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
Revealing Novel Insights into the Toughening Mechanism of Double Network Hydrogels via Uniaxial Tensile Tests
Jiapeng You, Zishun Liu
doi:10.1016/j.jmps.2024.105710
通过单轴拉伸试验揭示双网状水凝胶增韧机理的新见解
Toughening mechanism of the double network (DN) hydrogel has garnered significant attention in recent years. To interpret this mechanism effectively, studying the fracture toughness of DN gels becomes essential. In DN gels, the apparent fracture toughness is initially decomposed into two components: the dissipated fracture toughness and the intrinsic fracture toughness. However, further decomposition of these two components and understanding the relationships between them remain areas of ongoing investigation. In this study, we propose a fracture model aimed at elucidating the relationships between the components of apparent fracture toughness. By partitioning the area under the uniaxial tensile curve of the DN gel into five regions, we decompose the apparent fracture toughness into four components. The expressions for these components are derived, and we employ four quantities to characterize the toughening mechanism of the DN gel. The proposed fracture model quantitatively demonstrates that the fracture toughness of the DN gel is enhanced through the presence of two interpenetrating networks. Through tearing tests conducted on both as-prepared and swelling gel samples, the proposed fracture model is validated and exhibits good agreement with experimental results. This study introduces a method based on uniaxial tensile tests to interpret the toughening mechanism of DN gel, thereby facilitating the synthesis and design of future soft materials.
近年来,双网状水凝胶的增韧机理受到了广泛的关注。为了有效地解释这一机制,研究DN凝胶的断裂韧性变得至关重要。在DN凝胶中,表观断裂韧性最初分解为两部分:耗散断裂韧性和本征断裂韧性。然而,进一步分解这两个组成部分并了解它们之间的关系仍然是正在进行的研究领域。在这项研究中,我们提出了一个断裂模型,旨在阐明表观断裂韧性各组成部分之间的关系。通过将DN凝胶单轴拉伸曲线下的区域划分为5个区域,将表观断裂韧性分解为4个分量。推导了这些组分的表达式,并采用四个量来表征DN凝胶的增韧机理。所提出的断裂模型定量地表明,两个互穿网络的存在提高了DN凝胶的断裂韧性。通过对制备和膨胀凝胶试样的撕裂试验,验证了所提出的裂缝模型,与实验结果吻合较好。本研究引入了一种基于单轴拉伸试验的方法来解释DN凝胶的增韧机理,从而为未来软材料的合成和设计提供依据。
Understanding the effect of refractory metal chemistry on the stacking fault energy and mechanical property of Cantor-based multi-principal element alloys
Prashant Singh, William Trehern, Brent Vela, Prince Sharma, Tanner Kirk, Zongrui Pei, Raymundo Arroyave, Michael C. Gao, Duane D. Johnson
doi:10.1016/j.ijplas.2024.104020
了解难熔金属化学对cantor基多主元素合金层错能和力学性能的影响
Multi-principal-element alloys (MPEAs) based on 3d-transition metals show remarkable mechanical properties. The stacking fault energy (SFE) in face-centered cubic (fcc) alloys is a critical property that controls underlying deformation mechanisms and mechanical response. Here, we present an exhaustive density-functional theory study on refractory- and copper-reinforced Cantor-based systems to ascertain the effects of refractory metal chemistry on SFE. We find that even a small percent change in refractory metal composition significantly changes SFEs, which correlates favorably with features like electronegativity variance, size effect, and heat of fusion. For fcc MPEAs, we also detail the changes in mechanical properties, such as bulk, Young's, and shear moduli, as well as yield strength. A Labusch-type solute-solution-strengthening model was used to evaluate the temperature-dependent yield strength, which, combined with SFE, provides a design guide for high-performance alloys. We also analyzed the electronic structures of two down-selected alloys to reveal the underlying origin of optimal SFE and strength range in refractory-reinforced fcc MPEAs. These new insights on tuning SFEs and modifying composition-structure-property correlation in refractory- and copper-reinforced MPEAs by chemical disorder, provide a chemical route to tune twinning- and transformation-induced plasticity behavior in fcc MPEAs.
基于三维过渡金属的多主元素合金(mpea)具有优异的力学性能。面心立方合金的层错能(SFE)是控制变形机制和力学响应的关键性能。在这里,我们提出了一个详尽的密度泛函理论研究耐火材料和铜增强cantor为基础的系统,以确定耐火金属化学对SFE的影响。我们发现,即使耐火金属成分发生很小的变化,也会显著改变sfe,这与电负性变化、尺寸效应和熔合热等特征密切相关。对于fcc mpea,我们还详细介绍了力学性能的变化,如体积、杨氏模量和剪切模量以及屈服强度。采用labusch型溶质-溶质-强化模型对温度相关屈服强度进行了评估,并结合SFE对高性能合金的设计提供了指导。我们还分析了两种下选合金的电子结构,以揭示耐火增强fcc mpea中最佳SFE和强度范围的潜在来源。这些关于通过化学无序来调整sfe和改变耐火材料和铜增强mpea中成分-结构-性能相关性的新见解,为调整fcc mpea中孪生和转变诱导的塑性行为提供了一条化学途径。
Experimental investigation on vibration suppression of a new prestressed TMD for wind turbine towers
Zhenbo Lei, Gang Liu, Qingshan Yang, S.S. Law, Yang Li, Tengda Cui
doi:10.1016/j.tws.2024.112080
风电塔架新型预应力TMD减振试验研究
The pendulum tuned mass damper (PTMD) has been popular for vibration suppression due to its particular configuration form and frequency-tuning pattern. Based on the theoretical and numerical methods, a new prestressed TMD (PSTMD) has recently been presented which has better performances than the PTMD. To verify the improvement advantage and applicability comparatively, a comprehensive experimental study is carried out to investigate the vibration suppression of PSTMD in this paper. A wind turbine tower (WTT) with the lump-mass of the PSTMD can be represented by a two-degrees-of-freedom system, and its optimal design parameters can be analytically derived. Three test specimens, including the uncontrolled WTT, and the WTT with the PTMD or the PSTMD were tested in the laboratory with different equivalent wind and seismic loads via a shaking table. The presence of the PTMD or the PSTMD is noted changing only slightly the natural frequency and mode shape of the WTT, and the PSTMD exhibits the superior vibration suppression capability compared with the traditional PTMD.
摆调谐质量阻尼器由于其特殊的结构形式和频率调谐方式而受到广泛的应用。基于理论和数值方法,最近提出了一种新的预应力TMD (PSTMD),它具有比PTMD更好的性能。为了比较验证改进的优势和适用性,本文对PSTMD的减振效果进行了全面的实验研究。具有PSTMD块质量的风电塔架可以用二自由度系统表示,并可解析导出其最优设计参数。在不同的等效风荷载和地震荷载作用下,通过振动台对无控制的WTT、带PTMD的WTT和带PSTMD的WTT三种试件进行了室内试验。PTMD或PSTMD的存在仅对WTT的固有频率和模态振型有轻微的改变,与传统PTMD相比,PSTMD表现出更好的抑振能力。