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【新文速递】2024年5月1日固体力学SCI期刊最新文章

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今日更新:International Journal of Plasticity 1 篇,Thin-Walled Structures 1 篇

International Journal of Plasticity

Micro-mechanisms of anisotropic deformation in the presence of notch in commercially pure titanium: an in-situ study with CPFEM simulations

Vivek Kumar Sahu, Pritam Chakraborty, Manasij Yadava, Nilesh P. Gurao

doi:10.1016/j.ijplas.2024.103985

工业纯钛中存在缺口时各向异性变形的微观机制:用CPFEM模拟的原位研究

This study investigates the impact of notch severity and initial texture on the micro-mechanisms during low strain deformation in commercially pure titanium, exploiting in-situ electron back scatter diffraction (EBSD) experiments and crystal plasticity finite element model (CPFEM). In-situ tests were performed at different strain steps of un-notched and notched samples of transverse direction (TD) and rolling direction (RD) orientations. CPFEM, based on initial EBSD microstructures, predicted profuse prismatic slip traces and early activation of prismatic slip in notched sample, with RD orientation exhibiting higher activity. Further, CPFEM results revealed early activation of high CRSS slip systems as well as evidence of early twin activity at notch tip due to severely localized plastic deformation and steep strain gradient, as observed by GND maps causing higher stress at grain boundaries. At the notch tip, digital images correlation (DIC) at microscale indicated strain localization at 45° nd 90° to the tensile axis for TD and RD orientations, respectively. Furthermore, 2.5D and 3D CPFEM confirmed distinct strain patterns at notch tip: TD orientation exhibited combined basal and prismatic slip influences, while RD orientation displayed dominant prismatic slip systems at localized strain. The model also successfully predicted anisotropic surface roughness, contributing to early necking in RD orientation.

本研究利用原位电子背散射衍射(EBSD)实验和晶体塑性有限元模型(CPFEM),研究了缺口严重程度和初始纹理对商业纯钛低应变变形过程中的微观机制的影响。对横向(TD)和滚动方向(RD)的未缺口和缺口样品进行了不同应变阶跃的原位测试。CPFEM 根据最初的 EBSD 显微结构预测了缺口样品中大量的棱柱滑移痕迹和棱柱滑移的早期激活,其中 RD 方向表现出更高的活动性。此外,CPFEM 结果还显示了高 CRSS 滑移系统的早期激活,以及缺口顶端早期孪晶活动的证据,这是由于严重的局部塑性变形和陡峭的应变梯度造成的,正如 GND 图所观察到的那样,这些应变梯度在晶界处造成了较高的应力。在缺口顶端,微尺度数字图像相关(DIC)显示,TD 和 RD 方向的应变定位分别与拉伸轴成 45° 和 90°。此外,2.5D 和 3D CPFEM 证实了缺口顶端不同的应变模式:TD 方向表现出基底和棱柱滑移的综合影响,而 RD 方向则在局部应变时表现出主要的棱柱滑移系统。该模型还成功预测了各向异性的表面粗糙度,从而导致 RD 方向的早期颈缩。


Thin-Walled Structures

Research on hexagonal concrete-filled steel tubular transition pieces for wind turbine hybrid towers under axial compression

Kai-Yuan Jin, Xu-Hong Zhou, Wei Ren, Yu-Hang Wang, Wei Luo

doi:10.1016/j.tws.2024.111956

轴压作用下风电混合塔六角钢管混凝土过渡件研究

With the escalating height of wind turbine structures, wind turbine steel-concrete hybrid towers have gradually become a new type of structure to replace pure steel towers. As a component connecting the upper steel tower with the lower concrete tower, the transition piece assumes an indispensable role in the overall structure of the hybrid tower. The traditional reinforced concrete-type transition piece has necessitated enhancements owing to the complicated construction and concrete cracking problems. A hexagonal concrete-filled double skin steel tubular (CFDST) transition piece is proposed to fit the hexagonal steel-concrete hybrid tower. Studies that investigate the hexagonal CFDST structures are currently few. Based on this, three hexagonal CFDST stub columns were tested, with the variables in stiffened measures. The experimental portion included a thorough investigation of local buckling behaviors and failure modes in addition to the analysis of typical mechanical indexes. Further, the validated finite element (FE) model was then utilized for mechanism analysis about the contact stress between different interfaces, the stress distributions, and so on. Besides, a parametric study was done to identify the sensitive parameters affecting this kind of structure's peak loads. Ultimately, the peak load prediction formulas found in published studies and specifications were modified by incorporating the findings from this investigation.

随着风力机结构高度的不断提升,风力机钢-混凝土混合塔逐渐成为取代纯钢塔的一种新型结构。过渡件作为连接上部钢塔和下部混凝土塔的构件,在混合塔的整体结构中起着不可缺少的作用。传统的钢筋混凝土型过渡件由于施工复杂和混凝土开裂问题,需要对其进行改进。为适应六角形钢-混凝土混合塔结构,提出了一种六角形双皮钢管混凝土过渡件。目前对六方CFDST结构的研究很少。在此基础上,对3根CFDST短柱进行了加筋试验。除典型力学指标分析外,实验部分还包括对局部屈曲行为和破坏模式的深入研究。在此基础上,利用验证的有限元模型对不同界面间的接触应力、应力分布等进行了机理分析。此外,对影响该类结构峰值荷载的敏感参数进行了参数化研究。最终,在已发表的研究和规范中发现的峰值负荷预测公式通过纳入本调查的结果进行了修改。



来源:复合材料力学仿真Composites FEM
ACTMechanicalSystemDeformSTEPS电子试验
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首次发布时间:2024-11-14
最近编辑:16天前
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【新文速递】2024年4月14日复合材料SCI期刊最新文章

今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 2 篇,Composites Science and Technology 1 篇Composite StructuresPeriodic magnetically oriented gradient structures with flower-like surface for enhancing microwave absorption efficiencyLirui Wang, Miao Yu, Hao Zhang, Mi Zhudoi:10.1016/j.compstruct.2024.118121具有花状表面的周期性磁定向梯度结构提高微波吸收效率In order to overcome the inherent trade-off between magnetic absorber's effective absorption, filling concentration, and thickness while achieving real-time control over the effective absorption bandwidth (EAB) below −10 dB, periodic magnetically oriented gradient structures featuring flower-like surfaces that can be reconfigured using magnetic induction technology. The arch test results demonstrated that even with particle filling concentration of only 30 wt%, reflection loss (RL) of the magnetically oriented periodic gradient structures achieved −37.5 dB, and EAB could be extended to 6.5 GHz, outperforming samples 60 wt%-0 mT. Especially for samples 50 wt%-100 mT, which EAB with four distinct peaks in its EAB reaching 10.5 GHz. This was due to magnetically-oriented macro–micro structure that facilitated to reduce hyperosmotic threshold of conductive loss network of absorbing material. Meanwhile, the gradient structure with flower-like surface was conducive to absorption peaks, impedance matching patterns and electromagnetic wave scattering. The reconfigurable structure was also found to have remarkably stability, maintaining its nearly uniform electromagnetic loss capability even after 3 months. This study is scientifically important for establishing the regulatory mechanism of orientation distribution structure on EAB and absorption resonance peaks, as well as providing an experimental and theoretical foundation for exploring low detectable and electromagnetic protection devices.为了克服磁性吸收体的有效吸收、填充浓度和厚度之间的固有权衡,同时实现对有效吸收带宽(EAB)低于- 10 dB的实时控制,可以使用磁感应技术重新配置具有花状表面的周期性磁定向梯度结构。拱形测试结果表明,即使颗粒填充浓度仅为30 wt%,磁取向周期性梯度结构的反射损耗(RL)也达到- 37.5 dB, EAB可以扩展到6.5 GHz,优于60 wt%-0 mT的样品。特别是对于50 wt%-100 mT的样品,其EAB有四个明显的峰,达到10.5 GHz。这是由于磁性取向的宏观微观结构有利于降低吸收材料导电损失网络的高渗透阈值。同时,具有花状表面的梯度结构有利于吸收峰、阻抗匹配模式和电磁波散射。可重构结构还具有显著的稳定性,即使在3 个月后仍保持其几乎均匀的电磁损耗能力。本研究对于建立取向分布结构对EAB和吸收共振峰的调控机制,为探索低可探测和电磁保护装置提供实验和理论基础,具有重要的科学意义。Composites Part A: Applied Science and ManufacturingElectric-field-assisted fabrication of metal-class thermal-conductive and elastomer-class-flexible composites comprising plasma-surface-modified hexagonal boron nitride and polyrotaxaneRui Hasegawa, Kenichi Inoue, Hitoshi Muneoka, Tsuyohito Ito, Kazuhiro Kirihara, Yoshiki Shimizu, Yukiya Hakuta, Kohzo Ito, Kazuo Terashimadoi:10.1016/j.compositesa.2024.108197 电场辅助制备含等离子体表面改性六方氮化硼和聚轮烷的金属类导热和弹性体类柔性复合材料There is a growing demand for materials with high thermal conductivity, electrical insulation, flexibility, and toughness for application in flexible electronic devices. To develop materials with the aforementioned properties, composites comprising the flexible and tough polyrotaxane (PR) and highly thermally conductive hexagonal boron nitride particles (hBN) were fabricated in this study. An electric field was applied during the polymerization of the composites to improve their thermal conductivity in the out-of-plane direction of the composites without reducing their flexibility. Electric-field application during polymerization controlled the orientation of hBN in the as-synthesized composites, forming pillar-like structures comprising oriented hBN. The particle diameter and concentration of hBN were optimized to synthesize an electrically insulating composite with elastomer-class flexibility in the in-plane direction (a low Young’s modulus of 77 MPa) and metallic-alloy-class thermal conductivity in the out-of-plane direction (>10 W/mK) with a wide range of potential applications including thermal interface materials in electronic devices.在柔性电子器件中,对具有高导热性、电绝缘性、灵活性和韧性的材料的需求日益增长。为了开发具有上述性能的材料,本研究制备了由柔性和坚韧的聚轮烷(PR)和高导热六方氮化硼颗粒(hBN)组成的复合材料。在复合材料的聚合过程中施加电场以提高复合材料在面外方向的导热性,同时又不降低复合材料的柔韧性。聚合过程中的电场作用控制了hBN在合成的复合材料中的取向,形成了由取向hBN组成的柱状结构。优化了hBN的粒径和浓度,合成了一种面内弹性级(低杨氏模量77 MPa)和面外导热系数(>10 W/mK)的金属合金级电绝缘复合材料,具有广泛的应用前景,包括电子器件中的热界面材料。Towards automated characterisation of fatigue damage in composites using thermoelastic stress analysisW.J.R. Christian, P. Lambert, I.E. Tabrizi, C.A. Middleton, C. Przybyla, E.A. Pattersondoi:10.1016/j.compositesa.2024.108205利用热弹性应力分析实现复合材料疲劳损伤的自动化表征Composite materials demonstrate complicated fatigue behaviour due to their microstructure and the varied types of defects that can occur during loading. This necessitates experimentation to determine their performance under loading. In this study an algorithm is introduced for identifying and categorising different defects forming during fatigue tests. Thermoelastic stress analysis was used to obtain high spatial and temporal resolution stress information from the surface of notched composite specimens. Specimens with three different geometries were loaded in tension–tension fatigue to failure. An algorithm was used to identify when and where matrix cracking and delaminations formed within the specimens as well as quantify how this changed over time. By improving how damage events are identified and characterised, the algorithm reduces the amount of time needed to process experimental fatigue data and helps to provide greater understanding of fatigue processes in new materials from early small-scale cracking all the way to final failure.复合材料由于其微观结构和在加载过程中可能出现的各种类型的缺陷而表现出复杂的疲劳行为。这就需要通过实验来确定它们在载荷下的性能。本文提出了一种识别和分类疲劳试验中不同缺陷的算法。采用热弹性应力分析方法获取了缺口复合材料表面的高时空分辨率应力信息。三种不同几何形状的试件在拉伸-拉伸疲劳状态下加载至破坏。使用一种算法来确定样品中何时何地形成基质开裂和分层,并量化其随时间的变化情况。通过改进损伤事件的识别和表征方式,该算法减少了处理实验疲劳数据所需的时间,并有助于更好地理解新材料的疲劳过程,从早期的小规模开裂一直到最终失效。Composites Science and TechnologyMultiscale simulation study on radiation aging of EPDM and preparation of radiation-resistant materialsXueting Wang, Chaokun Huang, Xin Wang, Yanlong Luo, Xiujuan Wangdoi:10.1016/j.compscitech.2024.110595 EPDM辐射老化的多尺度模拟研究及耐辐射材料的制备With the wide application of ethylene propylene diene monomer (EPDM) in the field of nuclear engineering, exploring the irradiation aging mechanism of EPDM is of great significance to improve the radiation resistance of EPDM composites. In this paper, the radiation aging mechanism of EPDM was investigated by a combination of experiments and multiscale simulations, and EPDM composites with excellent radiation resistance were prepared. The radiation aging mechanism of EPDM involves the crosslinking and degradation of molecular chains. The aging of EPDM starts from the breakage of α-H in the 5-ethylidene-2-norbornene monomer. In addition, the screening strategy of radiation-resistant additives was proposed. Antioxidants N, N'-diphenyl-p-phenylene-diamine (H), N, N'-ditolyl-p-phenylenediamine (DTPD), and N, N'-di-2-naphthyl-p-phenylenediamine (DNP) were taken as the main research objects, and quantitative analysis was carried out from the aspects of chemical protection and physical protection. The screening results showed that DNP has excellent radiation resistance and migration resistance. The prepared EPDM-DNP composites showed outstanding radiation resistance with 94% tensile strength retention after 300 kGy irradiation. This work contributes to understand the mechanisms of radiation-induced material damage and guides the design of radiation-resistant materials.随着EPDM在核工程领域的广泛应用,探索EPDM辐照老化机理对提高EPDM复合材料的耐辐射性能具有重要意义。本文采用实验与多尺度模拟相结合的方法,研究了EPDM的辐射老化机理,制备了具有优异耐辐射性能的EPDM复合材料。EPDM的辐射老化机制涉及分子链的交联和降解。EPDM的老化始于5-乙基-2-降冰片烯单体中α-H的断裂。此外,提出了抗辐射添加剂的筛选策略。以抗氧化剂N, N′-二苯基-对苯二胺(H)、N, N′-二酰基-对苯二胺(DTPD)和N, N′-二-2-萘基-对苯二胺(DNP)为主要研究对象,从化学保护和物理保护两方面进行了定量分析。筛选结果表明,DNP具有优良的耐辐射性和抗迁移性。制备的EPDM-DNP复合材料在300 kGy辐照条件下具有优异的抗辐射性能,抗拉强度保持率达94%。这项工作有助于理解辐射材料损伤的机理,并指导抗辐射材料的设计。来源:复合材料力学仿真Composites FEM

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