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【新文速递】2024年6月7日复合材料SCI期刊最新文章

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今日更新:Composite Structures 1 篇,Composites Part B: Engineering 4 篇,Composites Science and Technology 1 篇

Composite Structures

Energy absorption characteristics of modular assembly structures under quasi-static compression load

Qiqi Li, Weijun Wang, Hailun Tan, Xiangyun Long, Fang Wang, Lin Hu

doi:10.1016/j.compstruct.2024.118260

准静态压缩载荷下模块化装配结构的能量吸收特性

Inspired by the assembly of building blocks, an innovative modular assembly structure (MAS) is proposed. With its modular design and versatility, MAS can be tailored to diverse working environments and task requirements. A prototype MAS is generated through three-dimensional (3D) printing, and subsequent compression tests consistently display energy absorption performance akin to a finite element model, affirming the validity of the simulations. Multiple MASs are obtained through the assembly of oblique cross cells, and the effect of compression direction on the energy absorption capacity of MASs is discussed. It is found that transverse compression outperforms longitudinal compression in energy absorption, and MAS with four cells and transverse loading demonstrates the highest specific energy absorption (SEA) value. Furthermore, quadrilateral, pentagonal, and hexagonal cells are proposed to obtain more MASs, and the compression performance of these MASs is evaluated by varying the frame structure thickness d and supporting structure thickness j of cells. Results highlight the superior energy absorption efficiency of the pentagonal element structure. Notably, parameter d has a more pronounced impact on energy absorption compared with parameter j. When j is 2.0 mm and d increases from 1.0 mm to 2.0 mm, the SEA values of quadrilateral, pentagonal, and hexagonal MASs increase by 113.70, 139.45, and 86.25 J/kg. In summary, MASs exhibit impressive energy absorption capabilities, promising versatile applications in energy absorption and anti-collision mechanisms across various scenarios.

受积木装配的启发,提出了一种创新的模块化装配结构(MAS)。凭借其模块化设计和多功能性,MAS可以根据不同的工作环境和任务要求进行定制。通过三维(3D)打印生成MAS原型,随后的压缩测试一致显示类似于有限元模型的能量吸收性能,证实了模拟的有效性。通过斜交叉单元的装配获得了多个质量,并讨论了压缩方向对质量吸能能力的影响。结果表明,横向压缩比纵向压缩更能吸收能量,且四胞体横向加载的MAS比能吸收(SEA)值最高。此外,还提出了四边形、五边形和六边形单元来获得更多的质量,并通过改变单元的框架结构厚度d和支撑结构厚度j来评估这些质量的压缩性能。结果表明,五边形单元结构具有较好的吸能效率。当j = 2.0 mm, d从1.0 mm增加到2.0 mm时,四边形、五边形和六边形质量的SEA值分别增加113.70、139.45和86.25 j /kg。总之,MASs表现出令人印象深刻的能量吸收能力,在各种情况下的能量吸收和防碰撞机制中有广泛的应用前景。


Composites Part B: Engineering

Large deformation behavior and energy absorption of rotating square auxetics

Fereshteh Hassani, Zia Javanbakht, Sardar Malek

doi:10.1016/j.compositesb.2024.111596

旋转方形消声器的大变形行为和能量吸收

This study focuses on large deformation in-plane response of rotating square (RS) auxetics under quasi-static tension with an emphasis on their energy absorption (EA). First, metallic RS samples were fabricated and tested under uniaxial tension and the results were used to establish validated numerical models using ANSYS. Gurson–Tvergaard–Needleman (GTN) model was employed to evaluate the ductile damage and its capability to predict failure of the RS structure was investigated. Numerical analyses were then conducted to compare the large tensile responses of a regular RS (R-RS) and a bio-inspired RS (Bio-RS-0) introduced by Sorrentino et al. (2022). Subsequently, a parametric study evaluated the effect of the size of a circular perforation in the square region of the Bio-RS-0 on the stress distribution, force–deformation response, failure mechanism, and specific energy absorption (SEA) of the structures. Bio-RS-0 enhanced the SEA of R-RS by more than five times due to the increased engagement of the geometry in plastic deformation. Large perforations significantly influenced the response in larger strains and their failure mode. Two failure mechanisms were identified which could be adjusted by perforation size. An optimum perforation size and the corresponding failure mode were identified for maximum SEA. Potential applications for energy absorbing auxetics in tension were discussed at the end.

本文主要研究了准静态张力作用下旋转方形结构的面内大变形响应,重点研究了其能量吸收特性。首先,制备金属RS试样并进行单轴拉伸试验,利用ANSYS软件建立验证的数值模型。采用Gurson-Tvergaard-Needleman (GTN)模型对RS结构的韧性损伤进行了评估,并对其预测破坏的能力进行了研究。然后进行数值分析,比较Sorrentino等人(2022)推出的普通RS (R-RS)和仿生RS (Bio-RS-0)的大拉伸响应。随后,进行了参数化研究,评估了Bio-RS-0方形区域中圆形穿孔的大小对结构应力分布、力-变形响应、破坏机制和比能吸收(SEA)的影响。Bio-RS-0将R-RS的SEA提高了5倍以上,因为它增加了几何形状在塑性变形中的参与度。大孔洞对大应变下的响应及其破坏模式有显著影响。确定了两种破坏机制,它们可以通过射孔尺寸来调节。确定了最佳射孔尺寸和相应的破坏模式,以获得最大的SEA。最后讨论了张力吸能助剂的潜在应用。


Design and manufacturing of a thermoplastic composite fan blade: Process-induced deformation simulation with fiber-draping analysis and its experimental validation

Thuan Ho-Nguyen-Tan, Min-Hyeok Jeon, Kyung Seok Jung, Jaesang Yu, Minkook Kim, Soon Ho Yoon

doi:10.1016/j.compositesb.2024.111599

 

热塑性复合材料风扇叶片的设计与制造:工艺变形模拟与纤维垂起分析及其实验验证

This paper presents an efficient methodology for designing and manufacturing a thermoplastic composite (TPC) fan blade. The structural thickness distribution is employed to define the lamination ply layup on middle shell mesh of the fan blade. Ply shape codes with high manufacturability are constructed using the marching square algorithm. A numerical analysis of fiber-draping is proposed to predict the distortion of fiber orientations due to shell curvatures and twisted angles. These fiber orientations are employed to simulate the process-induced deformation resulting from thermal anisotropy in the TPC fan blade. The simulated process-induced deformations accounting for the fiber-draping analysis closely align with experimental results.

本文提出了一种设计和制造热塑性复合材料(TPC)风扇叶片的有效方法。采用结构厚度分布来确定风机叶片中壳网的层压厚度。采用行进平方算法构造了具有高可制造性的铺层形状码。提出了一种纤维悬垂的数值分析方法,以预测由于壳体曲率和扭转角引起的纤维取向畸变。这些纤维取向被用来模拟由TPC风扇叶片的热各向异性引起的过程诱导变形。模拟过程引起的变形与实验结果吻合较好。


Biodegradable PLLA/PLGA Microspheres/Collagen Composites for Continuous Soft Tissue Augmentation

Xuan Li, Xiangyi Liao, Zhenzhen Jia, Shuaiyin Liu, Ping Li, Li Li, Wei Zhang, Xufeng Niu, Yubo Fan

doi:10.1016/j.compositesb.2024.111603

生物可降解PLLA/PLGA微球/胶原复合材料用于连续软组织增强

Skin aging is caused by a combination of endogenous and exogenous factors. The dryness, roughness, and pigmentation can be improved by chemical peeling and laser irradiation, while skin sagging mainly relies on dermal fillers. Although collagen fillers and microspheres fillers can fill the skin, neither of them can provide a sustained filling effect. Herein, a kind of dermal filler composed of collagen, poly(L-lactic acid) (PLLA) and poly(lactic-co-glycolic acid) (PLGA) (PLLA/PLGA microspheres/collagen) is developed to make up for the above shortcomings. PLLA/PLGA microspheres/collagen has good injectability and biocompatibility. In vitro studies indicate that PLGA microspheres of Col-50%PLLA/PLGA and Col-25%PLLA/PLGA show massive degradation on day 1 of complete collagen degradation, meeting the study objectives of continuous improvement of skin sagging. Furthermore, injecting composites into SD rats, 50%PLLA/PLGA and Col-25%PLLA/PLGA are proven with macrophage infiltration, TGF-β expression, and endogenous collagen regeneration. The developed PLLA/PLGA microspheres/collagen composites with good biocompatibility and sustained filling property hold great promise for improved treatment of skin sagging as well as other soft tissue augmentation.

皮肤老化是由内源性和外源性因素共同引起的。皮肤干燥、粗糙、色素沉着可以通过化学脱皮和激光照射来改善,而皮肤松弛主要依赖于真皮填充剂。虽然胶原蛋白填充剂和微球填充剂可以填充皮肤,但它们都不能提供持续的填充效果。为了弥补上述不足,本课题研制了一种由胶原蛋白、聚l -乳酸(PLLA)和聚乳酸-羟基乙酸(PLGA) (PLLA/PLGA微球/胶原)组成的真皮填充剂。PLLA/PLGA微球/胶原蛋白具有良好的注射性和生物相容性。体外研究表明,Col-50%PLLA/PLGA和Col-25%PLLA/PLGA微球在胶原蛋白完全降解第1天出现大量降解,满足持续改善皮肤松弛的研究目标。此外,将复合材料注射到SD大鼠体内,50%PLLA/PLGA和Col-25%PLLA/PLGA均证实了巨噬细胞浸润、TGF-β表达和内源性胶原再生。所开发的PLLA/PLGA微球/胶原复合材料具有良好的生物相容性和持续填充性能,在改善皮肤松弛和其他软组织增大的治疗方面具有很大的前景。


On asymmetric failure in additively manufactured continuous carbon fiber reinforced composites

Junjie Luo, Ke Zou, Quantian Luo, Qing Li, Guangyong Sun

doi:10.1016/j.compositesb.2024.111605

 

增材制造连续碳纤维增强复合材料的不对称失效研究

Due to a filament-by-filament and layer-by-layer structure produced by an additive manufacturing (or namely 3D printing) technique, mechanical properties of 3D printed materials diverge considerably from those of carbon fiber reinforced polymer (CFRP) composites made by traditional processes. This study aims to experimentally characterize their mechanical properties through the off-axis tensile, compressive and V-notch shear tests. Advanced imaging techniques, such as digital image correlation (DIC), scanning electron microscopy (SEM) and computed tomography (CT), are used to investigate anisotropic nature of materials and failure mechanisms of the 3D printed CFRP composites. The applicability of conventional failure criteria to the 3D printed CFRP composites, including Tsai-Wu, Tsai-Hill, Hoffman, Maximum Stress, Hashin, Puck and LaRC05, is assessed systematically. The experimental results divulge that the filament-by-filament and layer-by-layer features intrinsic to 3D printed CFRP composites lead to an uneven yet organized distribution of voids. This characteristic contributes on the development of claw mark strain patterns, parallel track inter-fiber failure patterns, and distinct compression failure modes such as delamination and interlayer crack under loading perpendicular to the fiber direction. The voids in the 3D printed CFRP materials are partially responsible for the significant asymmetry when off-axis angle increases. Notably, the conventional failure criteria exhibit limited capability for predicting the off-axis tensile strength accurately. This phenomenon can be attributed to the redistribution of inherent fiber waviness as the fiber encounters tensile loads. Based on the experimental results, the inter-fiber failure within LaRC05 is modified to obtain an enhanced failure criterion for predicting the off-axis tensile strength. This study is expected to provide fundamental understanding of structural characteristics and mechanical properties for 3D printed CFRP composites.

由于增材制造(即3D打印)技术生产的细丝和层层结构,3D打印材料的机械性能与传统工艺制造的碳纤维增强聚合物(CFRP)复合材料有很大差异。本研究旨在通过离轴拉伸、压缩和v形缺口剪切试验对其力学性能进行实验表征。采用数字图像相关(DIC)、扫描电子显微镜(SEM)和计算机断层扫描(CT)等先进成像技术,研究了3D打印CFRP复合材料的各向异性特性和破坏机制。系统评估了传统失效准则对3D打印CFRP复合材料的适用性,包括Tsai-Wu、Tsai-Hill、Hoffman、Maximum Stress、Hashin、Puck和LaRC05。实验结果表明,3D打印CFRP复合材料的细丝与逐层特性导致了不均匀但有组织的空隙分布。这一特性导致在垂直于纤维方向的载荷作用下产生爪痕应变模式、平行径迹纤维间破坏模式以及明显的分层和层间裂纹等压缩破坏模式。当离轴角增大时,3D打印CFRP材料中存在的空隙是造成不对称现象的部分原因。值得注意的是,传统的破坏准则在准确预测离轴抗拉强度方面的能力有限。这种现象可归因于纤维遇到拉伸载荷时固有纤维波纹度的重新分配。基于实验结果,对LaRC05纤维间破坏进行了修正,得到了预测离轴拉伸强度的增强破坏准则。这项研究有望为3D打印CFRP复合材料的结构特性和力学性能提供基本的理解。


Composites Science and Technology

“Dual-armor” strategy to prepare multifunctional carbonyl iron particle with corrosion resistance, self-healing and high microwave absorbing performances

Kaka Li, Junbo Ge, Dongjie Zhang, Ruoxi Zhao, Chao Wu, Zhongjun Cheng, Zhimin Xie, Yuyan Liu

doi:10.1016/j.compscitech.2024.110699

 

采用“双护甲”策略制备具有耐腐蚀、自愈和高吸收微波性能的多功能羰基铁颗粒

As a common and high microwave absorbing material, the application fields of carbonyl iron particle (CIP) are limited because of its poor corrosion resistance when working in harsh environments such as ocean, rainforest, or other high-humidity, high-salt places. Therefore, it is necessary to design a multifunctional CIP with good corrosion resistance and self-healing properties for ensuring its stable microwave absorbing performance. Herein, a “dual-armor” strategy is proposed to prepare multifunctional CIP (Composite particle), which is assembled with CIP coated by polyaniline (PANI/CIP) and Fe-DSe-M. Fe-DSe-M is Fe3+ responsive microcapsule whose shell contains -Se-Se- bonds and is magnetically adsorbed on the surface of PANI/CIP. PANI/CIP and Fe-DSe-M jointly undertake the function of microwave absorbing, anti-corrosion and self-healing. It is worth to note that the microwave absorbing performance of CIP after multi-functionalization has been greatly improved, and the minimum reflection loss value after accelerated corrosion is only reduced by 5.46 dB, which is much lower than PANI/CIP. These excellent properties of functional Composite particle benefit from PANI protective layer, Fe3+ responsive self-healing Fe-DSe-M and their synergistic effect. Our work provides a new approach to fabricate multifunctional microwave absorbing particle, which has a potential application in the corrosive environment.

羰基铁颗粒(CIP)作为一种常见的高吸波材料,在海洋、雨林或其他高湿、高盐场所等恶劣环境下工作时,由于其耐腐蚀性较差,其应用领域受到限制。因此,有必要设计一种具有良好耐腐蚀和自愈性能的多功能CIP,以确保其稳定的微波吸收性能。本文提出了一种“双护甲”策略来制备多功能CIP(复合粒子),该复合粒子由聚苯胺(PANI/CIP)和Fe-DSe-M包覆的CIP组装而成。Fe-DSe-M是一种Fe3+响应微胶囊,其外壳含有- se - se -键,并被磁吸附在PANI/CIP表面。PANI/CIP与Fe-DSe-M共同承担了微波吸收、防腐和自愈的功能。值得注意的是,CIP多功能化后的微波吸收性能有了很大的提高,加速腐蚀后的最小反射损失值仅降低了5.46 dB,远低于PANI/CIP。这些优异的性能得益于聚苯胺保护层、Fe3+响应自修复的fe - se - m及其协同作用。本研究为制备多功能微波吸收粒子提供了一条新途径,在腐蚀环境中具有潜在的应用前景。


来源:复合材料力学仿真Composites FEM
ACTMechanicalAdditiveSystemInspire复合材料碰撞化学电子增材海洋裂纹材料仿生试验装配
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首次发布时间:2024-11-20
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【新文速递】2024年6月10日复合材料SCI期刊最新文章

今日更新:Composite Structures 6 篇,Composites Part A: Applied Science and Manufacturing 2 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇Composite StructuresPredicting the mixed-mode fracture propagation in single-leg bending using a radial point interpolation meshless methodD.C. Gonçalves, L.D.C. Ramalho, R.D.S.G. Campilho, J. Belinhadoi:10.1016/j.compstruct.2024.118270用无网格径向点插值法预测单腿弯曲混合模式断裂扩展Adhesive bonding is a widely used joining technique with increasing applications in the automotive and aircraft industries. However, the numerical simulation of adhesively bonded joints is challenging due to the intricate mechanical behavior of the bonding layer, especially when structures are subjected to mixed-mode loading. This work proposes a meshless fracture propagation algorithm to simulate mixed-mode fracture propagation in single-leg bending (SLB) adhesive joints. The proposed algorithm combines the radial point interpolation method (RPIM) with a mixed-mode strain-based criterion to predict crack growth. The RPIM permits a flexible discretization of the fracture region and eases the geometric remeshing of the integration cells to account for the crack tip propagation. Additionally, the RPIM provides accurate and smooth strain/stress fields, allowing implementation of the mixed-mode fracture criterion. The numerical model was validated against experimental data for SLB adhesive joints with a brittle adhesive. The results showed that the proposed algorithm can accurately predict the resistance curves and critical energy release rates of the adhesive joints.粘接是一种应用广泛的连接技术,在汽车和飞机工业中的应用越来越广泛。然而,由于粘接层复杂的力学行为,特别是当结构受到混合模式加载时,粘接接头的数值模拟具有挑战性。本文提出了一种无网格断裂扩展算法来模拟单腿弯曲(SLB)粘接接头的混合模式断裂扩展。该算法将径向点插值法(RPIM)与基于应变的混合模式准则相结合来预测裂纹扩展。RPIM允许对断裂区域进行灵活的离散化,并简化了积分单元的几何网格划分,以考虑裂纹尖端的扩展。此外,RPIM提供准确、平滑的应变/应力场,允许实现混合模式断裂准则。对带有脆性胶粘剂的SLB胶粘剂接头进行了数值模拟和实验验证。结果表明,该算法能较准确地预测粘接接头的阻力曲线和临界能量释放率。Modal characteristics of functionally graded porous Timoshenko beams with variable cross-sectionsV.N. Burlayenko, H. Altenbach, S.D. Dimitrovadoi:10.1016/j.compstruct.2024.118273变截面功能梯度多孔Timoshenko梁的模态特性The study focuses on the free vibration analysis of beams composed of functionally graded porous materials and characterized by a variable cross-section along their length. A broad range of beams is examined encompassing various tapered configurations, porosity profiles, and porosity content. The equations of motion are derived using Hamilton’s principle within the framework of Timoshenko beam theory. These equations are solved semi-analytically using the differential transform method, which has been adapted to incorporate various boundary conditions such as clamped-clamped, clamped-free, clamped-pinned, and pinned-pinned constraints within a general formulation of the beam eigenvalue problem. To validate the proposed solution technique, computed natural frequencies are compared with existing literature results for tapered inhomogeneous beams and uniform porous beams. Notably, new results are obtained for tapered porous beams. In this regard, a comprehensive parametric study explores the influence of various factors on the natural frequencies and mode shapes of functionally graded porous beams with variable cross-sections. These factors include the type of porosity profiles, a range of porosity parameters, cross-section taper ratios, and specific boundary conditions. The findings deepen our understanding of the modal characteristics of functionally graded porous beams, providing valuable guidance for engineering design and structural optimization in relevant applications. Additionally, they may serve as benchmarks for other researchers.研究了由功能梯度多孔材料组成的具有变截面特征的梁的自由振动分析。广泛的梁被检查包括各种锥形配置,孔隙率剖面和孔隙率含量。在铁木辛柯梁理论的框架内,利用哈密顿原理推导出运动方程。这些方程是用微分变换方法半解析地解决的,该方法已被适应于在梁特征值问题的一般公式中纳入各种边界条件,如夹紧-夹紧,无夹紧,夹紧-固定和夹紧-固定约束。为了验证所提出的求解方法,将计算的固有频率与已有文献中锥形非均匀梁和均匀多孔梁的计算结果进行了比较。值得注意的是,对于锥形多孔梁,得到了新的结果。在这方面,一项全面的参数研究探讨了各种因素对变截面功能梯度多孔梁的固有频率和模态振型的影响。这些因素包括孔隙度剖面类型、孔隙度参数范围、截面锥度比和特定的边界条件。研究结果加深了我们对功能梯度多孔梁模态特性的理解,为相关应用的工程设计和结构优化提供了有价值的指导。此外,它们可以作为其他研究人员的基准。Three-dimensional heat transfer analysis of Hot Gas Torch (HGT)-assisted Automated Fiber Placement (AFP) for thermoplastic compositesLorenz Zacherl, Allyson Fontes, Farjad Shadmehridoi:10.1016/j.compstruct.2024.118256热塑性复合材料热气体火炬(HGT)辅助自动铺放纤维(AFP)的三维传热分析Automated Fiber Placement (AFP) is a key additive manufacturing process for the production of complex composite structures. This study focuses on the in-situ AFP process for thermoplastic composites with Hot Gas Torch (HGT), which includes heating, consolidation, and solidification steps. Temperature control is critical to achieving high quality parts as it affects bond quality, crystallization, and solidification. However, previous studies have oversimplified convective heat transfer by assuming a constant coefficient, resulting in discrepancies between simulations and experiments. This paper introduces a novel distribution function to model the convective heat transfer coefficient, thereby improving temperature predictions. An optimization loop is used to determine the parameters of the function, which ensures agreement with experimental data. The proposed approach accurately predicts the temperature distribution, which is validated against unseen experimental results. By incorporating the distribution of the convective heat transfer coefficient, this study improves the understanding of heat transfer mechanisms in AFP for thermoplastic composites, leading to improved manufacturing processes and part quality.自动铺放纤维(AFP)是复杂复合材料结构生产的关键增材制造工艺。本文主要研究了热塑性复合材料的热气体火炬原位AFP工艺,包括加热、固结和凝固步骤。温度控制是获得高质量零件的关键,因为它影响粘结质量、结晶和凝固。然而,以往的研究假设对流换热系数为常数,对对流换热进行了过度简化,导致模拟结果与实验结果不一致。本文引入了一种新的分布函数来模拟对流换热系数,从而提高了对温度的预测。利用优化循环确定函数参数,保证了与实验数据的一致性。该方法准确地预测了温度分布,并与未见的实验结果进行了验证。通过结合对流换热系数的分布,本研究提高了对热塑性复合材料AFP中传热机制的理解,从而改善了制造工艺和零件质量。Chaotic snap-through vibrations of bistable asymmetric deployable composite laminated cantilever shell under foundation excitation and application to morphing wingW. Zhang, L.L. Ren, Y.F. Zhang, X.T. Guodoi:10.1016/j.compstruct.2024.118261基础激励下双稳态非对称可展开复合材料层状悬臂壳的混沌破断振动及其在变形翼上的应用The realization of the dynamic snap-through behaviors provides the new design ideas in the fields of the morphing aircraft and piezoelectric energy harvesting. This paper studies 1:2 internal resonance, nonlinear vibrations and chaotic snap-through phenomena of the bistable asymmetric composite laminated (BSCL) cantilever shell with the lower-frequency and higher-frequency primary resonances for the first time. The transverse foundation excitation subjects to the fixed end of the bistable cantilever shell. The perturbation analysis of two-degrees-of-freedom nonlinear ordinary differential equations is carried out by using the first-order approximate multiple scale method. The analytical results of the frequency-amplitude and force-amplitude response curves are obtained under the small foundation excitation. The obtained results reveal that the BSCL cantilever shell exhibits the double-jumping characteristics when 1:2 internal and primary resonances occur. There is a continuous energy exchange back and forth between two modes of the bistable laminated cantilever shell. As the foundation excitation increases, the BSCL cantilever shell exhibits saturation phenomenon. Numerical simulations are finished to further investigate the effects of the large excitation on the chaotic, quasi-periodic and snap-through vibrations for the BSCL cantilever shell. The vibration experiment is carried out to investigate the internal resonance and dynamic snap-though motions of the BSCL cantilever shell. Using the snap-though behaviors of the BSCL cantilever shell, we obtain the morphing structure of the aircraft wing.动态通断行为的实现为变形飞行器和压电能量收集等领域的设计提供了新的思路。本文首次研究了具有低频和高频主共振的双稳态不对称复合材料层合层(BSCL)悬臂壳的1:2内共振、非线性振动和混沌卡断现象。横向基础激励受双稳悬臂壳固定端的影响。采用一阶近似多尺度法对两自由度非线性常微分方程进行了摄动分析。得到了小基础激励下的频率-幅值和力-幅值响应曲线的解析结果。结果表明,BSCL悬臂壳在发生1:2内共振和主共振时具有双跳变特性。双稳层合悬臂壳的两种模态之间存在着连续的能量交换。随着地基激励的增加,BSCL悬臂壳出现饱和现象。通过数值模拟进一步研究了大激励对BSCL悬臂壳混沌振动、准周期振动和卡断振动的影响。通过振动试验研究了BSCL悬臂壳的内部共振和动态跳脱运动。利用BSCL悬臂壳的吸通特性,得到了飞机机翼的变形结构。Experimental study on the vibrational response and damping of short fibre/unidirectional PEEK hybrid compositesJames Pheysey, Natalia Mazancova, Francesco De Cola, David Garcia Cava, Francisca Martinez-Herguetadoi:10.1016/j.compstruct.2024.118264短纤维/单向PEEK杂化复合材料振动响应及阻尼的实验研究This study investigates the vibrational performance of a new generation of hybrid composites based on a short fibre core for structural dynamic applications. The dynamic characterisation was conducted through dynamic mechanical analysis (DMA) and the free vibration of a cantilever beam at different lengths. The short fibre composite exhibited a superior specific damping capacity, producing a maximum damping of 0.42. The values extracted from DMA indicated no visco-plastic contribution from the PEEK resin system, implying that the internal microarchitecture drives the material damping, with friction at the fibre/matrix interface being the primary dissipation mechanism. The hybrid laminate presented an improvement in damping performance of 39% due to the addition of the short fibre core compared to a baseline quasi-isotropic laminate of similar flexural stiffness. These findings show hybridisation’s advantages in designing structural components with improved damping performance and reduced cost for a variety of dynamic applications in industries such as automotive.本文研究了新一代基于短纤维芯的混合复合材料的振动性能。通过动态力学分析(DMA)和悬臂梁在不同长度下的自由振动进行了动态表征。短纤维复合材料表现出优越的比阻尼能力,产生的最大阻尼为0.42。从DMA中提取的值表明PEEK树脂体系没有粘塑性贡献,这意味着内部微结构驱动材料阻尼,纤维/基体界面的摩擦是主要的耗散机制。与具有相似抗弯刚度的基准准各向同性层压板相比,由于添加了短纤维芯,混合层压板的阻尼性能提高了39%。这些发现表明,混合动力在设计结构部件方面具有改善阻尼性能和降低成本的优势,适用于汽车等行业的各种动态应用。Cyclic damage quantification in composite materials using discrete damage mechanicsNikolay V. Turbin, Kirill A. Shelkov, Nikolai O. Kononov, Ever J. Barberodoi:10.1016/j.compstruct.2024.118271基于离散损伤力学的复合材料循环损伤量化A method for fatigue damage quantification in composite materials, based on experimental stiffness degradation data for composite laminates subjected to cyclic load is proposed. Discrete damage mechanics theory is used to calculate crack density vs. number of cycles from elastic moduli-reduction data obtained during fatigue experiments. The calculated crack density simplifies fatigue testing by diminishing the need for counting cracks during testing. Accurate results are achieved and reported. The defect-nucleation rate, which controls the fatigue damage rate, is also obtained from processing the modulus-reduction data. It is observed that the defect-nucleation rate has a small scatter and is independent of applied load magnitude. Furthermore, the onset of delamination observed in the experiments correlates very well with the onset of deviation between the predicted and experimental curves of elastic moduli-reduction versus accumulated crack density. An additional parameter, the defect-nucleation threshold, is here proposed to further characterize the fatigue performance of the composite material under stress-controlled fatigue loading, in contrast to thermal fatigue results from the literature. Furthermore, the difference in damage nucleation rate between strain-controlled and stress-controlled was observed and discussed.提出了一种基于循环载荷下复合材料层合板刚度退化实验数据的复合材料疲劳损伤量化方法。利用离散损伤力学理论,从疲劳试验中获得的弹性模量缩减数据计算裂纹密度与循环次数的关系。计算出的裂纹密度减少了试验中对裂纹计数的需要,从而简化了疲劳试验。获得并报告准确的结果。通过对模量折减数据的处理,得到了控制疲劳损伤速率的缺陷形核率。观察到缺陷成核率具有较小的散射,并且与外加载荷大小无关。此外,实验中观察到的分层开始与弹性模量缩减与累积裂纹密度的预测曲线和实验曲线之间的偏差开始非常相关。本文提出了一个额外的参数,即缺陷成核阈值,以进一步表征复合材料在应力控制疲劳载荷下的疲劳性能,与文献中的热疲劳结果形成对比。此外,还观察并讨论了应变控制与应力控制在损伤成核速率上的差异。Composites Part A: Applied Science and ManufacturingFailure envelope prediction of 2D SiCf/SiC composites based on XGBoost modelBen Wang, Jingyu Zhao, Zaoyang Guo, Biao Wangdoi:10.1016/j.compositesa.2024.108287基于XGBoost模型的二维SiCf/SiC复合材料失效包络线预测In this paper, a multiple failure mechanisms-based progressive damage model is developed to capture the mechanical response and defect-induced nonlinear behavior of SiCf/SiC composites. This model is then adopted to simulate the stress–strain response of a representative volume element model under uniaxial loading, showing excellent agreement with experiments. The effects of the volume fraction of SiC fibers, as well as those of the porosity and microcrack density of SiC matrix, on the deformation and damage behavior of SiCf/SiC composites are predicted. Based on this, the failure envelopes related to micro-mesoscopic characteristics under combined loadings are generated as the database for the eXtreme Gradient Boosting (XGBoost) model training. Finally, a data-driven failure model is established for SiCf/SiC composites, whose prediction is compared with the formal failure criteria. The results demonstrate that the data-driven SiCf/SiC composite failure model is reliable in constructing the failure criteria related to micro-mesoscopic features.为了研究SiCf/SiC复合材料的力学响应和缺陷非线性行为,建立了一种基于多破坏机制的渐进损伤模型。采用该模型对具有代表性的体元模型进行了单轴加载下的应力-应变响应模拟,结果与实验结果吻合良好。预测了SiC纤维体积分数、SiC基体孔隙率和微裂纹密度对SiCf/SiC复合材料变形和损伤行为的影响。在此基础上,生成组合载荷作用下与细观特征相关的失效包络,作为极限梯度增压(eXtreme Gradient boost, XGBoost)模型训练的数据库。最后,建立了SiCf/SiC复合材料的数据驱动失效模型,并将其预测结果与形式失效准则进行了比较。结果表明,数据驱动的SiCf/SiC复合材料破坏模型在构建与细观特征相关的破坏准则方面是可靠的。A smart insulation material achieving self-reporting and autonomous repairing against electrical and mechanical damages based on targeted controllable microcapsulesWenlong Pang, Wenxia Sima, Potao Sun, Tao Yuan, Ming Yang, Xiaoxiao Chen, Zhaoping Lidoi:10.1016/j.compositesa.2024.108299一种基于目标可控微胶囊的智能绝缘材料,实现对电气和机械损伤的自我报告和自主修复Under the long-term action of electrical and mechanical stresses, irreversible micro-damages, such as electrical trees and cracks tend to occur inside solid insulation materials, leading to insulation failures, which have no effective countermeasures. This study develops a multi-responsive, target-controlled microcapsule to endow the epoxy resin with dual functions of self-reporting and autonomous repair against internal damage even under strong electric fields without human intervention. A turn-on mechanism for self-reporting signals is designed, to be applicable to electrical tree damage inside an epoxy matrix. In situ UV emissions generated by the partial discharge during electrical treeing are employed to automatically cure the microcapsule core material released into the damaged channel. This triggers aggregation-induced emission (AIE) signals and simultaneously repairs the damaged matrix. The polyurethane hybrid shell filled with magnetic particles endows the microcapsules with magnetic response characteristics. Under the control of a directional magnetic field, the microcapsule is concentrated around the vulnerable areas, obtaining high fluorescence emission intensity under low doping content without affecting the matrix performance. This method enables the autonomous inspection and maintenance of electric equipment and electronic devices under live working and provides new insight into the bionic intelligence of electrical and electronic insulation materials.在长期的电应力和机械应力作用下,固体绝缘材料内部容易出现电树、裂纹等不可逆的微损伤,导致绝缘失效,目前尚无有效的对策。本研究开发了一种多响应、靶标控制的微胶囊,使环氧树脂在强电场下无需人为干预,也具有自我报告和内部损伤自主修复的双重功能。设计了一种自我报告信号的开启机制,适用于环氧树脂基体内部的电气树损伤。利用电树过程中局部放电产生的原位紫外线辐射,自动固化释放到受损通道中的微胶囊芯材。这触发了聚集诱导发射(AIE)信号,同时修复了受损的基质。填充磁性颗粒的聚氨酯复合壳使微胶囊具有磁响应特性。在定向磁场的控制下,微胶囊在脆弱区域周围集中,在低掺杂含量下获得高荧光发射强度,而不影响基体性能。该方法实现了带电工作下电气设备和电子设备的自主检测和维护,为电气和电子绝缘材料的仿生智能提供了新的见解。Composites Part B: EngineeringSmart Polymer Composites with Vertically Oriented Boron Nitride and Carbon Fiber for Heat Management: Magneto-Thermal ResponsivenessFang Peng, Yuting Song, Tongle Xu, Menghuan Wang, Na Song, Sheng Sun, Peng Dingdoi:10.1016/j.compositesb.2024.111617智能聚合物复合材料与垂直取向氮化硼和碳纤维热管理:磁热响应Emerging structural materials for aerospace deformable structures, soft robotics, and advanced smart electronic devices necessitate reversible, lockable, and reprogrammable shape transformation capabilities. A challenge in this realm is heat accumulation in high-power density devices, which limited impedes broader applications of these materials. This study introduces magneto-thermal coupling response and efficient heat dissipation to structural composite, facilitating reversible and reprogrammable material deformation. Our composites prepared using bi-directional freeze casting strategy demonstrated excellent thermal management capabilities. When the composites were applied to the chip heat dissipation, the chip temperature was significantly reduced by 36.3 °C from 112.2 °C. Furthermore, the integration of a flexible boron nitride nanosheets (BNNS)/carbon fibers (CFs) network with magnetic Fe3O4 particles and phase-change material enables effective magneto-thermal response. This magnetically controlled thermal deformation behavior of composites provides a promising avenue for the development of multimodal morphing structures for soft robotics and aerospace applications.用于航空航天可变形结构、软机器人和先进智能电子设备的新兴结构材料需要可逆、可锁定和可重新编程的形状转换能力。这一领域的一个挑战是高功率密度器件的热积累,这限制了这些材料的广泛应用。本研究将磁-热耦合响应和高效散热引入结构复合材料,促进可逆和可编程材料变形。我们采用双向冷冻铸造策略制备的复合材料表现出出色的热管理能力。当复合材料应用于芯片散热时,芯片温度从112.2℃显著降低36.3℃。此外,柔性氮化硼纳米片(BNNS)/碳纤维(CFs)网络与磁性Fe3O4颗粒和相变材料的集成可以实现有效的磁热响应。这种磁控复合材料的热变形行为为软机器人和航空航天应用的多模态变形结构的发展提供了一条有前途的途径。Composites Science and TechnologyEnhanced interfacial interaction of graphene nanoplatelets/cellulose nanofiber matrix driven by pyranine-based dispersant for efficient thermal managing materialsYoojung Choi, Jae Hun Kim, Hyunseong Shin, Seong Dae Park, Hyunseung Yangdoi:10.1016/j.compscitech.2024.110698 pyranine分散剂驱动的石墨烯纳米片/纤维素纳米纤维基质界面相互作用增强,用于高效热管理材料With the development of high-density electronics, polymer-based thermal conductive composites with excellent thermal and mechanical performance are receiving great attention. For the development of polymer-based thermal conductive composites with superior properties, it is essential to reduce the agglomeration of fillers and enhance the interfacial interactions between thermal conductive fillers and the polymer matrix. Among the several thermal conductive materials, graphene nanoplatelets (GNPs) and cellulose nanofiber (CNFs) are attracting attention. However, poor interfacial interaction between GNP and CNF leads to interfacial separation, which in turn, deteriorates its properties. Herein, we synthesized a pyranine-functionalized polyether dispersant (PyPE), which can significantly improve the interfacial interactions between GNPs and CNFs. The effect of PyPE on the dispersion behavior of GNPs and the thermomechanical properties of GNP-CNF composite were monitored. Furthermore, we also performed molecular dynamics (MD) simulations to investigate the impact of applying PyPE dispersant on the interfacial interactions between the GNP and CNF matrix. The application of PyPE significantly enhanced the dispersibility of GNPs within the CNF matrix, resulting in a 15.5% increase in-plane thermal diffusivity and a 24.5% enhancement in tensile strength of the composite, demonstrating their potential applications in high power density electrical equipment and electronic devices.随着高密度电子技术的发展,具有优异热学性能和力学性能的聚合物基导热复合材料日益受到人们的重视。为了开发性能优越的聚合物基导热复合材料,必须减少填料的团聚,增强导热填料与聚合物基体之间的界面相互作用。在几种导热材料中,石墨烯纳米片(GNPs)和纤维素纳米纤维(CNFs)备受关注。然而,GNP与CNF之间的界面相互作用较差,导致界面分离,从而使其性能恶化。在此,我们合成了一种吡啶功能化聚醚分散剂(pyranne -功能化聚醚分散剂),它可以显著改善GNPs和CNFs之间的界面相互作用。考察了PyPE对GNPs分散行为和GNP-CNF复合材料热力学性能的影响。此外,我们还进行了分子动力学(MD)模拟,以研究应用PyPE分散剂对GNP和CNF矩阵之间界面相互作用的影响。PyPE的应用显著增强了CNF基体内GNPs的分散性,使复合材料的面内热扩散率提高了15.5%,抗拉强度提高了24.5%,显示了其在高功率密度电气设备和电子器件中的潜在应用。来源:复合材料力学仿真Composites FEM

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