首页/文章/ 详情

【新文速递】2024年5月7日固体力学SCI期刊最新文章

17天前浏览245

 

今日更新:International Journal of Solids and Structures 1 篇,Journal of the Mechanics and Physics of Solids 1 篇,Mechanics of Materials 1 篇,International Journal of Plasticity 3 篇,Thin-Walled Structures 2 篇

International Journal of Solids and Structures

Origin of bent ridge-kink based on disclination relaxation

Xueyu Zhang, Ryutaro Matsumura, Yuri Shinohara, Tomonari Inamura

doi:10.1016/j.ijsolstr.2024.112829

基于偏斜松弛的弯曲脊扭成因

In this study, we have developed a geometric model for bent kinks by introducing sequences of ortho-connected kink bands into ridge-kinks to provide insights into the possible reasons why kinks are bent and the resulting geometry when they are bent. We first formulated the Frank angles and coordinates of the disclinations formed in the bent kinks, which enable our discussion on the influence of the introduction of ortho-kinks on the Gibbs energy by utilizing Romanov’s disclination model. It turns out that the introduction of ortho-kinks can relax the elastic strain energy and thus reduce the Gibbs energy of the system under compression states with lower external stresses. On the other hand, the introduction of ortho-kinks increases the Gibbs energy at higher compression stresses, implying sharp ridge-kinks are preferred under such conditions. This trend resembles the experimental observations reported by previous studies that the shapes of newly formed kinks tend to transition from pre-kinks with bent shapes to ridge-kinks with sharp shapes as the compression test progresses. The smoothly bent kink with smoothly distributed misorientation, formed by increasing the number of introduced ortho-kinks, can further reduce the Gibbs energy at lower applied stresses. Subsequently, based on the Rank-1 condition for the connection of kink bands, we further analyzed the geometry of such smoothly bent kinks and derived the analytical equations for the constraints on the orientation distribution. Finally, we conducted EBSD measurements on bent kinks observed in directionally solidified (DS) LPSO-Mg alloys and confirmed that the derived equations for the orientation distribution are in good agreement with the experimental results.

在这项研究中,我们通过将正交连接的扭结带序列引入脊状扭结中,开发了弯曲扭结的几何模型,以深入了解扭结弯曲的可能原因以及弯曲时产生的几何形状。我们首先给出了弯曲扭结中形成的斜折的Frank角和坐标,这使得我们能够利用罗曼诺夫的斜折模型讨论正扭结的引入对吉布斯能量的影响。结果表明,正交扭结的引入可以使体系的弹性应变能松弛,从而降低体系在低外应力压缩状态下的吉布斯能。另一方面,在较高的压缩应力下,正扭结的引入增加了吉布斯能,这意味着在这种条件下,尖锐的脊状扭结是首选的。这一趋势与以往研究报告的实验观察结果相似,即随着压缩试验的进行,新形成的扭结的形状倾向于从弯曲形状的预扭结转变为尖锐形状的脊状扭结。在较低的外加应力下,通过增加引入的正扭结的数量,形成具有平滑分布的错取向的平滑弯曲扭结,可以进一步降低吉布斯能。随后,基于扭结带连接的Rank-1条件,进一步分析了这种光滑弯曲扭结的几何形状,并推导了其方向分布约束的解析方程。最后,我们对定向凝固(DS) LPSO-Mg合金中观察到的弯曲扭结进行了EBSD测量,证实了取向分布的推导方程与实验结果吻合较好。


Journal of the Mechanics and Physics of Solids

Quantized Impact of Rod on Plate

Qing Peng, Xiaoming Liu, Yue-Guang Wei

doi:10.1016/j.jmps.2024.105680

量化杆对板的影响

In this work, we attacked the problem of elastic impact of a rod on a plate. By considering wave propagation on the plate and along the rod, we established a mathematic model with delay differential equation that governs such impact. The proposed model could consolidate classical impact problems from bead-on-wall, bead-on-plate, to rod-on-wall impact. Solving the governing equation, we obtained a universal loading and unloading history of such impact: the unloading history exhibits quantized plateaus, the values of which are quantitatively provided in the present study. Also, the contact duration also shows a band structure while tuning the compliance of plate. In addition, we analyzed the overshoots leading the plateaus during unloading, which cause the final detachment between the rod and the plate.

在这项工作中,我们研究了杆对板的弹性冲击问题。考虑波在板上和杆上的传播,建立了控制这种影响的时滞微分方程数学模型。所提出的模型可以将经典的碰撞问题从头对壁、头对板到杆对壁进行整合。通过求解控制方程,我们得到了这种冲击的普遍加载和卸载历史:卸载历史表现为量化的平台,本研究定量地提供了其值。同时,在调整板的柔度时,接触时间也呈现带状结构。此外,我们分析了在卸载过程中导致平台的超调,这导致杆与板之间的最终脱离。


Mechanics of Materials

Predicting plastic behavior of magnesium alloy tube bending with comprehensive constitutive models

Han-Xu Zhang, Fei-Fan Li, Gang Fang

doi:10.1016/j.mechmat.2024.105030

用综合本构模型预测镁合金管材弯曲塑性行为

This paper aims to predict defects occurring in magnesium alloy tube bending through finite element simulations. Deformation tests were conducted to identify and characterize plastic anisotropy, tension-compression asymmetry, and differential hardening behaviors of extruded Mg–Al–Zn-RE alloy rectangular tubes. Limited by size, the deformation tests along the wall thickness of specimens are conducted through crystal plasticity analysis. To thoroughly investigate the material constitutive features affecting bending, two constitutive models, Yoon2014 and Hill48, are established and calibrated. The non-associative flow rule is adopted, and differential hardening is depicted using the yield-surface interpolation method. In comparison, the Yoon2014 model accurately predicts the strain distribution and tube shape collapse of the bent tube with negligible deviation from the experimental data, prior to the Hill48 model. This underscores the necessity of considering comprehensive plasticity models in tube bending simulations.

本文旨在通过有限元模拟对镁合金管材弯曲过程中出现的缺陷进行预测。通过变形试验确定和表征挤压Mg-Al-Zn-RE合金矩形管的塑性各向异性、拉压不对称性和不同硬化行为。受尺寸限制,沿试样壁厚方向的变形试验采用晶体塑性分析方法进行。为了深入研究影响弯曲的材料本构特征,建立并校准了Yoon2014和Hill48两个本构模型。采用非关联流动规律,采用屈服面插值法描述微分硬化。相比之下,Yoon2014模型较Hill48模型更准确地预测了弯曲管的应变分布和管形坍塌,与实验数据的偏差可以忽略不计。这强调了在管材弯曲模拟中考虑综合塑性模型的必要性。


International Journal of Plasticity

Orientation-dependent deformation mechanisms of alpha-uranium single crystals under shock compression

Yongfeng Huang, Pan Li, Songlin Yao, Kun Wang, Wangyu Hu

doi:10.1016/j.ijplas.2024.103991

激波压缩下α -铀单晶取向依赖性变形机制

Large-scale non-equilibrium molecular dynamics (NEMD) simulations were employed to investigate the dynamic deformations of alpha-uranium (α-U) single crystals subjected to varying shock strengths along low-index crystallographic orientations. The pronounced anisotropy of α-U gives rise to a complex microstructural evolution under shock loading. In-depth microstructural analysis of post-shock specimens reveals the identification of multiple dynamic deformation mechanisms. Notably, when the shock loading direction aligns with the a-axis, dynamic deformation of the α-U single crystals is primarily dominated by lattice instability, which attributes to a crystalline-to-amorphous transition serving as the dominant shear stress relaxation pathway. On the other hand, shock loading along the b-axis results in an abundance of deformation twins, with twinning planes identified as (130) and (13¯0). During the twinning event, the α-U matrix undergoes a transition to a metastable intermediate phase, subsequently decomposing into a composite structure comprising α-U twins and matrix. This unconventional twinning mechanism significantly deviates from classical theories. Furthermore, upon loading along the c-axis, twinning and a phase transition from α-U to body-centered tetragonal phase (bct-U) occur in α-U single crystal samples. Given that the pressure threshold of this phase transition predicted by ab initio calculations is as high as ∼270 GPa, the phase transition from α-U to bct-U might be implausible. An alternative interatomic potential of uranium with the higher pressure threshold was employed to reinvestigate the shock response of α-U single crystals along the c-axis. The phase transition of α-U to bct-U disappears, and twinning dominates the plastic deformation, with the twinning orientation conforming to the {112} twinning. The strong anisotropy of the α-U lattice triggers a wealth of orientation-dependent dynamic deformation mechanisms. The activation of the twinning system is evidently associated with the loading direction, constituting the potential cause for the discovery of multiple twinning variants during the deformation in polycrystalline uranium.

采用大规模非平衡分子动力学(NEMD)模拟研究了α-铀(α-U)单晶体在不同冲击强度下沿低指数晶体学取向的动态变形。α-U具有明显的各向异性,因此在冲击加载下会产生复杂的微观结构演变。通过对冲击后试样进行深入的微观结构分析,发现了多种动态变形机制。值得注意的是,当冲击加载方向与 a 轴一致时,α-U 单晶的动态变形主要由晶格不稳定性主导,这就导致晶体到非晶体的转变成为剪应力松弛的主要途径。另一方面,沿 b 轴的冲击加载导致了大量的变形孪晶,孪晶平面被识别为 (130) 和 (13¯0)。在孪生过程中,α-U 基体过渡到一个可蜕变的中间相,随后分解为由α-U孪晶和基体组成的复合结构。这种非传统的孪生机制大大偏离了经典理论。此外,在沿 c 轴加载时,α-U 单晶样品中会出现孪晶,并发生从α-U 到体心四方相(bct-U)的相变。鉴于根据原子序数计算预测的这种相变的压力阈值高达 ∼270 GPa,从 α-U 到 bct-U 的相变可能是难以置信的。我们采用了另一种具有更高压力阈值的铀原子间势来重新研究 α-U 单晶沿 c 轴的冲击响应。α-U到bct-U的相变消失了,孪晶主导了塑性变形,孪晶取向符合{112}孪晶。α-U晶格的强各向异性引发了大量取向相关的动态变形机制。孪晶系统的激活显然与加载方向有关,这也是在多晶铀变形过程中发现多种孪晶变体的潜在原因。


Spatially-resolved cluster dynamics modeling of irradiation growth

Matthew Maron, Yang Li, Inam Lalani, Kristopher Baker, Benjamin Ramirez Flores, Thomas Black, James Hollenbeck, Nasr Ghoniem, Giacomo Po

doi:10.1016/j.ijplas.2024.103989

辐射生长的空间分辨簇动力学模拟

We develop here a spatially resolved, three-dimensional continuum model coupling cluster dynamics (SR-CD) and crystal plasticity to investigate irradiation growth in zirconium. The model uses scale separation to divide the population of the irradiation cluster into mobile and immobile families. Small interstitial and vacancy clusters are modeled using anisotropic reaction–diffusion. Among the immobile clusters, an atomistically-informed vacancy cluster to vacancy loop transition is taken into account. The coupling between the evolution equation of CD and the plastic deformation of the material is two-fold, with stress-informed bias factors and local inelastic strains computed from the evolution of the evolving cluster population. The numerical implementation of the model utilizes the finite element method to analyze both single-crystal and polycrystalline samples. The growth strains that are computed align well with the experimental data provided by Carpenter for single-crystal Zr. Furthermore, the transformation of a vacancy cluster into a complete vacancy loop, occurring at a size of 14 nm, is in agreement with experimental observations and atomistic simulations. The density, size, and growth rate of the dislocation loops, denoted as〈c〉and 〈a〉, also exhibit good agreement with transmission electron microscopy (TEM) analysis of irradiated Zr and its alloys. Our findings demonstrate there is a spatial correlation of the growth of these dislocation loops and growth strains are significantly influenced by crystal size. To explain the expansion of the 〈a〉 axis and the contraction of the 〈c〉 axis in irradiated Zr, it is necessary to consider the diffusion anisotropy difference (DAD) of mobile interstitial species. We have shown that the PWR Kearns parameters, specifically fr = 0.63, ft = 0.32, fa = 0.05, confer enhanced irradiation resistance to Zr along the principal directions when compared to single crystals. Additionally, reducing the grain size to nanograins further enhances the resistance to irradiation-induced growth, particularly along the direction with the highest volume fraction of basal poles [0001].

我们在此建立了一个空间分辨的三维连续模型,该模型将团簇动力学(SR-CD)和晶体塑性耦合在一起,用于研究锆的辐照生长。该模型利用尺度分离将辐照簇群划分为移动和不移动家族。小的间隙簇和空位簇采用各向异性反应扩散模型。在不动簇中,考虑了原子信息空位簇到空位环的转变。CD 演化方程与材料塑性变形之间的耦合是双重的,应力偏置因子和局部非弹性应变是通过不断演化的团簇群体的演化计算得出的。该模型的数值实现采用了有限元方法,以分析单晶和多晶样品。计算出的生长应变与 Carpenter 提供的单晶锆的实验数据非常吻合。此外,一个空位簇转变为一个完整的空位环(大小为 14 纳米)与实验观察和原子模拟结果一致。以〈c〉和〈a〉表示的位错环的密度、尺寸和生长率也与辐照锆及其合金的透射电子显微镜(TEM)分析结果十分吻合。我们的研究结果表明,这些位错环的生长存在空间相关性,生长应变受到晶体尺寸的显著影响。要解释辐照锆中〈a〉轴的扩展和〈c〉轴的收缩,有必要考虑移动间隙物种的扩散各向异性差(DAD)。我们的研究表明,与单晶体相比,PWR Kearns 参数(特别是 fr = 0.63、ft = 0.32、fa = 0.05)可增强锆沿主要方向的抗辐照能力。此外,将晶粒尺寸减小到纳米晶粒可进一步增强抗辐照诱导生长的能力,尤其是沿基极体积分数最高的方向[0001]。


Effect of Ni4Ti3 precipitates on the functional properties of NiTi shape memory alloys: A phase field study

Bo Xu, Yuanzun Sun, Chao Yu, Jiachen Hu, Jiaming Zhu, Junyuan Xiong, Qianhua Kan, Chong Wang, Qingyuan Wang, Guozheng Kang

doi:10.1016/j.ijplas.2024.103993

Ni4Ti3析出物对NiTi形状记忆合金功能性能影响的相场研究

Ni4Ti3 precipitates, which generally exist in aged Ni-rich NiTi shape memory alloys (SMAs), can have a profound effect on material properties. However, the fundamental insights into the effects of Ni4Ti3 precipitates on the functional properties, including the superelasticity (SE), elastocaloric effect (eCE), and shape memory effects (SMEs), are not well understood yet, especially those originating from the B2-B19′ martensite transformation (MT). In this work, a phase field model coupling the precipitation of Ni4Ti3 and the B2-B19′ MT is proposed, where the thermo-mechanical coupling effect and grain size effect are considered. The precipitate-dependent SE, eCE, one-way SME (OWSME), and stress-assisted two-way SME (SATWSME) of single-crystal, polycrystalline, and gradient-nanograined NiTi SMAs are simulated. The effects of the precipitate density, grain orientation range (texture), and gradient-distributed precipitate are examined, and the underlying microscopic mechanisms are revealed. The simulation results and new findings not only contribute to a more comprehensive insight into the effect of Ni4Ti3 precipitates on the MT, martensite reorientation, and functional properties of NiTi SMAs but also provide a reference for the development of excellent SMA-based solid refrigerants or SMA smart materials with designable functional properties.

Ni4Ti3析出物普遍存在于时效富镍NiTi形状记忆合金中,对材料性能有着深远的影响。然而,Ni4Ti3析出物对功能性能的影响,包括超弹性(SE)、弹性热效应(eCE)和形状记忆效应(SMEs),特别是那些源自B2-B19′马氏体相变(MT)的影响,尚未得到很好的理解。本文建立了考虑热-机械耦合效应和晶粒尺寸效应的Ni4Ti3与B2-B19′MT相场耦合模型。模拟了单晶、多晶和梯度纳米NiTi sma的沉淀依赖SE、eCE、单向SME (OWSME)和应力辅助双向SME (SATWSME)。考察了析出相密度、晶粒取向范围(织构)和梯度分布的影响,揭示了其微观机制。模拟结果和新发现不仅有助于更全面地了解Ni4Ti3沉淀对NiTi SMA的MT、马氏体重取向和功能性能的影响,而且为开发具有可设计功能性能的优异SMA固体制冷剂或SMA智能材料提供参考。


Thin-Walled Structures

Low temperature effect on cyclic behavior of shape memory alloy U-shaped dampers

Jiahao Huang, Zhipeng Chen, Songye Zhu

doi:10.1016/j.tws.2024.111962

低温对形状记忆合金u型阻尼器循环性能的影响

Although Nickel-Titanium (NiTi) shape memory alloys (SMAs) have been widely studied as seismic response mitigation devices in civil structures, their temperature sensitivity due to the coupled thermo-mechanical behavior prevents their practical implementation in cold temperature environments. This paper investigated the effects of varying ambient temperatures (particularly low ambient temperature) on the hysteretic behavior and self-centering (SC) ability of shape memory alloy U-shaped dampers (SMAUDs) that were made of NiTi showing superelasticity (SE) at room temperature. Thermo-mechanical properties of SMAUDs were identified through differential scanning calorimetry (DSC) tests. Cyclic loading experiments on SMAUDs were conducted at a wide ambient temperature range from −40°C to 20°C. The variations in the hysteretic characteristics of the SMAUD, including partial superelasticity (SE), strength, stiffness, SC, and energy dissipation capabilities, at different ambient temperatures were investigated. In general, the decreasing ambient temperature leads to the degradation of the SC ability. At ambient temperatures below the phase transformation temperature, the SMAUDs lose the SE but still maintain certain levels of strength and energy dissipation, which is different from common axial-type SMA elements. Meanwhile, the SMAUDs can restore their SC ability and strength after the recovery from low temperatures to room temperature, making them suitable for use in a cold environment.

尽管镍钛(NiTi)形状记忆合金(SMAs)作为土木结构中的地震反应缓解装置已经得到了广泛的研究,但由于热-力耦合行为导致的温度敏感性阻碍了它们在低温环境中的实际应用。研究了室温下不同环境温度(特别是低温)对具有超弹性的NiTi形状记忆合金u型阻尼器(SMAUDs)滞回性能和自定心(SC)能力的影响。通过差示扫描量热法(DSC)测试鉴定了SMAUDs的热力学性能。SMAUDs的循环加载实验在- 40℃~ 20℃的宽环境温度范围内进行。研究了不同环境温度下SMAUD的滞回特性,包括部分超弹性(SE)、强度、刚度、SC和耗能能力的变化。一般来说,环境温度的降低会导致SC能力的下降。在低于相变温度的环境温度下,smaud失去了SE,但仍保持一定水平的强度和能量耗散,这与普通轴向型SMA元件不同。同时,smaud从低温恢复到室温后,可以恢复其SC能力和强度,适合在寒冷环境中使用。


Effect of bondline thickness on the mechanical performance of CFRP laminate with asymmetric damage repaired by double-sided adhesive patch

Xiao Han, Daoxin Li, Liangliang Sun, Dezhi Wang, Jiewang Xu, Wei Zhang

doi:10.1016/j.tws.2024.111976

粘结线厚度对双面胶贴修复不对称损伤CFRP复合材料力学性能的影响

As a common CFRP repair method, double-sided adhesive patch has been widely used in the automotive and aeronautic industry. More specific research is thus needed to help better understanding the effect of repairing parameters on the mechanical performance of CFRP structures after patch bonding. In this paper, experimental and Finite Element Modelling (FEM) efforts were made on the adhesive repaired CFRP laminate with different bondline thicknesses. Artificial damage was prefabricated in the centre of the CFRP laminate, which was then repaired through double-sided adhesive patch. Quasi-static tensile tests were conducted on the repaired specimen up to failure, to obtain the load-displacement curves. With a bondline thickness of 0.5 mm, the repaired CFRP structure reached its maximum peak load, increased by 25.3% and 26.4% compared to 0.2 mm and 1.0 mm bondline thicknesses, respectively. SEM observations were used to analyse the influence of adhesive thickness on the fracture modes. Combined with Cohesive Zone Model (CZM) for the adhesive layer and Hashin damage criterion for the CFRP, the FE model of the CFRP laminate repaired with double-sided adhesive patch subjected to tensile loading was established. Finally, the damage evolution as well as the failure modes in the parent laminate and adhesive layer with different bondline thicknesses were compared and analysed. It was revealed that bondline thickness can effectively affect the mechanical performance of CFRP laminate after adhesive patch repair.

双面粘接贴片作为一种常用的CFRP修补方法,在汽车和航空工业中得到了广泛的应用。因此,需要更具体的研究来帮助更好地了解修复参数对贴片粘合后CFRP结构力学性能的影响。本文对不同粘结线厚度的CFRP粘接修复层合板进行了实验和有限元模拟研究。在CFRP层压板的中心预制人工损伤,然后通过双面胶贴修复。对修复试件进行了破坏前的准静态拉伸试验,得到了试件的载荷-位移曲线。修复后的CFRP结构在粘结线厚度为0.5 mm时达到最大峰值载荷,比粘结线厚度为0.2 mm和1.0 mm时分别增加了25.3%和26.4%。利用扫描电镜分析了胶粘剂厚度对断裂模式的影响。结合粘接层的内聚区模型(CZM)和CFRP的哈辛损伤准则,建立了双面粘接修补CFRP层合板在拉伸载荷作用下的有限元模型。最后,对不同粘结线厚度的母层和粘结层的损伤演化及破坏模式进行了比较分析。结果表明,粘结线厚度对贴片修复后CFRP复合材料的力学性能有显著影响。


来源:复合材料力学仿真Composites FEM
ACTMechanicalSystemDeform断裂复合材料碰撞航空汽车电子ADS理论材料分子动力学控制试验
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:2024-11-14
最近编辑:17天前
Tansu
签名征集中
获赞 6粉丝 0文章 776课程 0
点赞
收藏
作者推荐

【新文速递】2024年5月11日复合材料SCI期刊最新文章

今日更新:Composite Structures 2 篇,Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇Composite StructuresCrashworthiness investigation on a Carbon Fiber Reinforced Plastic solar vehicleAlessandro Papavassiliou, Ana Pavlovic, Giangiacomo Minakdoi:10.1016/j.compstruct.2024.118147碳纤维增强塑料太阳能汽车的耐撞性研究This article presents a research study involving different simulations of crash tests by means of the finite element explicit dynamic software Ansys LS-Dyna to determine the roadworthiness of a fully composite chassis lightweight solar vehicle and its conformity to the World Solar Challenge (WSC) regulations. Furthermore, the paper describes the results of crash test simulations in conditions comparable with those of the standard homologation test, with an initial velocity of 15.5 m/s against a rigid barrier considering overlaps of 50% and 100%. The velocity measured at the base of the seat was later used in a sled test with a dummy to calculate the Head Injury Criterion (HIC), a number proportional to the probability of head injury caused by the impact. The values remained within the threshold of acceptability with overlap at 50% but exceeded the limit with the 100% overlap. With no load limiter implemented in the model, the seatbelt caused contact forces with the chest up to 14 kN against 6 kN of the typical load limiter used in road cars to limit damage to ribs and internal organs. Finally, the possibility of improving the front crash box was investigated by changing the crash box’s planar sandwich structure with corrugated ones and layup without foam between the carbon layers. Various values of semi-amplitudes (A) of the sinusoidal profile have been tested. With a value of A of 6 mm, the capacity to absorb energy from an impact at 9 m/s was close to the original configuration.本文采用有限元显式动力软件Ansys LS-Dyna进行了不同碰撞试验模拟研究,以确定全复合材料底盘轻型太阳能汽车的路适性及其符合世界太阳能挑战赛(WSC)规则。此外,本文还描述了在考虑50%和100%重叠的情况下,以15.5 m/s的初始速度撞击刚性屏障的碰撞试验模拟结果,与标准一致性试验的条件相当。在座椅底部测量的速度随后用于假人的雪橇试验,以计算头部损伤标准(HIC),该标准与撞击造成头部损伤的概率成正比。当重叠为50%时,这些值仍在可接受阈值范围内,但当重叠为100%时,这些值超过了可接受阈值。在模型中没有实施载荷限制器的情况下,安全带与胸部的接触力高达14千牛,而公路汽车中使用的典型载荷限制器为6千牛,以限制肋骨和内脏的损伤。最后,研究了将前碰撞箱的平面夹层结构改为波纹夹层结构和碳层间无泡沫叠层的可能性。对正弦剖面的各种半振幅(A)值进行了测试。当a值为6 mm时,吸收9 m/s冲击能量的能力接近于原始配置。Microstructure generation and full-field multi-scale analyses for short fiber reinforced thermoplastics: Application to PA66GF compositesFrancis Praud, Konrad Schneider, George Chatzigeorgiou, Fodil Meraghnidoi:10.1016/j.compstruct.2024.118175短纤维增强热塑性塑料的微观结构生成及现场多尺度分析:在PA66GF复合材料中的应用Short Fiber Reinfored Thermoplastics (SFRTs) like PA66GF composites are highly heterogeneous materials with a rather complex microstructure such that the characterization and the prediction of their mechanical behavior remain quite challenging. So far, most of the research efforts have employed phenomenologigal and mean-field multi-scale models to deal with SFRTs. The present contribution rather focuses on a full-field multi-scale approach that incorporates advanced techniques in terms of microstructural representation and material modeling, allowing a deep insight of the dominating deformation mechanisms occurring in PA66GF composites. The proposed approach is based on an automatic periodic mesh generation algorithm for matrix-inclusion Representative Volume Elements (RVE) with randomly positioned fibers that follow a given Orientation Distribution Function (ODF). At the microscopic scale, while the fibers are assumed to be elastic, the behavior of the thermoplastic matrix is described by a phenomenological multi-mechanism constitutive model accounting for viscoelasticity, viscoplasticity and ductile damage. It results an advanced multi-scale model that enables to visualize the local deformation and degradation mechanisms occurring at the microscopic scale while simultaneously analyzing their influence on the macroscopic response of the composite upon monotonic, persistent and cyclic loading. The potential of the proposed approach is further evaluated by comparing the predicted responses against experimental data.短纤维增强热塑性塑料(SFRTs),如PA66GF复合材料是高度非均相材料,具有相当复杂的微观结构,因此其力学行为的表征和预测仍然是相当具有挑战性的。到目前为止,大多数研究都是采用现象学和平均场多尺度模型来处理sfrt。目前的贡献主要集中在一个全领域的多尺度方法,该方法结合了微观结构表示和材料建模方面的先进技术,从而深入了解PA66GF复合材料中发生的主要变形机制。该方法是基于矩阵包含代表性体积元(RVE)的自动周期性网格生成算法,其中随机定位的纤维遵循给定的方向分布函数(ODF)。在微观尺度上,假设纤维是弹性的,热塑性基体的行为由考虑粘弹性、粘塑性和延性损伤的现象学多机制本构模型来描述。建立了一种先进的多尺度模型,可以在微观尺度上可视化局部变形和降解机制,同时分析它们对复合材料在单调、持久和循环加载下的宏观响应的影响。通过将预测响应与实验数据进行比较,进一步评估了所提出方法的潜力。Composites Part A: Applied Science and ManufacturingJapanese washi-paper-based green composites: Fabrication, mechanical characterization, and evaluation of biodegradabilityLovisa Rova, Alia Gallet-Pandellé, Zhenjin Wang, Hiroki Kurita, Fumio Naritadoi:10.1016/j.compositesa.2024.108261日本纸基绿色复合材料:制造、机械特性和生物降解性评价In this study, sheets of Japanese washi-paper were layered and hot pressed with films of poly(butylene succinate) (PBS) in order to produce a fiber-reinforced composite material that can be biodegraded. Using traditional Japanese washi-paper, a thin yet remarkably strong green composite with excellent biodegradability was produced, proving the potential of washi-paper as an attractive reinforcer in green composites. The composite was biodegraded in compost, and the ultimate aerobic biodegradability as well as weight loss and loss of mechanical properties during biodegradation was evaluated. Specimens fabricated from three layers of washi-paper and two layers of PBS film had remarkable mechanical properties, including an ultimate tensile strength of 59.85 MPa. Scanning electron microscopy was used to study the cross-sectional structure of the material, which showed that the hollow washi-paper provides a structure for the polymer to settle into and surround the cellulose fibers. The large contact area between the cellulose fibers and the PBS caused a large internal friction which prevented failure by fiber pull-out, dramatically increasing the strength compared to neat washi-paper and neat PBS. Concerning biodegradability, the material reached 82 % biodegradation after 35 days. During biodegradation, the composite lost its mechanical properties fast, and was extremely fragile after 2 weeks inside the compost. After 6 weeks, the biodegradation had progressed so far that it was difficult to distinguish the material inside the compost. Due to its fast biodegradation and good mechanical strength, the washi-based composite material is potentially used in packaging, furniture, and agricultural applications such as mulch film.在这项研究中,将日本的洗衣纸分层并与聚丁二酸丁二烯(PBS)薄膜热压,以生产一种可生物降解的纤维增强复合材料。以日本传统的废纸为原料,制备了一种薄而强且具有良好生物降解性的绿色复合材料,证明了废纸作为绿色复合材料增强剂的潜力。在堆肥中对复合材料进行生物降解,并对其最终的好氧生物降解性以及生物降解过程中的重量损失和机械性能损失进行了评价。三层水洗纸和两层PBS膜制备的试样具有显著的力学性能,其极限抗拉强度为59.85 MPa。利用扫描电子显微镜对材料的横截面结构进行了研究,结果表明,中空的卫生纸为聚合物进入并包围纤维素纤维提供了一种结构。纤维素纤维与PBS之间的大接触面积产生了很大的内摩擦,防止了纤维被拉出而破坏,与干净的卫生纸和干净的PBS相比,强度大大提高。在生物降解性方面,材料在35 天后达到82% %的生物降解。在生物降解过程中,复合材料的力学性能迅速丧失,在堆肥中放置2 周后极易破碎。6 周后,生物降解已经进展到难以区分堆肥内部的物质。由于其快速的生物降解和良好的机械强度,水洗基复合材料有潜力用于包装、家具和农业应用,如地膜。Composites Part B: EngineeringRational design and controlled synthesis of metal-organic frameworks to meet the needs of electrochemical sensors with different sensing characteristics: an overviewJingcheng Huang, Haowei Dong, Lingjun Geng, Rui Xu, Mengyue Liu, Zhen Guo, Jiashuai Sun, Xia Sun, Yemin Guodoi:10.1016/j.compositesb.2024.111536 合理设计和可控合成满足不同传感特性电化学传感器需求的金属有机骨架综述It is known that porous structure of materials offers opportunities for the creation of a new range of materials with precise functions. Metal-organic frameworks (MOFs) are ordered porous materials formed by self-assembly of metal nodes and organic ligands. The study found that MOFs are ideal sensing materials. Recently, increasing attention has focused on developing MOFs-based electrochemical (EC) sensors due to their adjusted pore sizes , large surface area, and excellent physical/chemical stability. Various pure MOFs with distinct structures and functions can be synthesized by selecting different metal centers and organic ligands, the MOFs family has been further extended through the exploration of MOFs-derived materials and MOFs composites. In this review, firstly, the classifications and synthesis methods of MOFs materials are presented. Subsequently, the relationship between structure and performance, as well as different strategies for the rational design and controlled synthesis of multifunctional MOFs materials according to the specific requirements of EC sensors are discussed in detail. Finally, it presents conclusive perspectives on the current challenges in using MOFs materials for EC sensors. This paper will offer important guidance in designing and applying MOFs materials in EC sensors.众所周知,材料的多孔结构为创造一系列具有精确功能的新材料提供了机会。金属有机骨架是由金属节点与有机配体自组装而成的有序多孔材料。研究发现mof是理想的传感材料。近年来,基于mofs的电化学(EC)传感器因其可调节孔径、大表面积和优异的物理/化学稳定性而受到越来越多的关注。通过选择不同的金属中心和有机配体,可以合成各种具有不同结构和功能的纯MOFs,通过对MOFs衍生材料和MOFs复合材料的探索,MOFs家族得到了进一步的扩展。本文首先介绍了mof材料的分类和合成方法。随后,详细讨论了结构与性能之间的关系,以及根据EC传感器的具体要求合理设计和控制合成多功能MOFs材料的不同策略。最后,它提出了结论性的观点,目前在使用mof材料的EC传感器的挑战。本文将对mof材料在电磁传感器中的设计和应用具有重要的指导意义。Composites Science and TechnologyElectrical properties of MAH-g-PP modified PP/SEBS matrix semi-conductive composite materialsXuejing Li, Tianzhen Liu, Xiaolong Chen, Yanhui Wei, Jinliang He, Guochang Lidoi:10.1016/j.compscitech.2024.110657MAH-g-PP改性PP/SEBS基半导电复合材料的电学性能Polypropylene (PP) becomes a superior candidate material for new environmental-friendly cable insulation layer with its excellent heat resistance, electrical properties and degradability. At present, most of studies focus on the insulation layer of PP cable. However, there are few studies on semi-conductive shielding layer of PP cable which match its insulation layer. In this paper, polypropylene (PP)/ styrene ethylene butylene styrene (SEBS) is adopted as matrix of PP cable semi-conductive layer to matching its insulation layer. Meanwhile, Maleic anhydride grafted polypropylene (MAH-g-PP) is used to cooperatively improve the compatibility between PP and SEBS. The physicochemical properties, space charge injection properties and compatibility of semi-conductive composites with different CB and MAH-g-PP contents is studied by combining experiment and simulation methods. The experimental results show that the surface roughness of the semi-conductive layer and the space charge inside the insulation layer decrease first and then increase with the increase of CB addition. Among them, the two parameters of 25phr CB semi-conductive layer is the lowest, respectively 13.98 nm and 2.25×10-8C. These two parameters are significantly reduced after the addition of compatibilizer MAH-g-PP, which decreased by 29.47% and 62.22%, respectively. The simulation results show that the Flory-Huggins interaction parameters (χ) of MAH-g-PP with PP and SEBS are -73.3 and -45.2, respectively, which are 236.24% and 107.34% lower than those of PP/SEBS. The χ value of MAH-g-PP/CB is 8.20, which is 33.27% and 9.59% lower than CB/PP and CB/SEBS, respectively. It shows that MAH-g-PP can effectively improve the compatibility of matrix and filler. This work has important guiding significance for the research of semi-conductive layer formulation of PP cable.聚丙烯(PP)以其优异的耐热性、电性能和可降解性成为新型环保电缆绝缘层的首选材料。目前对PP电缆绝缘层的研究大多集中在PP电缆绝缘层的研究上。然而,对于与PP电缆绝缘层相匹配的半导电屏蔽层的研究却很少。本文采用聚丙烯(PP)/苯乙烯乙烯丁烯苯乙烯(SEBS)作为PP电缆半导电层的基体,与其绝缘层相匹配。同时,用马来酸酐接枝聚丙烯(MAH-g-PP)协同改善PP与SEBS的相容性。采用实验与模拟相结合的方法,研究了不同CB含量和MAH-g-PP含量的半导电复合材料的理化性能、空间电荷注入性能和相容性。实验结果表明,随着炭黑添加量的增加,半导电层表面粗糙度和绝缘层内部空间电荷先减小后增大。其中,25phr CB半导电层的两个参数最低,分别为13.98 nm和2.25×10-8C。添加相容剂MAH-g-PP后,这两个参数分别降低了29.47%和62.22%。仿真结果表明,MAH-g-PP与PP和SEBS的Flory-Huggins相互作用参数(χ)分别为-73.3和-45.2,分别比PP/SEBS低236.24%和107.34%。MAH-g-PP/CB的χ值为8.20,分别比CB/PP和CB/SEBS低33.27%和9.59%。结果表明,MAH-g-PP能有效改善基体与填料的相容性。本工作对PP电缆半导电层配方的研究具有重要的指导意义。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 福利任务 兑换礼品
下载APP
联系我们
帮助与反馈