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【新文速递】2024年10月30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 A: Applied Science and Manufacturing 4 篇,Composites Part B: Engineering 3 篇,Composites Science and Technology 5 篇

Composite Structures

Low-velocity impact and quasi-static post-impact compression analysis of woven structural composites for automotive: Influence of fibre types and architectural structures

Sandeep Olhan, Bindu Antil, B.K. Behera

doi:10.1016/j.compstruct.2024.118676

汽车编织结构复合材料的低速冲击和准静态冲击后压缩分析:纤维类型和建筑结构的影响

This paper studied the effect of different fibres and their architectures on the low-velocity impact (LVI) and quasi-static compression after impact (CAI) characteristics of textile fibre-based structural composite materials (TFSCM) manufactured using the vacuum-assisted resin transfer molding (VARTM) method. All specimens were tested at three distinct impact energy levels: 20 J, 30 J, and 40 J. Subsequently, optical microscopy, field emission scanning electron microscope (FESEM), and 3D X-ray micro-computed tomography (µ-CT) techniques were utilized to examine and analyze the internal and external damage morphologies, failure mechanisms, and damage distribution within the structural composites. The experimental findings revealed that the basalt epoxy-based three-dimensional (3D) woven fabric-reinforced composites had superior energy absorption and deformation resistance than the glass and sisal-based unidirectional (UD) and bidirectional (2D) composites across all impact energy levels. Furthermore, µ-CT analysis showed that specimens impacted at 40 J experienced a 128.41 % and 154.36 % increase in damage volume compared to those impacted at 30 J and 20 J, leading to complete perforation damage and z-yarn bending and breakage without any delamination at the impact site. More importantly, composites reinforced with UD preforms impacted at 10 J exhibited higher CAI strength compared to both 2D and 3D composites.

研究了不同纤维及其结构对真空辅助树脂传递模塑(VARTM)方法制备的纺织纤维基结构复合材料(TFSCM)低速冲击(LVI)和准静态冲击后压缩(CAI)特性的影响。所有的样本都在三种不同的冲击能量水平下进行了测试:20 J, 30 J和40 J。随后,利用光学显微镜、场发射扫描电镜(FESEM)和三维x射线微计算机断层扫描(µ-CT)技术对结构复合材料内部和外部损伤形态、破坏机制和损伤分布进行了检查和分析。实验结果表明,玄武岩环氧树脂基三维(3D)机织增强复合材料在所有冲击能级上都比玻璃基和剑麻基单向(UD)和双向(2D)复合材料具有更好的吸能和抗变形能力。此外,微ct分析表明,与受30 J和20 J冲击的试件相比,受40 J冲击的试件的损伤体积分别增加了128.41 %和154.36 %,导致了完全的穿孔损伤和z纱弯曲和断裂,而在冲击部位没有发生分层。更重要的是,与2D和3D复合材料相比,受10 J冲击的UD预制体增强的复合材料具有更高的CAI强度。


A novel three-dimensional DEM model for recycled aggregate concrete considering material heterogeneity and microcrack evolution

Haiyang Zhao, Annan Zhou, Liangchi Zhang, Arul Arulrajah

doi:10.1016/j.compstruct.2024.118677

考虑材料非均质性和微裂纹演化的再生骨料混凝土三维DEM模型

Recycled aggregate concrete presents significant potential for sustainable construction. However, its widespread adoption is impeded by a lack of comprehensive understanding of how recycled aggregates impact its mechanical properties. This paper proposes an advanced discrete element model accurately representing the concrete’s meso-structure, including diverse interfacial transition zones, random adhering mortar distributions as well as heterogeneous material properties. Furthermore, this model also allows for the identification and dynamic monitoring of microcrack initiation and propagation. Results show that low-quality recycled aggregates promote direct crack propagation through the aggregates, significantly impairing concrete performance. Adhering mortar negatively impacts concrete properties due to its poor interfacial bond with the mortar matrix and its inferior mechanical properties. The influence of the replacement ratio on the concrete properties is closely tied to the recycled aggregate quality. High-quality aggregates allow for higher replacement ratios with limited property degradation in the concrete.

再生骨料混凝土为可持续建筑提供了巨大的潜力。然而,由于缺乏对再生骨料如何影响其机械性能的全面了解,其广泛采用受到阻碍。本文提出了一种先进的离散元模型,该模型准确地反映了混凝土的细观结构,包括不同的界面过渡区、随机粘接砂浆分布以及非均质材料特性。此外,该模型还允许识别和动态监测微裂纹的起裂和扩展。结果表明:低质量再生骨料促进裂缝直接穿过骨料扩展,严重影响混凝土性能;粘结砂浆与砂浆基体界面粘结性差,力学性能差,对混凝土性能产生负面影响。替代率对混凝土性能的影响与再生骨料质量密切相关。高质量的骨料在混凝土性能退化有限的情况下允许更高的替代率。


Fracture properties of carbon/glass fiber composite laminates with surface scratch damage

Pingping Luo, Wei Shen, Lifeng Chen, Zijia Yao, Qian Li, Lvtao Zhu

doi:10.1016/j.compstruct.2024.118673

表面划伤损伤的碳/玻璃纤维复合材料层合板断裂性能

Carbon/glass fiber reinforced polymer composite panels may experience minor surface scratches during processing or use. These shallow scratches can expand and potentially lead to dangerous fracture failure as the specimens are continually loaded. This study presents a closed form non-LEFM model for predicting the fracture performance of materials with slight scratches. First, 3-p-b tests and direct tensile tests were conducted on 115 carbon/glass fiber composite laminated panel specimens. A comparison of the two test methods revealed that 3-p-b tests were more suitable for analyzing quasi-brittle fracture in carbon/glass fiber composites. The tensile strength ft and fracture toughness KIC of 3-p-b specimens with and without notched were discussed using the weighted average calculation method to determine the thickness of the “composite” single-layer prepreg as the characteristic composite unit Cch. A normal distribution method was also introduced to analyze the experimental discrete points, covering almost all the experimental scatterers with desired reliability. Furthermore, the same method was applied to specimens with different layup methods, and the data analysis confirmed its effectiveness. As the seam-thickness ratio α increases within a certain range, the tensile strength ft showed an overall increasing trend and the peak load Pmax showed a decreasing trend. Additionally, the laboratory routine dimensions can be utilized to efficiently predict the fracture of large size members with defects at the same thickness, which is significant for the safe design of composite structures.

碳/玻璃纤维增强聚合物复合板材在加工或使用过程中可能会出现轻微的表面划痕。这些浅表划痕可能会随着试样的持续加载而扩大,并可能导致危险的断裂失效。本研究提出了一种封闭形式的非局部塑性应力模型,用于预测带有轻微划痕材料的断裂性能。首先,对115块碳/玻璃纤维复合层压板试样进行了3Pb测试和直接拉伸测试。比较两种测试方法发现,3Pb测试更适合分析碳/玻璃纤维复合材料的准脆性断裂。采用加权平均计算方法讨论了带有和不带有缺口的3Pb试样的拉伸强度ft和断裂韧性KIC,并确定了作为特征复合单元Cch的“复合”单层预浸料的厚度。还引入了正态分布方法来分析实验离散点,以覆盖几乎全部实验散点,并达到所需的可靠性。此外,该方法还应用于不同铺层方法的试样,数据分析证实了其有效性。当缝隙厚度比α在一定范围内增大时,拉伸强度ft总体上呈上升趋势,峰值载荷Pmax呈下降趋势。此外,实验室常规尺寸可用于高效预测相同厚度有缺陷的大尺寸构件的断裂,这对于复合结构的安全设计具有重要意义。


Composites Part A: Applied Science and Manufacturing

Enhancements of physical microstructure and chemical activation on interfacial bonding strength of carbon fiber reinforced polymer

Chengcheng Sun, Peng Gu, Hailang Wan, Mingjun Ren, Jianping Lin, Junying Min

doi:10.1016/j.compositesa.2024.108530

物理微观结构和化学活化对碳纤维增强聚合物界面结合强度的影响

Carbon fiber reinforced polymer (CFRP) has wide applications in aerospace and medical industries due to the characteristics of high strength and corrosion resistance. However, surface treatment is generally required to improve its interfacial bonding strength. This study employed imprinting and plasma treatments for physical and chemical modifications on CFRP surface. Results indicate that changing the groove orientation from 0° to 90° increased the interface bonding strength by 20.8% due to the reduction of stress concentration at the bonding interface. Air plasma treatment not only removes surface contaminants but also generates chemical functional groups, such as amino and hydroxyl, on CFRP surface, which enhances the bonding strength by 266.3%. Hydroxyl and amino groups increase van der Waals and Coulombic forces between CFRP surface and adhesive molecule. Therefore, this study proposes a coupling method of imprinting and plasma treatment to maximize the interfacial bonding strength of CFRP.

碳纤维增强聚合物(CFRP)具有高强度和耐腐蚀的特点,在航空航天和医疗工业中有着广泛的应用。然而,通常需要进行表面处理以提高其界面结合强度。本研究采用印迹和等离子体处理对CFRP表面进行物理和化学改性。结果表明,当坡口方向由0°变为90°时,界面结合强度提高了20.8%,这是由于结合界面处的应力集中减少所致。空气等离子体处理不仅能去除CFRP表面的污染物,还能在CFRP表面生成氨基、羟基等化学官能团,使CFRP的结合强度提高266.3%。羟基和氨基增加了CFRP表面与粘附分子之间的范德华力和库仑力。因此,本研究提出了一种印迹和等离子体处理的耦合方法,以最大限度地提高CFRP的界面结合强度。


A friction-based method for measuring the radial compaction response of fibre tows

J. Hares, P. Kelly, M. Battley, S. Bickerton

doi:10.1016/j.compositesa.2024.108541

一种基于摩擦的纤维束径向压实响应测量方法

High performance fibre reinforced composite components are typically compacted to a high fibre volume fraction during manufacture. As such, it is important to understand the compaction behaviour of these materials to better design and model composite manufacturing processes. While most manufacturing processes apply transverse compaction pressure to planar textiles, continuous fibre composite 3D printing processes can apply a radial compaction pressure to a single tow in the printing nozzle. A similar mode of compaction is also seen in processes such as pultrusion of circular cross-sections. This work describes a new friction-based method for measuring the radial compaction response of single tows, or groups of tows. The radial compaction behaviour of a single 40K carbon fibre tow is measured and presented. Radial compaction of the characterised tow showed a steeper nonlinear relationship between compaction pressure and fibre volume fraction, than typically found for transverse compaction of 2D textile reinforcements.

高性能纤维增强复合材料组件通常在制造过程中被压实到高纤维体积分数。因此,了解这些材料的压实行为对于更好地设计和模拟复合材料制造工艺非常重要。虽然大多数制造工艺对平面纺织品施加横向压实压力,但连续纤维复合材料3D打印工艺可以对打印喷嘴中的单个束施加径向压实压力。在圆形截面的拉挤等过程中也可以看到类似的压实模式。这项工作描述了一种新的摩擦为基础的方法来测量径向压实响应的单束,或组束。测量并介绍了40K碳纤维束的径向压实性能。特征束的径向压实在压实压力和纤维体积分数之间表现出更陡峭的非线性关系,而不是典型的二维纺织增强材料的横向压实。


Fabrication of core–shell nickel ferrite@polypyrrole composite for broadband and efficient electromagnetic wave absorption

Ruiwen Shu, Kunlong Yun, Xinyue Liu, Leilei Xu

doi:10.1016/j.compositesa.2024.108558

 

宽带高效电磁波吸收核壳镍ferrite@polypyrrole复合材料的制备

Herein, nickel ferrite@polypyrrole (NiFe2O4@PPy) composite was prepared by a simple two-step route of solvothermal synthesis and in-situ oxidation polymerization reaction. The results of micromorphology analysis showed that the obtained NiFe2O4@PPy composite had a unique core–shell structure, good magnetic performance and electrical conductivity. Furthermore, the as-prepared magnetic/conductive NiFe2O4@PPy composite exhibited notably enhanced electromagnetic wave (EMW) absorption performance than pure NiFe2O4 and PPy. When the filling ratio was 17.5 wt% and the matching thickness was 2.24 mm, the optimal minimum reflection loss (RLmin) of −56.25 dB and a broad effective absorption bandwidth (EAB) of 5.2 GHz were achieved for NiFe2O4@PPy composite. With slightly increasing the matching thickness to 2.6 mm, the maximum EAB of 7.12 GHz could be reached. Additionally, the probable EMW absorption mechanism was elucidated. Therefore, this work could provide a valuable reference for the preparation of magnetic ferrite/conductive polymer composites as broadband and high-efficiency EMW absorbers.

在本工作中,采用简单的两步法——溶剂热合成和原位氧化聚合反应制备了镍铁氧体@聚吡咯(NiFe2O4@PPy)复合材料。微观形貌分析结果表明,制得的NiFe2O4@PPy复合材料具有独特的核壳结构,具有良好的磁性能和电导率。此外,制备的磁性/导电NiFe2O4@PPy复合材料的电磁波吸收性能显著优于纯NiFe2O4和PPy。当填充率为17.5 wt%,匹配厚度为2.24 mm时,NiFe2O4@PPy复合材料的理想最小反射损耗(RLmin)为-56.25 dB,有效吸收带宽(EAB)为5.2 GHz。将匹配厚度略微增加到2.6 mm时,最大EAB为7.12 GHz。此外,还阐明了可能的电磁波吸收机制。因此,该工作可为制备宽带、高效电磁波吸收剂的磁性铁氧体/导电聚合物复合材料提供有价值的参考。


Flexible conductive adhesives with high conductivity and infrared stealth performance

Chengwei Jiang, Chunfang Zi, Jing Li, Changxiang Hao, Shaoyong Cai, Yiqi Xu, Fengyu Su, Ge Cao, Yanqing Tian

doi:10.1016/j.compositesa.2024.108559

具有高导电性和红外隐身性能的柔性导电胶粘剂

While extensively employed in electronic packaging, the prevailing electrically conductive adhesives (ECAs) are currently constrained by their lack of flexibility, excessive manufacturing costs, and limited multifunctionality. In this work, the antimony-doped tin oxide flexible conductive adhesives (AFCAs) were prepared by incorporating the antimony-doped tin oxide (ATO) nanoparticles into a thermoplastic polyurethane (TPU) matrix along with silver flakes. The ATO nanoparticles acted as conductive bridges for sliver flakes to enhance the electrical conductivity and mechanical integrity of the composites. The AFCAs formulated with a mere 60 % Ag and 7 % ATO nanoparticles exhibited an exceptionally low volume resistivity of 2.01 × 10-5 Ω·cm. After 10,000 mechanical bending cycles, the resistance change of AFCAs was only 8 %. Remarkably, the AFCA films also demonstrated excellent infrared stealth capabilities by infrared thermal imaging. This study demonstrates a facile strategy to develop high-performance and multifunctional AFCAs for flexible electrics with excellent electrical stability and infrared stealth capabilities.

虽然广泛应用于电子封装,但目前普遍使用的导电粘合剂(eca)由于缺乏灵活性,制造成本过高和多功能性有限而受到限制。在这项工作中,将掺锑氧化锡(ATO)纳米颗粒与银片一起掺入热塑性聚氨酯(TPU)基体中,制备了掺锑氧化锡柔性导电胶粘剂(AFCAs)。ATO纳米颗粒作为银片的导电桥,提高了复合材料的导电性和机械完整性。仅含有60 % Ag和7 % ATO纳米粒子的AFCAs具有非常低的体积电阻率,为2.01 × 10-5 Ω·cm。经过1万次机械弯曲循环后,AFCAs的电阻变化仅为8 %。值得注意的是,AFCA薄膜还通过红外热成像显示了出色的红外隐身能力。该研究展示了一种开发高性能多功能柔性电气afca的简单策略,该afca具有优异的电气稳定性和红外隐身能力。


Composites Part B: Engineering

Unleashing the elastocaloric cooling potential of 3D-printed NiTi alloy with heterogeneous microstructures and Ni4Ti3 nanoparticles

Jianbin Zhan, Ruijin Ma, Liang Zhu, Jiahui Fang, Kun Li, David Z. Zhang, Lawrence E. Murr

doi:10.1016/j.compositesb.2024.111918

 

释放具有非均相组织和Ni4Ti3纳米颗粒的3d打印NiTi合金的弹热冷却潜力

Toward the development of elastocaloric (eC) refrigeration applications, this study examines how Ni4Ti3 nanoparticles improve the eC properties of laser powder bed-fused (LPBF) NiTi alloys, with a focus on the formation of a NiTi/Ni4Ti3 nanocomposite. The LPBF-produced microstructure offers significant advantages: i) a heterogeneous grain structure that provides complementary benefits—fine grains offer higher deformation resistance while coarse grains initiate phase transformation (PT) earlier, releasing more latent heat; ii) a strong <001>//building direction texture that enhances recoverability. However, these benefits are partially limited by grain boundary slip during PT, leading to lower cooling efficiency and increased energy dissipation in as-built NiTi alloys. To address these issues, Ni4Ti3 nanoparticles are introduced through aging treatment, forming a composite structure that strengthens grain boundaries. Given the challenges of applying severe plastic deformation to 3D-printed components, this approach may offer a more practical solution. The study also reveals that Ni4Ti3 nanoparticles contribute to: 1) reducing Ni content in the matrix, increasing lattice size and enthalpy, which enhances the temperature drop (ΔTad); and 2) promoting R phase formation, which hinders the B2↔B19' PT, reducing energy dissipation and improving the coefficient of performance (COPmat). The balance of these effects depends on nanoparticle size, with smaller particles (∼5–12 nm) amplifying the second effect, while larger particles (∼130 nm) increase the first effect. At 350°C aging, the optimized nanocomposite exhibits a maximum COPmat of 15 and ΔTad of 14K, representing a 163% improvement over the as-built alloy. This work highlights the potential of NiTi composites in 3D-printed eC components.

本研究旨在推动弹性卡热(eC)制冷技术的发展,重点研究Ni4Ti3纳米粒子如何改善激光粉末床融合(LPBF)NiTi合金的eC性能,并专注于NiTi/Ni4Ti3纳米复合材料的形成。LPBF工艺产生的微观结构具有显著优势:i)异质的晶粒结构,提供互补的优点——细晶粒具有更高的塑性变形抵抗力,粗晶粒较早引发相变(PT),释放更多的潜热;ii)强烈的[001]//建筑方向织构,增强可恢复性。然而,这些优点在相变过程中的晶界滑移作用下受到部分限制,导致未经处理的NiTi合金冷却效率降低和能量损耗增加。为了解决这些问题,通过时效处理向合金中引入Ni4Ti3纳米粒子,形成一种增强晶界强度的复合结构。鉴于将严重塑性变形应用于3D打印组件的挑战,这种方法可能提供更实用的解决方案。该研究还表明,Ni4Ti3纳米颗粒有助于:1) 减少基体中的Ni含量,增大晶格尺寸和熵,从而提高温度下降量(ΔTad);2) 促进R相的形成,阻碍B2↔B19' PT,减少能量损耗并提高性能系数(COPmat)。这些效应的平衡取决于纳米颗粒的大小,较小的纳米颗粒(约5-12 nm)会放大第二种效应,而较大的纳米颗粒(约130 nm)会增加第一种效应。在350°C老化后,优化的纳米复合材料具有最大COPmat 15和ΔTad 14K,比原始合金提高了163%。这项工作强调了NiTi复合材料在3D打印电子元件中的潜力。


A Novel Mechanism to Accelerate Stress Relaxation of Toughened Blends: Stress-Induced Core-Shell Morphological Reconstruction and Its Application in Thermoforming and Dimensional Stabilization

Jielong Lin, Shibing Ye, Yong Zhang, Xiaoyun Yang, Jiqing Liu, Long Chen, Hongyao Xu

doi:10.1016/j.compositesb.2024.111910

 

一种加速增韧共混物应力松弛的新机制:应力诱导核壳形态重构及其在热成型和尺寸稳定中的应用

Improving thermoforming efficiency and dimensional stability in thermoplastic products is a common challenge. This study investigates toughened polyamide 612 (PA612) blends made by adding maleic anhydride-functionalized SEBS (mSEBS) elastomers, along with high-density polyethylene (HDPE), polyphenylene Oxide (PPO), and polyphenylene Sulfide (PPS). Analyses showed that mSEBS forms a core-shell structure with HDPE or PPO and a sea-island structure with PPS in the PA612 matrix. The study uniquely examines how these structures affect stress relaxation. The results, modeled by a steady-state creep model, revealed that the core-shell structures reduced the characteristic relaxation time (λ) by over three orders of magnitude compared to PA612/mSEBS blends. Additionally, PA612/mSEBS/HDPE blends were more temperature-sensitive, reducing λ by six orders of magnitude compared to PA612/mSEBS/PPO blends. Further analysis showed that stress-induced core-shell morphological reconstruction (SCMR) significantly improved stress relaxation by promoting extensive plastic deformation and energy dissipation. These toughened PA612 blends exhibited excellent thermoforming efficiency and dimensional stability. A 3D finite element model confirmed SCMR as an effective strategy for stress relaxation, providing valuable insights for designing toughened blends with superior processing efficiency and stability.

提高热塑性塑料制品的热成型效率和尺寸稳定性是一个共同的挑战。本研究研究了通过添加马来酸酐功能化SEBS (mSEBS)弹性体以及高密度聚乙烯(HDPE)、聚苯氧乙烯(PPO)和聚苯硫醚(PPS)制成的增韧聚酰胺612 (PA612)共混物。分析表明,在PA612基体中,mSEBS与HDPE或PPO形成核壳结构,与PPS形成海岛结构。这项研究独特地考察了这些结构如何影响压力放松。通过稳态蠕变模型模拟的结果表明,与PA612/mSEBS共混物相比,核壳结构将特征弛豫时间(λ)降低了3个数量级以上。此外,PA612/mSEBS/HDPE共混物对温度更敏感,与PA612/mSEBS/PPO共混物相比,λ降低了6个数量级。进一步分析表明,应力诱导的核壳形态重建(SCMR)通过促进广泛的塑性变形和能量耗散,显著改善了应力松弛。这些增韧PA612共混物表现出优异的热成型效率和尺寸稳定性。3D有限元模型证实了SCMR是一种有效的应力松弛策略,为设计具有卓越加工效率和稳定性的增韧共混物提供了有价值的见解。


Effect of admixed silicone emulsion on water and chloride transport properties of concrete

Fengjiang Li, Yu Fu, Jiangwei Zhu, Yuchen Wu, Jie Hu, Haoliang Huang, Fanghua Lei, Jiangxiong Wei, Qijun Yu

doi:10.1016/j.compositesb.2024.111916

 

掺合硅酮乳液对混凝土水氯输运性能的影响

The addition of silicone is effective method for improving both surface and internal hydrophobicity of concrete, thus clarifying its effect on transport property of concrete is very important. In this study, both water and chloride transport properties of concrete incorporated with three silicone emulsions based on different active ingredients (silane oligomers or silane monomers) were evaluated and investigated. The results show that all three silicone emulsions exhibit no obvious negative effect on hydration and microstructure of cement paste; however, the admixed silicone emulsions increase both the thickness and porosity of ITZ in concrete. Therefore, the admixed silicone emulsions result in reduced compressive strength of concrete. Further, the incorporated silicone emulsions efficiently increase surface and internal water contact angle of concrete, thus mitigating both water absorption and chloride transport in concrete. Due to more pronounced interaction between silane oligomers and hydration products based on molecular dynamics simulation, the beneficial effect on improving hydrophobicity of concrete and halting water and chloride transport is more significant for the admixed silicone emulsion with silane oligomers as active ingredient.

硅酮的加入是改善混凝土表面疏水性和内部疏水性的有效方法,因此阐明其对混凝土输运性能的影响是十分重要的。在本研究中,评估和研究了三种基于不同活性成分(硅烷低聚物或硅烷单体)的硅烷乳液掺入混凝土的水和氯离子传输性能。结果表明:三种硅酮乳液对水泥浆体水化和微观结构均无明显的负面影响;硅酮乳液的掺入增加了混凝土中ITZ的厚度和孔隙率。因此,掺入硅酮乳液会降低混凝土的抗压强度。此外,掺入的硅酮乳液有效地增加了混凝土的表面和内部水接触角,从而减轻了混凝土中的吸水率和氯离子的迁移。由于基于分子动力学模拟的硅烷低聚物与水化产物之间的相互作用更为明显,因此以硅烷低聚物为活性成分的混合硅酮乳液在改善混凝土疏水性和阻止水氯离子传输方面的有利作用更为显著。


Composites Science and Technology

Fully automated measurement of the spatial distribution of both fibre length and orientation from micro-CT images of short fibre reinforced polymers.

L.M. Martulli, M. Sordi, A. Dinosio, A. Bernasconi

doi:10.1016/j.compscitech.2024.110943

 

从短纤维增强聚合物的微ct图像中自动测量纤维长度和方向的空间分布。

The morphology of Short Fibre Reinforced Polymers (SFRPs) plays a fundamental role in determining their stiffness, strength and fracture behaviour. Measurements tools for the analysis of their microstructure are therefore of paramount importance. To this end, a fully automated algorithm able to segment single fibres from X-ray micro-computed tomography images was developed. This method was tailored to effortlessly reconstruct the microstructure of large volumes of material; in particular, to acquire fibre length, position and orientation, even dealing with low-resolution images. The algorithm was tested on different specimens of short glass fibre-reinforced polyamide and it was validated comparing the fibre orientation with the one obtained with commercial software analysis and the fibre length with the experimentally determined one. Therefore, the proposed algorithm allows to easily identify microstructural trends without requiring the usual complex evaluating procedures.

短纤维增强聚合物(SFRPs)的形貌在决定其刚度、强度和断裂行为方面起着至关重要的作用。因此,用于分析其微观结构的测量工具至关重要。为此,开发了一种能够从x射线微计算机断层扫描图像中分割单个纤维的全自动算法。该方法适合于毫不费力地重建大量材料的微观结构;特别是,即使处理低分辨率图像,也能获得纤维的长度、位置和方向。在不同的短玻璃纤维增强聚酰胺试样上进行了实验,并将所得的纤维取向与商业软件分析结果进行了比较,将所得的纤维长度与实验测定的长度进行了比较,对算法进行了验证。因此,所提出的算法可以很容易地识别微观结构趋势,而不需要通常复杂的评估程序。


Array infrared thermography for visualization of defects in bonded fiber reinforced polymer joints

Xingxing Zou, Mengyao Li, Hao Xu, Xiaofeng Lu

doi:10.1016/j.compscitech.2024.110930

 

阵列红外热成像技术用于粘结纤维增强聚合物接头缺陷的可视化

Fiber reinforced polymer (FRP) is widely used in new and existing structures, however, interfacial defects in the bonded joints pose a significant threat to structural integrity. Therefore, detection of interfacial defects is imperative for ensuring structural safety. This study proposes array infrared thermography (IRT) as a novel non-destructive evaluation method to visualize interfacial defects. Array IRT provides uniform heat excitation within the spatial domain, which overcomes the problem of heat concentration by conventional IRT. Forty-five bonded FRP plate specimens were tested using array IRT, results of which show that interfacial defects can be accurately detected within (8h+8) s (where h is the thickness of the upper layer of FRP in mm). Array IRT achieves high accuracy in detecting shapes, particularly sharp corners of defects. A pre-processing method was proposed to eliminate the twisted angles of thermal camera and to more clearly show the defects in the thermograms. A database containing tested thermograms and the corresponding predefined defects was established. Intelligent algorithms - UNet, Deeplabv3, and YOLOv8 - were used to segment the defected regions for array IRT analysis, results of which show a precision of 95.8%, 94.4%, and 94.1%, respectively.

纤维增强聚合物(FRP)在新建和既有结构中得到了广泛的应用,但其粘结接头的界面缺陷对结构的完整性构成了严重的威胁。因此,界面缺陷检测是保证结构安全的必要手段。本研究提出阵列红外热像仪(IRT)作为一种新的界面缺陷无损检测方法。阵列红外热成像在空间范围内提供均匀的热激发,克服了传统红外热成像的热集中问题。采用阵列红外热成像技术对45个粘结玻璃钢板试件进行了测试,结果表明,在(8h+8) s (h为玻璃钢上层厚度,单位为mm)内可以准确检测到界面缺陷。阵列IRT在检测形状,特别是缺陷的尖角方面具有很高的精度。提出了一种消除热像仪畸变的预处理方法,使热像图中的缺陷更清晰地显示出来。建立了一个包含测试热图和相应的预定义缺陷的数据库。利用UNet、Deeplabv3、YOLOv8等智能算法对缺陷区域进行分割,进行阵列IRT分析,精度分别为95.8%、94.4%、94.1%。


Efficient property-oriented design of composite layups via controllable latent features using generative VAE

Huaixiang Sun, Xiaodong Wang, Jiaxue Li, Zengshan Li, Zhidong Guan

doi:10.1016/j.compscitech.2024.110936

 

基于生成式VAE的可控潜在特征的高效面向属性的复合布局设计

Fiber-reinforced composites provide substantial tailoring potential, while the extensive parameters and complex coupling mechanisms pose formidable challenges to layup designs. This paper presents an efficient inverse design framework for composite layups utilizing a variational autoencoder (VAE), which is applicable to non-conventional laminates. By leveraging the VAE's exceptional feature extraction and generative capabilities, the decoder rapidly produces layups with desired properties through controllable feature vectors. Based on the stacking characteristics of layups, multi-scale one-dimensional convolutions precisely extract sequence features relevant to mechanical properties and specific manufacturing constraints. A customized loss function is formulated to constrain the latent features, while addressing the non-uniqueness problem for layups with certain mechanical properties. The developed property-oriented VAE can generate 100,000 layups in seconds, achieving an average success rate of 66.9% under comprehensive in-plane and bending stiffness design, and remains effective for 100-ply thick laminate. For comparison, the VAE model outperforms the genetic algorithm and the logic-based method in reinforced panel designs, reducing the retrieval error by 46.4% and 38.1%, respectively. The proposed approach demonstrates flexible and efficient design advantages using generative machine learning models, and is easily extendable to other inverse design scenarios.

纤维增强复合材料提供了巨大的定制潜力,但其广泛的参数和复杂的耦合机制给层合设计带来了巨大的挑战。本文提出了一种基于变分自编码器(VAE)的复合材料分层反设计框架,该框架适用于非常规层压板。通过利用VAE出色的特征提取和生成能力,解码器通过可控的特征向量快速生成具有所需属性的布局。多尺度一维卷积基于层叠材料的堆叠特性,精确提取与力学性能和特定制造约束相关的序列特征。提出了一种自定义的损失函数来约束潜在特征,同时解决了具有一定力学性能的铺层的非唯一性问题。开发的面向性能的VAE可在秒内生成10万层,在综合面内和弯曲刚度设计下平均成功率达到66.9%,并且对100层厚的层压板仍然有效。相比之下,VAE模型在加固板设计中优于遗传算法和基于逻辑的方法,检索误差分别降低了46.4%和38.1%。该方法利用生成式机器学习模型展示了灵活高效的设计优势,并且易于扩展到其他逆向设计场景。


Anti-ballistic properties of hybrid UHMWPE fiber-reinforced composite armour

Jun Lin, Yongqiang Li, sheng Liu, Hualin Fan

doi:10.1016/j.compscitech.2024.110941

 

超高分子量聚乙烯纤维增强复合装甲的抗弹道性能

The ballistic performance of three hybrid composite plates, including ultra-high molecular weight polyethylene (UHMWPE), UHMWPE/Aramid, and UHMWPE/CFRP with similar surface density, was studied in the paper. These plates were tested under the impact of 7.62×25 mm full metal jacket (FMJ) bullets, with the dynamic back deformation (BFD) captured using Digital Image Correlation (DIC) technology. The effects of material combinations and striking faces on the dynamic response were discussed. The deformation and penetration mechanisms were analyzed using optical microscopy and micro-CT tomography. The results indicated that the UHMWPE/CFRP plate exhibited the lowest BFD, followed by UHMWPE and the UHMWPE/Aramid plate. When UHMWPE severed as the striking face, the fibers underwent through-thickness compression, which transitioned to in-plane tension and led to an elongated fracture of yarns. Similarly, Aramid fibers also experienced tensile fractures under similar conditions. In contrast, carbon fibers had brittle shear fractures when CFRP was the striking face. Additionally, the “V-shaped” cone traveling hinge velocity was calculated using DIC results, and the effects of the plate bending stiffness and wave impedance on protective performance were discussed. The findings emphasize the importance of an optimal material configuration to mitigate the propagation of compressive waves in the thickness direction and enhance bending stiffness, which is crucial for improving protection within ballistic limits.

研究了具有相似表面密度的超高分子量聚乙烯(UHMWPE)、超高分子量聚乙烯/芳纶和超高分子量聚乙烯/CFRP三种杂化复合材料的弹道性能。这些板在7.62×25 mm全金属夹套(FMJ)子弹的冲击下进行了测试,并使用数字图像相关(DIC)技术捕获了动态背变形(BFD)。讨论了材料组合和冲击面对动态响应的影响。利用光学显微镜和微ct断层扫描分析了其变形和穿透机理。结果表明,UHMWPE/CFRP板的BFD性能最低,其次是UHMWPE和UHMWPE/芳纶板。当UHMWPE作为冲击面切断时,纤维受全厚压缩,由全厚压缩过渡为面内拉伸,导致纱线伸长断裂。同样,在相似的条件下,芳纶纤维也发生了拉伸断裂。CFRP为冲击面时,碳纤维发生脆性剪切断裂。此外,利用DIC计算结果计算了“v”形锥移动铰链速度,并讨论了板的弯曲刚度和波阻抗对保护性能的影响。研究结果强调了优化材料配置的重要性,以减轻压缩波在厚度方向上的传播,并提高弯曲刚度,这对于提高弹道极限内的保护至关重要。


A superhydrophobic Fe3O4@MSN-PDMS based composite coating with icephobicity, long-term durability and self-healing property for anti-/de-icing

Lechun Deng, Zongwen Wang, Junzhi Wu, Xingshi Gu, Hao Yu, Yang Li, Yaru Cao, Fa Luo, Xianhu Liu, Qiang Chen

doi:10.1016/j.compscitech.2024.110937

 

一种基于Fe3O4@MSN-PDMS的超疏水复合涂层,具有疏冰性、长期耐久性和自愈性,用于防/除冰

Ice formation is a ubiquitous phenomenon in various fields and often leads to catastrophic consequence. Despite numerous anti-icing coating strategies have been exploited, there are still multiple roadblocks in the way of developing anti-icing coatings with durable and effective anti-/de-icing properties. In this work, Fe3O4 was coated in-situ with mesoporous silica nanoparticle (MSN), in which high dosage of polydimethylsiloxane (PDMS) was then loaded. As-obtained core-shelled Fe3O4@MSN-PDMS aggregates were incorporated into silicone resin to construct an NIR responsive anti-/de-icing coating via spraying method. The as-prepared coating exhibited superhydrophobicity (156.7 ° of water contact angle) and delayed icing to 412 s under -20 °C. Besides, the prepared coating could heat and release PDMS to constitute a PDMS/water double-layer lubricant under NIR irradiation, significantly reducing ice adhesion strength from 90.60 kPa to 12.04 kPa. Furthermore, the prepared coating demonstrates self-healing properties and high durability, releasing PDMS stored in the coating sustainably to heal the damaged coating surface and keeping superhydrophobicity after chemical etching and mechanical erosion. Finally, the de-icing applicability of the coating was validated using a homemade rotor wing model. Such core-shelled anti-/de-icing materials would provide theoretical basis and brand-new design strategy for development and application of anti-/de-icing materials.

结冰是各个领域普遍存在的现象,往往会导致灾难性的后果。尽管已经开发了许多防冰涂层策略,但在开发具有耐用和有效防/除冰性能的防冰涂层的道路上仍然存在许多障碍。本研究采用中孔二氧化硅纳米颗粒(MSN)原位包覆Fe3O4,并在其表面负载高剂量的聚二甲基硅氧烷(PDMS)。将获得的核壳Fe3O4@MSN-PDMS骨料加入到有机硅树脂中,通过喷涂方法构建近红外响应的防/除冰涂层。制备的涂层具有超疏水性(156.7°的水接触角),在-20°C下延迟结冰至412 s。此外,制备的涂层在近红外照射下可以加热释放PDMS,形成PDMS/水双层润滑剂,冰的粘附强度从90.60 kPa显著降低到12.04 kPa。此外,制备的涂层具有自修复性能和高耐久性,可以持续释放涂层中储存的PDMS来修复受损的涂层表面,并在化学蚀刻和机械侵蚀后保持超疏水性。最后,利用自制的旋翼模型验证了涂层的除冰适用性。这种芯壳式防除冰材料将为防除冰材料的开发和应用提供理论依据和全新的设计策略。



来源:复合材料力学仿真Composites FEM
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【新文速递】2024年9月17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 1 篇Composite StructuresBuckling optimization of Double-Double (DD) laminates with gradual thickness taperingDan Wang, Zhoucheng Su, Sridhar Narayanaswamy, Stephen W.L. Tsaidoi:10.1016/j.compstruct.2024.118568厚度逐渐变细的双双层(DD)层合板的屈曲优化Double-double (DD) laminates are promising replacements for conventional Quad laminates in aerospace applications because of their inherent design simplicity and, more importantly, the ease of tapering. However, the thickness thinning due to tapering will significantly increase the risk of buckling failure. In this paper, we proposed an implicit global &amp; local model for thickness tapering optimization of DD laminates to maximize buckling resistance under the given weight constraint or weight reduction under buckling constraints. Firstly, a global model is established for buckling load calculation, with material properties calculated from homogenization of local laminates using the classical laminate theory. Then, nodal repeats of a four-plies DD sub-laminate are chosen as design variables to interpolate the tapered thickness profile. Sensitivities of structural responses are calculated semi-analytically to achieve efficient gradient-based optimization. Tapering spacing constraints between adjacent thicknesses are introduced to mitigate the potential delamination due to the stress concentrations caused by sharp thickness variation at the cost of a reduced optimization effect. Finally, typical numerical examples show that DD laminates with optimal gradual thickness tapering can remarkably increase the structural buckling resistance or the weight reduction.双双(DD)层压板由于其固有的设计简单,更重要的是易于变细,在航空航天应用中有望取代传统的四层层压板。然而,由于变细导致的厚度变薄将显著增加屈曲破坏的风险。在本文中,我们提出了一个隐式的全局和局部模型来优化DD层压板的厚度变细,以在给定的重量约束下最大化屈曲抗力或在屈曲约束下减少重量。首先,建立了屈曲载荷计算的全局模型,利用经典的层合板理论,从局部层合板的均匀化角度计算材料性能;然后,选择四层DD亚层压板的节点重复次数作为设计变量来插值锥形厚度轮廓。采用半解析方法计算结构响应灵敏度,实现基于梯度的有效优化。引入相邻厚度之间的渐窄间距约束,以减轻由于厚度急剧变化引起的应力集中而导致的潜在分层,但代价是降低了优化效果。最后,通过典型的数值算例表明,采用最优渐变厚度的DD层压板可以显著提高结构的抗屈曲能力或减轻结构的重量。Multi-scale modeling of damage evolution for particle-filled polymer compositesTao Shen, Yuxuan Fang, Yujiao Zhang, Jia Lou, Jianke Dudoi:10.1016/j.compstruct.2024.118572颗粒填充聚合物复合材料损伤演化的多尺度建模In this study, a multi-scale modeling framework that spans from molecular chains to macroscopic structure was proposed for a typical particle-filled polymer composite (HTPB propellants). The cohesive zone model (CZM) is utilized in the RVE model of HTPB propellants to capture the debonding phenomena at the AP/HTPB interface. For the HTPB matrix, a free energy function based on the Gaussian chain network is employed. To depict the chain scission behavior, the phase fracture (PF) method along with gradient-damage theory is introduced. Subsequently, microscale fracture behavior under uniaxial tensile load was investigated based on the constructed RVE model, and a phenomenological macroscopic damage model was developed correspondingly. In this developed model, two damage factors related to the debonding of AP/HTPB interface and the growth of voids in matrix are introduced respectively. Thus, it can not only predict the macroscopic stress–strain response, but also can give the microscopic damage evolution information. Overall, this multi-scale modeling framework can offer us a deeper insight into the microstructural changes and the resulting macroscopic mechanical behavior of HTPB propellants.在本研究中,针对典型的颗粒填充聚合物复合材料(HTPB推进剂)提出了从分子链到宏观结构的多尺度建模框架。在HTPB推进剂的RVE模型中采用内聚区模型(CZM)来捕捉AP/HTPB界面的脱粘现象。对于HTPB矩阵,采用基于高斯链网络的自由能函数。为了描述断链行为,引入了相断裂法和梯度损伤理论。随后,基于构建的RVE模型,研究了单轴拉伸载荷作用下的微尺度断裂行为,建立了相应的现象学宏观损伤模型。在该模型中,分别引入了与AP/HTPB界面脱粘和基体空隙生长有关的两个损伤因素。因此,它不仅可以预测宏观应力应变响应,而且可以给出微观损伤演化信息。总的来说,这种多尺度建模框架可以让我们更深入地了解HTPB推进剂的微观结构变化和由此产生的宏观力学行为。Nanofluid minimum quantity lubrication assisted grinding force model considering anisotropy of SiCf/SiC ceramic matrix compositesQi Zhang, Ben Wang, Chang Song, Hao Wang, Tianlong Zhudoi:10.1016/j.compstruct.2024.118577考虑SiCf/SiC陶瓷基复合材料各向异性的纳米流体最小量润滑辅助磨削力模型SiCf/SiC ceramic matrix composites with excellent thermal stability, light weight and oxidation resistance have become key components in advanced aircraft engines. Nanofluid minimal quantity lubrication (NMQL) exhibits significant potential in enhancing heat transfer and lubrication efficiency during the grinding process. The technological challenge lies in thoroughly investigating the theoretical variation rule of grinding force, assisted by nanofluid minimal quantity lubrication, and subsequently achieving low-damage machining of SiCf/SiC composites. In this study, a prediction model for the grinding force during NMQL-assisted grinding was established, integrating diverse lubrication methods, grinding wheel geometric parameters, wear degree, process parameters, the anisotropy and damage degree of SiCf/SiC composites. The model was subsequently experimentally validated through grinding tests conducted on SiCf/SiC composites under various conditions, including dry grinding (DG), flood grinding (FG), minimum quantity lubrication (MQL), and carbon nanotube nanofluids (NMQL-CNTs), across multiple grinding depths. The present investigation’s grinding force forecasting model is evidenced to possess high accuracy of precision, showcasing mean deviations of 6.64 % and 11.97 % in the perpendicular (Fn) and tangential (Ft) grinding force components, respectively. Additionally, employing NMQL-CNTs facilitates the achievement of minimal grinding force and surface finish quality. At depths of 0.4 mm and 0.6 mm during grinding, the mean Fn magnitudes under the NMQL-CNTs lubrication approach underwent a decrease of 66.7 % and 74.5 %, respectively, in contrast, the mean Ft magnitudes experienced a reduction of 55 % and 67.2 %, correspondingly, in comparison to the DG lubrication technique. Notwithstanding the consistency in the material’s brittle removal mechanism across varying lubrication strategies, the NMQL-CNTs approach effectively alleviates fiber abrasion. Concisely, the research presented herein provides foundational theoretical insights and practical technological assistance for the achievement of low damage SiCf/SiC composite processing.SiCf/SiC陶瓷基复合材料具有优异的热稳定性、重量轻、抗氧化性能,已成为先进航空发动机的关键部件。纳米流体最小量润滑(NMQL)在提高磨削过程的传热和润滑效率方面具有显著的潜力。该技术的挑战在于深入研究磨削力的理论变化规律,并辅以纳米流体的微量润滑,从而实现SiCf/SiC复合材料的低损伤加工。在本研究中,综合多种润滑方式、砂轮几何参数、磨损程度、工艺参数、SiCf/SiC复合材料各向异性和损伤程度,建立了nmql辅助磨削磨削力预测模型。随后,对SiCf/SiC复合材料进行了多种条件下的磨削试验,包括干式磨削(DG)、洪式磨削(FG)、最小量润滑(MQL)和碳纳米管纳米流体(NMQL-CNTs),并在多个磨削深度下对模型进行了实验验证。所建立的磨削力预测模型具有较高的精度,在磨削力垂直分量(Fn)和切向分量(Ft)上的平均偏差分别为6.64 %和11.97 %。此外,采用NMQL-CNTs有助于实现最小的磨削力和表面光洁度质量。在磨削深度为0.4 mm和0.6 mm处,与DG润滑相比,NMQL-CNTs润滑方式下的Fn平均强度分别降低了66.7 %和74.5 %,而Ft平均强度分别降低了55 %和67. %。尽管在不同的润滑策略中材料的脆性去除机制是一致的,但NMQL-CNTs方法有效地减轻了纤维磨损。总之,本文的研究为实现低损伤SiCf/SiC复合材料的加工提供了基础的理论见解和实际的技术支持。Elasticity solutions for functionally graded beams with arbitrary distributed loadsChangwei Tang, Guansuo Dui, Yuyao Fudoi:10.1016/j.compstruct.2024.118578具有任意分布荷载的功能梯度梁的弹性解This paper derives the exact general elasticity solution for functionally graded rectangular beams subjected to arbitrary normal and tangential loads and with arbitrary end constraints. The general solution consists of bending moments and their integrals and derivatives, along with load-independent function sequences of the longitudinal coordinate. The method for determining function sequences has been established based on the stress function method. General solution formulas for stresses, strains and displacements have been derived and used to solve explicit special solutions for six cases involving concentrated forces, uniformly loads, and quadratically distributed loads with different displacement constraints scenarios. The results obtained are compared with existing exact solutions and those of Euler–Bernoulli and Timoshenko beams, and the errors of the latter two are analysed.本文导出了在任意法向和切向荷载作用下具有任意端部约束的功能梯度矩形梁的精确一般弹性解。通解包括弯矩及其积分和导数,以及纵坐标的与荷载无关的函数序列。在应力函数法的基础上,建立了确定功能序列的方法。推导了应力、应变和位移的通解公式,并将其用于求解具有不同位移约束的集中力、均匀载荷和二次分布载荷六种情况下的显式特解。将所得结果与已有的精确解以及Euler-Bernoulli和Timoshenko光束的精确解进行了比较,并对后两者的误差进行了分析。Design-manufacturing-performance of electromagnetic absorbing/load bearing three-dimensional honeycomb woven compositesWenbin Yao, Xinghai Zhou, Yuan Gao, Yongfang Qian, Lihua Lyudoi:10.1016/j.compstruct.2024.118581电磁吸收/承载三维蜂窝编织复合材料的设计制造与性能研究Structural electromagnetic wave (EMW) absorbing composites play a critical role in both civilian and military applications. However, traditional sandwich honeycomb EMW absorbing composites have poor out-of-plane mechanical properties and load-bearing performance.This study introduces the development of a three-dimensional honeycomb woven composite (3DHWC) that integrates EMW absorption and load-bearing capabilities. A weaving loom was used to fabricate a three-dimensional honeycomb woven structure fabric (3DHSWF) with varying structural parameters. Subsequently, the composites were formed using carbon black (CB), multi-walled carbon nanotubes (MWCNTs), and carbonyl iron powder (CIP) as hybrid absorbers, epoxy resin as the matrix, combined with the vacuum-assisted resin transfer molding (VARTM) process. Testing confirmed the material’s excellent EMW absorption and mechanical properties, achieving a maximum reflection loss (RL) of −30.9 dB and an adequate EMW absorption bandwidth (EAB) of 14.58 GHz. The maximum bending load reached 5799.1 N, with no delamination observed in the samples. This material demonstrates outstanding EMW absorption performance and exhibits superior load-bearing capacity while maintaining structural integrity. Our research provides valuable insights into the design of honeycomb EMW absorbing composites, offering significant advancements in EMW absorption efficiency and bending mechanical properties.结构电磁波吸波复合材料在民用和军用领域都发挥着重要作用。然而,传统的夹层蜂窝吸波复合材料的面外力学性能和承载性能较差。本研究介绍了一种集EMW吸收和承载能力于一体的三维蜂窝编织复合材料(3DHWC)的开发。利用织布机制备了具有不同结构参数的三维蜂窝结构织物(3DHSWF)。随后,以炭黑(CB)、多壁碳纳米管(MWCNTs)和羰基铁粉(CIP)为杂化吸收剂,环氧树脂为基体,结合真空辅助树脂传递模塑(VARTM)工艺制备复合材料。测试证实该材料具有优异的EMW吸收和机械性能,最大反射损耗(RL)为−30.9 dB, EMW吸收带宽(EAB)为14.58 GHz。最大弯曲载荷达到5799.1 N,样品未出现分层现象。这种材料具有出色的EMW吸收性能,在保持结构完整性的同时具有优越的承载能力。我们的研究为蜂窝吸收EMW复合材料的设计提供了有价值的见解,在EMW吸收效率和弯曲力学性能方面取得了重大进展。Investigation of the degradation over steel/GFRP single lap joint: UV radiation and immersion at different temperaturesHiasmim Rohem Gualberto, João Marciano Laredo dos Reis, Mônica Calixto de Andrade, Hector Reynaldo Meneses Costa, Domenio de Souza Faria, Julian David Hunt, Felipe do Carmo Amorimdoi:10.1016/j.compstruct.2024.118590钢/玻璃钢单搭接接头的降解研究:不同温度下的紫外线辐射和浸渍Adhesive joints with composite components are used in various fields and under diverse environmental conditions. Exposure to UV radiation, temperature fluctuations, and immersion in different mediums can influence their performance. This study focuses on the degradation of steel/GFRP (glass fiber reinforced polymer) adhesive joints by immersing them in distilled and salt water at three different temperatures (40 °C, room temperature, and 4 °C), with and without prior exposure to UV radiation. Water absorption over time was evaluated under different degradation conditions, studying the absorption of the joints, composite, and adhesive, both individually and in combination. Mechanical shear tests on the joints and three-point bending tests on the composites were conducted, along with an assessment of failure modes influenced by water absorption and UV degradation. The results indicate that immersion temperature affects water absorption, post-curing, and the stiffness of the matrix and polymers, while UV radiation promotes post-curing and facilitates water absorption. The combined degradation conditions exhibit different effects on the materials compared to individual degradation, highlighting the complexity of service environmental conditions.具有复合构件的粘接接头用于各种领域和各种环境条件。暴露于紫外线辐射、温度波动和浸泡在不同的介质中都会影响它们的性能。本研究的重点是通过将钢/GFRP(玻璃纤维增强聚合物)粘合接头浸泡在三种不同温度(40 °C,室温和4 °C)的蒸馏水和盐水中,并事先暴露在紫外线辐射下和不暴露在紫外线辐射下,来降解钢/GFRP(玻璃纤维增强聚合物)粘合接头。在不同的降解条件下,评估了吸水率随时间的变化,研究了接头、复合材料和粘合剂的吸水率,无论是单独的还是组合的。对接头进行了力学剪切试验,对复合材料进行了三点弯曲试验,并对吸水率和紫外线降解对复合材料破坏模式的影响进行了评估。结果表明,浸没温度影响基体和聚合物的吸水率、后固化率以及刚度,而紫外线辐射促进后固化并促进吸水率。与单独降解相比,复合降解条件对材料的影响不同,凸显了服役环境条件的复杂性。Composites Part A: Applied Science and ManufacturingPhysics-informed machine learning for loading history dependent fatigue delamination of composite laminatesLiaojun Yao, Jiexiong Wang, Mingyue Chuai, Stepan V. Lomov, V. Carvellidoi:10.1016/j.compositesa.2024.108474基于物理的复合材料层合板加载历史疲劳分层的机器学习Fiber bridging has retardation effect on Mode I fatigue delamination, making the damage loading history dependent. This research creates a physics-informed machine learning (ML) model for characterizing this fatigue delamination propagation. After a training, the model can predict fatigue crack growth rate for a given crack length, accounting for a certain amount of bridging fibers. Mode I fatigue experiments were first performed to obtain sufficient data for the ML. A semi-empirical Paris-type correlation determines fatigue damage evolution with bridging retardation. This correlation was integrated as a physical constraint into the physics-informed neural network (PINN). PINN demonstrates excellent performance: the predictions of the delamination fall within a narrow scatter band of 1.5 times by crack growth rate, outperforming both the non-physics-informed ML model and the Paris-type correlation. The proposed ML model can be applied for the development, characterization and comparison of composite materials, and for composite structure design and life evaluation.纤维桥接对I型疲劳分层有阻滞作用,使损伤加载历史具有依赖性。本研究创建了一个物理信息的机器学习(ML)模型来表征这种疲劳分层传播。经过训练后,该模型可以预测在给定裂纹长度下,在桥接纤维数量一定的情况下,疲劳裂纹的扩展速率。首先进行了I型疲劳试验,以获得足够的数据。半经验paris型相关性确定了疲劳损伤随桥接延迟的演变。这种相关性作为物理约束集成到物理信息神经网络(PINN)中。PINN表现出优异的性能:分层的预测落在裂缝增长率的1.5倍的窄散射带内,优于非物理信息ML模型和paris型相关。该模型可用于复合材料的开发、表征和比较,以及复合材料的结构设计和寿命评估。来源:复合材料力学仿真Composites FEM

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