首页/文章/ 详情

【新文速递】2024年12月14日复合材料SCI期刊最新文章

4天前浏览17
 
 

今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 3 篇,Composites Part B: Engineering 3 篇,Composites Science and Technology 1 篇

Composite Structures

Investigating the mode one interlaminar performance of semi-woven 3D printed hybrid composites

Cheng Huang, Michael Norton, Mathew W. Joosten

doi:10.1016/j.compstruct.2024.118802

研究半编织3D打印杂化复合材料的模一层间性能

Interlaminar performance governs a composites’ ability to resist delamination and cracking between layers. It’s hypothesized that the interlaminar fracture toughness of hybrid composites exhibit a linear relationship with the fibre composition content. To validate the hypothesis, the interlaminar performance of 3D printed intraply hybrid semi-woven composites was investigated using double cantilever beam (DCB) samples in the present study. The hybrid composites were fabricated from two types of tow-preg filaments that consist of either carbon or glass fibres impregnated with polyamide, referred to as low elongation (LE) and high elongation (HE) materials respectively. The experimental results of propagation interlaminar fracture toughness of semi-woven hybrid composites aligns well with the linear rule of mixtures (ROM) predictions. Scanning electron microscopy (SEM) provided microstructural insights into fracture mechanisms, exhibiting different fracture surface features that varied with the ratio of low elongation (LE) material. These findings show that the linear ROM can predict the interlaminar performance of semi-woven intraply hybrid composites based on the material properties of the constituent material properties, offering a straightforward method for optimising fracture toughness by adjusting the ratio of fibres within the composite structure.

层间性能决定了复合材料抵抗层间分层和开裂的能力。假设混杂复合材料的层间断裂韧性与纤维组分含量呈线性关系。为了验证这一假设,本研究采用双悬臂梁(DCB)样品对3D打印层间混杂半编织复合材料的层间性能进行了研究。杂化复合材料由两种类型的低延伸(LE)和高延伸(HE)材料制成,分别由碳或玻璃纤维浸渍聚酰胺组成。半编织混杂复合材料层间断裂韧度的实验结果与线性混合规律(ROM)的预测结果吻合较好。扫描电子显微镜(SEM)提供了断裂机制的微观结构洞察,显示出不同的断口表面特征随低延伸率(LE)材料比例的变化而变化。这些发现表明,线性ROM可以根据组成材料的材料性能预测半编织层间混杂复合材料的层间性能,为通过调整复合材料结构中纤维的比例来优化断裂韧性提供了一种直接的方法。


Composites Part A: Applied Science and Manufacturing

Enhancing honeycomb surface quality by harnessing vortex effect in electrochemical grinding

Zhenghui Ge, Maolong Chen, Rui Wang, Bing Zhang, Yongwei Zhu

doi:10.1016/j.compositesa.2024.108641

利用电化学磨削中的涡流效应提高蜂窝表面质量

Superalloy honeycomb structures have been widely used in aerospace components due to its excellent mechanical and physical performances. Electrochemical grinding offers great potential in reducing honeycomb core defects. However, the porous characteristics pose new machining challenges like excessive corrosion. Herein, the vortex effect generated by the honeycomb pores was investigated to restrain excessive corrosion, thereby effectively improving the honeycomb surface quality. Simulation results indicate that the flow field on honeycomb surfaces significantly differ from solid surfaces, with the electrolyte injection angle playing a crucial role in influencing the vortex effect. The electrolyte injection angle of 50° has been optimized to enhance the vortex effect, which promote the residue accumulation and reduce excessive corrosion. Experimental results demonstrate that the maximum excessive corrosion depth can be significantly reduced from around 70 μm to less than 20 μm. This research provides valuable insights into leveraging the vortex effect for advanced honeycomb components.

高温合金蜂窝结构由于其优异的力学性能和物理性能,在航空航天部件中得到了广泛的应用。电化学磨削在减少蜂窝芯缺陷方面具有很大的潜力。然而,多孔特性带来了新的加工挑战,如过度腐蚀。本文研究了蜂窝孔产生的涡流效应来抑制过度腐蚀,从而有效改善蜂窝表面质量。仿真结果表明,蜂窝表面的流场与固体表面的流场存在显著差异,其中电解质注入角度对旋涡效应的影响至关重要。优化了50°的电解液注入角,增强了涡流效应,促进了残渣的积累,减少了过度腐蚀。实验结果表明,最大过腐蚀深度可以从70 μm左右显著降低到20 μm以下。这项研究为利用先进蜂窝部件的涡流效应提供了有价值的见解。


Investigation of hole quality Enhancement in new glass/flax laminates via hybrid drilling techniques

Hao Ye, Jiong Zhang, Yunshu Shang, Guiyin Xu, Jiaming Zhan, Steven Marguet, Habiba Bougherara, Redouane Zitoune, Hao Wang

doi:10.1016/j.compositesa.2024.108651

复合钻孔技术提高新型玻璃/亚麻层压板孔质量的研究

Flax/epoxy composites are commonly used natural fibre-reinforced materials with potential applications in aviation, automotive, and marine industries. To enhance the mechanical and hygrothermal properties of flax/epoxy laminates, glass/epoxy layers are incorporated, creating a novel glass/flax composite. However, drilling this composite encounters some problems, particularly due to poor hole quality and insufficient understanding of the associated damage mechanisms. Hence, this study systematically addresses these problems via various drilling conditions, including dry drilling, drilling with backup support, cryogenic drilling, and hybrid drilling methods. The drilling force and machining quality such as delamination, surface roughness and topography of the hole were studied. Moreover, multi-scale damage characterization was performed using micro-computed tomography (micro-CT) and scanning electron microscopy (SEM). Delamination was classified into two types according to its shape and distribution. Analysis of the defects reconstructed by the micro-CT method revealed that the hybrid drilling reduces the delamination volumes of the entry and the exit by 64.8% and 78.9%, respectively, compared to those in dry drilling.

亚麻/环氧复合材料是一种常用的天然纤维增强材料,在航空、汽车和海洋工业中具有潜在的应用前景。为了增强亚麻/环氧层压板的机械和湿热性能,加入了玻璃/环氧层,创造了一种新型的玻璃/亚麻复合材料。然而,钻井这种复合材料会遇到一些问题,特别是由于井眼质量差和对相关损伤机制的了解不足。因此,本研究通过各种钻井条件系统地解决了这些问题,包括干钻、后备支撑钻井、低温钻井和混合钻井方法。研究了钻孔力和加工质量,如孔的分层、表面粗糙度和形貌。此外,使用微计算机断层扫描(micro-CT)和扫描电子显微镜(SEM)进行了多尺度损伤表征。分层根据其形态和分布可分为两种类型。通过显微ct重建缺陷分析发现,与干钻相比,混合钻可使入口和出口的分层体积分别减少64.8%和78.9%。


Robust flexural performance of modified bamboo through strategic delignification and carboxymethyl cellulose modification

Yuchen Ben, Hongyun Luo, Wen Liu, Ziyu Ba, Jie Cui, Zhaoliang Guo, Renshan Sun

doi:10.1016/j.compositesa.2024.108655

通过战略性脱木质素和羧甲基纤维素改性改性竹子的强健弯曲性能

Developing sustainable structural materials from biological sources is highly essential. In this study, a simple three-step method, involving “alkali treatment − carboxymethyl cellulose (CMC) modification − convection drying” was introduced to fabricate high-performance bamboo materials. By strategically controlling the alkali treatment time at room temperature, an optimized lignin content was obtained. Meanwhile, further incorporation of green binding agent CMC facilitates the formation of hydrogen bonds, thereby improved the interfacial bonding strength. The modified bamboo exhibits robust flexural properties, with a flexural strength reaching three times that of natural bamboo, measuring at 418 MPa. By employing acoustic emission technology and fracture micromorphology analysis, the influence of hydrogen bonds in enhancing load transmission at the interface was revealed. This work proposes a green modification strategy for bamboo materials to enhance mechanical performance, broadening the application of bamboo in the field of green manufacturing ranging from construction to transportation.

从生物来源开发可持续的结构材料是非常必要的。采用碱处理-羧甲基纤维素(CMC)改性-对流干燥三步法制备高性能竹材料。通过对常温下碱处理时间的控制,获得了最佳的木质素含量。同时,绿色结合剂CMC的进一步掺入有利于氢键的形成,从而提高了界面的结合强度。改性竹具有强健的抗弯性能,抗弯强度达到天然竹的3倍,测量值为418 MPa。通过声发射技术和裂纹微观形貌分析,揭示了氢键在界面处增强载荷传递的影响。本文提出了一种提高竹材料力学性能的绿色改性策略,拓宽了竹在绿色制造领域的应用范围,从建筑到交通运输。


Composites Part B: Engineering

Microstructure and damage evolution in short carbon fibre 3D-printed composites during tensile straining

José Humberto S. Almeida, Arttu Miettinen, Fabien Léonard, Brian G. Falzon, Philip J. Withers

doi:10.1016/j.compositesb.2024.112073

短碳纤维3d打印复合材料在拉伸应变过程中的微观结构与损伤演化

Short-fibre thermoplastic composites offer a balance between cost, processability, and performance, as well as providing a use for recycled fibres making them attractive in various industrial applications. However, the fibres tend to be misaligned due to their low aspect ratio, which can impact mechanical performance. This work examines the as-manufactured microstructure of a chopped carbon fibre-reinforced nylon composite made by material extrusion additive manufacturing in terms of fibre misalignment, void content, shape and distribution before going on to determine its effect on damage evolution under tensile straining by in-situ time-lapse synchrotron computed tomography (CT). To this end, CT scans have been acquired at various stages throughout straining. A high degree of fibre alignment is observed with ≈ 86% within 14 ∘ of the extrusion axis, giving a Krenchel orientation factor of 0.75. The time-lapse CT image sequence reveals that because the mean fibre length ( ≈ 98 μ m .) is below the critical fibre length fibre fracture does not take place during plastic straining. Instead, failure occurs during straining from pre-existing voids and newly nucleated ones mainly located at fibre ends, their growth and coalescence. The experimental elastic modulus and strength are compared against the Cox-Krenchel and Kelly-Tyson analytical models that take into account fibre misalignment and length, which demonstrates that the fibre orientation is sufficient and future improvements in properties could be achieved by reducing the initial void content ( ≈ 2.3%) and increasing the length and volume fraction of the reinforcing fibres.

短纤维热塑性复合材料在成本、可加工性和性能之间取得了平衡,并为回收纤维提供了一种用途,使其在各种工业应用中具有吸引力。然而,由于其低纵横比,纤维往往会错位,这可能会影响机械性能。本研究考察了材料挤压增材制造的短切碳纤维增强尼龙复合材料在纤维错位、空隙含量、形状和分布方面的制造微观结构,然后通过原位延时同步加速器计算机断层扫描(CT)确定其对拉伸应变下损伤演变的影响。为此,在整个拉伸过程的各个阶段都获得了CT扫描。在距挤压轴14°的范围内,可以观察到高度约86%的纤维取向,因此克伦切尔取向系数为0.75。延时CT图像序列显示,由于纤维的平均长度(≈98 μ m)小于临界长度,纤维在塑性应变过程中没有发生断裂。相反,破坏发生在主要位于纤维末端的先前存在的空洞和新成核的拉伸过程中,它们的生长和合并。将实验弹性模量和强度与考虑纤维错位和长度的Cox-Krenchel和Kelly-Tyson分析模型进行了比较,结果表明纤维取向是充分的,未来可以通过降低初始空隙含量(≈2.3%)和增加增强纤维的长度和体积分数来改善性能。


Preparation of Continuous Glass Fiber Reinforced PEEK Filaments and High-Temperature Performance for Additive Manufacturing

Hao Zhang, Yiwei Chen, Wenzhe Song, Jinghua Zheng, Congze Fan, Zhongde Shan, Yuejie Wen, Xize Wang

doi:10.1016/j.compositesb.2024.112078

连续玻璃纤维增强PEEK长丝的制备及其增材制造的高温性能

Aerospace composite components are moving towards structural-functional integration. Aircraft conformal radomes, for example, are required to meet stringent criteria for structural support and dielectric performance under aerothermal conditions. Additively manufactured continuous glass fiber-reinforced polyetheretherketone (CGF/PEEK) shows promising application prospects due to its high-temperature resistance, excellent dielectric properties, and high forming flexibility. In this study, a set of CGF/PEEK prepreg filament forming equipment was designed, and the influence of process parameters on the forming quality of CGF/PEEK prepreg filaments was analyzed. Subsequently, CGF/PEEK components were additively manufactured, and their mechanical and dielectric properties under high-temperature environments were investigated. The failure mechanism and performance evolution with increasing temperature were revealed. At 250 °C, the tensile strength of the samples decreases by 27.6%, and the flexural strength decreases by 69.7%. The obtained data and theoretical insights contribute to a foundational understanding of the application of CGF/PEEK additive manufacturing components, particularly in high-temperature service conditions prevalent in the aerospace field.

航空航天复合材料部件正朝着结构功能一体化的方向发展。例如,飞机的保形天线罩需要在空气热条件下满足严格的结构支撑和介电性能标准。增材制造的连续玻璃纤维增强聚醚醚酮(CGF/PEEK)具有耐高温、优异的介电性能和较高的成型柔韧性,具有广阔的应用前景。设计了一套CGF/PEEK预浸长丝成型设备,分析了工艺参数对CGF/PEEK预浸长丝成型质量的影响。随后,通过增材制造CGF/PEEK组件,并对其在高温环境下的力学性能和介电性能进行了研究。揭示了其破坏机理和性能随温度升高的演化规律。在250℃时,试样的抗拉强度下降了27.6%,抗折强度下降了69.7%。获得的数据和理论见解有助于对CGF/PEEK增材制造组件应用的基本理解,特别是在航空航天领域普遍存在的高温服务条件下。


Composites Science and Technology

Concurrent Enhanced Energy Density and Efficiency in a Novel Designed Asymmetric Four-Layer Structure Composite Film via Macro-Interface Regulation

Yongjing Zhang, Ying Lin, Yanlong Ma, Qibin Yuan, Haibo Yang

doi:10.1016/j.compscitech.2024.111013

基于宏观界面调控的新型非对称四层复合材料膜的能量密度和效率提高

With the development of renewable energy sources, dielectric capacitors play a pivotal role in energy conversion devices. However, the current commercial dielectric film materials, due to their low energy density, struggle to meet the requirements for device miniaturization and modularization. In recent years, significant improvements in the discharged energy density (Ue) of composite films have been achieved through the incorporation of various ceramic fillers and the design of topological layer structures. Nonetheless, the energy storage efficiency (η) of these composite films remains low due to inevitable energy loss at the ceramic-polymer micro-interface, limiting their large-scale commercial application. To address this issue, our work introduces a novel strategy: by designing an asymmetric multilayer structure, multiple macro-interfaces are introduced to replace some of the micro-interfaces within composite films, thereby reducing energy loss and enhancing η. Specifically, we propose an innovative asymmetric four-layer structure composite film, which achieves a stellar Ue value of 34.54 J cm-3 and an unprecedented η value of 95.82% at 660 MV m-1. This design adequately reduces the adverse impact of internal micro-interfaces on the energy storage characteristics of the composite films, achieving the optimal integrated energy storage performance so far.

随着可再生能源的发展,介电电容器在能量转换设备中扮演着关键角色。然而,由于现有商业化介电薄膜材料的能量密度较低,它们难以满足设备微型化和模块化的要求。近年来,通过采用各种陶瓷填料和设计拓扑层结构,复合薄膜的放电能量密度(Ue)得到了显著提高。然而,由于陶瓷-聚合物微界面不可避免的能量损失,这些复合薄膜的能量存储效率(η)仍然较低,限制了它们的大规模商业应用。为了解决这一问题,我们的工作提出了一种新的策略:通过设计非对称多层结构,在复合薄膜中引入多个宏观界面,以替代其中的一些微界面,从而减少能量损失并提高η。具体来说,我们提出了一种创新的非对称四层结构复合薄膜,在660 MV m-1下实现了34.54 J cm-3的卓越Ue值和前所未有的95.82%的η值。该设计有效地降低了复合膜内部微界面对能量存储特性的不利影响,实现了迄今为止最佳的集成能量存储性能。



来源:复合材料力学仿真Composites FEM
ACTMechanicalAdditiveSystem断裂复合材料化学航空航天汽车建筑电子UG裂纹理论材料多尺度控制
著作权归作者所有,欢迎分享,未经许可,不得转载
首次发布时间:2024-12-18
最近编辑:4天前
Tansu
签名征集中
获赞 6粉丝 0文章 795课程 0
点赞
收藏
作者推荐

【新文速递】2024年11月29日固体力学SCI期刊最新文章

今日更新:Journal of the Mechanics and Physics of Solids 2 篇,Mechanics of Materials 1 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 3 篇Journal of the Mechanics and Physics of SolidsRate dependency and fragmentation response of phase field models with micro inertia and micro viscosity termsGiang D. Huynh, Reza Abedidoi:10.1016/j.jmps.2024.105971含微惯性和微粘度项的相场模型的速率依赖性和破碎响应We present elliptic, parabolic, and hyperbolic phase field (PF) equations, referred to as EPF, PPF, and HPF, for cohesive zone model (CZM) and Linear Elastic Fracture Mechanics (LEFM) PF models. The micro viscosity and micro inertia terms result in PPF and HPF, that can be solved explicitly in time. The additional advantage of the HPF is implying a finite damage propagation speed and a more favorable time advance limit. The desired micro-viscosity for the HPF is shown to correspond to a damping factor of one. The appropriate length and time scales, nondimensional equations, and (asymptotic) strain-stress solutions are provided for each differential equation. Two sources of rate sensitivity are discussed. First, when the fields are spatially uniform (0D solution) the rate effect arises from the form of differential equation. Asymptotic solutions show that at high loading rates, the energy dissipation has the rates of 2/3 and 1 for the PPF and HPF, respectively, with the former matching the Grady’s rate-sensitivity. The dynamic strength and failure strain show half of this rate. The analysis is extended to damage models with stress-based and bounded driving forces. Second, the rate effect arises from the deviation of 1D from 0D solutions as the damage exceeds a critical value and fragments form. Since this critical value tends to zero for quasi-static loading, this rate-effect is mainly present for low loading rates. This results in lower- and upper-shelf energy limits for the EPF at low and high loading rates, resembling some experimentally observed sigmoidal rate models for energy dissipation.我们提出了椭圆,抛物线和双曲相场(PF)方程,即EPF, PPF和HPF,用于内聚区模型(CZM)和线性弹性断裂力学(LEFM) PF模型。微粘度项和微惯性项导致了可及时显式求解的PPF和HPF。HPF的另一个优点是意味着有限的损伤传播速度和更有利的时间提前限制。HPF所需的微粘度对应于阻尼系数为1。为每个微分方程提供了适当的长度和时间尺度、无量纲方程和(渐近)应变-应力解。讨论了速率敏感性的两个来源。首先,当场是空间均匀的(0D解)时,速率效应由微分方程的形式产生。渐近解表明,在高加载速率下,PPF和HPF的能量耗散率分别为2/3和1,前者符合Grady的速率敏感性。动强度和破坏应变为该速率的一半。将分析扩展到基于应力和有界驱动力的损伤模型。其次,当损伤超过临界值并形成碎片时,由于1D与0D溶液的偏差而产生速率效应。由于该临界值在准静态加载时趋于零,因此这种速率效应主要出现在低加载速率下。这导致EPF在低和高加载速率下的下架和上架能量限制,类似于一些实验观察到的能量耗散的s型速率模型。Thermomechanical coupling during large strain deformation of polycarbonate: Experimental studyPeihao Song, David Chapman, Aaron Graham, Akash Trivedi, Clive Siviourdoi:10.1016/j.jmps.2024.105976聚碳酸酯大应变变形时的热-机耦合实验研究Polycarbonate is a widely used ductile glassy polymer that can undergo large strain deformation before failure. During the plastic deformation process, some mechanical energy is converted to heat, which, if the specimen is loaded at rates sufficient that the heat cannot conduct out of the material, can result in significant temperature rises that affect the mechanical response. Typically, this is expected to result in a reduction in stress at large strain, compared to the behaviour under isothermal conditions; however, compared to other glassy polymers, it has been observed that less softening than expected is experienced in polycarbonate at high strain rates. The current paper describes a thorough investigation of temperature rises in polycarbonate. Compression experiments are performed using a screw-driven machine, a hydraulic machine, and a long split Hopkinson bar, all instrumented with a high-speed infrared camera to measure temperature rises at strain rates between 0.01 and 2600 s-1 at a starting temperature around 20°C. Further, temperature rises in compression experiments at 0.5 s-1 and starting temperatures between -80 to 150°C are measured using embedded thermocouples. These span the range of the secondary- to glass-transitions of polycarbonate, allowing investigation of the effect of these transitions. These experiments are supported by finite element simulations, which use a phenomenological viscoplastic model, to ensure the thermal boundary conditions are adiabatic. Temperature rises are observed in both temperature and rate-dependent tests: experiments at higher strain rates and lower temperatures experience a greater temperature rise because of the higher yield stress; however, there are differences in the conversion ratio between plastic work and heat (Taylor Quinney coefficient), which is both temperature and rate dependent, and strongly affected by both the secondary and glass transitions.聚碳酸酯是一种广泛使用的延展性玻璃状聚合物,在破坏前可以承受较大的应变变形。在塑性变形过程中,一些机械能被转化为热量,如果试样的加载速度足以使热量不能从材料中传导出去,则会导致显著的温度升高,从而影响机械响应。通常,与等温条件下的行为相比,这有望导致大应变下应力的降低;然而,与其他玻璃状聚合物相比,已经观察到聚碳酸酯在高应变速率下的软化比预期的要少。本文对聚碳酸酯的温升进行了深入的研究。压缩实验采用螺杆机、液压机和长裂霍普金森杆进行,均配有高速红外摄像机,测量了在20℃左右的起始温度下,应变速率在0.01 ~ 2600 s-1之间的温升。此外,使用嵌入式热电偶测量了0.5 s-1压缩实验中的温升和-80至150°C之间的起始温度。这些跨越了聚碳酸酯的二级到玻璃转变的范围,允许研究这些转变的影响。为了确保热边界条件是绝热的,这些实验得到了有限元模拟的支持,该模拟使用了现象学粘塑性模型。在温度和速率相关的试验中都观察到温升:由于屈服应力较高,在较高应变率和较低温度下的实验经历了较大的温升;然而,塑料功与热之间的转换率(泰勒昆尼系数)存在差异,这既取决于温度也取决于速率,并且受到二次和玻璃化转变的强烈影响。Mechanics of MaterialsEnhancing strength-ductility synergy of multilayer metals by periodic necking: experiments and simulationsJianfeng Zhao, Baoxi Liu, Wenxing Yu, Zengmeng Lin, Xiaochong Lu, Xu Zhang, Hui Chendoi:10.1016/j.mechmat.2024.105210利用周期性颈缩增强多层金属的强度-延性协同效应:实验与模拟Multilayer metals are typical heterostructured materials where superior strength-ductility synergy is sought by combining materials with significant mismatches in mechanical properties. Strain delocalization has been identified as a pivotal mechanism for improving their ductility. However, the strategy for achieving this enhancement through manipulating the critical geometrical and mechanical factors pertaining to multilayer materials remains unclear. In this study, the uniaxial tensile behavior of multilayer TWIP/maraging steels is investigated through experiments, which unveil periodic necking-assisted plasticity regulated by the properties of constituent materials, rendering the multilayer steel both strong and ductile (Ultimate strength∼1.5GPa, fracture strain∼15%). To explore optimized strategies for enhancing this advantage, detailed finite element simulations are performed on the tensile deformation of multilayer TWIP/maraging steels with varying geometrical and mechanical parameters. The formation of periodic necks observed in experiments is successfully reproduced by employing a ductile damage model for the constituent material and a cohesive zone model for the interface. Comprehensive simulation results revealed that within the parameter range studied in this work, the layer thickness ratio is the most relevant factor dominating the strength-ductility synergy, while the layer thickness, interface strength, interface thickness, and strain hardening ability of the TWIP steel mainly affect the ductility rather than strength. This research contributes to our understanding of ductility mediated by strain delocalization and provides valuable insights for the design of multilayer metals.多层金属是典型的异质结构材料,通过将力学性能显著不匹配的材料组合在一起,寻求优异的强度-延性协同效应。应变离域已被确定为提高其延性的关键机制。然而,通过操纵与多层材料有关的关键几何和机械因素来实现这种增强的策略仍不清楚。在本研究中,通过实验研究了多层TWIP/马氏体时效钢的单轴拉伸行为,揭示了由组成材料性能调节的周期性颈状辅助塑性,使多层钢具有强韧性(极限强度~ 1.5GPa,断裂应变~ 15%)。为了探索增强这一优势的优化策略,对不同几何和力学参数的多层TWIP/马氏体时效钢的拉伸变形进行了详细的有限元模拟。利用组成材料的延性损伤模型和界面的内聚区模型成功地再现了实验中观察到的周期性颈部的形成。综合模拟结果表明,在本文研究的参数范围内,层厚比是主导强度-延性协同效应的最相关因素,而TWIP钢的层厚、界面强度、界面厚度和应变硬化能力主要影响延性而非强度。该研究有助于我们对应变离域介导的延性的理解,并为多层金属的设计提供了有价值的见解。International Journal of PlasticityA parallelised algorithm to identify arbitrary yield surfaces in multiscale analysesJakob Platen, Johannes Storm, Michael Kaliskedoi:10.1016/j.ijplas.2024.104183多尺度分析中任意屈服面识别的并行算法Plasticity is a common phenomenon in many materials. Furthermore, it is also commonly applied in multiscale analyses. Plasticity is mainly characterised by the yield function. This function distinguishes between the elastic and the plastic material domain. The transition surface is denoted as the yield surface, and characterises the material behaviour significantly. In the contribution at hand, an algorithm is proposed, which can identify arbitrary yield surfaces. No assumptions regarding the geometry, kinematics, or material model need to be incorporated. The algorithm can identify yield surfaces as long as a function can be formulated, which measures the distance of any point in the principal stress space to the yield surface, and an indicator exists, which characterises the behaviour of the material to be elastic or plastic. Hence, a very general algorithm is achieved, which can also be applied to crystal plasticity. The property of star-convexity of yield surfaces is exploited. This algorithm is also well suited for the application in high performance computing environments. Furthermore, the proposed algorithm can be applied to the identification of initial damage surfaces as well. The proposed algorithm is validated on one macroscopically formulated yield function. Subsequently, it is applied to multiscale frameworks to highlight the benefits of the proposed approach. Furthermore, the capabilities of the algorithm to also identify yield surfaces after hardening are presented. Important properties of such yield surfaces are highlighted. The good scalability within distributed memory systems is shown, and the applicability for anisotropic yield surfaces is demonstrated.塑性是许多材料普遍存在的现象。此外,它也常用于多尺度分析。塑性主要表现为屈服函数。该函数区分了弹性材料域和塑性材料域。过渡面表示为屈服面,并显著表征材料的性能。在现有的贡献中,提出了一种可以识别任意屈服曲面的算法。没有关于几何,运动学或材料模型的假设需要纳入。该算法可以识别屈服面,只要可以制定一个函数,测量主应力空间中任何一点到屈服面的距离,并存在一个指标,表征材料的弹性或塑性行为。因此,获得了一个非常通用的算法,也可以应用于晶体塑性。利用屈服曲面的星形凸性。该算法也非常适合在高性能计算环境下的应用。此外,该算法还可用于初始损伤面的识别。该算法在一个宏观表述的屈服函数上得到了验证。随后,将其应用于多尺度框架,以突出所提出方法的优点。此外,该算法还可以识别硬化后的屈服面。这类屈服面的重要性质被强调。在分布式存储系统中显示了良好的可扩展性,并证明了各向异性屈服面的适用性。Thin-Walled StructuresExperimental and numerical simulation of explosion resistance of composite structure of shallow-buried box steel structure and polyurethane elastomer supports under the action of ground explosionHang Xu, Youquan Qin, Weifeng Zhang, Yingxiang Wu, Tainian Chen, Yunke Lu, Xiangyu Xudoi:10.1016/j.tws.2024.112751浅埋箱钢结构与聚氨酯弹性体支架复合结构在地面爆炸作用下的抗爆性能试验与数值模拟The light weight of thin-walled steel structures and their ease of transport and installation have great advantages for protection works that need to be constructed quickly. With the improvement of weapon accuracy and destructive effects, there is an urgent need to improve the resistance of shallow buried steel protection works. However, according to the design concept of traditional protection structures relying on the strength of materials and structural rigidity to resist explosive load, the size of structural components will also increase, and the advantage of rapid construction is seriously reduced. In this study, a composite structure (hereinafter referred to as a composite structure) consisting of a polyurethane elastomer (PUE) set as supports underneath a box steel structure consisting of sandwich plates is proposed to improve the blast resistance of shallow buried box steel structures from ground explosions without increasing the size of the components. Explosive tests and numerical simulations were used to study the blast resistance of the composite structure and its blast resistance mechanism. Other factors affecting the blast resistance of the composite structure, such as the PUE stress-strain relationship and thickness and arrangement of the PUE supports, were also analyzed. The results show that the composite structure is able to generate overall motion and convert part of the explosive energy into kinetic energy of the overall motion of the structure, which is absorbed by the PUE support, thus reducing the structural load and internal force while decreasing deformation and improving the blast resistance performance. While the PUE stress-strain relationship and arrangement of the composite structure have a significant impact on the enhancement of blast resistance, the influence of the thickness of the PUE support is small.薄壁钢结构重量轻,便于运输和安装,对于需要快速施工的防护工程具有很大的优势。随着武器精度和杀伤效果的提高,迫切需要提高浅埋钢防护工程的抗冲击能力。但是,按照传统的依靠材料强度和结构刚度来抵抗爆炸载荷的防护结构的设计理念,结构构件的尺寸也会增大,快速施工的优势严重降低。为了在不增加构件尺寸的情况下提高浅埋箱钢结构的抗地面爆炸能力,本研究提出在夹芯板箱钢结构下部设置聚氨酯弹性体(PUE)作为支撑的复合结构(以下简称复合结构)。通过爆炸试验和数值模拟研究了复合材料结构的抗爆性能及其抗爆机理。分析了影响复合材料结构抗爆性能的其他因素,如PUE应力-应变关系、PUE支架的厚度和布置。结果表明,复合结构能够产生整体运动,并将部分爆炸能量转化为结构整体运动的动能,被PUE支架吸收,从而在减小结构载荷和内力的同时减小变形,提高抗爆性能。PUE的应力-应变关系和复合结构的布置对增强抗爆性能有显著影响,而PUE支架厚度的影响较小。Ballistic performance of additive manufacturing metal lattice structuresXIE Zhihao, FU Xinqiang, ZHANG Qin, LIU Lulu, ZHU Xinying, REN Yi, CHEN Weidoi:10.1016/j.tws.2024.112763增材制造金属晶格结构的弹道性能For the purpose of elucidating the destruction and energy absorption mechanisms of lattice structures during ballistic impacts, this study explored the behavior of two additively manufactured metal lattice structures (BCC and BCCZ) under quasi-static/dynamic compression and ballistic impact through experiments and numerical simulations. Both structures exhibited typical stress-strain behaviors during quasi-static compression, with stress plateauing after reaching yield strength and then sharply declining upon failure. The vertical struts in the BCCZ structure resulted in higher yield strength but lower normalized failure strain compared to the BCC structure, especially at higher strain rates. The ballistic limit of the BCC lattice sandwich target plate at 199 m/s and that of the BCCZ lattice sandwich target plate at 195 m/s. At an impact velocity of 207 m/s, the energy absorbed by the BCC lattice structure itself (498 J) was marginally lower than that absorbed by the BCCZ structure (505 J). The BCC structure, characterized by lower stiffness and yield strength but a larger failure strain, absorbed energy primarily through greater deformation during impact. In contrast, the BCCZ structure, with a smaller failure strain, depended on its higher stiffness and yield strength for energy absorption.为了阐明点阵结构在弹道冲击中的破坏和能量吸收机理,本研究通过实验和数值模拟研究了两种增材制造金属点阵结构(BCC和BCCZ)在准静态/动态压缩和弹道冲击下的行为。两种结构在准静态压缩过程中均表现出典型的应力-应变行为,在达到屈服强度后应力趋于稳定,破坏后应力急剧下降。与BCC结构相比,BCCZ结构中的垂直支板具有更高的屈服强度和更低的归一化破坏应变,特别是在高应变率下。BCC晶格夹层靶板的弹道极限为199 m/s, BCCZ晶格夹层靶板的弹道极限为195 m/s。在207 m/s的冲击速度下,BCC晶格结构自身吸收的能量(498 J)略低于BCCZ结构吸收的能量(505 J), BCC结构刚度和屈服强度较低,但破坏应变较大,主要通过较大的冲击变形吸收能量。相比之下,BCCZ结构具有较小的破坏应变,依赖于其较高的刚度和屈服强度来吸收能量。Experimental and numerical multiscale testing of CFRP bonded stepped repairsJean-Baptiste Orsatelli, Eric Paroissien, Frédéric Lachaud, Sébastien Schwartz, Nathalie Barrièredoi:10.1016/j.tws.2024.112764CFRP粘结阶梯式修复的多尺度试验与数值分析Bonded stepped repairs to aircraft composite structures offer many advantages, such as a smooth aerodynamic surface, high strength, and low mass addition. However, their design remains challenging due to the varying stiffness along the bondline in a thin laminate. This study investigates, numerically and experimentally, to what extent an “equivalent” stepped joint can be used to design a stepped repaired panel. In the proposed case, failure is driven by laminate fracture instead of patch disbonding. Tension tests on stepped repairs at the scale of coupons and panels were carried out in 11 different configurations. Specimens were obtained by hot-bonding as it would be done to perform in-situ repairs. Finite element modelling was performed with cohesive zone modelling to account for disbonding and delamination, and continuum damage mechanics to simulate composite failure. This multiscale experimental study showed that stepped repaired coupons have a similar behaviour to repaired panels in terms of damage mechanisms, failure onset location, and tensile strength. It supports the idea to use coupons instead of whole panels to carry out experimental testing of stepped repairs. A good agreement with 2D and 3D numerical simulations was also found. They predicted accurately the strength of the repairs and highlighted a failure location compatible with the experimental results. As a conclusion, an equivalent stepped joint can be representative for the strength of a stepped repaired panel, including when failure occurs inside the laminates.飞机复合材料结构的粘合阶梯式修复具有许多优点,如光滑的气动表面、高强度和低质量附加。然而,它们的设计仍然具有挑战性,因为在薄层压板中沿结合线的刚度变化。本文从数值和实验两方面探讨了“等效”阶梯节点在多大程度上可以用于设计阶梯修复板。在这种情况下,破坏是由层压断裂而不是贴片剥离驱动的。在11种不同的配置下,按票板和面板的比例对阶梯式修复进行了张力试验。试样是通过热粘接获得的,因为它将进行原位修复。有限元建模采用内聚区建模来考虑剥离和分层,连续损伤力学来模拟复合材料的破坏。该多尺度实验研究表明,阶梯修复板在损伤机制、破坏发生位置和抗拉强度方面与修复板具有相似的行为。它支持使用优惠券而不是整个面板来进行阶梯式修复的实验测试的想法。与二维和三维数值模拟结果吻合较好。他们准确地预测了修复的强度,并突出了与实验结果相符的故障位置。因此,等效阶梯节点可以代表阶梯修复板的强度,包括层板内部发生破坏时的强度。来源:复合材料力学仿真Composites FEM

未登录
还没有评论
课程
培训
服务
行家
VIP会员 学习计划 福利任务
下载APP
联系我们
帮助与反馈