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【新文速递】2025年1月2日复合材料SCI期刊最新文章

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今日更新:Composites Part A: Applied Science and Manufacturing 6 篇,Composites Part B: Engineering 2 篇,Composites Science and Technology 1 篇

Composites Part A: Applied Science and Manufacturing

Extrinsic toughening in bonded joints with hybrid thermoset-thermoplastic bondline: Experimental evidence and modeling strategy

Arifian Sandovic Perdana, Annisa Jusuf, Arief Yudhanto, Gilles Lubineau, Ran Tao, Bambang Kismono Hadi

doi:10.1016/j.compositesa.2024.108686

热固性热塑性复合粘结线粘结接头的外部增韧:实验证据和建模策略

Adhesive bonded composite joints with an embedded insert consisting of an interfacial hybrid thermoset-thermoplastic bondline could activate an extrinsic toughening mechanism that quadruples the mode I fracture toughness. However, the mechanisms of extrinsic toughening (anchoring, debonding, stretching, detachment), their associated energy dissipation, and the role of bondline parameters (wavelength, porosity, ductility) have not been detailed thus far. Here, we developed double cantilever beam (DCB) finite element models consisting of two rigid composite adherends and an elastoplastic bondline. We prescribed a spatially arranged interfacial/cohesive pattern to simulate the extrinsic toughening and evaluate the increase in fracture toughness. DCB tests were performed to validate the load–displacement curves, fracture toughness, and extrinsic toughening mechanisms obtained from the finite element models. The elastic–plastic energy dissipation during the crack-bridging process was also evaluated using the models. Despite the two-dimensional nature, the modeling results are in reasonable agreement with the experiments, providing an option for further developing a new heterogeneous bondline concept.

由热固性-热塑性复合材料界面杂化结合线组成的嵌套可激活一种外在增韧机制,使I型断裂韧性提高四倍。然而,外在增韧(锚定、脱粘、拉伸、脱离)的机制、它们相关的能量耗散以及粘接线参数(波长、孔隙率、延性)的作用迄今尚未得到详细的研究。在这里,我们建立了双悬臂梁(DCB)有限元模型,该模型由两个刚性复合材料附着体和一个弹塑性结合线组成。我们规定了一个空间排列的界面/内聚模式来模拟外部增韧和评估断裂韧性的增加。DCB试验验证了从有限元模型中获得的载荷-位移曲线、断裂韧性和外部增韧机制。利用该模型对桥接过程中的弹塑性能量耗散进行了计算。尽管是二维性质,但建模结果与实验结果基本一致,为进一步发展新的异质键合线概念提供了一种选择。


Interface engineering of Fe/Fe3C@C magnetic-carbon composites for superior microwave absorption

Yihui Zhou, Jin Qian, Zhe Qiang, Weiqing Kong, Changhuai Ye, Meifang Zhu

doi:10.1016/j.compositesa.2024.108700

 

铁/Fe3C@C磁碳复合材料的界面工程

Heterogeneous interfaces are crucial for enhancing the polarization loss in composite materials, thereby improving microwave absorption capabilities. However, creating well-defined multiple heterogeneous interfaces essential for optimal absorber performance presents a significant challenge. Herein, Fe/Fe3C@C magnetic-carbon composites featuring Fe-Fe3C-C multiple heterogeneous interfaces were fabricated through in-situ growth of Fe3O4 on polydopamine nanospheres, followed by thermal reduction and carbonization. Owing to the controllable Fe-Fe3C-C multiple heterointerface design, the outer-layer magnetic components not only significantly improve impedance matching but also enhance the interface polarization loss. The optimized Fe/Fe3C@C-9–1 composite exhibits excellent microwave absorption performance, achieving a minimum reflection loss (RLmin) of −64.4 dB and a broad effective absorption bandwidth (EAB) of 6.0 GHz at a thin matching thickness of only 1.5 mm, surpassing neat carbon nanospheres and most magnetic-carbon materials. Additionally, simulations conducted using Computer Simulation Technology (CST) demonstrate that the Fe/Fe3C@C-9–1 coating significantly reduces radar cross-section (RCS), with values below −20 dB across nearly the entire frequency range of 2–18 GHz, highlighting its potential for radar stealth applications. This work provides a simple yet effective approach for tuning the interface properties of carbon-based materials, underscoring the promise of Fe-Fe3C-C multiple heterogeneous interfaces in the development of broadband, thin microwave absorbers.

非均相界面是提高复合材料极化损耗从而提高微波吸收能力的关键。然而,创建良好定义的多异质界面对于最佳吸收器性能至关重要,这是一个重大挑战。本文通过在聚多巴胺纳米球上原位生长Fe3O4,然后进行热还原和碳化,制备了Fe- fe3c -c多非均相界面的Fe/Fe3C@C磁碳复合材料。由于可控的Fe-Fe3C-C多异质界面设计,外层磁性元件不仅显著改善了阻抗匹配,而且提高了界面极化损耗。优化后的Fe/Fe3C@C-9 -1复合材料具有优异的微波吸收性能,最小反射损耗(RLmin)为- 64.4 dB,有效吸收带宽(EAB)为6.0 GHz,匹配厚度仅为1.5 mm,超过了纯碳纳米球和大多数磁性碳材料。此外,利用计算机模拟技术(CST)进行的模拟表明,Fe/Fe3C@C-9 -1涂层显著降低了雷达横截面(RCS),在几乎整个2-18 GHz的频率范围内,RCS值低于- 20 dB,突出了其在雷达隐身应用中的潜力。这项工作为调整碳基材料的界面特性提供了一种简单而有效的方法,强调了Fe-Fe3C-C多非均质界面在宽带薄微波吸收器开发中的前景。


Enhanced tensile properties of continuous fiber-reinforced composites using robotic coaxial photopolymer extrusion

Pooyan Nayyeri, Zachary Platnick, Kourosh Zareinia, Habiba Bougherara

doi:10.1016/j.compositesa.2024.108701

 

利用机器人同轴光聚合物挤压增强连续纤维增强复合材料的拉伸性能

This paper introduces an additive manufacturing (AM) approach by integrating a coaxial photopolymer composite extruder with a robotic manipulator. Specimens made of continuous Kevlar fiber-reinforced PLA, with about 30 % fiber volume content, were manufactured by coaxial photopolymer extruder (CPCE) and compression molding (CMPC) for comparison purposes. Test results showed that the tensile properties of the robotic extrusion specimens were comparable to those produced through compression molding techniques. Specifically, the difference in tensile strength, modulus, and elongation at break between the specimen sets were 0.4 %, 7.5 %, and 1.3 %, respectively. Furthermore, testing and analysis using optical and scanning electron microscopy revealed that CPCE specimens exhibited 45% less void content than CMPC specimens. The proposed CPCE method demonstrates mechanical performance comparable to, and in some cases superior to, AM-manufactured Kevlar-reinforced composites in the literature. Additionally, this method provides enhanced design flexibility, reduced design-to-manufacture time, and lower void content than compression molding.

本文介绍了一种将同轴光聚合物复合材料挤出机与机械臂相结合的增材制造方法。采用同轴光聚合物挤出(CPCE)和压缩成型(CMPC)制备了纤维体积含量约为30 %的连续凯夫拉纤维增强PLA样品进行比较。试验结果表明,机器人挤压试样的拉伸性能与通过压缩成型技术生产的试样相当。具体来说,试样组之间的抗拉强度、模量和断裂伸长率的差异分别为0.4 %、7.5 %和1.3 %。此外,通过光学和扫描电子显微镜的测试和分析表明,CPCE样品的孔隙含量比CMPC样品低45%。提出的CPCE方法证明了机械性能与文献中am制造的凯夫拉增强复合材料相当,在某些情况下甚至优于。此外,这种方法提供了增强的设计灵活性,减少了从设计到制造的时间,并且比压缩成型更低的空隙含量。


Cutting force prediction of longitudinal-torsional ultrasonic assisted milling based on synergistic prediction ensemble learning model: A case study on CFRP

Tianming Yan, Lida Zhu, Wentian Shi, Shaoqing Qin, Mingxi Chen, Qiuyu Qin

doi:10.1016/j.compositesa.2024.108702

基于协同预测集成学习模型的纵扭超声辅助铣削切削力预测——以碳纤维布为例

To obtain accurate force predictions for longitudinal-torsional ultrasonic-assisted milling (LTUAM) of carbon fiber reinforced polymers (CFRP) across any milling path, a milling force model is proposed that considers the cutting force coefficient in the fiber direction, longitudinal-torsional ultrasonic milling thickness, and tool impact force. The milling angle and curvature features were shown to significantly influence the coefficient matrix of the milling force model through experiments and SHAP analysis, the coefficient matrix in the milling force model can then be solved by the established synergetic predictive ensemble learning model (SPE), which is used to obtain the CFRP-LTUAM force. The strong robustness and prediction accuracy of the SPE can be attributed to its integration of multiple structured base learners and the use of various decision-making strategies. The prediction accuracy and adaptability of the CFRP-LTUAM force model were validated through experiments, with effective support provided for process parameter optimization and stability control.

为了准确预测碳纤维增强聚合物(CFRP)纵向扭转超声辅助铣削(LTUAM)的铣削力,提出了考虑纤维方向切削力系数、纵向扭转超声铣削厚度和刀具冲击力的铣削力模型。实验和SHAP分析表明,铣削角度和曲率特征对铣削力模型的系数矩阵有显著影响,利用建立的协同预测集成学习模型(SPE)求解铣削力模型中的系数矩阵,得到CFRP-LTUAM力。SPE具有较强的鲁棒性和预测精度,这主要归功于其集成了多个结构化基础学习器和多种决策策略的使用。通过实验验证了CFRP-LTUAM力模型的预测精度和适应性,为工艺参数优化和稳定性控制提供了有效支持。


Unification and parameterization of 2D woven FRP and sensitivity analysis of their in-plane moduli and strength respect to diverse constituent parameters

Tiantong Lv, Xihai Zhang, Ke Duan, Xuanyi Liu, Dengfeng Wang, Xuejing Du

doi:10.1016/j.compositesa.2024.108703

 

二维编织FRP的统一参数化及其面内模量和强度对不同成分参数的敏感性分析

This study presents a parameterization method for 2D woven fiber-reinforced polymers (FRPs), accounting for the extensive variations unique to twill and satin weaves, which have received limited attention in the literature. By incorporating a user-defined elastoplastic-damage constitutive model for the matrix and a fiber bundle elastic-damage model based on the 3D Hashin failure criterion, this approach enables accurate virtual testing across diverse weave patterns, manufacturing parameters, and hybrid yarn compositions. Validation on representative specimens—including plain, 1/3 and 2/2 twill, and 5-harness 2-shift and 8-harness 3-shift satin weaves in carbon, carbon & glass, and carbon & Kevlar fiber composites—demonstrates model reliability. Building on this, a comprehensive parametric study is conducted to elucidate the effects of weave configuration, manufacturing settings, and material hybridization on tensile and shear performance. This framework provides an effective approach to understanding the structural and mechanical complexities of 2D woven FRPs, highlighting correlations and distinctions in their performance.

本研究提出了一种二维编织纤维增强聚合物(frp)的参数化方法,该方法考虑了斜纹和缎纹织物特有的广泛变化,这在文献中受到了有限的关注。通过结合用户定义的矩阵弹塑性损伤本构模型和基于3D哈欣失效准则的纤维束弹性损伤模型,该方法可以对不同的编织模式、制造参数和混合纱线成分进行精确的虚拟测试。在代表性样品上的验证-包括平原,1/3和2/2斜纹,以及碳,碳和玻璃,碳和凯夫拉纤维复合材料的5束2挡和8束3挡缎面织物-证明了模型的可靠性。在此基础上,进行了全面的参数研究,以阐明编织结构,制造设置和材料杂交对拉伸和剪切性能的影响。该框架提供了一种有效的方法来理解二维编织frp的结构和机械复杂性,突出其性能的相关性和区别。


Double-layer microencapsulated piperazine pyrophosphate towards fire-safe styrenic thermoplastic elastomer composites with remarkably improved mechanical properties

Quanqing Cui, Na Sun, Hongliang Ding, Xiaowei Mu, Wei Wang, Yan Zhang, Keqing Zhou, Liancong Wang, Bin Yu

doi:10.1016/j.compositesa.2024.108688

双层微胶囊化焦磷酸哌嗪制备防火型苯乙烯热塑性弹性体复合材料,其力学性能显著提高

The flammable nature of thermoplastic elastomer (TPE) leads to poor fire safety performance. It is difficult to be flame-retardant. A large amount of flame retardant (30–46 wt%) is usually added, weakening their mechanical properties heavily. To address these issues, this study prepared a novel core–shell flame retardant, PAPP@MF@TA, by encapsulating melamine formaldehyde resin (MF) and tannic acid (TA) on the surface of piperazine pyrophosphate (PAPP). Benefiting by the bridging effect of the core–shell structure, the compatibility between TPE and PAPP@MF@TA was improved, and the tensile strength of TPE/PAPP@MF@TA increased by 25.6% compared to TPE/PAPP. The flame-retardant performance was also enhanced. Compared to pure TPE, the peak heat release rate, total heat release and total smoke production of TPE/PAPP@MF@TA decreased by 73.7%, 37.9% and 35.5%, respectively. Besides, the flame-retardant mechanism was studied. This study provides a new approach for designing of TPE composites with comprehensively enhanced flame retardancy and mechanical properties.

热塑性弹性体(TPE)的易燃性导致其防火性能较差。很难做到阻燃。通常加入大量阻燃剂(30-46 wt%),严重削弱其机械性能。为了解决这些问题,本研究将三聚氰胺甲醛树脂(MF)和单宁酸(TA)包封在焦磷酸哌嗪(PAPP)表面,制备了一种新型核壳阻燃剂PAPP@MF@TA。得益于核壳结构的桥接作用,TPE与PAPP@MF@TA的相容性得到改善,TPE/PAPP@MF@TA的抗拉强度比TPE/PAPP提高了25.6%。阻燃性能也得到了提高。与纯TPE相比,TPE/PAPP@MF@TA的峰值放热率、总放热率和总产烟率分别降低了73.7%、37.9%和35.5%。并对阻燃机理进行了研究。本研究为设计综合增强阻燃性能和力学性能的TPE复合材料提供了新的途径。


Composites Part B: Engineering

A superelastic ceramic aerogel for flexible pressure sensor in harsh environment

Wei Xiao, Lianjie Lu, Zhenjin Xu, Yong Huang, Qibin Zhuang, Xianwei Qian, Xin Liu, Haoneng Zhou, Yiyi Zhang, Yang Yang, Dezhi Wu

doi:10.1016/j.compositesb.2024.112110

 

一种用于恶劣环境下柔性压力传感器的超弹性陶瓷气凝胶

With the rapid development in fields such as aerospace and intelligent firefighting, there are increasing demands for flexible pressure sensors to exhibit enhanced temperature resistance and stability. Here, we present a capacitive flexible ceramic aerogel pressure sensor (FCAPS) that operates stably over a wide temperature range from -196 to 800 °C. A dielectric layer of ZrO2-SiO2 nanofiber aerogel (ZSNFA) was constructed using oxide ceramic nanofibers with Si-O-Si cross-linked structures, which enables the sensor to maintain superior stability and high resilience under extreme temperatures. Flexible electrodes with high stability, fabricated using the direct ink writing (DIW) technique based on the Weissenberg effect and composed of interwoven Ag-Pd paste and fibers, enhance the sensor’s high conformal adaptability. Experimental results demonstrate that when the temperature is 800 °C, the sensor exhibits long-term stability with over 1000 cycles and a sensitivity up to 0.262 kPa-1. Furthermore, by leveraging deep learning technology, a firefighting pressure tactile glove integrated with a sensor array was developed, enabling precise object recognition, which has significant implications for the advancement of intelligent firefighting.

随着航空航天和智能消防等领域的快速发展,对柔性压力传感器的耐温性和稳定性的要求越来越高。在这里,我们提出了一种电容式柔性陶瓷气凝胶压力传感器(FCAPS),该传感器在-196至800°C的宽温度范围内稳定工作。采用具有Si-O-Si交联结构的氧化陶瓷纳米纤维构建了ZrO2-SiO2纳米纤维气凝胶(ZSNFA)的介电层,使传感器在极端温度下保持优异的稳定性和高回弹性。采用基于Weissenberg效应的直接墨水书写(DIW)技术制备的高稳定性柔性电极,由Ag-Pd浆料和纤维交织而成,增强了传感器的高保形适应性。实验结果表明,当温度为800°C时,传感器具有超过1000次循环的长期稳定性,灵敏度高达0.262 kPa-1。此外,通过利用深度学习技术,开发了一种集成传感器阵列的消防压力触觉手套,实现了精确的物体识别,这对智能消防的发展具有重要意义。


Formation of Electric Conductive SEI Layers in Hybrid Li-Ion/Metal Anodes for Stabilizing Coulombic Efficiency

Sungwoo Park, Kyubin Shim, Chang-Yeon Kim, Jong-Seong Bae, Jin Bae Lee, Hye-Jin Cho, Hae Jin Kim

doi:10.1016/j.compositesb.2024.112109

 

在锂离子/金属杂化阳极中形成稳定库仑效率的导电SEI层

Li hybrid anodes, which harness the Li storage mechanisms of both Li ion and metal anodes, offer considerable potential for effectively balancing the significant tradeoff between the cycle life and energy density of Li metal anodes. However, similar to Li metal anodes, Li hybrid anodes exhibit poor cycling stability, which is attributed to dendritic Li growth. In this study, we propose that the loss of electrical contact between carbon-based host materials due to large volume changes during Li deposition and stripping is the primary cause of the degradation of hybrid anodes. Additionally, immobilizing Ag nanodots in solid electrolyte interface (SEI) layers to improve electrical conductivity helped maintain electrical contact. The conductive SEI layers between each carbon host served as electron transfer pathways, mitigating electric contact loss, and resulting in stable Coulombic efficiencies and excellent cyclic stabilities in both carbonate- and ether-based electrolytes. Therefore, the enhancement of the electrical conductivity of the SEI is a new approach for overcoming the anode degradation that occurs during Li deposition.

锂杂化阳极利用了锂离子和金属阳极的锂存储机制,为有效平衡锂金属阳极的循环寿命和能量密度之间的重要权衡提供了相当大的潜力。然而,与锂金属阳极类似,锂杂化阳极表现出较差的循环稳定性,这归因于枝晶锂的生长。在这项研究中,我们提出,由于锂沉积和剥离过程中体积的巨大变化导致碳基主体材料之间电接触的损失是导致杂化阳极降解的主要原因。此外,将银纳米点固定在固体电解质界面(SEI)层中以提高导电性有助于保持电接触。每个碳主体之间的导电SEI层作为电子转移途径,减轻了电接触损耗,并在碳酸盐和醚基电解质中产生稳定的库仑效率和优异的循环稳定性。因此,提高SEI的电导率是克服锂沉积过程中阳极退化的新途径。


Composites Science and Technology

Cerium oxide-modified fly-ash-based porous calcium silicate filler for enhancing the mechanical properties and thermo-oxidative aging resistance of silicone rubber composites

Weijiang Wang, Junmin Sun, Lin Yang, Yinmin Zhang, Yongfeng Zhang

doi:10.1016/j.compscitech.2024.111032

 

用氧化铈改性粉煤灰基多孔硅酸钙填料提高硅橡胶复合材料的力学性能和抗热氧化老化性能

The thermo-oxidative aging resistance of polysiloxane elastomers can be improved by dispersing CeO2, a common heat stabilizer, within the elastomer matrix. However, this approach is limited by the small specific surface area of commercial CeO2 and inefficient dispersion methods. To overcome these issues, fly-ash-based porous calcium silicate (PCS) as a CeO2 carrier is introduced in this study. Using the CeO2-loaded PCS-reinforced fillers fabricated via a solvothermal method, a series of silicone rubber composites are prepared. The effect of thermos-oxidative aging on the mechanical properties and network structures of composites with various filler compositions and CeO2 loadings are analyzed. The micromorphologies and microstructures of the composites and the CeO2 mechanism of action are investigated using scanning electron microscopy, attenuated total reflectance Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy. After 12 h at 300 °C, the PCS-filled silicon rubber composites loaded with CeO2 exhibit superior mechanical properties and thermos-oxidative aging resistance than the composites to which CeO2 is directly added. This enhancement is partly attributed to the substitution of micro-PCS by nano-CeO2 and to the uniform distribution of CeO2 on the surface and between the layers of PCS. The uniform dispersion of CeO2 increases the specific surface area of the filler, thereby promoting filler–polymer interactions. Furthermore, the trapping of free radicals by Ce4+ inhibits the thermo-oxidative aging of the composites. The proposed CeO2-loaded PCS-reinforced filler can be used in developing silicone rubber composites suitable for high-temperature applications.

聚硅氧烷弹性体的抗热氧化老化性能可以通过在弹性体基体中分散常见的热稳定剂CeO2来提高。然而,这种方法受到商用CeO2的小比表面积和低效分散方法的限制。为了克服这些问题,本研究引入了粉煤灰基多孔硅酸钙(PCS)作为CeO2载体。采用溶剂热法制备了负载ceo2的聚氯乙烯增强填料,制备了一系列硅橡胶复合材料。分析了热氧化老化对不同填料和CeO2负载的复合材料力学性能和网状结构的影响。利用扫描电子显微镜、衰减全反射傅里叶变换红外光谱和x射线光电子能谱研究了复合材料的微观形貌和微观结构,并对CeO2的作用机理进行了研究。在300℃下加热12 h后,负载CeO2的pcs填充硅橡胶复合材料的力学性能和抗热氧化老化性能优于直接添加CeO2的复合材料。这种增强部分归因于纳米CeO2取代了微型PCS,以及CeO2在PCS表面和层间的均匀分布。CeO2的均匀分散增加了填料的比表面积,从而促进了填料与聚合物的相互作用。此外,Ce4+对自由基的捕获抑制了复合材料的热氧化老化。所制备的ceo2 - pcs增强填料可用于开发适合高温应用的硅橡胶复合材料。


来源:复合材料力学仿真Composites FEM
ACTMechanicalAdditiveOpticalMAGNET断裂复合材料隐身光学航空航天电子增材消防参数优化材料控制试验
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【新文速递】2024年12月17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,International Journal of Plasticity 1 篇,Thin-Walled Structures 2 篇International Journal of Solids and StructuresTheoretical solution for 3D transient thermal–hydraulic–mechanical coupled axisymmetric problem and its application to casing–cement–formation systemLianzhi Yang, Zijian Zhang, Jiyun Shen, Hongfei Jidoi:10.1016/j.ijsolstr.2024.113197三维瞬态热-水-力耦合轴对称问题的理论解及其在套管-水泥-地层系统中的应用In geomechanics and geoscience, the study of coupled processes is of paramount importance. This paper presents a theoretical solution, grounded in Biot’s theory, for the 3D transient thermal–hydraulic–mechanical (THM) coupled axisymmetric problem. Mathematical techniques such as the Laplace transform, Fourier expansion and the stress function method are employed to derive the THM solution. The Laplace transform is employed to manage time-dependent terms in transient equations, Fourier expansion is used to meet boundary conditions and stress functions establish connections between the stress field, seepage field, and temperature field. The validity of the THM solution is subsequently confirmed, demonstrating its accuracy. The theoretical solution is then applied to a casing–cement–formation system, a crucial structure frequently encountered in the oil industry. Given that the casing is generally considered impermeable, particular focus is placed on the boundary conditions at the casing–cement interface. A modeling of casing–cement–formation system is then conducted to show the THM coupling effect due to the temperature–pressure load. Furthermore, contour plots are employed to analyze the response of the system to linear loads.在地质力学和地球科学中,耦合过程的研究是至关重要的。本文以Biot理论为基础,提出了三维瞬态热-液-力耦合轴对称问题的理论解。采用拉普拉斯变换、傅立叶展开和应力函数法等数学方法推导了THM解。利用拉普拉斯变换对瞬态方程中的时变项进行处理,利用傅立叶展开满足边界条件,利用应力函数建立应力场、渗流场和温度场之间的联系。随后证实了THM解决方案的有效性,证明了其准确性。然后将理论解决方案应用于套管-水泥-地层系统,这是石油工业中经常遇到的关键结构。考虑到套管通常被认为是不透水的,特别关注的是套管-水泥界面的边界条件。然后对套管-水泥-地层系统进行了建模,以显示温度-压力载荷引起的THM耦合效应。此外,采用等高线图分析了系统在线性荷载作用下的响应。Journal of the Mechanics and Physics of SolidsMechanistic Cohesive Zone Laws for Fatigue Cracks: Nonlinear Field Projection and In Situ Synchrotron X-Ray Diffraction (S-XRD) MeasurementsH. Tran, D. Xie, P.K. Liaw, H.B. Chew, Y.F. Gaodoi:10.1016/j.jmps.2024.106010疲劳裂纹的机械粘接区规律:非线性场投影和原位同步加速器x射线衍射(S-XRD)测量A weak interface model with a predefined traction-separation relationship (denoted as the cohesive zone law), when embedded in a bulk solid, is oftentimes adopted to simulate the crack advancement and thus determine the crack resistance under either monotonic or cyclic loading conditions. To-date, various types of loading-unloading irreversibility and hysteresis are only presumed in the cohesive zone law for fatigue crack growth, but without any direct determination from experimental measurements. Using a fine-grained Mg alloy and synchrotron X-ray diffraction (S-XRD) measurements with a sub-millimeter beam, in situ lattice strain mapping can be obtained with the needed resolution to cover both the “messy” process zone as modeled by the cohesive zone law and the “clean” process zone caused by plastic deformation. We extend our previously developed nonlinear field projection method, and create trial elastic fields from the S-XRD-measured elastic strain fields at different loading levels when choosing the fully unloaded state as the new reference. From the Maxwell-Betti's reciprocal theorem, we reconstruct a mechanistic cohesive zone law for fatigue cracks, where the reciprocity gap is governed by the residual stress field at the fully unloaded state. Combining our inverse approach with S-XRD measurements, it is discovered that the fatigue-crack cohesive zone exhibits a bilinear unloading and reloading behavior that is distinctively different than all prior works. This particular form suggests the origin of irreversibility be primarily from crack-surface oxidation and the hysteresis from dislocation plasticity in surrounding grains.嵌入块体时,通常采用具有预先定义的牵引-分离关系的弱界面模型(称为黏聚区定律)来模拟裂纹的发展,从而确定单调或循环加载条件下的裂纹抗力。迄今为止,疲劳裂纹扩展的粘聚区规律中仅假定了各种类型的加载-卸载不可逆性和迟滞性,而没有从实验测量中直接确定。利用细晶镁合金和亚毫米光束同步加速器x射线衍射(S-XRD)测量,可以获得所需分辨率的原位点阵应变映射,以覆盖由内聚区定律模拟的“凌乱”过程区和由塑性变形引起的“干净”过程区。我们扩展了已有的非线性场投影方法,在选择完全卸载状态作为新的参考时,从s - xrd测量的不同加载水平下的弹性应变场中创建了试验弹性场。本文从Maxwell-Betti互易定理出发,重构了疲劳裂纹的机械内聚区规律,其中互易间隙由完全卸载状态下的残余应力场控制。将我们的反方法与S-XRD测量相结合,发现疲劳裂纹黏聚区表现出双线性卸载和再加载行为,这与所有先前的研究结果明显不同。这种特殊的形式表明,不可逆性的来源主要是裂纹表面氧化和周围晶粒位错塑性的迟滞。International Journal of PlasticityIntegrated modeling framework for the interactions of plastic deformation, magnetic fields, and electrical circuits: Theory and applications to physics-informed real-time material monitoringYoung-Dae Shim, Changhyeon Kim, Jihun Kim, Dae-Hyun Yoon, WooHo Yang, Eun-Ho Leedoi:10.1016/j.ijplas.2024.104212塑性变形、磁场和电路相互作用的集成建模框架:物理信息实时材料监测的理论和应用This study aims to develop a thermodynamic modeling framework for the electromagnetic-plastic deformation response coupled with circuit analysis. To accomplish this objective, we derived the thermodynamic balance laws for materials exposed to electromagnetic fields while undergoing plastic deformation. The balance laws serve as the foundation for refining the connection between the plastic deformation and electrical conductivity of materials. This study also modeled the relationship between dislocation density and Matthiessen's rule. The constitutive equations were subsequently implemented into a crystal plasticity model, thereby calibrating and validating the model. The derived modeling framework considers the 1st and 2nd laws of thermodynamics. The model was then transformed into a circuit model for a monitoring system by formulating equations to analyze the changes in material impedance resulting from the evolution of plastic deformation. This lays the groundwork for creating a monitoring system featuring a real-time prediction algorithm designed to assess material properties during manufacturing processes, thereby enhancing quality control and productivity. This monitoring system is used to monitor all materials in production lines of factories, where full-field measurement methods have limitations. Numerical simulations and experiments were conducted to validate the model and system performance. The results of these validation tests demonstrate that the model not only accurately predicts the relationship between electromagnetic fields and plastic deformation at the material level but also provides practical applicability within the realm of circuit theory, thus making it suitable for real-world system implementation.本研究旨在建立一个电磁塑性变形响应的热力学建模框架,并结合电路分析。为了实现这一目标,我们推导了材料在电磁场作用下发生塑性变形时的热力学平衡定律。这些平衡规律是细化材料塑性变形与导电性之间关系的基础。本研究还建立了位错密度与Matthiessen法则之间的关系模型。随后将本构方程应用到晶体塑性模型中,从而对模型进行校准和验证。推导的建模框架考虑了热力学第一和第二定律。通过建立方程,将该模型转化为监测系统的电路模型,分析了塑性变形演化导致的材料阻抗变化。这为创建一个监测系统奠定了基础,该系统具有实时预测算法,旨在评估制造过程中的材料特性,从而提高质量控制和生产力。该监控系统用于监控工厂生产线上的所有材料,而现场测量方法具有局限性。通过数值仿真和实验验证了该模型和系统的性能。验证试验结果表明,该模型不仅在材料层面上准确地预测了电磁场与塑性变形之间的关系,而且在电路理论领域具有实际的适用性,适合于实际系统的实现。Thin-Walled StructuresNew interaction ratios and modification factors for combined web-crippling and bending behaviour of cold-formed steel unlipped channel bearer sections in panelised construction under stud support removal scenariosSohini Mishra, Daniel P. McCrumdoi:10.1016/j.tws.2024.112843在螺柱支撑移除的情况下,板式结构中冷弯型钢无唇槽承载截面腹板破坏和弯曲行为的新相互作用比率和修正因子Cold-formed steel (CFS) unlipped channel sections are the most commonly used bearers in panelised buildings, supporting gravity loads from the floor panels. The bearers are typically laterally retrained at floor joist locations and vertically supported on CFS-lipped channel studs. Existing web-crippling and combined web-crippling-bending tests of bearers employ laterally and torsionally stable test setups formed by two identical channel sections connected either toe to toe in a box-beam arrangement or back-to-back and three-point bending static loading applied through the section's shear center (i.e., the loading induces no torsional moment to the sample), without employing any lateral restraint to the sample. No research has been conducted thus far to investigate CFS unlipped channel bearer sections' combined web-crippling and bending behaviour in stud(s) or single panel vertical support removal static loading scenarios. This research experimentally and analytically investigated the combined web-crippling and bending behaviour of CFS unlipped channel bearers with structural arrangements similar to CFS panelised buildings i.e., intermediate lateral restraints (representing floor-joists) and simply supported boundary conditions under stud vertical support removal static loading scenarios. The static loading circumstances consist of one stud (Case I), two studs (Case II), and three studs/single panel (Case III) vertical support removal. Twenty-four industry-standard bearers were tested with lateral restraint under Case I. Ninety-six parametric studies were conducted with finite element analysis models validated by testing under Cases I, II, and III. Results showed the bearers failed predominantly due to web-crippling with the interior one flange (IOF) and end one flange (EOF) mechanism being the most critical under Case I and III, respectively. Five different web-crippling equations in literature and web-crippling-bending interaction equations in Eurocode 3 (EC3) and AISI S100 were evaluated considering the above five different web-crippling capacities (developed based on static loading) and torsional moments (which the design codes do not mention). It was revealed that the EC3 and AISI interaction equations are unconservative when the torsional moment is excluded and over-conservative when the torsional moment is included. New characteristic nominal web-crippling-bending interaction ratios at IOF and modification factors to nominal EOF web-crippling capacities are proposed for the bearers' efficient design under stud(s) or single-panel vertical support removal static loading scenarios.冷弯型钢(CFS)无唇槽钢截面是板式建筑中最常用的承重体,用于支撑来自楼板的重力荷载。托架通常在地板托梁位置进行横向再训练,并在cfs唇形通道螺柱上进行垂直支撑。现有的腹板断裂和复合腹板断裂弯曲试验采用横向和扭转稳定试验装置,由两个相同的通道部分组成,在箱梁布置中首尾相连,或通过截面的剪切中心施加背靠背的三点弯曲静载荷(即加载不会对样品产生扭转力矩),而不对样品施加任何横向约束。到目前为止,还没有研究CFS无唇通道承载截面在螺柱或单板垂直支撑拆除静载荷情况下的联合腹板破坏和弯曲行为。本研究通过实验和分析的方法研究了CFS无唇通道承载体在去除柱钉垂直支撑的静态载荷情况下,与CFS板式建筑类似的结构布置,即中间横向约束(代表楼板托)和简支边界条件下的腹板破坏和弯曲行为。静态加载情况包括一个螺柱(情况I),两个螺柱(情况II)和三个螺柱/单面板(情况III)垂直支撑拆除。在案例I下,对24名行业标准承载者进行了横向约束测试。96项参数研究采用了通过案例I、II和III测试验证的有限元分析模型。结果表明,在第一种和第三种情况下,内单翼缘(IOF)和末端单翼缘(EOF)机制分别是最关键的。考虑上述五种不同的网页破坏能力(基于静荷载)和扭转力矩(设计规范未提及),对文献中五种不同的网页破坏方程以及欧洲规范3 (EC3)和AISI S100中的网页破坏-弯曲相互作用方程进行了评估。结果表明,EC3和AISI相互作用方程在不考虑扭转矩时为非保守方程,在考虑扭转矩时为过保守方程。为了在柱钉或单板垂直支撑拆除静态载荷情况下,支座的有效设计,提出了新的特性标称EOF断网-弯曲相互作用比和标称EOF断网能力的修正因子。Machine learning accelerated design of lattice metamaterials for customizable energy absorptionMiao Zhao, Xinwei Li, Xi Yan, Naixun Zhou, Bowen Pang, Bei Peng, Zhi Zengdoi:10.1016/j.tws.2024.112845机器学习加速设计可定制能量吸收的晶格超材料Lattice metamaterials have received extensive research interest for their superior mechanical properties. However, because of the nonlinear relationship between structure and mechanical responses, designing lattice metamaterials with optimal plastic response for energy absorption still remains a challenge. This study proposes a novel convolutional neural network (CNN) accelerated design approach for lattice metamaterials with customized mechanical properties. The CNN input datasets consist of pseudo-randomized strut geometries and their respective strain-stress curves that are simulated. The trained CNN shows the capabilities of accurate prediction and exploration of new lattice metamaterials that surpass the performance of the original input datasets. From the extended datasets, a new lattice metamaterial with the highest specific energy absorption is obtained, which also surpasses other lattice metamaterials reported in the literature. The new lattice metamaterial exhibits a stretch-dominated failure, with stresses distributed equally in the vertically aligned regions. These regions are supported by the adjacent unit cells, which avoids large expansion and further strengthens load-bearing capability during compression. Overall, the proposed design approach is based on a data-driven model without relying on the complex theory of solid mechanics, which is extendable for numerous new engineering applications.晶格超材料因其优异的力学性能而受到广泛的研究。然而,由于结构与力学响应之间的非线性关系,设计具有最佳吸能塑性响应的晶格超材料仍然是一个挑战。本研究提出了一种新颖的卷积神经网络(CNN)加速设计方法,用于具有定制力学性能的晶格超材料。CNN输入数据集由模拟的伪随机结构及其相应的应变-应力曲线组成。训练后的CNN显示出准确预测和探索新晶格超材料的能力,超过了原始输入数据集的性能。从扩展的数据集中,获得了一种比能吸收最高的新型晶格超材料,也超过了文献中报道的其他晶格超材料。新的晶格超材料表现出拉伸为主的破坏,应力均匀分布在垂直排列的区域。这些区域由相邻的单元格支撑,避免了大的膨胀,进一步增强了压缩时的承载能力。总体而言,所提出的设计方法基于数据驱动模型,而不依赖于复杂的固体力学理论,可扩展到许多新的工程应用。来源:复合材料力学仿真Composites FEM

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