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【新文速递】2023年12月23日复合材料SCI期刊最新文章

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今日更新:Composite Structures 3 篇,Composites Part B: Engineering 6 篇,Composites Science and Technology 3 篇

Composite Structures

Composite curved hourglass cellular structures: design optimization for stiffness response and crashworthiness performance

Amin Farrokhabadi, Dimitrios Chronopoulos

doi:10.1016/j.compstruct.2023.117834

复合材料曲面沙漏蜂窝结构:刚度响应和防撞性能的优化设计

Auxetic lattice structures are known for their superior stiffness-to-density and strength-to-density ratios. Re-entrant hourglass exhibits an acceptable equivalent elastic modulus and remarkable energy absorption capacity among various auxetic configurations due to their flexibility and hinge deflecting during crushing loads. This study introduces a curved hourglass honeycomb which can be produced using 3D printing with pure or reinforced filaments incorporating continuous fibers. New closed-form formulations are analytically derived using an energy method by considering an extracted unit cell to predict the equivalent in-plane mechanical properties for the first time. The plateau stress of the proposed honeycomb is evaluated at the densification state of a unit cell using the energy conservation theory, equating external work with plastic energy dissipation. The accuracy of these extended relations is validated against experimental outcomes, demonstrating good agreement between analytical and experimental results. Additionally, robust linear and nonlinear finite element analyses are conducted to assess the accuracy of the obtained relations, including the equivalent stiffness and plateau stress for structures produced with reinforced filaments. The nonlinear finite element code employs appropriate subroutines to model plasticity/damage events. Based on the established analytical relations for stiffness and plateau stress, multi-objective optimization using Genetic Algorithm is applied to define optimum values for the Pareto front chart's objective functions of stiffness and plateau stress. The optimization process involves exploring the design space and defining the values of geometrical parameters to achieve the desired objectives. In conclusion, this study presents a novel approach to developing curved re-entrant honeycomb structures, with analytical formulations validated against experimental and numerical results. Optimization helps to identify optimal configurations concerning stiffness and plateau stress, offering potential applications in lightweight and high-strength materials design. According to the obtained results, for selection of the best value for curved strut angle which results in the optimum value of stiffness and plateau stress, a range between 10°-34° can be considered depending on the volume fraction of fibers.

辅助晶格结构以其优异的刚度密度比和强度密度比而闻名。在各种辅助结构中,重入式沙漏具有可接受的等效弹性模量和显著的能量吸收能力,这得益于它们的柔韧性和挤压载荷时的铰链偏转。本研究介绍了一种弧形沙漏蜂窝材料,这种材料可通过三维打印技术用纯纤维丝或包含连续纤维的增强纤维丝制成。通过考虑提取的单元格,使用能量法分析得出了新的闭式公式,首次预测了等效面内力学性能。利用能量守恒理论,将外功等同于塑性能量耗散,在单元格的致密化状态下评估了拟议蜂窝的高原应力。实验结果验证了这些扩展关系的准确性,表明分析结果与实验结果之间具有良好的一致性。此外,还进行了稳健的线性和非线性有限元分析,以评估所获得关系的准确性,包括使用增强丝制作的结构的等效刚度和高原应力。非线性有限元代码采用适当的子程序来模拟塑性/损伤事件。根据已建立的刚度和高原应力分析关系,采用遗传算法进行多目标优化,以确定帕累托前线图的刚度和高原应力目标函数的最佳值。优化过程包括探索设计空间和确定几何参数值,以实现预期目标。总之,本研究提出了一种开发曲面重入式蜂窝结构的新方法,并根据实验和数值结果验证了分析公式。优化有助于确定有关刚度和高原应力的最佳配置,为轻质和高强度材料设计提供了潜在应用。根据所获得的结果,要选择能产生最佳刚度和高原应力值的最佳弯曲支杆角度值,可根据纤维的体积分数在 10°-34° 之间进行考虑。


Design of manufacturable variable stiffness composite laminates using spectral Chebyshev and normalized cut segmentation methods

Mohammad Sheikhi, Mirmeysam Rafiei Anamagh, Bekir Bediz, Lutfi Taner Tunc

doi:10.1016/j.compstruct.2023.117836

利用切比雪夫光谱法和归一化切割分割法设计可制造的可变刚度复合材料层压板

The in-plane fiber orientations of variable stiffness (VS) laminates can be tailored to achieve enhanced structural properties compared to conventional constant stiffness (CS) laminates. However, VS laminate manufacturing faces challenges such as wrinkles, gaps, and overlaps. To address these challenges, we present a novel three-step design methodology. First, the laminate is modeled using lamination parameters (LPs) and the spectral Chebyshev method, and the optimal LPs are determined to maximize the fundamental frequency. Then, the discrete fiber angles are retrieved using the optimal LP distribution. Lastly, a normalized-cut segmentation method is applied to divide the domain into clusters and to generate manufacturable curvilinear fiber paths. Case studies focusing on designing clusters containing both straight and curvilinear fiber paths demonstrate that the designed VS composites can significantly enhance the dynamic performance with up to 20% enhancement in the fundamental frequency compared to CS laminates, under fully clamped boundary conditions with manufacturing constraints.

与传统的恒定刚度(CS)层压板相比,可变刚度(VS)层压板的面内纤维取向可根据需要进行调整,以获得更强的结构特性。然而,VS 层压板的制造面临着褶皱、间隙和重叠等挑战。为了应对这些挑战,我们提出了一种新颖的三步设计方法。首先,使用层压参数(LP)和频谱切比雪夫方法对层压板进行建模,并确定最佳 LP,以最大限度地提高基频。然后,利用最优 LP 分布检索离散纤维角。最后,应用归一化切割分割法将域划分为簇,并生成可制造的曲线光纤路径。案例研究的重点是设计包含直线和曲线纤维路径的簇,结果表明,与 CS 复合材料相比,设计的 VS 复合材料能显著提高动态性能,在完全夹紧的边界条件和制造限制条件下,基频最多可提高 20%。


Elliptical concrete-filled FRP tubes with an embedded H-shaped steel under axial compression and cyclic lateral loading: Experimental study and modelling

Bing Zhang, Yutao Peng, Sumei Zhang, Shuhong Lin, Chong Zhou, Guan Lin

doi:10.1016/j.compstruct.2023.117839

带有嵌入式 H 型钢的椭圆形混凝土填充玻璃钢管在轴向压缩和循环侧向载荷作用下的性能:实验研究与建模

Concrete-filled FRP tubes (CFFTs) have found increasing applications due to their superior ductility and remarkable corrosion resistance. In published literature, circular CFFTs and rectangular CFFTs have been investigated extensively, while there are relatively few studies on elliptical CFFTs. There is no research about elliptical CFFTs with an embedded H-shaped steel (i.e., HS-ECFFTs) under axial compression and cyclic lateral loading. Against this background, this paper investigated the seismic behaviour of HS-ECFFTs experimentally and numerically. Test results indicated that: (1) all HS-ECFFTs performed well with remarkable energy dissipation ability; (2) due to the effective FRP confinement, the local buckling of the H-shaped steel was prohibited; (3) the elliptical aspect ratio had limited influences on the ductility, the stiffness degradation and the energy dissipation; (4) the FRP thickness, after a certain threshold, showed beneficial but limited influences on the peak load, the stiffness degradation and the energy dissipation; (5) the HS-ECFFT specimen performed much better in terms of the peak load, the ductility, the stiffness degradation and the energy dissipation when it was bending around the strong axis. The proposed numerical model established on the OpenSees platform could generate reasonably accurate numerical results for all HS-ECFFTs.

混凝土填充玻璃纤维管道(CFFT)因其优越的延展性和显著的耐腐蚀性,应用日益广泛。在已发表的文献中,对圆形 CFFT 和矩形 CFFT 进行了广泛研究,而对椭圆形 CFFT 的研究相对较少。目前还没有关于在轴向压缩和循环侧向荷载下嵌入 H 型钢的椭圆 CFFT(即 HS-ECFFT)的研究。在此背景下,本文对 HS-ECFFT 的抗震性能进行了实验和数值研究。试验结果表明(1) 所有 HS-ECFFT 均表现良好,具有显著的耗能能力;(2) 由于玻璃钢的有效约束,H 型钢的局部屈曲被禁止;(3) 椭圆形长宽比对延性、刚度退化和耗能的影响有限;(5) HS-ECFFT 试样在绕强轴弯曲时,在峰值载荷、延性、刚度退化和能量耗散方面表现更好。在 OpenSees 平台上建立的拟议数值模型可以为所有 HS-ECFFT 生成相当精确的数值结果。


Composites Part B: Engineering

A comparative study on the low velocity impact behavior of UD, woven, and hybrid UD/woven FRP composite laminates

Binlin Ma, Xiaofei Cao, Yu Feng, Yujian Song, Fei Yang, Ying Li, Deyue Zhang, Yipeng Wang, Yuting He

doi:10.1016/j.compositesb.2023.111133

 

关于 UD、编织和 UD/ 编织混合 FRP 复合层压板低速冲击行为的比较研究

This study is aimed at comparing the response and damage of unidirectional (UD), woven fabric (WF) and hybrid UD/WF fiber reinforced polymer (FRP) laminates subjected to low velocity impact. The unidirectional tape and/or woven fabric (plain weave) carbon/epoxy prepregs are laminated and hot-pressed to produce UD, WF and sandwich-like hybrid UD/WF specimens. Impact responses of specimens are determined through low velocity impact (LVI) tests with impact energies of 10 J, 17 J and 25 J. After the LVI tests, the damage of specimens is characterized and analyzed using a combination of visual inspection, ultrasonic phased-array inspection, micro-computed tomography (CT) inspection, cross-sectional microscopic observation, and thermal de-ply test. Also, the LVI damage mechanisms of the three types of specimens are quantitatively compared by using the inter fiber crack volume ratio, total delamination area and fiber fracture length. It is concluded that the fiber architecture plays an important role in determining low velocity impact behavior of composite laminates. Especially, for the sandwich-like hybrid UD/WF laminates whose surface is a WF layer and the core is a UD layer, the WF layer on the surface plays an important role in reducing matrix cracking, delamination and fiber fracture, thus improving its LVI resistance.

本研究旨在比较单向(UD)、编织(WF)和 UD/WF 混合纤维增强聚合物(FRP)层压板在受到低速冲击时的响应和损坏情况。单向带和/或编织物(平纹)碳/环氧预浸料经层压和热压后可制成 UD、WF 和夹层式混合 UD/WF 试样。试样的冲击响应通过冲击能量为 10 J、17 J 和 25 J 的低速冲击(LVI)试验来确定。在 LVI 试验后,结合使用目视检查、超声相控阵检查、微型计算机断层扫描(CT)检查、横截面显微镜观察和热脱附试验,对试样的损伤进行表征和分析。此外,还利用纤维间裂纹体积比、总分层面积和纤维断裂长度对三种试样的 LVI 损伤机制进行了定量比较。结论是,纤维结构在决定复合材料层压板的低速冲击行为方面起着重要作用。特别是对于表面为 WF 层、核心为 UD 层的三明治状 UD/WF 混合层压板,表面的 WF 层在减少基体开裂、分层和纤维断裂方面发挥了重要作用,从而提高了其抗低速冲击性能。


Fire-retardant braided electronic rope with a hierarchical core-shell structure for fire rescue operations

Haoran Gong, Zhiyong Peng, Yingcun Liu, Ze Chen, Shiyu Fei, Ruoxian Xu, Keshuai Liu, Duo Xu, Yizhu Guo

doi:10.1016/j.compositesb.2023.111152

用于消防救援行动的具有分层芯壳结构的阻燃编织电子绳索

Effective rope rescue is crucial for evacuating individuals trapped in high-rise fires and for ensuring their safety in extreme fire environments. However, conventional fire rescue ropes often prioritize mechanical properties and flame retardancy, neglecting the crucial aspects of escape monitoring and position acquisition. Herein, we present a facile strategy to fabricate flame-retardant braided electronic rope (FBER) with a core-shell structure by large-scale braiding techniques. The pressure-sensing performance of the FBER was optimized by altering the braiding structure, which relies on the cross-contact between the core-braided composite yarns (CBCYs) at the sensing point. The unique structural design of FBER effectively prevents thermal transfer, ensuring pressure-sensing stability in extreme environments. Our results demonstrate that the FBER exhibits high sensitivity, rapid response, and excellent durability over 3500 cycles at 200 °C. The optimized FBER can be integrated into fire rescue detection systems for real-time escape monitoring, position acquisition, and safety detection during fire rescue operations. The scalable and multifunctional design of the FBER can significantly aid the development of fire rescue ropes.

有效的绳索救援对于疏散高层火灾中的被困人员以及确保他们在极端火灾环境中的安全至关重要。然而,传统的消防救援绳索往往优先考虑机械性能和阻燃性能,而忽视了逃生监测和位置获取等关键环节。在此,我们提出了一种通过大规模编织技术制造具有芯壳结构的阻燃编织电子绳(FBER)的简便策略。通过改变编织结构,FBER 的压力传感性能得到了优化,这主要依赖于传感点处芯壳编织复合纱线(CBCY)之间的交叉接触。FBER 的独特结构设计有效地防止了热传递,确保了在极端环境下的压力传感稳定性。我们的研究结果表明,FBER 具有灵敏度高、响应速度快的特点,并且在 200 °C 的条件下可循环使用 3500 次,经久耐用。经过优化的 FBER 可集成到消防救援检测系统中,用于消防救援行动中的实时逃生监测、位置采集和安全检测。FBER 的可扩展性和多功能设计可极大地促进消防救援绳索的发展。


Color adjustable, mechanically robust, flame-retardant and weather-resistant TiO2/MMT/CNF hierarchical nanocomposites coatings toward intelligent fire cyclic warning and protection

Yan-Bin Shen, Ke-Xin Yu, Ye-Jun Wang, Yun-Hao Qu, Long-Qian Pan, Cheng-Fei Cao, Kun Cao, Jie-Feng Gao, Yongqian Shi, Pingan Song, Jianming Yong, Min Hong, Guo-Dong Zhang, Li Zhao, Long-Cheng Tang

doi:10.1016/j.compositesb.2023.111159

颜色可调、机械坚固、阻燃和耐候的 TiO2/MMT/CNF 分层纳米复合材料涂层,用于智能火灾循环预警和保护

Fire safety and protection are very important but still show a critical global challenge. Developing smart fire warning materials with combined passive flame retardancy and active fire alarm response is promising for reducing or avoiding blade fire disasters. Various nano-fillers (e.g., graphene oxide and MXene) based coatings have proven to be effective fire warning material for monitoring high fire risk of various combustible materials; however, they still show some shortages, for example, high cost, black color, poor weather resistance and complicated fabricating process. Here, we report a green, cost effective and large-scale strategy for fabricating water-based 3D-titania/2D-montmorillonite/1D-celluose nanofiber (TiO2/MMT/CNF) hierarchical nanocomposite coatings with adjustable color, mechanical robustness, good flame retardancy, long-term weather resistance and sensitive fire cyclic alarming response. The formation of strong chemical bonding and hydrogen bonding interactions among polyethylene glycol molecules and multi-scale nano-fillers together with silane surface modification can produce good mechanical flexibility (folded crane), surface hydrophobicity (water contact angle of 152°) and exceptional flame resistance (good structure integrity after 120 s flame exposure). Notably, the optimized nanocomposite coatings exhibit ultrafast fire alarm response (<3.5 s) and stable fire cyclic alarming capability via the possible band transition of the TiO2 network under flame. Further, such color-adjustable nanocomposite coatings can be easily fabricated for large-scale production, and they show excellent stable flame retardancy and stable fire cyclic warning response even after more than one-year outdoor exposure. This work provides a novel and green fire warning nanocomposite coatings with combined passive-active functionalities for fire warning and protection.

消防安全和保护非常重要,但仍然是一个严峻的全球性挑战。开发兼具被动阻燃性和主动火灾报警响应功能的智能火灾预警材料,对于减少或避免叶片火灾灾难大有可为。各种基于纳米填料(如氧化石墨烯和 MXene)的涂层已被证明是有效的火灾预警材料,可用于监测各种可燃材料的高火灾风险;但它们仍存在一些不足,如成本高、颜色黑、耐候性差、制造工艺复杂等。在此,我们报告了一种绿色、低成本、大规模制造水基三维-钛/二维-蒙脱石/一维-纤维素纳米纤维(TiO2/MMT/CNF)分层纳米复合涂层的策略,该涂层具有颜色可调、机械坚固、阻燃性好、长期耐候性和灵敏的火灾循环报警响应等特点。聚乙二醇分子与多尺度纳米填料之间形成的强化学键和氢键相互作用,再加上硅烷表面改性,可产生良好的机械柔韧性(折叠式起重机)、表面疏水性(水接触角为 152°)和优异的阻燃性(120 秒火焰暴露后仍具有良好的结构完整性)。值得注意的是,优化后的纳米复合涂层具有超快的火灾报警响应(<3.5 秒)和稳定的火灾循环报警能力,这是通过二氧化钛网络在火焰下可能发生的带跃迁实现的。此外,这种颜色可调的纳米复合材料涂层易于制造,可进行大规模生产,即使在室外暴露一年以上,也能表现出优异的稳定阻燃性和稳定的火灾循环报警响应。这项研究提供了一种新型绿色火灾预警纳米复合涂料,具有被动和主动相结合的火灾预警和防护功能。


Customized triphasic cartilage composite scaffold simulating hypoxic microenvironment for osteochondral regeneration

Chuan Guo, Zixuan Su, Lianghu Zhao, Renjin Chen, Yu Wang, Ye Wu, Haider Mohammed Khan, Walter Munesu Chirume, Zhigang Zhou, Pin Feng, Yuheng Liu, Chen Fan, Canyu Gao, Changchun Zhou, Qingquan Kong, Yujiang Fan

doi:10.1016/j.compositesb.2023.111161

 

模拟缺氧微环境的定制三相软骨复合支架用于骨软骨再生

The regeneration of the osteochondral complex in situ presents a significant challenge. The inherent hypoxic microenvironment of cartilage plays a critical role in facilitating osteochondral repair. The successful regeneration of the osteochondral complex necessitates the utilization of materials and structures that closely mimic its composition. In this study, carboxymethyl chitosan (CCS), oxidized hyaluronic acid (OHA), and tannic acid (Ta) were employed to fabricate an injectable and self-healing hydrogel (Ta@gel). The incorporation of Ta within the hydrogel network enables preferential oxidation, thereby creating an anoxic microenvironment within the hydrogel. Bone marrow-derived mesenchymal stem cells (BMSCs) were encapsulated within microspheres composed of methacrylic anhydride gelatin (GelMA). These microspheres were subsequently loaded into a Ta@gel. The resulting bionic hydrogel composite was then combined with a three-dimensional (3D) printed hydroxyapatite (HAp) scaffold coated with poly-l-lysine (PLL). This combination resulted in the formation of a bionic three-layer composite structure (HAp@PLL + Ta@gel + GelMA@BMSCs) that closely resembles the complex composition and structure of natural osteochondral complex. The efficacy of this customized triphasic composite scaffold in promoting osteochondral complex regeneration has been demonstrated in vitro and in vivo. Consequently, this study provided a new sight for inducing the in situ regeneration of cartilage.

骨软骨复合体的原位再生是一项重大挑战。软骨固有的缺氧微环境在促进骨软骨修复方面起着至关重要的作用。要想成功实现骨软骨复合体的再生,就必须使用能密切模拟其成分的材料和结构。在这项研究中,羧甲基壳聚糖(CCS)、氧化透明质酸(OHA)和单宁酸(Ta)被用来制造一种可注射的自愈合水凝胶(Ta@gel)。在水凝胶网络中加入钽可实现优先氧化,从而在水凝胶中形成缺氧微环境。骨髓间充质干细胞(BMSCs)被包裹在由甲基丙烯酸酐明胶(GelMA)组成的微球中。随后将这些微球装入 Ta@ 凝胶中。然后,将生成的仿生水凝胶复合材料与涂有聚赖氨酸(PLL)的三维(3D)打印羟基磷灰石(HAp)支架相结合。这种组合形成了仿生三层复合结构(HAp@PLL + Ta@gel + GelMA@BMSCs),与天然骨软骨复合体的复杂成分和结构非常相似。这种定制的三相复合支架在促进骨软骨复合体再生方面的功效已在体外和体内得到证实。因此,这项研究为诱导软骨的原位再生提供了新的视角。


Large-scale production of boron nitride nanosheets for flexible thermal interface materials with highly thermally conductive and low dielectric constant

Xiangdong Kong, Yapeng Chen, Rongjie Yang, Yandong Wang, Zhenbang Zhang, Maohua Li, Hanxi Chen, Linhong Li, Ping Gong, Jianxiang Zhang, Kang Xu, Yong Cao, Tao Cai, Qingwei Yan, Wen Dai, Xinfeng Wu, Cheng-Te Lin, Kazuhito Nishimura, Zhongbin Pan, Nan Jiang, Jinhong Yu

doi:10.1016/j.compositesb.2023.111164

 

大规模生产具有高导热性和低介电常数的柔性热界面材料氮化硼纳米薄片

As the operating power of electronic devices used in 5G technology continues to rapidly progress, demand is increasing for thermal conductive composites with exceptional dielectric insulating properties. Boron nitride nanosheets (BNNS)-based composites have garnered significant attention owing to the extraordinary inherent thermal conductivity and excellent dielectric insulation of BNNS. However, a bottleneck of mass exfoliation high-quality BNNS severely delays the advancement of BNNS-based composites. Herein, the large-scale production BNNS are attained through novel exfoliation method by rationally introducing vigorous ultrasonication treatment with an ultra-high power up to 1200 W. By acquiring approximately 32 g of high-quality BNNS in 5 cycles, the yield can be increased to around 40 %. The multilevel casting strategy prepared polydimethylsiloxane PDMS/BNNS composite exhibits a significantly enhanced κ⊥ of achieve to 3.82 W m−1 K−1 at 50 wt % of BNNS loading along with a low interfacial thermal resistance of 38 K mm2 W−1 and dielectric constant below 3. This finding provides a promising path for the massively producing high-quality BNNS and thermal interface materials to enhance thermal transport from electronics to heat sink.

随着用于 5G 技术的电子设备的工作功率不断快速提高,对具有优异介电绝缘性能的导热复合材料的需求也在不断增加。基于氮化硼纳米片(BNNS)的复合材料因其非凡的固有热导率和优异的介电绝缘性能而备受关注。然而,高质量 BNNS 的大规模剥离瓶颈严重阻碍了 BNNS 基复合材料的发展。在此,通过合理引入高达 1200 W 的超高功率剧烈超声处理,采用新颖的剥离方法实现了 BNNS 的大规模生产。多层次浇铸策略制备的聚二甲基硅氧烷 PDMS/BNNS 复合材料在 BNNS 含量为 50 wt % 时,κ⊥ 显著增强,达到 3.82 W m-1 K-1,同时界面热阻低至 38 K mm2 W-1,介电常数低于 3。


In-situ manipulation of TiB whisker orientation and investigation of its high-temperature mechanical properties in titanium matrix composites

Qiang Wang, Zhao-Hui Zhang, Luo-Jin Liu, Xiao-Tong Jia, Yang-Yu He, Xian-Yu Li, Xing-Wang Cheng

doi:10.1016/j.compositesb.2023.111165

钛基复合材料中 TiB 晶须取向的原位控制及其高温力学性能研究

“SPS pre-sintering + SPS reactive hot extrusion” (SPSHE) is a promising technique for manipulating the orientation of TiB whiskers (TiBw) in discontinuously reinforced titanium matrix composites (DRTMCs). In the current study, (12.4 vol % TiBw +2.9 vol % TiC)/Ti6Al4V composites were prepared using SPSHE technology, successfully achieving both the normalization of TiBw orientation and a high aspect ratio. Specifically, the [010] axis of TiBw was aligned with the extrusion direction, and the average aspect ratio was 24.86. Tensile tests were conducted on the DRTMC samples at temperatures of 873 K, 923 K, and 973 K. The results demonstrate that SPSHE significantly enhances the high-temperature strength of the composite. At 873 K, the DRTMC exhibited an exceptionally high tensile strength of 732.2 ± 20 MPa. The main strengthening mechanisms of the DRTMC include load transfer strengthening from TiBw and TiC particles, solution strengthening, fine grain strengthening and dislocation strengthening. Moreover, at 873 K and 923 K, the dominant failure mode of the reinforcement was a load-bearing fracture. However, as the test temperature increased to 973 K, a mixed failure mode of load-bearing fracture and interface debonding was observed in the reinforcement.

"SPS预烧结+SPS反应热挤压"(SPSHE)是操纵非连续增强钛基复合材料(DRTMC)中TiB晶须(TiBw)取向的一种很有前途的技术。本研究利用 SPSHE 技术制备了(12.4 vol % TiBw +2.9 vol % TiC)/Ti6Al4V 复合材料,成功实现了 TiBw 取向的正常化和高纵横比。具体来说,TiBw 的 [010] 轴与挤压方向一致,平均纵横比为 24.86。在 873 K、923 K 和 973 K 温度下对 DRTMC 样品进行了拉伸试验。在 873 K 时,DRTMC 的拉伸强度高达 732.2 ± 20 MPa。DRTMC 的主要强化机制包括 TiBw 和 TiC 颗粒的载荷传递强化、溶液强化、细晶粒强化和位错强化。此外,在 873 K 和 923 K 时,加固材料的主要破坏模式是承载断裂。然而,当试验温度升高到 973 K 时,在加固材料中观察到了承载断裂和界面脱粘的混合破坏模式。


Composites Science and Technology

Experimental and theoretical study on the electromagnetic shielding performance of polymer nanocomposites consisting of basalt fiber and CNTs

Ze-Xin Chen, Chao Chang, Xiu Yue, Hui Li, Cun-Guang Liang, Peng-Cheng Ma

doi:10.1016/j.compscitech.2023.110399

   

玄武岩纤维和碳纳米管聚合物纳米复合材料电磁屏蔽性能的实验和理论研究

In this paper, we substantiated the mechanism behind the absorption and multiple reflection shielding in the nanocomposites (2 mm in thickness) consisting of basalt fiber loaded with carbon nanotubes and polydimethylsiloxane when exposed to the X-band frequency (8.2–12.4 GHz). The experimental results confirmed that the interface polarization, capacitor-like structure, together with internal conducting networks contributed to the electromagnetic shielding effect in the material. Furthermore, calculation and simulation were employed to analyze the propagation of electromagnetic wave within the nanocomposites, giving direct evidence that the electromagnetic irradiation could be efficiently absorbed while the reflection loss played a marginal role in this process. The findings of this study shed light on the structural design and optimization of the nanocomposites for high-efficiency electromagnetic shielding.

在本文中,我们证实了由含碳纳米管和聚二甲基硅氧烷的玄武岩纤维组成的纳米复合材料(厚度为 2 毫米)在 X 波段频率(8.2-12.4 GHz)下产生吸收和多重反射屏蔽的机理。实验结果证实,界面极化、类似电容器的结构以及内部导电网络共同促成了材料的电磁屏蔽效应。此外,通过计算和仿真分析了电磁波在纳米复合材料内部的传播,直接证明了电磁辐照可被有效吸收,而反射损耗在此过程中的作用微乎其微。该研究结果为高效电磁屏蔽纳米复合材料的结构设计和优化提供了启示。


Adjustable Ti2C3Alx-based segregated composite network for enhanced electromagnetic shielding and fire safety

Wei Wang, Haowen Sun, Yuan Liu, Qi Wang

doi:10.1016/j.compscitech.2023.110400

   

基于 Ti2C3Alx 的可调节分隔复合网络,用于增强电磁屏蔽和防火安全

With the rapid development of communication technology and portable electronic devices, the demand for the design of electronic devices with superior electromagnetic interference shielding and fire safety performance is increasing. Herein, epoxy resins (EPs) with typical segregated networks were designed by emulsion polymerization and adhesion self-assembly strategies and novel polyphosphonitrile microspheres (PZS) synthesized by precipitation polymerization were used to improve the fire safety of EP composites. It is worth noting that the oil-water (EP to water) ratio in emulsion polymerization is closely related to the microscopic morphology of the segregated network. A smaller ratio of EP to water results in more paths for electrical charge transfer through the EP composites. As a result, EP/PT-3 with a minimum oil-to-water ratio exhibits a high EMI SE (electromagnetic interference shielding effectiveness) in the X-band ranging from 40.12 to 40.30 dB at a loading of 7.20 vol% Ti3C2Alx. Besides, the synergistic action of the adjustable Ti3C2Alx network with PZS endows EP superior flame retardant performance. Compared with EP, the PHRR and THR values of EP/PT-3 are down 55.7 % and 72.6 %, respectively. There is no doubt that EP/PT-3 has provided a new route for the preparation of Ti3C2Alx-based electromagnetic shielding and fireproof materials.

随着通信技术和便携式电子设备的快速发展,人们对设计具有优异电磁干扰屏蔽和防火安全性能的电子设备的要求越来越高。本文通过乳液聚合和粘附自组装策略设计了具有典型离析网络的环氧树脂(EP),并利用沉淀聚合合成的新型聚磷腈微球(PZS)提高了 EP 复合材料的防火安全性。值得注意的是,乳液聚合中的油水(EP 与水)比与离析网络的微观形态密切相关。EP 与水的比例越小,通过 EP 复合材料的电荷转移路径就越多。因此,油水比最小的 EP/PT-3 在装载 7.20 vol% Ti3C2Alx 时,在 X 波段表现出较高的 EMI SE(电磁干扰屏蔽效果),范围在 40.12 至 40.30 dB 之间。此外,可调节的 Ti3C2Alx 网络与 PZS 的协同作用赋予 EP 优异的阻燃性能。与 EP 相比,EP/PT-3 的 PHRR 和 THR 值分别下降了 55.7% 和 72.6%。毫无疑问,EP/PT-3 为制备基于 Ti3C2Alx 的电磁屏蔽和防火材料提供了一条新的途径。


Fabrication of robust superhydrophobic surface on silicone rubber

Lie Chen, Gongqi Huang, Tao Hu, Qianliang Li, Jian Cheng, Dun Liu

doi:10.1016/j.compscitech.2023.110401

   

在硅橡胶上制作坚固的超疏水表面

Robust superhydrophobic surfaces with periodic array structures composed of circular silica islands on silicone rubber substrates were fabricated using a combination of multi-laser exposure and chemical modification. Abrasion tests with sandpaper demonstrate that hard silica regions on the surface can protect the silicone rubber region from external damage, resulting in long-lasting superhydrophobicity. Moreover, with an increase in area fraction and a decrease in array hole radius, the wear of the filled superhydrophobic silica is slowed while the protection for the silicone rubber region is enhanced. Particularly, the optimum surface geometry had an area fraction of 35 % and array hole radius of 100 μm retaining its hydrophobicity up to 63 times of abrasion, eight times more than that of the superhydrophobic surface processed by lasers alone. The results of a sand impact test confirmed the resulting surface's resilience in an aeolian sand environment. This research demonstrated the feasibility of producing robust, superhydrophobic surfaces on flexible silicone rubber substrates and providing a foundation for improving and innovating related products.

利用多激光曝光和化学修饰相结合的方法,在硅橡胶基底上制造出了由圆形二氧化硅岛组成的周期性阵列结构的坚固超疏水表面。用砂纸进行的磨损测试表明,表面上坚硬的二氧化硅区域可以保护硅橡胶区域免受外部损伤,从而获得持久的超疏水性能。此外,随着面积分数的增加和阵列孔半径的减小,填充超疏水二氧化硅的磨损速度减慢,而对硅橡胶区域的保护作用增强。特别是,面积分数为 35 %、阵列孔半径为 100 μm 的最佳表面几何形状在 63 次磨损后仍能保持疏水性,是仅用激光加工的超疏水性表面的八倍。沙粒撞击测试结果证实了所产生的表面在风沙环境中的弹性。这项研究证明了在柔性硅橡胶基材上制作坚固的超疏水表面的可行性,并为改进和创新相关产品奠定了基础。



来源:复合材料力学仿真Composites FEM
ACTMechanicalSystemMAGNET断裂复合材料非线性化学电子ADS消防通信裂纹理论化机材料多尺度仿生控制
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【新文速递】2023年12月6日固体力学SCI期刊最新文章

今日更新:International Journal of Solids and Structures 1 篇,Mechanics of Materials 1 篇,Thin-Walled Structures 7 篇International Journal of Solids and StructuresStrain-gradient GBEM-based thermomechanical performance of architected, uniform and graded 2D materials and beam-type structuresDimitrios C. Rodopoulos, Nikolaos Karathanasopoulosdoi:10.1016/j.ijsolstr.2023.112603 基于应变梯度 GBEM 的建筑、均匀和分级二维材料及梁型结构的热力学性能The current contribution investigates the strain-gradient thermomechanical performance of architected materials and structures with uniform and graded inner material designs. To that scope, an integral representation of strain-gradients in thermoelasticity, along with its Galerkin Boundary Element Method (GBEM) implementation are elaborated. The formulation accounts for both mechanical and thermal strain-gradients for the first time. Thereupon, the complete strain-gradient response upon uniaxial tensile (UT) and thermal loading (Th) is analyzed, performing direct comparisons among the strain-gradient fields induced in each case and providing summarizing statistics that associate higher-order thermal and mechanical effects. The numerical framework is used as a basis for the quantification of the impact of the underlying structural patterns on the equivalent internal length parameters of architected beam-type structures under thermomechanical loads in the context of simple gradient theory. It is found that thermal loads relate to comparable, yet lower, internal length parameters with respect to the ones obtained for uniaxially tensioned structures with uniform inner cellular designs. Both internal length and temperature variation contributions determine the strain-gradient thermomechanical response of beam-type architected structures, for which, exact, higher-order equivalent 1D displacement field solutions are first derived. Thermally-induced, higher-gradient displacements are found to be comparable with the ones obtained in UT-loaded structures with uniform inner cellular topologies. Moreover, inner material gradings are found to be able to considerably mitigate higher-order effects, a sensitivity that is not reproduced in the UT loading case. The results provided, along with the numerical and analytical methodologies elaborated, set the basis for the thermomechanical strain-gradient analysis of advanced architected media well-beyond the designs here investigated.本论文研究了具有均匀和分级内部材料设计的建筑材料和结构的应变梯度热机械性能。为此,本文阐述了热弹性应变梯度的积分表示法及其伽勒金边界元素法(GBEM)的实现。该方法首次考虑了机械应变梯度和热应变梯度。因此,分析了单轴拉伸(UT)和热加载(Th)时的完整应变梯度响应,对每种情况下引起的应变梯度场进行了直接比较,并提供了与高阶热效应和机械效应相关的汇总统计数据。在简单梯度理论的背景下,该数值框架被用来量化底层结构模式对热机械载荷下架构梁型结构等效内部长度参数的影响。研究发现,热荷载与具有均匀内部蜂窝设计的单轴拉伸结构的内长参数具有可比性,但内长参数更低。内部长度和温度变化都决定了梁式结构的应变梯度热机械响应,为此,首先推导出了精确的高阶等效一维位移场解决方案。研究发现,热诱导的高梯度位移与具有均匀内部蜂窝拓扑结构的UT负载结构中获得的位移相当。此外,还发现内部材料分级能够大大减轻高阶效应,而这种敏感性在UT加载情况下无法再现。所提供的结果以及所阐述的数值和分析方法,为先进结构介质的热机械应变梯度分析奠定了基础,远远超出了本文所研究的设计范围。Mechanics of MaterialsCalibration of constitutive models using genetic algorithmsJoseph D. Robson, Daniel Armstrong, Joseph Cordell, Daniel Pope, Thomas F. Flintdoi:10.1016/j.mechmat.2023.104881使用遗传算法校准构成模型Constitutive models, describing material response to load, are an essential part of computational materials engineering. Semi-empirical constitutive laws including the Johnson–Cook and Zerilli–Armstrong models are widely used in finite element simulation for easy computability and rapid run time. The reliability of these models depends on accurate and reproducible fitting of parameters. This work presents a genetic algorithm (GA) based tool to fit parameters in constitutive models. The GA approach is capable of finding the global optimum parameter set in a robust, repeatable, and computationally efficient manner. It has been demonstrated that the obtained fits are better than those using traditional term-wise optimisation. Allowed to fit freely, the GA method will be likely to produce non-physical parameter values. However, by constraining the fit, the GA method can produce parameters that are physically reasonable and minimise the error when extrapolating to unseen data. Finally, the GA method may be used to choose between a variety of possible constitutive models based on a transparent best fit approach. The model has been demonstrated by using datasets from the literature for DH–36 steel and Ti–6Al–4V. This includes data from different studies, in which there are both random and systematic variations. The framework developed here is made freely available and modifiable, and may be extended to include other constitutive models as required.描述材料对载荷响应的构效模型是计算材料工程的重要组成部分。包括约翰逊-库克模型和泽里里-阿姆斯特朗模型在内的半经验构成定律因其易于计算和运行时间短而被广泛应用于有限元模拟。这些模型的可靠性取决于参数拟合的准确性和可重复性。这项工作提出了一种基于遗传算法(GA)的工具,用于拟合构成模型中的参数。GA 方法能够以稳健、可重复和计算高效的方式找到全局最优参数集。事实证明,所获得的拟合效果优于传统的按项优化法。如果允许自由拟合,GA 方法很可能会产生非物理参数值。然而,通过约束拟合,GA 方法可以产生物理上合理的参数,并在推断未见数据时将误差降至最低。最后,基于透明的最佳拟合方法,GA 方法可用于在各种可能的构成模型中进行选择。该模型已通过使用文献中有关 DH-36 钢和 Ti-6Al-4V 的数据集进行了验证。这包括来自不同研究的数据,其中既有随机变化,也有系统变化。此处开发的框架可免费使 用和修改,并可根据需要扩展到其他构成模型。Thin-Walled StructuresMechanical behavior of austenitic stainless steels produced by wire arc additive manufacturingMan-Tai Chen, Zhichao Gong, Tianyi Zhang, Wenkang Zuo, Yang Zhao, Ou Zhao, Guodong Zhang, Zhongxing Wangdoi:10.1016/j.tws.2023.111455线弧快速成型技术生产的奥氏体不锈钢的力学性能Wire arc additive manufacturing (WAAM) is an innovative technology with the potential to drive the transformation and upgrading of metallic manufacturing industry and construction sector. The advantages of WAAM technology in rapid manufacturing, design freedom, and energy saving have attracted attentions in the construction field. This research study focuses on investigating the microstructural and mechanical behavior of austenitic stainless steels produced by wire arc additive manufacturing through test programs. The stainless steel plates were first additively manufactured using cold metal transfer technology with three types of feedstock wires (ER304, ER308L, ER316L). Tensile coupon specimens and microstructural observation samples were extracted from the WAAM plates. The electron backscatter diffraction (EBSD) experiments were conducted to identify and analyze the microstructures of the WAAM austenitic stainless steels. Five test orientations, namely θ = 0˚, 30˚, 45˚, 60˚, 90˚ relative to the printing layer direction, were designed to investigate the mechanical properties anisotropy. Two types of specimen surface condition (milled type and as-built type) were considered to assess the impact of geometric undulation. The geometric features of the as-built specimens were obtained using 3D laser scanning. A total of 60 tensile tests with the aid of digital image correlation (DIC) system were conducted to obtain the stress-strain responses of the WAAM austenitic stainless steels. The mechanical properties anisotropy of the WAAM austenitic stainless steels was analyzed in detail.线弧快速成型技术(WAAM)是一项创新技术,具有推动金属制造业和建筑业转型升级的潜力。WAAM 技术在快速制造、自由设计和节能方面的优势已引起建筑领域的关注。本研究主要通过测试程序研究线弧快速成型技术生产的奥氏体不锈钢的微观结构和力学行为。首先采用冷金属转移技术,使用三种原料线材(ER304、ER308L、ER316L)对不锈钢板进行增材制造。从 WAAM 钢板中提取了拉伸试样和微观结构观察样品。电子反向散射衍射(EBSD)实验用于识别和分析 WAAM 奥氏体不锈钢的微观结构。设计了五个测试方向,即相对于印刷层方向的 θ = 0˚、30˚、45˚、60˚、90˚,以研究力学性能各向异性。为评估几何起伏的影响,考虑了两种类型的试样表面条件(铣削型和原样型)。竣工试样的几何特征是通过三维激光扫描获得的。借助数字图像相关(DIC)系统共进行了 60 次拉伸试验,以获得 WAAM 奥氏体不锈钢的应力-应变响应。详细分析了 WAAM 奥氏体不锈钢的机械性能各向异性。Wind loads on structural members of rack-supported warehousesAntonino Maria Marra, Bernardo Nicese, Tommaso Massai, Gianni Bartolidoi:10.1016/j.tws.2023.111458支架支撑仓库结构构件的风荷载Rack-supported warehouses represent a modern typology of storage racks in which cladding panel weight and corresponding applied loads, such as wind or snow load, are supported by storage racks, in addition to pallet load and seismic action. Although this structural system allows for reducing the amount of structural steel, the uprights and beams, composing each rack, are directly exposed to the wind during the earliest erection phases. This load condition may govern the design of the uprights or that of temporary bracings. Wind load estimation requires the knowledge of the aerodynamic coefficients of each structural member section, for any angles of wind incidence. Unlike any common structural steelwork section, no data are available in the literature for RSW member sections. The current work represents a first step to cover this lack in the literature by reporting the results of an extensive wind tunnel campaign carried out on several portions of uprights and beams commonly designed and produced for RSWs. The results highlight the need for wind tunnel tests on RSW member sections when the producers can no longer afford an overestimation of the wind load. In addition, conservative values of the aerodynamic coefficients are provided for preliminary wind load estimations or temporary bracings design. Empirical relationships for the aerodynamic coefficients by changing an equivalent side ratio are also reported. Finally, design recommendations are provided by highlighting a critical structural configuration during the early erection phases of RSWs that govern the design of the uprights or temporary bracings. A worked example is then developed to clarify the application of the present results in the definition of wind loads.货架支撑仓库代表了现代仓储货架的一种类型,其中除了托盘载荷和地震作用外,包层板的重量和相应的外加载荷(如风载荷或雪载荷)都由货架支撑。虽然这种结构系统可以减少结构钢的用量,但组成每个货架的立柱和横梁在最早的安装阶段会直接暴露在风中。这种荷载条件可能会影响立柱或临时支撑的设计。风荷载估算需要了解每个结构部件在任何风入射角度下的空气动力系数。与任何常见的钢结构截面不同,文献中没有关于 RSW 构件截面的数据。目前的工作是弥补文献不足的第一步,报告了对 RSW 通常设计和生产的几部分立柱和横梁进行广泛风洞试验的结果。研究结果突出表明,当生产商无法再承受高估的风荷载时,有必要对 RSW 构件截面进行风洞试验。此外,还为初步风荷载估算或临时支撑设计提供了空气动力系数的保守值。还报告了通过改变等效侧比来计算空气动力系数的经验关系。最后,通过强调 RSW 早期安装阶段的关键结构配置,提供了设计建议,这些配置对直立支柱或临时支撑的设计具有指导作用。随后,还通过一个工作示例来说明本成果在风荷载定义中的应用。AAC-Block Walls with Surface Application of Non-Structural Plastering Materials as Newly Configured and Improved Structures Subjected to ShearingMarta Kałużadoi:10.1016/j.tws.2023.111459表面使用非结构性抹灰材料的 AAC 砌块墙,作为受剪切力影响的新配置和改进结构This research evaluates the use of non-structural materials, in the form of plastering grids and adhesive mortars, to create a newly configured structure with better shear properties than the original one, i.e. AAC blocks walls. Four types of glass fibre grid and two adhesive mortars were used. The results of 35 tested models subjected to diagonal compression show significantly improved performance by avoiding brittle failure, providing a significant increase in strength and ensuring relatively safe working conditions at large deformations. The best improvement in shear properties provided a relatively ‘weak’ grid with small openings and a highly deformable mortar.这项研究评估了非结构材料(抹灰网格和粘合砂浆)的使用情况,以创建一种新配置的结构,其剪切性能比原来的结构(即 AAC 砌块墙)更好。共使用了四种玻璃纤维网格和两种粘合砂浆。对 35 个模型进行对角压缩测试的结果表明,通过避免脆性破坏、显著提高强度和确保大变形时相对安全的工作条件,其性能得到了明显改善。剪切性能改善最好的是具有小开口的相对 &quot;弱 &quot;网格和高变形砂浆。Micromechanical study of intragranular stress and strain partitioning in an additively manufactured AlSi10Mg alloyV. Romanova, R. Balokhonov, A. Borodina, O. Zinovieva, E. Dymnich, S. Fortuna, A. Shugurovdoi:10.1016/j.tws.2023.111464 添加式制造的 AlSi10Mg 合金晶内应力和应变分配的微观力学研究This study addresses the effect of a cellular-dendritic microstructure on the intragranular deformation behavior of an additively manufactured AlSi10Mg alloy. Experimental investigations have revealed the Al dendritic cells with a characteristic size of several hundred nanometers. The cells are decorated by a thin eutectic layer which consists of an aluminum matrix reinforced by silicon nanoparticles. Based on the experimental data, a set of micromechanical models are constructed and implemented in finite-element calculations. The constitutive behavior of an aluminum phase is described in terms of anisotropic elasticity to take into account the crystal lattice effects. Calculation results are analyzed and discussed with the main focus being placed on the effect of microstructure-resolved stress and strain partitioning between Al and Si phases. The silicon content is shown to impact the range of stress variation at the intragranular scale and the places of stress concentration in the Al phase. The eutectic layer behaves as a metal matrix composite where reinforcing silicon particles restrict deformation of the aluminum matrix.本研究探讨了细胞树枝状微结构对添加剂制造的 AlSi10Mg 合金晶内变形行为的影响。实验研究发现,铝树枝状细胞的特征尺寸为几百纳米。这些细胞由薄共晶层装饰,共晶层由硅纳米颗粒增强的铝基体组成。根据实验数据,构建了一套微机械模型,并在有限元计算中实施。铝相的构成行为用各向异性弹性来描述,以考虑晶格效应。对计算结果进行了分析和讨论,重点关注微观结构应力和应变在铝相和硅相之间分配的影响。结果表明,硅含量会影响晶粒内部的应力变化范围以及铝相的应力集中位置。共晶层表现为金属基复合材料,其中强化硅颗粒限制了铝基体的变形。Experimental and Numerical Investigation on Mechanical and Fatigue Performance of Corroded Q690D High-Strength SteelLiang Zong, Heng Liu, Jiaxuan Wang, Yang Dingdoi:10.1016/j.tws.2023.111466锈蚀 Q690D 高强度钢机械和疲劳性能的实验和数值研究As a prevalent environmental factor in the service process of steel structures, corrosion have a significant impact on the mechanical and fatigue properties of steel, thus deteriorating service safety. In this article, focused on corroded Q690D high-strength steel, experimental and numerical investigations have been performed. Electrolytic accelerated corrosion experiments were conducted, and 3D surface morphology measurements were employed to analyse the surface properties of specimens with various corrosion degrees. Mechanical and high-cycle fatigue tests were carried out on the corroded specimens, then degradation models between the mechanical behaviours and corrosion characteristics were established. Furthermore, the fatigue damage evolution model of Q690D high-strength steel was calibrated based on continuum damage mechanisms (CDM), and numerical simulations of the corroded specimen corresponding to the monotonic tensile tests and high cycle fatigue tests were conducted. The results show that with the increase of corrosion degree, the elastic modulus, yield stress, and tensile stress would decrease, and the fatigue performance would deteriorate. Corrosion has a greater effect on the fatigue life of long-life range and the slopes of the S-N curves after corrosion are more uniform. With the CDM parameters of non-corroded Q690D and the numerical model with consideration of surface roughness, the fatigue life of corroded Q690D could be well simulated.锈蚀是钢结构服役过程中普遍存在的环境因素,对钢材的力学性能和疲劳性能有重大影响,从而降低服役安全性。本文以锈蚀的 Q690D 高强度钢为研究对象,进行了实验和数值研究。进行了电解加速腐蚀实验,并采用三维表面形貌测量来分析不同腐蚀程度试样的表面特性。对腐蚀试样进行了机械和高循环疲劳试验,然后建立了机械行为与腐蚀特性之间的退化模型。此外,基于连续损伤机理(CDM)校准了 Q690D 高强度钢的疲劳损伤演化模型,并对腐蚀试样进行了与单调拉伸试验和高循环疲劳试验相对应的数值模拟。结果表明,随着腐蚀程度的增加,弹性模量、屈服应力和拉伸应力都会降低,疲劳性能也会恶化。腐蚀对长寿命范围的疲劳寿命影响更大,腐蚀后的 S-N 曲线斜率更均匀。利用未腐蚀 Q690D 的 CDM 参数和考虑表面粗糙度的数值模型,可以很好地模拟腐蚀 Q690D 的疲劳寿命。Performance Assessment of Steel Frame Buildings with Hybrid Self-centering Braces under Extremely Rare Far-field EarthquakesFei Shi, Wenlang Yuan, Osman E. Ozbulut, Chao Zhang, Yun Zhoudoi:10.1016/j.tws.2023.111456采用混合自定心支撑的钢结构建筑在极罕见远场地震下的性能评估This paper investigates the seismic performance enhancement of steel frame buildings using a novel hybrid self-centering braces (HSBs) under extremely rare earthquake events. The hybrid self-centering brace consists of shape memory alloy (SMA) cables and viscoelastic (VE) dampers. A prototype bracing system is designed and fabricated to explore its basic mechanical behavior and working mechanism under cyclic loading, with a focus on its failure modes under large deformation loading condition. A multi-material mechanical model is developed to capture the mechanical behavior and failure of the HSB. Furthermore, five steel frame buildings with different parameterized HSBs are designed and modeled in OpenSees. Nonlinear dynamic analyses and incremental dynamic analyses are conducted on the five case-study frames using 44 far-field ground motions. The risk-based seismic performances of steel buildings with HSB are evaluated to assess the performance of HSB during extremely rare seismic events. The results show that the hybrid self-centering brace exhibits excellent self-centering and energy dissipation capabilities with the maximum equivalent viscous damping ratio reaching 9.4%. Even under large deformations, VE dampers continue to work effectively after the failure of SMA cables, demonstrating remarkable redundancy. Numerical simulations further reveal that the redundancy of HSB can improve the structural seismic resilience in terms of inter-story drift ratio, residual drift, and floor absolute acceleration. The higher the redundancy of HSB in the case-study frames, the smaller the seismic response and mean annual frequency of exceedance of the engineering demand parameters, thereby indicating a significant improvement in seismic performance.本文研究了在极罕见地震事件下,使用新型混合自定心支撑(HSB)提高钢结构建筑抗震性能的问题。混合自定心支撑由形状记忆合金(SMA)缆索和粘弹性(VE)阻尼器组成。设计并制造了一个原型支撑系统,以探索其在循环加载下的基本机械行为和工作机制,重点研究其在大变形加载条件下的失效模式。开发了一个多材料力学模型,以捕捉 HSB 的力学行为和失效。此外,还在 OpenSees 中设计和模拟了五栋具有不同参数化 HSB 的钢框架建筑。利用 44 种远场地震动对五个案例研究框架进行了非线性动力分析和增量动力分析。评估了采用 HSB 的钢结构建筑的抗震性能风险,以评估 HSB 在极罕见地震事件中的性能。结果表明,混合自定心支撑具有出色的自定心和消能能力,最大等效粘性阻尼比达到 9.4%。即使在大变形情况下,VE 阻尼器也能在 SMA 电缆失效后继续有效工作,显示出显著的冗余性。数值模拟进一步表明,HSB 的冗余性可以在层间漂移比、残余漂移和楼层绝对加速度方面提高结构的抗震能力。在案例研究框架中,HSB 的冗余度越高,地震响应和工程要求参数的年平均超标频率就越小,从而表明抗震性能得到了显著改善。Microscale modeling of the ductile fracture behavior of thin stainless steel sheetsMehdi Karimi Firouzjaei, Hassan Moslemi Naeini, Mohammad Mehdi Kasaei, Mohammad Javad Mirnia, Lucas FM da Silvadoi:10.1016/j.tws.2023.111457不锈钢薄板韧性断裂行为的微尺度建模This study aims to model the fracture behaviour of thin stainless steel sheets in the microscale, which are widely used in the manufacturing of thin-walled structures such as bipolar plates, while considering the effects of geometry and grain size. To achieve this, 304 austenitic stainless steel with two different thicknesses is heat-treated to obtain samples with distinctive grain sizes. Uniaxial tensile tests and cup drawing tests are performed on the resulting samples, and the fracture strains are measured using a digital image correlation system. The morphology of fracture surfaces is also analysed to understand fracture mechanisms in the microscale. A new ductile fracture model based on the normalized Cockcroft-Latham criterion is developed to take the size effect into account, which is then applied in finite element analysis to predict damage evolution and fracture initiation during the tests. The results reveal a significant reduction in the fracture strain with decreasing sheet thickness and increasing grain size. Furthermore, the fracture mode changed from tensile fracture of a polycrystalline metal to shear fracture of a single-crystal metal as the number of grains across the thickness decreased. It is confirmed that the proposed model accurately replicates the decrease of the fracture strain as the plastic deformation scaled down to the microscale and successfully predicts the displacement at the onset of fracture under different loading conditions. Based on these results, it can be concluded that the proposed model has great potential for predicting fracture in microforming processes.不锈钢薄板广泛用于制造双极板等薄壁结构,本研究旨在建立微尺度不锈钢薄板断裂行为模型,同时考虑几何形状和晶粒大小的影响。为此,对两种不同厚度的 304 奥氏体不锈钢进行了热处理,以获得具有不同晶粒尺寸的样品。对所得样品进行单轴拉伸试验和杯状拉伸试验,并使用数字图像相关系统测量断裂应变。此外,还对断裂表面的形态进行了分析,以了解微观尺度的断裂机制。基于归一化 Cockcroft-Latham 准则开发了一种新的韧性断裂模型,将尺寸效应考虑在内,然后将其应用于有限元分析,以预测试验过程中的损伤演变和断裂起始。结果表明,随着薄片厚度的减小和晶粒尺寸的增大,断裂应变明显减小。此外,随着厚度上晶粒数量的减少,断裂模式也从多晶金属的拉伸断裂转变为单晶金属的剪切断裂。研究证实,所提出的模型准确地复 制了塑性变形缩小到微尺度时断裂应变的减小,并成功地预测了不同加载条件下断裂发生时的位移。基于这些结果,可以得出结论:所提出的模型在预测微成形过程中的断裂方面具有巨大潜力。来源:复合材料力学仿真Composites FEM

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