【新文速递】2024年6月6日复合材料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 2 篇Journal of the Mechanics and Physics of SolidsCorrelation between synthesis parameters and hyperelasticity of hydrogels: experimental investigation and theoretical modelingZhicheng Wang, Danming Zhong, Rui Xiao, Shaoxing Qudoi:10.1016/j.jmps.2024.105733合成参数与水凝胶超弹性的关系:实验研究与理论建模The mechanical properties of hydrogels are significantly influenced by synthesis parameters. Although the mapping from the space of synthesis parameters to the space of properties has been investigated experimentally, a quantitative theoretical framework is still lacking. In this work, the effect of synthesis parameters on the hyperelastic behaviors of hydrogels was experimentally studied. Subsequently, we conducted theoretical analysis by combining the constitutive model and polymer physics to quantify the correlation between synthesis parameters (the initial water content, current water content, and degree of cross-linking) and hyperelasticity (the elastic modulus, degree of entanglement, and stress-stretch ratio curve) of hydrogels. The internal relation between critical polymer content for entanglement and both the initial water content and degree of cross-linking arises from the scaling laws. By analyzing the critical polymer content for entanglement and comparing it with the current polymer content, hydrogels are categorized as either cross-linking-dominated or entanglement-dominated. The current study indicates that a low degree of cross-linking, i.e., a long-chain structure, is an important prerequisite for plenty of entanglements. Hydrogels with low cross-linking are highly entangled, whether they possess high initial water content/low current water content or low initial water content/high current water content. This work paves the way for the systematic design of synthesis parameters, thereby guiding the modulation and optimization of the overall mechanical properties and the application of hydrogels.水凝胶的力学性能受合成参数的影响较大。虽然已经对合成参数空间到性质空间的映射进行了实验研究，但仍然缺乏定量的理论框架。实验研究了合成参数对水凝胶超弹性行为的影响。随后，我们结合本构模型和高分子物理学进行理论分析，量化水凝胶的合成参数(初始含水量、当前含水量、交联度)与超弹性(弹性模量、缠结度、应力-拉伸比曲线)之间的相关性。缠结的临界聚合物含量与初始含水量和交联度之间的内在关系源于标度定律。通过分析导致缠结的关键聚合物含量，并将其与现有聚合物含量进行比较，将水凝胶分为交联为主和缠结为主两类。目前的研究表明，低交联度，即长链结构，是大量缠结的重要前提。低交联的水凝胶，无论是高初始含水量/低电流含水量，还是低初始含水量/高电流含水量，都是高度纠缠的。这项工作为系统设计合成参数铺平了道路，从而指导水凝胶整体力学性能的调制和优化以及水凝胶的应用。International Journal of PlasticityOnset of dynamic void coalescence in porous ductile solidsZ.G. Liu, W.H. Wong, T.F. Guodoi:10.1016/j.ijplas.2024.104019多孔延性固体中动态孔洞聚并的开始This paper investigates void growth and coalescence in porous ductile solids under dynamic loading condition. A physical definition for the onset of void coalescence in porous ductile solids under dynamic loading is proposed. The onset is deemed to occur when the third invariant of the tensorial form of the Hill–Mandel condition attains a zero value. The definition allows for systematic investigations on the effects of dimensionless stress rate κ and stress state, defined by the stress triaxiality T and Lode parameter L, on the onset of void coalescence via micromechanical analyses. The analyses reveal that the critical macroscopic effective strain for the onset of void coalescence displays an increasing–decreasing transition trend as the dimensionless stress rate increases, for all levels of T and L considered. The macroscopic effective strain at the transition is identified as the “ductile–brittle” transition strain. The dimensionless stress rate at which the transition strain occurs is found to be relatively constant. A mapping in the κ−T space for L=−1, representative of a generalized uniaxial tension typical in spall fracture experiments, is established which depicts regions where coalescence and non–coalescence can take place, as well as the ductile–brittle regions demarcated by a ductile–brittle transition curve. The results also show that the critical void volume fraction and macroscopic effective strain at the onset of void coalescence are insensitive to inertia at high stress triaxialities at L=−1.本文研究了动态加载条件下多孔韧性固体中的空隙增长和凝聚。本文提出了动态加载条件下多孔韧性固体中空隙凝聚开始的物理定义。当希尔-曼德尔（Hill-Mandel）条件的张量形式的第三个不变量达到零值时，即认为开始凝聚。根据这一定义，可以通过微观力学分析系统地研究无量纲应力速率 κ 和应力状态（由应力三轴度 T 和洛德参数 L 定义）对空洞凝聚开始的影响。分析表明，在考虑的所有 T 和 L 水平上，随着无量纲应力率的增加，空洞凝聚开始时的临界宏观有效应变呈现出由增到减的过渡趋势。过渡时的宏观有效应变被确定为 “韧性-脆性 ”过渡应变。过渡应变发生时的无量纲应力速率相对恒定。建立了 L=-1 的 κ-T 空间映射，代表了典型的剥落断裂实验中的广义单轴拉伸，描绘了可能发生凝聚和非凝聚的区域，以及由延性-脆性过渡曲线划分的延性-脆性区域。结果还表明，在 L=-1 的高应力三轴度条件下，空隙凝聚开始时的临界空隙体积分数和宏观有效应变对惯性不敏感。Thin-Walled StructuresThermal instability and vibration characteristics of laminated composite struts with Graphene reinforcements: An analysis of distribution patterns and geometrical imperfectionsS.F. Nikrad, A.H. Akbarzadeh, M. Bodaghi, M. Hamidinejad, Z.T. Chendoi:10.1016/j.tws.2024.112083石墨烯增强层压复合材料支撑的热不稳定性和振动特性:分布模式和几何缺陷分析This study explores the effect of local buckling on the compressive performance of slender structural elements, particularly those with thin-walled sections. The phenomenon of local buckling significantly reduces the axial compressive stiffness, leading to a notable decrease in the load-bearing capacity of these elements. The main goal of this research is to examine how the post-buckling characteristics of polymeric composite channel section struts can be improved under thermal loading by incorporating multi-layer graphene reinforcements. The solution methodology incorporates the von Karman geometrical nonlinearity and is based on the layerwise third-order shear deformation theory (LW-TSDT). To ascertain the precision and computational performance of the results derived from LW-TSDT, a three-dimensional (3D) finite element model is created in ABAQUS for comparative evaluation. An extensive analysis of nonlinear thermal instability in perfect and geometrically imperfect FG-GRC laminated channel section struts is undertaken to discern the graphene distribution patterns that are most and least effective in elevating the critical buckling temperature and natural frequencies through pre- and post-buckling conditions. The comparative analysis indicates that employing the FG-X graphene distribution pattern across the thickness of the web and flanges in channel section struts leads to a projected increase of 12% in the critical buckling temperature for clamped channel section struts, in contrast to those that adopt the FGO graphene distribution pattern. For cases with simply-supported boundary conditions, this increase is noted to be approximately 9%. Moreover, findings confirm that incorporating an asymmetric graphene distribution pattern (FGV) or introducing geometrical imperfections in the flanges and web that generate a bending moment within the structure from the beginning of thermal loading effectively prevents the primary natural frequencies of FG-GRC channel section struts from declining to zero close to the critical buckling temperature. This is significantly different from scenarios involving perfectly structured and symmetrically reinforced graphene distribution patterns such as FGX.本研究探讨了局部屈曲对细长构件，特别是薄壁构件抗压性能的影响。局部屈曲现象显著降低了轴向抗压刚度，导致这些构件的承载能力显著降低。本研究的主要目的是研究如何通过加入多层石墨烯增强材料来改善聚合物复合通道截面支板在热载荷下的后屈曲特性。求解方法结合了von Karman几何非线性，基于分层三阶剪切变形理论(LW-TSDT)。为了确定LW-TSDT结果的精度和计算性能，在ABAQUS中建立了三维(3D)有限元模型进行比较评价。本文对完美和几何不完美的FG-GRC层压通道截面支板的非线性热不稳定性进行了广泛的分析，以识别在屈曲前和屈曲后提高临界屈曲温度和固有频率方面最有效和最无效的石墨烯分布模式。对比分析表明，与采用FGO石墨烯分布模式相比，采用FG-X石墨烯分布模式的通道截面支板在腹板和法兰厚度上的临界屈曲温度预计提高了12%。对于具有简单支持边界条件的情况，这一增加约为9%。此外，研究结果证实，在法兰和腹板中加入不对称石墨烯分布模式(FGV)或引入几何缺陷，可以有效防止FG-GRC通道截面支撑的主要固有频率在接近临界屈曲温度时降至零。这与完美结构和对称增强石墨烯分布模式(如FGX)的情况有很大不同。Experimental and numerical investigations on the mechanical behaviour of large-span circular steel-concrete composite slabs for wind power towerLiang-Dong Zhuang, Mu-Xuan Tao, Ji-Zhi Zhao, Ke-Yang Yangdoi:10.1016/j.tws.2024.112107风电塔用大跨度圆形钢-混凝土组合板力学性能试验与数值研究Circular slabs as novel structural shapes offer excellent application possibilities for offshore wind power foundations. By applying a steel-concrete composite structure to a circular slab, steel consumption can be reduced, and the foundation span can be increased compared to steel structures. In addition, it further reduces the structural height and lightens the self-weight of the structure compared to concrete slabs. In this study, experimental investigations and theoretical analysis analyses were combined. First, four circular steel-concrete composite slab components were produced, and a quasi-static experimental study was conducted. Secondly, based on the elastic-plastic theory, the bearing capacity of the circular steel-concrete composite slab was theoretically derived, and the main parameters affecting the bearing capacity were determined. Finally, a finite element model of a circular steel-concrete composite slab was created and verified based on the test results. A parameter analysis was conducted on the circular composite slab to investigate the influence of factors such as the number of main beams, stiffening rib design, concrete strength, steel strength, and boundary conditions on the ultimate bearing capacity of the structure. A design method for this type of circular steel-concrete composite slab is summarised, which provides a theoretical basis and engineering recommendations for the application of this new type of structure.圆形板作为一种新颖的结构形式，为海上风电基础提供了良好的应用前景。通过在圆板上采用钢-混凝土组合结构，与钢结构相比，可以减少钢材消耗，并增加基础跨度。此外，与混凝土板相比，它进一步降低了结构高度，减轻了结构的自重。本研究采用实验研究与理论分析相结合的方法。首先，制作了4个圆形钢-混凝土组合板构件，进行了准静力试验研究。其次，基于弹塑性理论，对圆形钢-混凝土组合楼板的承载力进行了理论推导，确定了影响其承载力的主要参数;最后，建立了圆形钢-混凝土组合楼板的有限元模型，并根据试验结果进行了验证。对圆形组合楼板进行了参数分析，探讨了主梁数、加筋设计、混凝土强度、钢材强度、边界条件等因素对结构极限承载力的影响。总结了这种型钢-混凝土组合板的设计方法，为这种新型结构的应用提供了理论依据和工程建议。来源：复合材料力学仿真Composites FEM