了解其多物理场机制;最后,提出了一种新的多尺度模拟序列耦合算法,用于综合多场耦合计算。本研究的主要结果表明,在水-机械荷载作用下,ac级配路面容易出现“自上而下”裂缝,而ogfc级配路面则可能同时出现“自上而下”和“自上而下”裂缝。在ac级配路面中,增加水头可以降低应力集中,而在ogfc级配路面中,渗透系数的变化对力学响应的影响较小。在细观水平上,高温下沥青砂浆中的拉应力浓度显著降低。此外,与ac -分级RVE模型相比,ogfc分级RVE模型在沥青砂浆中表现出更高的拉应力。International Journal of PlasticityHigh-temperature creep mechanism of Ti-Ta-Nb-Mo-Zr refractory high-entropy alloys prepared by laser powder bed fusion technologyJunyi Feng, Binghao Wang, Yintao Zhang, Peilei Zhang, Changxi Liu, Xiaoli Ma, Kuaishe Wang, Lechun Xie, Ning Li, Liqiang Wangdoi:10.1016/j.ijplas.2024.104080 激光粉末床熔合Ti-Ta-Nb-Mo-Zr难熔高熵合金高温蠕变机理Creep resistance, which is one of the most important deformation modes, is rarely reported for refractory high entropy alloys (RHEAs). The experiment investigated the high-temperature creep mechanism of Ti-Ta-Nb-Mo-Zr RHEA prepared by laser powder bed fusion (LPBF) technology. The high cooling rate of LPBF suppresses most of the elemental segregation, but there are still over-solidified precipitates and a few continuous precipitates (CP). In the range of 923-1023 K, the stress exponent and activation energy were determined to be 3.2-3.4 and 261.5 ± 19.5 kJ/mol, respectively. Compared with other conventional alloys and HEAs, a large reduction of the minimum creep rate is found in the LPBF-built Ti1.5Ta0.5NbZrMo0.5 RHEA, indicating a significant improvement in high-temperature properties. The dislocation tangles at the interface is formed during the creep process and new Zr-rich CP phases are generated in the dislocation tangles region. The interfacial dislocation tangles is the result of the interaction between dislocations and two-phase mismatch stresses. The dislocation tangles prevents dislocations from further cutting the matrix phase, which is very favorable to the high-temperature creep performance. At the same time, the formation of this dislocation tangles greatly accelerates the nucleation process and growth rate of the new CP phase. The present work provides a pathway to design novel HEAs with improved high-temperature creep resistance.高温高熵合金的蠕变抗力是其最重要的变形模式之一,但目前对高温高熵合金的蠕变抗力研究较少。实验研究了激光粉末床熔融(LPBF)技术制备Ti-Ta-Nb-Mo-Zr RHEA的高温蠕变机理。高冷却速率抑制了大部分元素偏析,但仍存在过凝固析出相和少量连续析出相(CP)。在923 ~ 1023 K范围内,应力指数为3.2 ~ 3.4,活化能为261.5±19.5 kJ/mol。与其他传统合金和HEAs相比,lpbf构建的Ti1.5Ta0.5NbZrMo0.5 RHEA的最小蠕变速率大幅降低,表明其高温性能得到了显著改善。蠕变过程中在界面处形成位错缠结,在位错缠结区生成新的富zr CP相。界面位错缠结是位错与两相失配应力相互作用的结果。位错缠结阻止了位错进一步切削基体相,有利于提高材料的高温蠕变性能。同时,这种位错缠结的形成大大加快了新CP相的成核过程和生长速度。本工作为设计具有更好的高温蠕变性能的新型HEAs提供了途径。Thin-Walled StructuresRandom thermal-vibration mechanisms of sandwich ventral fin-type plate-shell systems with porous functionally graded coreShuangwei Hu, Qingshan Wang, Rui Zhong, Bin Qindoi:10.1016/j.tws.2024.112333多孔功能梯度岩心夹层腹鳍型板壳系统的随机热振动机理The stochastic thermal-vibration mechanisms within a sandwich ventral fin-type plate-shell system, featuring a porous functionally graded (FG) core, are exhaustively analyzed under various random loading conditions employing an innovative node-based, meshless computational approach. The studied structure is decoupled into several plates and open cylindrical panel according to the geometric characteristics, and the mechanical relationships at the structural boundaries or connection interfaces are equivalently simulated by using penalty parameters. Following the general Hamilton's principle, the meshless approach combined with the first-order shear deformation theory (FSDT) incorporating thermal effects is employed to derive the vibration equations of the sandwich ventral fin-type plate-shell systems. Also, the pseudo excitation method (PEM) is introduced to calculate stationary and nonstationary random responses. In order to verify the accuracy of the meshless algorithm in this study, the convergence and correctness are studied comprehensively. And then, the effects of some parameters such as temperature variation, porosity parameters, power-law index and random excitations on the thermal vibration characteristics of the sandwich ventral fin-type plate-shell systems with porous FG core are presented. The results show that the power-law index and temperature can increase the frequency parameter of the structure. The smooth power spectral density (PSD) excitation only affects the amplitude of the response curve, and does not affect the frequency corresponding to the peak. In the analysis of non-stationary random vibration, the influence of modulation parameters on response is very significant.采用创新的基于节点的无网格计算方法,对具有多孔功能梯度(FG)核心的夹层腹鳍型板壳系统在各种随机载荷条件下的随机热振动机制进行了详尽分析。将所研究的结构根据几何特性解耦为若干板和开式圆柱板,采用罚参数等效模拟结构边界或连接界面处的力学关系。根据Hamilton原理,采用无网格法结合考虑热效应的一阶剪切变形理论(FSDT),推导了夹层腹鳍型板壳系统的振动方程。同时,引入了伪激励法(PEM)来计算平稳和非平稳随机响应。为了验证本文无网格算法的准确性,对其收敛性和正确性进行了全面的研究。然后,研究了温度变化、孔隙率参数、幂律指数和随机激励等参数对多孔FG芯夹层腹鳍型板壳系统热振动特性的影响。结果表明,幂律指数和温度可以提高结构的频率参数。平滑功率谱密度(PSD)激励只影响响应曲线的幅值,而不影响峰值对应的频率。在非平稳随机振动分析中,调制参数对响应的影响是非常显著的。Nonlinear thermo-mechanical static stability analysis of FG-TPMS shallow spherical shellsDang Thuy Dong, Tran Quang Minh, Bui Tien Tu, Kim Q. Tran, H. Nguyen-Xuandoi:10.1016/j.tws.2024.112343FG-TPMS浅球壳的非线性热-机械静稳定性分析An analytical solution for the nonlinear static stability problem of functionally graded triply periodic minimal surface (FG-TPMS) shallow spherical shells is studied in the current research for the first time. Three common TPMS structures including Primitive (P), Gyroid (G), and I-graph and Wrapped Package-graph (IWP) with three models of functionally graded porosity distribution along the thickness are considered. The shallow spherical shells (shallow SSs) are subjected to combined thermo-mechanical loadings and rested on a nonlinear elastic foundation. The fundamental formulas are expressed based on the higher-order shear deformation theory (HSDT) and von Kármán's geometrical nonlinearities. Employing the Ritz energy minimization method, the explicit relationship between load and deflection is derived. Subsequently, the static stability behavior of FG-TPMS shallow SSs is investigated. Numerical illustrations are investigated to show the superior thermo-mechanical load-carrying performance of the FG-TPMS SSs compared to corresponding isotropic structures of the same weight. The significant effects of geometric parameters, nonlinear elastic foundation parameters, and the type of FG-TPMS structures on the nonlinear static stability behavior of shallow SSs are further considered.本文首次研究了功能梯度三周期最小表面(FG-TPMS)浅球壳非线性静稳定性问题的解析解。考虑了三种常见的TPMS结构,包括Primitive (P), Gyroid (G), I-graph和Wrapped Package-graph (IWP),以及沿厚度的三种功能梯度孔隙度分布模型。浅球壳在非线性弹性基础上承受热-力复合载荷。基本公式是基于高阶剪切变形理论(HSDT)和von Kármán的几何非线性来表达的。采用里兹能量最小化方法,推导了载荷与挠度之间的显式关系。随后,研究了FG-TPMS浅层SSs的静稳定性行为。数值计算表明,与同等重量的各向同性结构相比,FG-TPMS SSs具有优越的热机械承载性能。进一步考虑了几何参数、非线性弹性基础参数和FG-TPMS结构类型对浅层SSs非线性静力稳定行为的显著影响。Integrating parametric HFGMC and isogeometric RZT^{3,2} for multiscale damage modeling of composite structures: A numerical and experimental studyAryan Kheyabani, Adnan Kefaldoi:10.1016/j.tws.2024.112344将参数 HFGMC 和等几何 RZT^{3,2} 整合用于复合材料结构的多尺度损伤建模: 数值和实验研究In this research effort, a novel multiscale analysis scheme is proposed for damage modeling of composite laminates, sandwich structures, and stiffened plates relying on capabilities of the parametric HFGMC and isogeometric RZT^{3,2} formulations. The Ramberg Osgood (RO) model is incorporated into the micromechanics model to reflect polymer matrix material nonlinearities on the overall homogenized composite behavior. Carbon fibers are assumed to behave in a linear transversely isotropic manner. The higher order RZT^{3,2} theory employed at the macro level facilitates efficient applicability of the model to thick composite laminates and soft core sandwiches. On the other hand, it generates all three-dimensional stress components and thus ensures dimensional consistency between micro and macro levels. Numerical discretization and prediction of RZT^{3,2} kinematic variables are enabled by performing NURBS based isogeometric analysis (IGA) thereby enhancing modeling efficacy to a significant degree. Soft core plasticity and failure in the composite are evaluated at the macro level through the RO model and Hashin criteria, respectively. Applicability of the method is presented for thin and thick flat composite and sandwich laminates; and further extended to stiffened plates via developing a multipatch formulation. A comprehensive validation of our analysis is conducted by comparing the results with established benchmarks from the literature, experimental data, and three-dimensional finite element method (3D-FEM) simulations. Initially, a moderately thick, simply supported square laminate under transverse loading is examined, a common verification benchmark. Then, results from standard mechanical tests, including tensile, shear, and four-point bending tests on thin laminates, followed by experiments on moderately thick sandwich structures subjected to four-point bending, are presented. Finally, the analysis is extended to a stiffened plate under uniform pressure, demonstrating the method’s accuracy and applicability across diverse structural configurations.在这项研究工作中,利用参数 HFGMC 和等几何 RZT^{3,2} 公式的能力,为复合材料层压板、夹层结构和加劲板的损伤建模提出了一种新的多尺度分析方案。微观力学模型中加入了 Ramberg Osgood(RO)模型,以反映聚合物基体材料对整体均质复合材料行为的非线性影响。碳纤维被假定为线性横向各向同性材料。在宏观层面上采用的高阶 RZT^{3,2} 理论有助于将模型有效地应用于厚复合材料层压板和软芯三明治。另一方面,它生成了所有三维应力分量,从而确保了微观和宏观层面的尺寸一致性。通过执行基于 NURBS 的等几何分析 (IGA),实现了 RZT^{3,2} 运动变量的数值离散化和预测,从而在很大程度上提高了建模效率。通过 RO 模型和 Hashin 标准,分别对复合材料的软芯塑性和失效进行了宏观评估。该方法适用于薄、厚平板复合材料和三明治夹芯层压板,并通过开发多补丁配方进一步扩展到加劲板。通过将分析结果与文献、实验数据和三维有限元法(3D-FEM)模拟的既定基准进行比较,对我们的分析进行了全面验证。首先,对横向载荷作用下的中等厚度简支撑方形层压板进行了研究,这是一种常见的验证基准。然后,介绍标准机械测试的结果,包括薄层板的拉伸、剪切和四点弯曲测试,接着是中等厚度夹层结构承受四点弯曲的实验。最后,将分析扩展到均匀压力下的加劲板,证明了该方法在不同结构配置中的准确性和适用性。来源:复合材料力学仿真Composites FEM

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