首页/文章/ 详情

【新文速递】2024年7月23日固体力学SCI期刊最新文章

1小时前浏览10

 

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,Thin-Walled Structures 4 篇

International Journal of Solids and Structures

Crack initiation and propagation from a closing flaw with frictional contact in a natural quasi-brittle orthotropic solid

Sailendu Biswal, Gaurav Singh

doi:10.1016/j.ijsolstr.2024.112989

天然准脆正交各向异性固体中具有摩擦接触的闭合裂纹的裂纹萌生和扩展

This work considers the frictional closing of a pre-existing flaw in a natural quasi-brittle orthotropic medium (wood) under compression. The effect of the flaw face friction at multiple orientations of the flaw, on the peak load-bearing capacity are investigated. The failure due to crack growth initiation from the periphery of the pre-existing flaw and its propagation was investigated experimentally and modeled numerically. The experimental investigation was carried out using New Zealand Pine wood with a pre-existing flaw under a quasi-static compression test. In the numerical investigation, an eXtended finite element (XFEM)-based cohesive zone model (CZM) is employed in the modeling of the local crack initiation and propagation. The onset of the crack initiation is modeled using a stress-based criterion and the progressive degradation due to crack propagation is traction-separation based damage evolution. The XFEM-based CZM captures the crack initiation and propagation well consistent with the experimental results. The numerical results also show the impact of flaw face friction on the peak load bearing capacity as well as the local stress response.

这项工作考虑了在压缩下天然准脆性正交各向异性介质(木材)中预先存在缺陷的摩擦关闭。研究了裂纹面多方向摩擦对裂纹峰值承载能力的影响。通过实验和数值模拟研究了由裂纹扩展引发的破坏及其扩展过程。采用带缺陷的新西兰松木进行准静态压缩试验。在数值研究中,采用基于扩展有限元(XFEM)的黏聚区模型(CZM)来模拟局部裂纹的萌生和扩展。裂纹的起裂采用基于应力的准则进行建模,裂纹扩展的逐步退化是基于牵引分离的损伤演化。基于xfem的CZM能较好地捕捉到裂纹的萌生和扩展过程,与实验结果吻合较好。数值结果还显示了缺陷面摩擦对峰值承载能力和局部应力响应的影响。


Journal of the Mechanics and Physics of Solids

A simple hydrodynamic model for clay

Max Wiebicke, Itai Einav

doi:10.1016/j.jmps.2024.105789

粘土的简单水动力模型

Laboratory description of clay normally distinguishes the scale of atoms from the scale of clay particles and aggregates. Contemporary constitutive models for clay tend to ignore this scale separation, and rather focus on phenomenology. By considering scale separation, this paper introduces a robust physics-based phenomenological constitutive model for clay that qualitatively captures their broad spectrum of rate-dependent mechanical features. The model is derived using the thoroughly rigorous hydrodynamic procedure. While some imagine that by considering rigour and physics, their models would get complicated, the resulting set of equations reveal a surprising degree of simplicity. The derivation strongly benefits from the principle of two-stage irreversibility, which describes energy flow within the material from the continuum scale down to the atomistic micro-scale, through the meso-scale of clay aggregates. While thermal and meso-related temperatures capture atomistic and clay aggregate fluctuating motions, a sink term from the latter to the former underpins the direction of the energy flow. The model’s standout feature is in pinpointing new transport coefficients that drive both volumetric and shear plastic flows in a thermodynamically coupled manner. A novel scheme is then proposed to calibrate these coefficients from conventional steady-state observations. Thanks to the formulation the model shows a remarkable level of predictiveness, despite being relatively simple mathematically. In particular, the model can readily explain the broad spectrum of rate-dependent phenomena during transient loading, along with creep and relaxation processes. Given the generality of hydrodynamics, it is anticipated that the new model could be expanded to capture fluid-solid transitions between liquid-like soft mud and plastic-like stiff clay responses, contingent on water content variations.

实验室对粘土的描述通常将原子尺度与粘土颗粒和聚集体的尺度区分开来。当代粘土本构模型倾向于忽略这种尺度分离,而更注重现象学。通过考虑尺度分离,本文引入了一个健壮的基于物理的粘土现象学本构模型,该模型定性地捕获了它们的广谱速率相关的力学特征。该模型是用完全严格的流体力学程序推导出来的。虽然有些人认为,考虑到严格性和物理学,他们的模型会变得复杂,但最终的一组方程显示出惊人的简单程度。该推导得益于两阶段不可逆性原理,该原理描述了材料内部从连续体尺度到原子微观尺度,通过粘土聚集体的中观尺度的能量流动。当热和中观相关的温度捕获原子和粘土集 合体的波动运动时,从后者到前者的汇项支撑着能量流的方向。该模型的突出特点是确定了新的输运系数,这些系数以热力学耦合的方式驱动体积和剪切塑性流动。然后提出了一种新的方案来校准这些系数从传统的稳态观测。尽管在数学上相对简单,但由于这个公式,这个模型显示出了显著的预测性。特别是,该模型可以很容易地解释瞬态加载过程中与速率相关的广谱现象,以及蠕变和松弛过程。考虑到流体力学的普遍性,预计新模型可以扩展到捕获流体-固体之间的过渡,类液体软泥和类塑料硬粘土响应,取决于含水量的变化。


Mechanics of Materials

Contributing Factors to Preterm Pre-Labor Rupture of The Fetal Membrane: Biomechanical Analysis of The Membrane Under Different Physiological Conditions

Daniel S. Fidalgo, Kayvan Samimi, Melissa C. Skala, Renato M.N. Jorge, Marco P.L. Parente, Ewelina Malanowska, Kristin M. Myers, Dulce A. Oliveira

doi:10.1016/j.mechmat.2024.105104

早产胎膜产前破裂的影响因素:不同生理条件下胎膜的生物力学分析

The fetal membranes are a complex biological structure essential for pregnancy, comprising two main layers: the amnion and the chorion. Characterizing each layer from a mechanical perspective is extremely important to understand the rupture process of the membrane at term or preterm. It is still unclear what factors lead to preterm pre-labor rupture of the membrane (PPROM) due to ethical and technical factors associated with in-vivo experimental tests. Numerical simulations may offer some answers, clarifying the biomechanics of the fetal membrane during gestation. This work uses a validated multilayer fetal membrane model to evaluate whether certain physiological conditions occurring during pregnancy contribute to PPROM. The following factors are evaluated: (i) contact conditions between the amnion and the chorion, (ii) normal and abnormal intrauterine pressures, (iii) amnion and chorion thicknesses, and (iv) orientation of the collagen fibers within the amnion layer. Our results show that PPROM might be potentiated under certain physiological circumstances: (i) the existence of interconnection (friction or tied contact) between the two main layers of the fetal membrane increases the stress in the mechanical dominant amnion, (ii) larger intrauterine pressures and (iii) smaller amnion and chorion thicknesses lead to the same increase in stress, and (iv) different off-plane angles of the collagen fibers tend to modify the stress distribution and thickness variation in both layers.

胎膜是一个复杂的生物结构,对怀孕至关重要,包括两层:羊膜和绒毛膜。从力学角度描述每一层对于理解足月或早产时膜的破裂过程是非常重要的。由于与体内实验测试相关的伦理和技术因素,目前尚不清楚是什么因素导致早产产前膜破裂(PPROM)。数值模拟可能提供一些答案,澄清胎膜在妊娠期间的生物力学。这项工作使用了一个经过验证的多层胎膜模型来评估怀孕期间发生的某些生理状况是否会导致PPROM。评估以下因素:(i)羊膜和绒毛膜之间的接触条件,(ii)正常和异常的宫内压力,(iii)羊膜和绒毛膜厚度,(iv)羊膜层内胶原纤维的方向。我们的研究结果表明,在一定的生理条件下,PPROM可能会被增强:(1)胎膜两主要层之间相互连接(摩擦或捆绑接触)的存在增加了机械优势羊膜中的应力,(2)较大的宫内压力和(3)较小的羊膜和绒毛膜厚度导致应力增加相同,(4)胶原纤维的不同离面角度倾向于改变两层的应力分布和厚度变化。


Thin-Walled Structures

Spectral element-finite element modeling and dynamic analysis of a fluid-delivering cracked pipe subjected to both pulsation and base excitations

Wenhao Ji, Hongwei Ma, Honghao Liu, Wei Sun, Donghai Wang

doi:10.1016/j.tws.2024.112242

谱元-有限元建模及受脉动和基底激励的输液管的动力学分析

Previous studies on cracked pipes have predominantly focused on single excitation, but in practical engineering, pipe systems often experience a combined effect of fluid pulsation and base excitations, which can potentially trigger more complex dynamic behaviors. Moreover, the solid finite element (FE) models are generally adopted to simulate the breathing effect and stress singularity, but the solution efficiency is unacceptable. Therefore, this study presents a spectral element-finite element (SE-FE) method to construct the dynamic models of the fluid-delivering cracked pipes (FDCPs), which combines the efficiency of spectral element (SE) with the adaptability of FE. Furthermore, a fluid pulsation model is constructed using measured data. Specifically, dynamic models of intact and cracked pipe segments are constructed using SE and FE, respectively, and interface coupling is achieved by the penalty function method. Subsequently, an experimental system for fluid pulsation excitation is established, and then a fluid pulsation model is constructed. Finally, the dynamic behaviors of a FDCP under compound excitation are analyzed. The results show that the fluid pulsation in the FDCP is higher than that in the intact pipe due to the breathing effect. Moreover, the beat vibration will be triggered when the pulsation frequency approaches the base excitation frequency. This study can provide a better understanding for the dynamic behaviors of FDCP, thereby providing a reference for crack damage detection.

以往对裂纹管道的研究主要集中在单一激励上,但在实际工程中,管道系统经常会受到流体脉动和基底激励的综合影响,这可能会引发更复杂的动力行为。此外,通常采用实体有限元模型来模拟呼吸效应和应力奇点,但求解效率令人难以接受。为此,本研究提出了一种结合谱元(SE)效率和有限元适应性的谱元-有限元(SE-FE)方法来构建输液裂纹管道(fdps)的动力学模型。利用实测数据建立了流体脉动模型。其中,完整管段和裂纹管段分别采用SE和FE建立动力模型,并采用罚函数法实现界面耦合。在此基础上,建立了流体脉动激励实验系统,建立了流体脉动模型。最后,分析了FDCP在复合激励下的动态特性。结果表明,由于呼吸效应的影响,FDCP管内的流体脉动比完整管道内的流体脉动要大。当脉动频率接近基激励频率时,将触发脉动振动。该研究可以更好地了解FDCP的动态行为,从而为裂纹损伤检测提供参考。


A data-driven computational optimization framework for designing thin-walled lenticular deployable composite boom with optimal load-bearing and folding capabilities

Junwei Sun, Qigang Han, Xianhe Cheng, Hexuan Shi, Rundong Ding, Mingdi Shi, Chunguo Liu

doi:10.1016/j.tws.2024.112244

具有最佳承载和折叠能力的薄壁透镜可展开复合材料臂设计的数据驱动计算优化框架

The thin-walled lenticular deployable composite boom (LDCB) is promising for aerospace engineering applications due to its lightweight and compact nature, but its mechanical behaviors are the main challenges limiting its practical application. Here, the axial compression and folding behaviors of LDCB were numerically simulated and the simulation results were verified according to the experimental data in the literature. Then, a new double chains quantum genetic algorithm (DCQGA)-gaussian process regression (GPR) model and data-driven computational optimization framework were proposed and the new model was trained using a database with 400 simulation results, the superiority of which was demonstrated by prediction accuracy evaluation. Additionally, benchmarking five state-of-the-art algorithms found that the coupling technology of DCQGA-GPR-non-dominated sorting genetic algorithm III (NSGA-III) is an excellent optimization strategy to obtain a well-designed structure of LDCB that maximizes the effectiveness of the material while satisfying the lightweight. The optimized LDCB design exhibits a significant performance improvement, with a 26.3% reduction in the folding moment, a 34.2% reduction in the maximum Tsai-Hill failure index, a 43.6% increase in the critical load, and an 11% reduction in linear density of mass compared to the initial design.

薄壁透镜式可展开复合材料臂架(LDCB)由于其轻量化和紧凑的特性,在航空航天工程中有着广阔的应用前景,但其力学性能是限制其实际应用的主要挑战。本文对LDCB的轴向压缩和折叠行为进行了数值模拟,并根据文献中的实验数据对模拟结果进行了验证。然后,提出了一种新的双链量子遗传算法(DCQGA)-高斯过程回归(GPR)模型和数据驱动的计算优化框架,并利用400个仿真结果的数据库对新模型进行了训练,通过预测精度评价证明了新模型的优越性。此外,对五种最先进的算法进行了基准测试,发现dcqga - gpr -非主导排序遗传算法III (NSGA-III)的耦合技术是一种优秀的优化策略,可以获得设计良好的LDCB结构,使材料的有效性最大化,同时满足轻量化。优化后的LDCB与初始设计相比,折叠弯矩降低了26.3%,最大Tsai-Hill破坏指数降低了34.2%,临界载荷提高了43.6%,质量线密度降低了11%。


Stability analysis of sandwich double nanobeam-system with varying cross-section interconnected by Kerr-type three-parameter elastic layer

M. Soltani, M.H. Momenian, O. Civalek

doi:10.1016/j.tws.2024.112249

克尔型三参数弹性层连接变截面夹层双纳米梁系统的稳定性分析

In this study, the endurable buckling load of the elastically connected parallel sandwich nano-beams with varying cross-sections is assessed. In this regard, a layered beam system consisting of two parallel axially loaded tapered sandwich nanobeams that are interconnected via a Kerr-type three-parameter elastic foundation is considered. The geometric properties are assumed to be changed exponentially along the length of the beam element. The governing equilibrium equations of the system are described by a set of three coupled homogeneous differential equations, which originates in the context of Eringen's non-local elasticity theory and Euler beam model. Then, the numerical differential quadrature technique is used to estimate the endurable axial critical loads. Eventually, a comprehensive parameterization research is performed to investigate the sensitivity of linear buckling resistance to tapering ratio, nonlocal parameter, stiffness of elastic connections, volume fraction exponent, and thickness ratio. The research work of the present study is novel, and the attained numerical outcomes can be used as benchmarks for future researches in this field.

在本研究中,评估了弹性连接的不同截面的平行夹层纳米梁的耐屈曲载荷。在这方面,考虑了由两个平行轴向加载的锥形夹层纳米梁组成的层状梁系统,这些纳米梁通过kerr型三参数弹性基础相互连接。假定几何性质沿梁单元长度呈指数变化。系统的控制平衡方程由三个耦合齐次微分方程来描述,该微分方程起源于Eringen的非局部弹性理论和欧拉梁模型。在此基础上,利用数值微分正交技术估算了轴向临界载荷。最后,进行了全面的参数化研究,探讨了线性屈曲抗力对锥度比、非局部参数、弹性连接刚度、体积分数指数和厚度比的敏感性。本文的研究工作是新颖的,所获得的数值结果可以作为该领域未来研究的基准。


Geometrically nonlinear analysis of plates and shells by a cell-based smoothed CS-MITC18+ flat shell element with drilling degrees of freedom

Thanh Chau-Dinh, Nghia Tran-Chi, Van-Hau Nguyen, Trung-Kien Nguyen

doi:10.1016/j.tws.2024.112254

基于网格光滑CS-MITC18+平面壳单元的板壳几何非线性分析

A development of a 3-node triangular flat shell element to analyze geometric nonlinearity of plate and shell structures is presented in this study. The proposed flat shell element has 6 degrees of freedom per node, including the drilling rotational ones, by using the Allman-type approximations for the in-plane displacements and the bending displacement approximations enriched by a cubic shape function at the bubble node located at the element's centroid. The geometrically nonlinear behaviors are described by the von Karman's large deflection assumption. The membrane and bending strains of the presented flat shell elements are averaged over sub-triangular elements based on the cell-based smoothed (CS) technique. To attenuate the shear locking phenomenon, the transverse shear strains are re-interpolated following the mixed interpolation of tensorial components (MITC) technique designed for the 3-node triangular degenerated shell elements enriched by a cubic bubble function (MITC3+). Combined with the Newton-Raphson iterations and load increments predicted by the arc-length method, the suggested 3-node triangular flat shell elements, namely the CS-MITC18+ element, can analyze moderately geometrical nonlinearity, including the snap-thought and snap-back behaviors, of various plates and shells with the different shapes, thickness, and boundaries. The numerical investigations show that the load-displacement curves provided by the CS-MITC18+ flat shell elements well agree with other references.

本文提出了一种用于板壳结构几何非线性分析的三节点三角形平壳单元。通过使用allman型面内位移近似和弯曲位移近似,所提出的平壳单元在单元质心处的气泡节点上丰富了三次形状函数,每个节点具有6个自由度,包括钻井旋转节点。几何非线性行为由von Karman大挠度假设描述。基于单元平滑(CS)技术,将平面壳单元的膜应变和弯曲应变平均到次三角形单元上。为了减弱剪切锁紧现象,采用基于三节点三角形退化壳单元的三次立方泡函数(MITC3+)的张量分量混合插值(MITC)技术对横向剪切应变进行了重新插值。结合弧长法预测的Newton-Raphson迭代和载荷增量,建议的3节点三角形扁平壳单元CS-MITC18+单元可以分析不同形状、厚度和边界的各种板壳的适度几何非线性,包括弹思和弹回行为。数值研究表明,CS-MITC18+平壳单元提供的荷载-位移曲线与其他文献吻合较好。




来源:复合材料力学仿真Composites FEM
ACTMechanicalSystemMarc振动复合材料非线性航空航天ADS裂纹理论材料控制试验管道
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:2024-11-21
最近编辑:1小时前
Tansu
签名征集中
获赞 3粉丝 0文章 679课程 0
点赞
收藏
作者推荐

【新文速递】2024年7月25日复合材料SCI期刊最新文章

今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 6 篇,Composites Part B: Engineering 3 篇Composite StructuresAnalytical homogenization for equivalent in-plane elastic moduli of prestressed lattices based on the micropolar elasticity modelZhi Guo, Xiang Liu, Li Huang, S. Adhikari, Xifeng Liangdoi:10.1016/j.compstruct.2024.118391基于微极弹性模型的预应力网格等效面内弹性模量解析均匀化Highly compressible and stretchable lattice materials have gained significant attention due to their advanced structural characteristics. However, most existing research on homogenization relies on linear classical elasticity theory, omitting nonlinear deformation and/or the micropolar elasticity rotation. This paper addresses this gap by introducing a novel analytical homogenization method for the in-plane equivalent elastic moduli of prestressed two-dimensional lattices that incorporates both nonlinear elastic deformation and micropolar elastic effects. First, the stiffness matrices of a lattice cell wall under axial force is formulated. Based on the micropolar elasticity theory, the micropolar elastic constitutive relations for four lattice materials under prestresses were established, i.e., rectangular, diamond, equilateral triangular, and mixed diamond lattices. Then, the micropolar elastic constants for different prestressed lattices are formulated. The closed-form expressions for the equivalent elastic moduli of nonlinear micropolar elastic bodies were derived from these micropolar elastic constants by their physical significance. The analytical expressions for the lattice elastic moduli are validated by using independent nonlinear finite element simulation in ANSYS with relative errors less than 4%. The proposed analytical method and new closed-form expressions provide a framework with high computational efficiency and accuracy for the analysis and parametric design of lattice materials under external stress.高可压缩和高可拉伸晶格材料因其先进的结构特性而受到广泛关注。然而,现有的均匀化研究大多依赖于线性经典弹性理论,忽略了非线性变形和/或微极弹性旋转。本文通过引入一种新的二维预应力网格面内等效弹性模量的解析均匀化方法来解决这一空白,该方法同时考虑了非线性弹性变形和微极弹性效应。首先,建立了轴向力作用下晶格胞壁的刚度矩阵。基于微极弹性理论,建立了矩形、菱形、等边三角形和混合菱形四种晶格材料在预应力作用下的微极弹性本构关系。然后,给出了不同预应力格的微极弹性常数。根据这些微极弹性常数的物理意义,导出了非线性微极弹性体等效弹性模量的封闭表达式。通过ANSYS独立非线性有限元仿真,验证了晶格弹性模量解析表达式的正确性,相对误差小于4%。所提出的解析方法和新的封闭表达式为晶格材料在外加应力作用下的分析和参数化设计提供了一个计算效率高、精度高的框架。Composites Part A: Applied Science and ManufacturingModified lap shear test for intralaminar shear failure of fiber reinforced compositesMalik John, John Park, Kedar Kiranedoi:10.1016/j.compositesa.2024.108368纤维增强复合材料层间剪切破坏的改进搭接剪切试验This work presents a modification of the lap shear test for application to the intralaminar shear failure of fiber reinforced composites. The proposed method involves an S-shaped double-cracked specimen loaded under uniaxial in-plane compression. The resulting loading is akin to a lap shear test but inducing intralaminar shear failure (not interlaminar). Elastic stress analysis confirms a shear dominated stress state in specimen ligament, and numerical contour-integral confirms a mode II dominance in the near tip region. Experimental results for an epoxy/carbon twill woven composite are presented, demonstrating the ease of the test method. Nonlinear quasi-ductile behavior is observed, as expected, and necessitates the use of elastoplastic fracture mechanics to interpret the fracture toughness. The estimated initiation toughness values are successfully verified via cohesive crack simulations. The presented test represents a simple and repeatable method to characterize the intralaminar shear failure of fiber-reinforced composites.提出了一种适用于纤维增强复合材料层间剪切破坏的搭接剪切试验的改进方法。所提出的方法涉及一个s形双裂纹试件,在单轴面内压缩下加载。由此产生的荷载类似于搭接剪切试验,但会引起层内剪切破坏(而不是层间)。弹性应力分析证实了试样韧带的剪切主导应力状态,数值轮廓积分证实了近尖端区域的II型主导应力状态。最后给出了环氧/碳斜纹织物复合材料的实验结果,证明了该测试方法的可行性。正如预期的那样,观察到非线性准延性行为,需要使用弹塑性断裂力学来解释断裂韧性。通过内聚裂纹模拟成功验证了估算的起裂韧性值。本试验为表征纤维增强复合材料层间剪切破坏提供了一种简单、可重复的方法。Copper oxide decorated one-dimensional mineral nanorods: Construction of strengthened gas-phase and condensed-phase coupled intumescent flame retardantZeyang Gao, Yu Zhu, Xiaoyong Liu, Bihe Yuan, Ranzhao Shen, Kailin Li, Yao Yin, Zhipeng Zhangdoi:10.1016/j.compositesa.2024.108373氧化铜修饰一维矿物纳米棒:强化气相-冷凝相耦合膨胀阻燃剂的构建Polycarbonate/acrylonitrile–butadiene–styrene (PC/ABS) features superior mechanical properties but suffers from high flammability, presenting a grand challenge in enhancing its flame retardancy with halogen-free additives. Herein, we developed an efficient flame-retardant system (BH/CuATP) by incorporating phosphazene additive (HP), copper oxide modified attapulgite (CuATP) and bisphenol A bis (diphenyl phosphate) (BDP). This system achieves a UL-94V-0 rating without melt-dripping and leads to reductions in the peak heat release rate (43.1 %), total heat release (29.8 %) and total smoke production (5.7 %). The strength effect of CuATP in both gas-phase and condensed-phase significantly contributes to its enhanced fire safety. Additionally, the mechanical properties of PC/ABS/B1H1/CuATP1 are improved due to the rod-like CuATP, showing enhanced comprehensive properties superior to other reported systems. This work presents valuable insights into the effectiveness of mineral-strength intumescent flame retardancy for PC/ABS, offering practical guidance for the development of high-performance PC/ABS composites.聚碳酸酯/丙烯腈-丁二烯-苯乙烯(PC/ABS)具有优异的机械性能,但具有较高的可燃性,使用无卤添加剂增强其阻燃性是一个巨大的挑战。本文采用磷腈添加剂(HP)、氧化铜改性凹凸棒土(CuATP)和双酚A双(二苯基磷酸)(BDP)为原料,研制了一种高效阻燃体系(BH/CuATP)。该系统达到UL-94V-0等级,无熔滴,并导致峰值放热率(43.1% %),总放热率(29.8% %)和总烟雾产量(5.7% %)的降低。CuATP在气相和冷凝相中的强度效应显著提高了其防火安全性。此外,由于棒状CuATP的存在,PC/ABS/B1H1/CuATP1的力学性能得到了改善,其综合性能优于其他已报道的体系。本工作对PC/ABS矿物强度膨胀阻燃的有效性提出了有价值的见解,为高性能PC/ABS复合材料的开发提供了实践指导。Developing an efficient analytical model for predicting the electrical conductivity of polymeric nanocomposites containing hybrid carbon nanotube/carbon black nanofillersMaedeh Saberi, Alireza Moradi, Reza Ansari, Mohammad Kazem Hassanzadeh-Aghdam, Jamaloddin Jamalidoi:10.1016/j.compositesa.2024.108374建立了一种预测含碳纳米管/炭黑纳米填料的聚合物纳米复合材料电导率的有效分析模型Inter-cluster bridging of carbon nanotubes (CNTs) and carbon black (CB) nanoparticles conjoins inactive branches of carbonaceous nanofillers within the matrix and reduces the electron tunneling distance. This mechanism moderately overcomes quantum tunneling and provides percolative polymer networks exhibiting favorable electrical responses. This study focuses on devising an analytical procedure to scrutinize the electrical conductivity and percolation threshold of CNT/CB/polymer nanocomposites. To involve the physics of electrical processes, the modeling approach considers cylindrical CNTs and spherical CB nanoparticles surrounded by a continuum interphase, which serves as an electron hopping duct. This model is extended in a bottom-up micromechanics generalization to a level where it is capable of predicting the effects of a wide range of microstructural properties. The comparison of predictions with those obtained via experimental examinations, while affirming the infrastructure for investigating the electrical behavior of binary systems, convincingly captures the electrical conductivity/percolation threshold of ternary nanocomposites containing CNT/CB nanofillers.碳纳米管(CNTs)和炭黑(CB)纳米颗粒簇间桥接连接了基体内碳基纳米填料的非活性分支,减少了电子隧穿距离。这种机制适度地克服了量子隧道效应,并提供了具有良好电响应的渗透聚合物网络。本研究的重点是设计一种分析程序来仔细检查碳纳米管/碳炭黑/聚合物纳米复合材料的电导率和渗透阈值。为了涉及电过程的物理学,建模方法考虑了圆柱形碳纳米管和球形碳纳米管,它们被一个连续的界面所包围,作为一个电子跳跃管道。该模型在自下而上的微观力学推广中扩展到能够预测各种微观结构特性的影响的水平。将预测结果与实验结果进行比较,确定了研究二元体系电学行为的基础设施,并令人信服地捕获了含有碳纳米管/碳纳米管纳米填料的三元纳米复合材料的电导率/渗透阈值。Regulating the bimodal structure and strength-ductility synergy of Zn-decorated Ti particles reinforced AZ91 composite through high-volume fraction Mg17Al12 precipitationsYuhui Zhang, Shengli Han, Pengfei Gao, Pengju Chen, Jun Xia, Jianbo Li, Jia She, Xianhua Chen, Kaihong Zheng, Fusheng Pandoi:10.1016/j.compositesa.2024.108376通过高体积分数Mg17Al12析出调节zn修饰Ti颗粒增强AZ91复合材料的双峰结构和强度-塑性协同作用In this work, Mg-9Al-1Zn (AZ91) alloy reinforced with zinc-decorated titanium (Zn@Ti) particles was fabricated using the powder metallurgy method. Zn nanoparticles effectively dissolved into magnesium (Mg) matrix, which led to a reduction in the solid solubility of aluminum (Al) and precipitations of submicron sized Mg17Al12. As a result, the Zn@Ti/AZ91 composite displays a bimodal grain structure, achieving a remarkable balance between strength and ductility, with a yield strength of 248 ± 3.5 MPa, an ultimate tensile strength of 378 ± 5.3 MPa, and an elongation of 15.0 ± 2.8 %. The improved strength of Zn@Ti/AZ91 composite primarily stems from the synergistic effect of a significant volume fraction of submicron sized Mg17Al12 and Al8Mn5 precipitations strengthening, Zn solid solution strengthening, and grain boundary strengthening. Regarding ductility mechanisms, the presence of Mg17Al12 and Al8Mn5 precipitations effectively impede crack propagation and enhance ductility. This innovative approach represents a promising strategy for developing high strength and ductility of Mg composites.本文采用粉末冶金方法制备了锌修饰钛(Zn@Ti)颗粒增强Mg-9Al-1Zn (AZ91)合金。锌纳米粒子有效地溶解在镁基体中,导致铝的固溶性降低,亚微米级Mg17Al12析出。因此,Zn@Ti / AZ91复合显示双峰晶粒结构,实现非凡的强度和延性之间的平衡,屈服强度248 ±3.5  MPa,极限抗拉强度378 ±5.3  MPa,和15.0的伸长 ±2.8  %。Zn@Ti/AZ91复合材料强度的提高主要源于大量体积分数的亚微米级Mg17Al12和Al8Mn5析出强化、Zn固溶体强化和晶界强化的协同作用。在延性机制方面,Mg17Al12和Al8Mn5析出物的存在有效地阻碍了裂纹扩展,增强了延性。这种创新的方法代表了开发高强度和高塑性镁复合材料的一种有前途的策略。Experimental investigation on microstructure, mechanical and optical properties of RB-SiC ablated by nanosecond pulsed laser in nitrogen atmosphereHong An, Yongfeng Qian, Zhiyu Zhang, Hu Huang, Jiwang Yandoi:10.1016/j.compositesa.2024.108377氮气氛下纳秒脉冲激光烧蚀RB-SiC的显微组织、力学和光学性能的实验研究Reaction-bonded silicon carbide (RB-SiC) has gained significant attention owing to its exceptional physical and chemical properties. Improving the photovoltaic efficiency and mechanical properties of RB-SiC is conducive to further enhancing its applicability. Laser gas nitriding is an effective strategy to simultaneously reduce the surface reflectivity and enhance the surface hardness of materials. Accordingly, the evolution of microstructure, mechanical and optical properties of RB-SiC composite ablated by nanosecond pulsed laser in nitrogen atmosphere was comprehensively investigated. After laser gas nitriding, the surface hardness of RB-SiC composite was increased by 10.6–44.6 %. The chemical composition analysis indicated that Si-based nitride was formed on the laser-ablated surface, which was mainly responsible for the hardness enhancement. Additionally, the reflectivity of the laser-ablated surface was reduced by up to 95.2 % compared to the original RB-SiC composite. This study provides a straightforward and effective method to simultaneously improve the mechanical and optical properties of RB-SiC composites.反应键合碳化硅(RB-SiC)由于其优异的物理和化学性能而受到广泛关注。提高RB-SiC的光伏效率和力学性能有利于进一步增强其适用性。激 光气体氮化是降低材料表面反射率、提高材料表面硬度的有效方法。在此基础上,对纳秒脉冲激光在氮气气氛下烧蚀RB-SiC复合材料的显微组织、力学性能和光学性能的演变进行了全面研究。激光 气体氮化后,RB-SiC复合材料的表面硬度提高了10.6 ~ 44.6% %。化学成分分析表明,激光烧蚀表面形成了硅基氮化物,这是硬度增强的主要原因。此外,激光烧蚀表面的反射率比原始RB-SiC复合材料降低了95.2% %。本研究为同时提高RB-SiC复合材料的力学性能和光学性能提供了一种简单有效的方法。Data-driven thermal modeling of in-situ Automated Fiber PlacementAllyson Fontes, Farjad Shadmehridoi:10.1016/j.compositesa.2024.108379原位自动铺放纤维的数据驱动热建模This study proposes a data-driven model for thermal history prediction during in-situ Automated Fiber Placement of thermoplastic composites. Temperature data was experimentally collected with fast-response thermocouples placed within carbon fiber AS4/PEEK composite substrates. The temperature for various combinations of hot gas torch temperatures, heat source velocity, and locations through the thickness and width were collected. A feedforward neural network (FNN) was developed to predict the entire 3-dimensional thermal history. The FNN had five input features and one output: the temperature at a given position and a combination of the process parameters. The FNN predictions for data unseen during training are validated for cases of interpolation and extrapolation. As expected, suitable performance was obtained for cases of interpolation, but predictions suffered in extrapolation. The computational efficiency of FNNs makes them an appropriate candidate for on-line thermal history prediction or process optimization, given that they are used within their training range本研究提出了一种数据驱动模型,用于热塑性复合材料原位自动铺放纤维过程中的热历史预测。温度数据通过放置在碳纤维AS4/PEEK复合材料衬底内的快速响应热电偶进行实验采集。收集了不同温度组合下的温度、热源速度以及不同厚度和宽度下的位置。提出了一种前馈神经网络(FNN)来预测整个三维热历史。FNN有五个输入特征和一个输出特征:给定位置的温度和过程参数的组合。FNN对训练期间未见数据的预测在插值和外推的情况下得到验证。正如预期的那样,在插值的情况下获得了合适的性能,但外推的预测受到影响。fnn的计算效率使其成为在线热历史预测或过程优化的合适候选者,因为它们在其训练范围内使用Composites Part B: EngineeringApplications of Artificial Intelligence/Machine Learning to High-Performance CompositesYifeng Wang, Kan Wang, Chuck Zhangdoi:10.1016/j.compositesb.2024.111740人工智能/机器学习在高性能复合材料中的应用With the booming prosperity of artificial intelligence (AI) technology, it triggers a paradigm shift in engineering fields including material science. The integration of AI and machine learning (ML) techniques in material science brings significant advancements in understanding and characterizing underlying physics. Due to the overall outstanding properties compared to conventional metallic materials, high-performance fiber reinforced polymer (FRP) composites have attracted great interest. This article aims to provide a comprehensive review of the state-of-the-art works of applying AI/ML methods in high-performance FRP composites, focusing on four critical stages throughout the product life cycle, i.e., design, manufacturing, testing, and monitoring. This present study covers the tasks of material development and selection, process modeling and optimization, material property prediction, and damage diagnosis and prognosis in the four stages, which are conducted with the aid of advanced AI/ML algorithms. An outlook for the incorporation of modern advanced AI/ML models into FRP composite research is provided by the identification of current challenges and potential future research directions.随着人工智能(AI)技术的蓬勃发展,引发了包括材料科学在内的工程领域的范式转变。人工智能和机器学习(ML)技术在材料科学中的整合,在理解和表征基础物理方面取得了重大进展。由于与传统金属材料相比,高性能纤维增强聚合物(FRP)复合材料的整体性能突出,引起了人们的极大兴趣。本文旨在全面回顾在高性能FRP复合材料中应用AI/ML方法的最新工作,重点关注整个产品生命周期的四个关键阶段,即设计、制造、测试和监控。本研究采用先进的AI/ML算法,完成了材料开发与选择、工艺建模与优化、材料性能预测、损伤诊断与预测四个阶段的工作。通过确定当前的挑战和潜在的未来研究方向,展望了将现代先进的AI/ML模型纳入FRP复合材料研究的前景。Based on the preparation of dual-absorber agents using Ni and Ni/rGO for the fabrication of a dual honeycomb nested structure for wideband microwave absorptionShaokang Liu, Fangxin Zhang, Bin Chao, Wenxin Fu, Kaixin Deng, Yan Li, Haihua Wudoi:10.1016/j.compositesb.2024.111735本文在制备双吸收剂的基础上,利用Ni和Ni/rGO制备了用于宽带微波吸收的双蜂窝嵌套结构Designing absorbers with structural support to achieve ultra-wideband and wide-angle absorption properties is crucial for addressing the growing concern of electromagnetic pollution. In this study, a strategy is proposed to further broaden the bandwidth of structural absorbers by applying different materials to different structures and then nesting these different structures. Six composite materials were prepared using Ni and rGO as absorbers, and a dual honeycomb nested structure was fabricated using 3D printing technology. The minimum reflection loss (RL) of the two types of composite materials was −19.3 dB and −15.8 dB, respectively, with effective absorption bandwidths (EAB) of 4.6 GHz and 4.4 GHz, demonstrating mechanical compatibility and electromagnetic substitutability. The dual honeycomb nested structure utilized a multiscale design approach, achieving broadband absorption up to 14.27 GHz and compressive strength of 5.92 MPa. Furthermore, stable frequency response of transverse electric (TE) waves was observed within an incident angle range of 0°–40°, while absorption frequencies exceeded 12 GHz as transverse magnetic (TM) waves incident angle varied from 0° to 60°, highlighting wide-angle absorption characteristics. The dual composite preparation strategy of materials and structures for absorber fabrication provides a new perspective for further expanding the bandwidth of absorbers.设计具有结构支撑的吸波器以实现超宽带广角吸收特性是解决日益受到关注的电磁污染问题的关键。本研究提出了一种策略,通过将不同的材料应用于不同的结构,然后将这些不同的结构嵌套,进一步拓宽结构吸收器的带宽。以Ni和还原氧化石墨烯为吸波剂制备了6种复合材料,并利用3D打印技术制备了双蜂窝嵌套结构。两种复合材料的最小反射损耗(RL)分别为- 19.3 dB和- 15.8 dB,有效吸收带宽(EAB)分别为4.6 GHz和4.4 GHz,具有良好的机械相容性和电磁可替代性。双蜂窝嵌套结构采用多尺度设计方法,实现了高达14.27 GHz的宽带吸收和5.92 MPa的抗压强度。此外,在0°~ 40°入射角范围内,横电波的频率响应稳定,而横磁波在0°~ 60°入射角范围内,吸收频率超过12 GHz,显示出广角吸收特征。材料和结构的双重复合制备策略为进一步扩大吸波器的带宽提供了新的前景。Multi-Objective Optimization Through Desirability Function Analysis on the Crashworthiness Performance of Thermoplastic/Thermoset Hybrid StructuresMahmoud M. Awd Allah, Marwa A. Abd El-bakydoi:10.1016/j.compositesb.2024.111742基于期望函数分析的热塑性/热固性混合结构耐撞性能多目标优化This paper aims to optimize the crashworthiness capability of glass-reinforced epoxy composites (GFRE) over wrapped polyvinyl chloride (PVC) circular tubes with cutouts. The intended tubes were prepared by a wet wrapping method; then subjected to quasi-static axial compression. To compute crashworthiness indications, three design parameters, each at three levels, were used. The design parameters are the hole diameter (d), the hole’s number (n), and the hole position (L). A few runs were accompanied by the L9 orthogonal array based on the Taguchi technique. With the lowest initial peak crash force () and the largest absorbed energy (U), the optimal parameters were found. Furthermore, the main effect, signal-to-noise ratio (S/N), as well as the analysis of variance (ANOVA), have been studied using the commercial software program MINITAB 18. Furthermore, to optimize the process parameters in terms of the crashworthiness indicators, desirability function analysis (DFA) was applied. Lastly, tests for confirmation were performed to verify the predicted values in light of the experimental results and compare them with the intact tubes. Regarding the single optimization, the optimum tube is smaller than the intact PVC tube and intact hybrid tube, at 24.01 and 72.85%, respectively. Nonetheless, the optimal U was 21.43% lower than the intact hybrid tube and 152.75% greater than the intact PVC tube. While, for and U, the multi-objective optimization specimen achieves 5.13 and 70.02% greater than the intact PVC tube. But it was 62.44% and 47.14% less than what the intact hybrid tube had accomplished.本文旨在优化玻璃增强环氧复合材料(gfr)覆盖有切口的聚氯乙烯(PVC)圆管的耐撞性能。所述管采用湿包膜法制备;然后进行准静态轴向压缩。为了计算耐撞性指标,使用了三个设计参数,每个参数在三个级别上。设计参数为孔直径(d)、孔数(n)和孔位置(L)。少量井眼采用基于田口技术的L9正交阵列。以最小的初始峰值碰撞力()和最大的吸收能量(U)为最优参数。此外,利用商业软件MINITAB 18对主效应、信噪比(S/N)以及方差分析(ANOVA)进行了研究。在此基础上,应用理想函数分析(DFA)方法,从耐撞性指标出发对工艺参数进行优化。最后,根据实验结果对预测值进行了验证,并与完整管进行了对比。对于单次优化,最优管材比完整PVC管材和完整杂化管材小,分别为24.01和72.85%。最优U值比杂交管材整体低21.43%,比聚氯乙烯管材整体高152.75%。而对于和U,多目标优化试样比完整PVC管分别大5.13和70.02%。但与完整杂交管相比,分别降低了62.44%和47.14%。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