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【新文速递】2024年9月2日复合材料SCI期刊最新文章

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今日更新:Composite Structures 4 篇,Composites Part A: Applied Science and Manufacturing 3 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇

Composite Structures

A comprehensive review on mechanical properties and damage mechanisms of 3DWCs under various influencing factors

Yonghao Xu, Wensuo Ma, Xiaoqiang Wang, Ma Zhenyu, Huang Zhaohua, Man Ruidong

doi:10.1016/j.compstruct.2024.118523

各种影响因素下3DWCs的力学性能及损伤机理综述

Three-dimensional woven composites (3DWCs) have received widespread attention due to their advantages, such as integral near-net molding of complex components and high damage tolerance. However, 3DWCs exhibit significant variations in mechanical behavior under various influencing factors, which poses challenges in selecting appropriate application scenarios. In recent years, there has been rapid development in the performance analysis and modeling strategies for 3DWCs, leading to substantial results. This paper provides a comprehensive overview of the mechanical properties and damage mechanisms of 3DWCs under various influencing factors, aiming to facilitate the selection of 3DWCs for different engineering applications and to complement the existing database of mechanical properties.

三维机织复合材料(3DWCs)因其具有复杂部件整体近净成型和高损伤容限等优点而受到广泛关注。然而,在各种影响因素下,3DWCs的力学性能表现出明显的变化,这给选择合适的应用场景带来了挑战。近年来,针对3DWCs的性能分析和建模策略得到了快速发展,并取得了丰硕的成果。本文全面综述了各种影响因素下3DWCs的力学性能和损伤机理,旨在为不同工程应用选择3DWCs提供方便,并对现有的力学性能数据库进行补充。


Enhancing the thermal conductivity of polystyrene/polyamide 6/graphene nanoplatelets composites through elongational flow

Shuai Wen, Jianming Chen, Jingjing Zhang, Zhangyuan Peng, Tinghui Huang, Zhansong Yin, Ruijie Xu, Anfu Chen, Caihong Lei

doi:10.1016/j.compstruct.2024.118527

通过拉伸流动增强聚苯乙烯/聚酰胺6/石墨烯纳米片复合材料的导热性

Migration and distribution of thermal conduct fillers in polymer blend are key factors in the preparation of enhanced thermal conductivity composite. In this study, polystyrene(PS)/polyamides 6(PA6)/graphene nanoplatelets(GNPs) composites with enhanced thermal conductivity were prepared under elongational flow, and the migration and distribution of GNPs were investigated by molecular dynamics simulation and experiments. The results showed that when GNPs immigrate from PA6 phase to PS phase, the elongational flow caused the orientation of the PS phase and GNPs, reducing the migration rate of GNPs from the PA6 phase to the PS phase. At the same time, the stretching viscosity of the PS phase increases, which prevents GNPs entering the PS phase. As a result, GNPs remain within the PA6 phase near the interface of the two phases. The effective distribution density of GNPs increased, making it easier for them to interconnect and form thermal conduction paths, thereby improving the thermal conductivity of the composites. Particularly, the composite prepared under the elongational flow with the 50/50 vol ratio of PS/PA6, the in-plane thermal conductivity of PS/PA6/GNPs composites reached a maximum of 1.64 W/(m·K).

导热填料在聚合物共混物中的迁移和分布是制备增强导热复合材料的关键因素。本研究在拉伸流动条件下制备了具有增强导热性的聚苯乙烯(PS)/聚酰胺6(PA6)/石墨烯纳米片(GNPs)复合材料,并通过分子动力学模拟和实验研究了GNPs的迁移和分布。结果表明:当GNPs从PA6相向PS相迁移时,拉长流动引起PS相和GNPs的取向,降低了GNPs从PA6相向PS相迁移的速率;同时,PS相的拉伸粘度增大,阻止了GNPs进入PS相。因此,GNPs停留在两相界面附近的PA6相内。GNPs的有效分布密度增加,使其更容易相互连接并形成导热路径,从而提高了复合材料的导热性。特别是当PS/PA6的 体积比为50/50时,PS/PA6/GNPs复合材料的面内导热系数达到了1.64 W/(m·K)的最大值。


A preparation method for microstructure of flexible pressure sensors based on origami craft

Liangsong Huang, Yu Zhang, Peng Zhang, Zhongkai Zhao, Zhifu Chen

doi:10.1016/j.compstruct.2024.118544

基于折纸工艺的柔性压力传感器微结构制备方法

With the development of flexible pressure sensors, an increasing number of microstructures and their preparation methods have been developed. However, how to reduce the cost and complexity of microstructure preparation while ensuring sensors’ performance and microstructure diversity remains a significant challenge. This paper explores the feasibility and diversity of origami craft in the microstructure preparation. Based on origami craft, various different microstructures, such as linear, cross, wrinkle and wave, could be prepared using low-cost silicone paper as mold material and simple steps. Due to the diversity of origami craft in microstructure preparation, our sensors with different microstructures also have their own advantage interval of pressure detection (0–4.4 kPa: the sensitivities of piezoresistive sensors with linear and cross microstructures are So = -0.31 kPa−1, St = -0.34 kPa−1; 4.4–13.3 kPa: the sensitivity of the piezoresistive sensor with wave microstructure is Swa = -0.028 kPa−1), some of the sensors have rapid response times, excellent response characteristics, repeatability, and hysteresis. Sensors designed for low-pressure applications can detect pressures as low as 22 Pa. Additionally, it was observed that they possess significant potential in human motion environments, office environments, and equipment testing environments. This indicates that origami craft offers excellent diversity and feasibility in the preparation of sensor microstructures.

随着柔性压力传感器的发展,人们开发了越来越多的微结构及其制备方法。然而,如何降低微结构制备的成本和复杂性,同时确保传感器的性能和微结构的多样性,仍然是一个重大挑战。本文探讨了折纸工艺在微结构制备中的可行性和多样性。在折纸工艺的基础上,使用低成本的硅胶纸作为模具材料和简单的步骤,可以制备出各种不同的微结构,如线形、十字形、皱纹形和波浪形。由于折纸工艺在微结构制备方面的多样性,我们采用不同微结构的传感器在压力检测方面也有各自的优势区间(0-4.4 kPa:采用线性和交叉微结构的压阻传感器的灵敏度分别为 So = -0. 31 kPa-1,St = -0.34 kPa-1;4.4-13.3 kPa:具有波状微结构的压阻传感器的灵敏度为 Swa = -0.028 kPa-1),部分传感器具有快速响应时间、优异的响应特性、重复性和滞后性。此外,据观察,这些传感器在人体运动环境、办公环境和设备测试环境中具有巨大的潜力。这表明,折纸工艺在制备传感器微结构方面具有出色的多样性和可行性。


Bond strength prediction of externally bonded reinforcement on groove method (EBROG) using MARS-POA

Pouyan Fakharian, Younes Nouri, Ali Reza Ghanizadeh, Farzad Safi Jahanshahi, Hosein Naderpour, Ali Kheyroddin

doi:10.1016/j.compstruct.2024.118532

基于MARS-POA的凹槽法(EBROG)外粘接钢筋粘结强度预测

The Externally Bonded Reinforcement on Grooves (EBROG) method represents an advancement in externally bonded reinforcement (EBR) techniques, specifically addressing the challenge of premature debonding often encountered in conventional Fiber Reinforced Polymer (FRP) applications directly bonded to concrete. This article introduces a novel and straightforward mathematical equation for predicting bond strength in the EBROG method using soft computing techniques for the first time. The study delves into the combined potential of the Multivariate Adaptive Regression Spline (MARS) model and the Pelican Optimization Algorithm (POA) for bond strength prediction in this method. The input parameters include FRP width, FRP thickness, elasticity modulus of FRP, concrete strength, groove length, groove width, and groove depth, while the output is EBROG bond strength. The study demonstrates exceptional accuracy with R2 values of 0.9629 for training and 0.9598 for testing, highlighting the model’s precision. The proposed bond strength prediction equation for the EBROG method undergoes validation against existing models, encompassing thirteen equations for EBR and a recent one specific to EBROG. Statistical metrics confirm the accuracy and reliability of the proposed equation. Notably, FRP stiffness emerges as the parameter with the highest relative importance, while groove width exhibits the lowest impact on bond strength.

沟槽外粘接加固(EBROG)方法代表了外粘接加固(EBR)技术的进步,特别是解决了直接粘合到混凝土上的传统纤维增强聚合物(FRP)应用中经常遇到的过早脱粘的挑战。本文首次采用软计算技术,在EBROG法中提出了一种新颖、直观的预测粘结强度的数学方程。研究了多变量自适应回归样条(MARS)模型和鹈鹕优化算法(POA)在该方法中结合预测粘结强度的潜力。输入参数为FRP宽度、FRP厚度、FRP弹性模量、混凝土强度、沟槽长度、沟槽宽度、沟槽深度,输出参数为EBROG粘结强度。研究表明,该模型的准确率非常高,训练的R2值为0.9629,测试的R2值为0.9598,突出了模型的精度。提出的EBROG方法的粘结强度预测方程经过对现有模型的验证,包括13个EBR方程和最近一个特定于EBROG的方程。统计指标证实了所提方程的准确性和可靠性。值得注意的是,FRP刚度是相对重要性最高的参数,而槽宽对粘结强度的影响最小。


Composites Part A: Applied Science and Manufacturing

Effect of stacking pattern of multilayered polyetheretherketone/boron nitride composites on the mechanical and thermal properties: Experiments and molecular dynamics simulations

Yuna Oh, Kwak Jin Bae, Yonjig Kim, Jaesang Yu

doi:10.1016/j.compositesa.2024.108441

 

多层聚醚酮/氮化硼复合材料堆积方式对力学和热性能的影响:实验和分子动力学模拟

The effect of stacking patterns in multilayered polyetheretherketone (PEEK)/boron nitride (BN) composites was investigated to improve the thermal conductivity and mechanical properties. The thick PEEK and BN layers in the multilayered composite were the best multilayer structure, resulting in high mechanical properties and in-plane thermal conductivity due to the many strong electrostatic interaction sites between boron nitride nanosheets (BNNSs). Molecular dynamics simulations were used to clarify the enhanced mechanism of multilayered structure on thermal conductivity. The multilayered structure with combinations of PEEKs and thick BN layers composed of large BNNSs led to the optimization of heat transfer due to the effective phonon transfer path. The best multilayered composite had the highest in-plane thermal conductivity, which was 471% higher than that of a PEEK. This study provides information about the filler size and stacking patterns for more effective multilayer structures with polymer and filler layers to achieve high performance on mechanical and thermal properties.

研究了多层聚醚酮(PEEK)/氮化硼(BN)复合材料中堆叠方式对其导热性能和力学性能的影响。由于氮化硼纳米片(BNNSs)之间存在许多强静电相互作用位点,因此多层复合材料具有较高的力学性能和面内导热系数。利用分子动力学模拟阐明了多层结构对导热性能的增强机理。由于有效的声子传递路径,peek和由大BNNSs组成的厚BN层组合的多层结构导致了传热的优化。最佳的多层复合材料具有最高的面内导热系数,比PEEK高出471%。本研究为更有效的聚合物和填料层多层结构提供了填料尺寸和堆叠模式的信息,以实现高性能的机械和热性能。


Synergy performance of hybrid fiber-reinforced ultra-high-performance cementitious composites with low fiber contents

Ngoc Thanh TRAN, Duy Hung NGUYEN, Tuan Kiet TRAN, Dong Joo KIM, Duy-Liem NGUYEN

doi:10.1016/j.compositesa.2024.108423

低纤维含量混杂纤维增强超高性能胶凝复合材料的协同性能研究

This study aims to assess the synergistic tensile performance resulting from the hybridization of long and short fibers. Three types of long steel,fibers, i.e., twisted, hooked, and smooth fibers, along with two types of short fibers, i.e., smooth and polyamide fibers, were incorporated into ultra-high-performance concrete (UHPC) at a total volume content of 1.5%. To predict the tensile resistance of the hybridizations, various machine learning models, including artificial neural network (ANN), decision tree (DT), random forest (RF), and support vector machine (SVM), were applied by utilizing a significant number of collected experimental results. Experimental findings demonstrated that the hybridization of long and short fibers effectively enhanced tensile resistance compared to mono fibers. These hybridizations exhibited negative synergy factors in post-cracking strength but positive synergy factors in both strain capacity and specific work to fracture. Predictions using machine learning models revealed that the RF model exhibited outstanding performance in predicting the tensile resistance of the hybridizations. Furthermore, the compressive strength of the matrix was found to be the most important factor affecting post-cracking strength, whereas fiber length had the most substantial impact on the strain capacity.

本研究旨在评估长、短纤维杂交后的协同拉伸性能。将三种长纤维(捻、钩、光面纤维)和两种短纤维(光面纤维和聚酰胺纤维)以1.5%的体积含量掺入高性能混凝土(UHPC)中。为了预测杂交的抗拉性,利用收集到的大量实验结果,应用了各种机器学习模型,包括人工神经网络(ANN)、决策树(DT)、随机森林(RF)和支持向量机(SVM)。实验结果表明,与单纤维相比,长纤维和短纤维的杂交有效地提高了抗拉性能。这些杂化在开裂后强度方面表现为负协同因子,而在应变能力和断裂比功方面表现为正协同因子。使用机器学习模型的预测表明,RF模型在预测杂交的拉伸阻力方面表现出出色的性能。此外,发现基体的抗压强度是影响开裂后强度的最重要因素,而纤维长度对应变能力的影响最大。


Development of sandwich test coupons with continuous protective layers for accurate determination of the tensile failure strain of unidirectional carbon fibre reinforced composites

Gergely Czél

doi:10.1016/j.compositesa.2024.108440

为准确测定单向碳纤维增强复合材料拉伸破坏应变而研制的连续保护层夹芯试验片

Recently introduced unidirectional (UD) carbon fibre reinforced epoxy (CF/EP) tensile test coupons with continuous protective layers were developed further by comparing three coupon designs with different layer integration techniques. Consistent experimental data was generated with high sample number and low scatter. Thermal residual strains were considered in case of two coupon designs where the layers were integrated at elevated temperature. A curve-fitting-based strength evaluation method is proposed for the sandwich coupons since this parameter cannot be evaluated directly. The sandwich type coupons yielded statistically significant increase in their average failure strain compared to that of the baseline tabbed coupons. In contrast, the three sandwich coupon types did not show significant differences. Therefore, the sandwich coupon type made by bonding cured UD composite layers together at room temperature is proposed for further application as they allow for full delamination at CF/EP layer fracture and do not require thermal strain correction during the evaluation.

通过对三种不同保护层集成技术的单向碳纤维增强环氧树脂(CF/EP)拉伸试验片的比较,进一步开发了具有连续保护层的单向碳纤维增强环氧树脂(CF/EP)拉伸试验片。实验数据一致,样本数高,散点低。热残余应变的情况下,考虑两个联片设计,其中层在高温下集成。针对夹芯板的强度参数无法直接评估的问题,提出了一种基于曲线拟合的夹芯板强度评估方法。与基线标签式夹芯板相比,夹芯板的平均破坏应变在统计上显著增加。相比之下,三种三明治优惠券类型没有显着差异。因此,在室温下将固化的UD复合材料层粘合在一起制成的三明治夹片类型可以在CF/EP层断裂时完全分层,并且在评估过程中不需要热应变校正,因此可以进一步应用。


Composites Science and Technology

Influence of reinforcement phase content on mechanical properties of hydroxyapatite/carbon fiber/polyether-ether-ketone composites 3D printed by screw extrusion

Beining Zhang, Siwei Lu, Jingyi Niu, Chuncheng Yang, Changning Sun, Dichen Li

doi:10.1016/j.compscitech.2024.110843

 

增强相含量对羟基磷灰石/碳纤维/聚醚醚酮复合材料3D打印力学性能的影响

Hydroxyapatite/polyether-ether-ketone (HA/PEEK) composites are promising prosthesis materials due to their biological activity, but they often have mechanical properties that fall short of clinical requirements, typically with HA content below 40 wt%. This study utilized a customized screw extrusion-based 3D printhead, incorporating carbon fiber (CF) to produce HA/CF/PEEK composites with enhanced mechanical properties and HA content up to 60 wt%. The investigation focused on the effects of HA and CF content on the crystallization process and mechanical properties. Results showed that HA and CF affect crystallization differently due to varying densities; a phase volume ratio above 20% inhibits crystallization. The elongation at break for composites with 10 wt% HA was 27.9%, a record for 3D-printed HA/PEEK composites. The tensile strength for composites with 10 wt% HA and 40 wt% CF reached 115.7 MPa, the highest among the tested three-phase composites. Data fitting indicated that the effects of HA and CF on strength are independent. The toughness decreases exponentially with increased reinforcing phase content. This study explored a new method for preparing HA/PEEK and HA/CF/PEEK composites, expanding the performance boundaries of PEEK composites, enhancing their potential applications in bone implants.

羟基磷灰石/聚醚酮(HA/PEEK)复合材料由于其生物活性是很有前途的假体材料,但它们的机械性能往往达不到临床要求,通常HA含量低于40%。这项研究使用了定制的基于螺杆挤压的3D打印头,结合碳纤维(CF)来生产具有增强机械性能和HA含量高达60%的HA/CF/PEEK复合材料。研究了HA和CF含量对结晶过程和力学性能的影响。结果表明:HA和CF对结晶的影响因密度的不同而不同;大于20%的相体积比抑制结晶。含10 wt% HA的复合材料的断裂伸长率为27.9%,创造了3d打印HA/PEEK复合材料的记录。含10 wt% HA和40 wt% CF的复合材料抗拉强度达到115.7 MPa,在所测试的三相复合材料中最高。数据拟合表明,HA和CF对强度的影响是独立的。随着增强相含量的增加,韧性呈指数级下降。本研究探索了一种制备HA/PEEK和HA/CF/PEEK复合材料的新方法,拓展了PEEK复合材料的性能边界,增强了其在骨植入物中的潜在应用。



来源:复合材料力学仿真Composites FEM
ACTMechanicalHPCSTEPS断裂复合材料UGUM材料分子动力学试验模具
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【新文速递】2024年9月6日固体力学SCI期刊最新文章

今日更新:International Journal of Solids and Structures 1 篇,Mechanics of Materials 2 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 2 篇International Journal of Solids and StructuresA “poor-man’s” deformation plasticity based approach to topology optimization of elastoplastic structuresKai Li, Mathias Wallin, Matti Ristinmaa, Gengdong Chengdoi:10.1016/j.ijsolstr.2024.113056基于“穷人”变形塑性的弹塑性结构拓扑优化方法This paper presents a topology optimization framework utilizing a deformation plasticity model to approximate the isotropic hardening von-Mises incremental elastoplasticity model under monotone proportional loading. One advantage of the model is that it is based on a yield surface allowing for precise matching to uniaxial elastoplastic isotropic hardening response. The deformation plasticity model and the incremental plasticity model coincides for proportional loading and since the deformation plasticity model is path-independent, the computational cost and implementation complexity reduce significantly compared to the conventional incremental elastoplasticity. To investigate the deformation plasticity model combined with topology optimization, we compare three common elastoplastic optimization objectives: stiffness, strain energy and plastic work. The possibility to limit the peak local plastic work while maximizing the strain energy is also investigated. The consistent analytical sensitivity analysis which only requires the terminal state is derived using adjoint method. Numerical examples demonstrate that the proportionality assumption is reasonable and the deformation plasticity model combined with topology optimization is a competitive alternative to cumbersome incremental elastoplasticity.本文提出了一种利用变形塑性模型近似单调比例加载下各向同性硬化von-Mises增量弹塑性模型的拓扑优化框架。该模型的一个优点是,它是基于屈服面,允许精确匹配的单轴弹塑性各向同性硬化响应。在比例加载条件下,变形塑性模型与增量塑性模型吻合,且由于变形塑性模型与路径无关,与传统增量弹塑性模型相比,计算成本和实现复杂度显著降低。为了研究与拓扑优化相结合的变形塑性模型,我们比较了三种常用的弹塑性优化目标:刚度、应变能和塑性功。在最大限度地提高应变能的同时限制局部塑性功峰值的可能性也进行了研究。利用伴随法导出了只要求终端态的一致性分析灵敏度分析。数值算例表明,比例假设是合理的,结合拓扑优化的变形塑性模型是替代繁琐的增量弹塑性的有力选择。Mechanics of MaterialsPhysically recurrent neural network for rate and path-dependent heterogeneous materials in a finite strain frameworkM.A. Maia, I.B.C.M. Rocha, D. Kovačević, F.P. van der Meerdoi:10.1016/j.mechmat.2024.105145在有限应变框架下速率和路径相关非均质材料的物理递归神经网络In this work, a hybrid physics-based data-driven surrogate model for the microscale analysis of heterogeneous material is investigated. The proposed model benefits from the physics-based knowledge contained in the constitutive models used in the full-order micromodel by embedding the material models in a neural network. Following previous developments, this paper extends the applicability of the physically recurrent neural network (PRNN) by introducing an architecture suitable for rate-dependent materials in a finite strain framework. In this model, the homogenized deformation gradient of the micromodel is encoded into a set of deformation gradients serving as input to the embedded constitutive models. These constitutive models compute stresses, which are combined in a decoder to predict the homogenized stress, such that the internal variables of the history-dependent constitutive models naturally provide physics-based memory for the network. To demonstrate the capabilities of the surrogate model, we consider a unidirectional composite micromodel with transversely isotropic elastic fibers and elasto-viscoplastic matrix material. The extrapolation properties of the surrogate model trained to replace such micromodel are tested on loading scenarios unseen during training, ranging from different strain-rates to cyclic loading and relaxation. Speed-ups of three orders of magnitude with respect to the runtime of the original micromodel are obtained.在这项工作中,研究了一种基于混合物理的数据驱动代理模型,用于非均质材料的微尺度分析。该模型通过将材料模型嵌入到神经网络中,利用全阶微模型中本构模型中包含的物理知识。根据先前的发展,本文通过在有限应变框架中引入适用于速率相关材料的架构,扩展了物理递归神经网络(PRNN)的适用性。该模型将微模型的均匀化变形梯度编码为一组变形梯度,作为嵌入本构模型的输入。这些本构模型计算应力,这些应力组合在一个解码器中以预测均匀的应力,这样,依赖于历史的本构模型的内部变量自然地为网络提供基于物理的记忆。为了证明替代模型的能力,我们考虑了一个具有横向各向同性弹性纤维和弹粘塑性基体材料的单向复合微模型。在训练期间未见的加载场景下,从不同的应变率到循环加载和松弛,测试了替代微模型的替代模型的外推特性。相对于原始微模型的运行时间,获得了三个数量级的加速。Effect of porous microstructure and fiber arrangement of thermal protection composites on effective thermal conductivityFan Yang, Weihua Xie, Songhe Mengdoi:10.1016/j.mechmat.2024.105147热防护复合材料的孔隙结构和纤维排列对有效导热系数的影响The inclusions in a high-temperature resistant matrix can significantly influence the radiative heat transfer of composite materials at elevated temperatures; therefore, the microstructure design of composites for thermal protection during atmospheric re-entry require a more accurate prediction of thermal insulation performance. In this paper, the Rosseland approximation was used to investigate the radiative heat transfer within thermal protection materials, e.g., porous carbon-based material and ultra-high-temperature ceramics (e.g., ZrB2-SiC), and the discrete dipole scattering method was used to evaluate the extinction efficiency across the inclusions with different types of microstructures. The effect of inclusion parameters, such as inclusion size, shape coefficient, volume fraction, orientation, and size distribution, on the radiative and effective thermal conductivity (ETC) at various temperatures was analyzed in detail. Test results obtained from the existing literature were used to validate the ETC of porous ceramics predicted by the proposed model. The results indicated that the microstructures in thermal protection materials play a fundamental role in improving the heat-shielding properties. The present study deepens the understanding of the relationship between microstructures and thermal radiation properties and provides theoretical design guidelines for thermal protection materials with improved thermal insulation properties.耐高温基体中的夹杂物对复合材料在高温下的辐射传热有显著影响;因此,用于大气再入热防护的复合材料微结构设计需要对其隔热性能进行更精确的预测。本文采用Rosseland近似研究了多孔碳基材料和超高温陶瓷(如ZrB2-SiC)等热防护材料内部的辐射传热,并采用离散偶极子散射方法评估了不同类型显微结构夹杂间的消光效率。详细分析了包裹体尺寸、形状系数、体积分数、取向、尺寸分布等参数对不同温度下的辐射导热系数和有效导热系数的影响。利用现有文献的测试结果验证了所提出模型预测的多孔陶瓷的ETC。结果表明,热防护材料的显微组织对热防护性能的提高起着至关重要的作用。本研究加深了对微结构与热辐射性能关系的认识,为提高隔热性能的热防护材料的设计提供了理论指导。International Journal of PlasticityInfluence of textural variability on plastic response of porous crystal embedded in polycrystalline aggregate: A crystal plasticity studySagar Chandra, Suranjit Kumar, Mahendra K. Samal, Vivek M. Chavandoi:10.1016/j.ijplas.2024.104117多晶骨料中嵌入多孔晶体的织构变化对塑性响应的影响:晶体塑性研究Damage evolution in polycrystalline aggregates is complicated by the intricate interplay of crystallographic orientation of the porous grain and the surrounding anisotropic matrix. Therefore, formulation of design rules and damage models for polycrystalline materials proves daunting due to relative lack of thorough understanding of the underlying heterogeneity at the mesoscale. This work explores the orientation dependent void growth in a porous crystal embedded in an anisotropic polycrystalline matrix with different initial textures. Polycrystalline face-centered cubic based aggregate is simulated within the framework of crystal plasticity finite element method. Porosity is first modeled in the form of a single pre-existing spherical void in the central grain of the randomly oriented polycrystal. One-hundred crystallographic orientations of the central grain in three-dimensional Euler space are analyzed to reveal the orientation dependent trends of the porous grain. To account for textural variability, the analysis is repeated for polycrystals exhibiting preferred textures like Cube, Brass, Copper and Goss. In this manner, interesting orientation dependent trends in basic tenets of void growth like yield strength, coalescence strain and porosity evolution are unraveled across various polycrystalline textures. To account for spatial heterogeneity as well, porosity in the central grain is then re-distributed and the aforementioned analysis is repeated for all the crystallographic orientations of the central grain embedded in polycrystals with different textures. Owing to the large amount of data thus generated, statistical analysis is invoked to identify stimulating trends and key statistical variables governing the strength and toughness. Consequently, a statistical void growth model is also presented by assessing the CP simulation results and identifying suitable distribution function governing the growth of voids in polycrystals. The modeling framework is expected to inform porous plasticity models aimed at capturing damage evolution in porous grains embedded in polycrystalline materials exhibiting topological and crystallographic anisotropy.多孔颗粒的晶体取向与周围各向异性基体的相互作用使多晶团聚体的损伤演化变得复杂。因此,由于相对缺乏对中尺度潜在非均质性的透彻理解,多晶材料的设计规则和损伤模型的制定是艰巨的。本研究探索了嵌入在具有不同初始结构的各向异性多晶基质中的多孔晶体中与取向相关的空洞生长。采用晶体塑性有限元法对多晶面心立方基骨料进行了数值模拟。孔隙度首先以随机取向多晶的中心颗粒中单个预先存在的球形空隙的形式建模。对中心晶粒在三维欧拉空间的100个晶体取向进行了分析,揭示了多孔晶粒的取向依赖趋势。为了解释纹理的可变性,对具有立方体、黄铜、铜和高斯等优选纹理的多晶重复分析。通过这种方式,在不同的多晶结构中揭示了屈服强度、聚结应变和孔隙度演化等空洞生长基本原理中有趣的取向依赖趋势。为了考虑空间异质性,中心晶粒的孔隙度被重新分配,并对嵌入在不同纹理的多晶体中的中心晶粒的所有晶体取向重复上述分析。由于产生了大量的数据,因此需要进行统计分析,以确定刺 激的趋势和控制强度和韧性的关键统计变量。在此基础上,通过对CP模拟结果的评估,确定了控制多晶中孔洞生长的合适分布函数,提出了孔洞生长的统计模型。该模型框架有望为多孔塑性模型提供信息,这些模型旨在捕捉嵌入在具有拓扑和晶体各向异性的多晶材料中的多孔颗粒的损伤演变。Thin-Walled StructuresFree vibration analysis of a functionally graded porous triangular plate with arbitrary shape and elastic boundary conditions using an isogeometric approachMilad Izadi, Maryam Abedi, Paolo S. Valvodoi:10.1016/j.tws.2024.112422用等几何方法分析任意形状和弹性边界条件下功能梯度多孔三角形板的自由振动This paper presents a comprehensive analysis of the free vibrations of functionally graded porous (FGP) triangular plates with arbitrary shapes and elastic boundary conditions using Isogeometric Analysis (IGA). We express the triangular shapes by using non-uniform rational B-splines (NURBS). The impact of porosity, geometry, and boundary conditions on the natural frequencies is investigated, with a focus on three key factors: porosity coefficient, geometric shape, and type of boundary conditions. Results show that increasing porosity generally leads to an increase in natural frequencies for thin plates, while thicker plates exhibit the opposite trend. The effect of geometric shape, characterized by different angles, is investigated and reveals distinct trends in natural frequencies. The study also investigates both classical and elastic boundary conditions, illustrating the impact of arbitrary boundary conditions on the natural frequency response. Validation against previous references and finite element methods establishes the accuracy of the presented results. The paper concludes with an extension of the analysis to various scenarios, offering valuable insights into the intricate interplay of porosity, geometry, and boundary conditions on the vibrational behavior of FGP triangular plates.本文采用等几何分析方法对具有任意形状和弹性边界条件的功能梯度多孔(FGP)三角形板的自由振动进行了综合分析。用非均匀有理b样条(NURBS)表示三角形。研究了孔隙度、几何形状和边界条件对固有频率的影响,重点研究了孔隙度系数、几何形状和边界条件类型这三个关键因素。结果表明,孔隙率的增加通常会导致薄板固有频率的增加,而厚板则相反。研究了不同角度的几何形状的影响,揭示了固有频率的不同趋势。该研究还研究了经典边界条件和弹性边界条件,说明了任意边界条件对固有频率响应的影响。通过对先前文献和有限元方法的验证,确定了所提出结果的准确性。本文最后将分析扩展到各种情况,为FGP三角形板的振动行为的孔隙率,几何形状和边界条件的复杂相互作用提供了有价值的见解。On energy absorption capability and controllable failure modes of CFRP circular tube using numerical simulationHongyuan Yang, Yiru Rendoi:10.1016/j.tws.2024.112423 基于数值模拟的CFRP圆管能量吸收能力及可控失效模式研究Enhancing the energy absorption (EA) capacity of carbon fiber reinforced plastic (CFRP) structures by inducing controlled failure modes is significant for lightweight design in aerospace. In the present work, four triggers including inward horizontal trigger, inward tilted trigger, outward horizontal trigger and outward tilted trigger are proposed to induce specific failure modes of CFRP circular tubes under axial loading. Under the framework of maximum stress and traction-separation damage criterion, the numerical model that can accurately predict load response and fracture behavior is established. The results showed that circular tubes with horizontal triggers have higher energy absorption (0.98%–15.62%). The circular tubes with tilted triggers were able to achieve higher crushing load efficiency (12.16%–22.97%). The damage state of the material becomes controllable and mainly manifests as tensile and compressive damage in the axial fiber direction. To clarify the strengthening mechanism, the influence of typical structural parameters of the trigger on the crashworthiness is investigated. It is found that increasing the groove width can effectively reduce the peak load. Finally, the controlled failure principle of CFRP tubes is analyzed and revealed. The results confirm the effectiveness of the trigger mechanism.通过诱导可控失效模式来提高碳纤维增强塑料(CFRP)结构的吸能能力,对航空航天轻量化设计具有重要意义。本文提出了向内水平触发、向内倾斜触发、向外水平触发和向外倾斜触发四种触发机制来诱导CFRP圆管在轴向载荷作用下的特定破坏模式。在最大应力和牵引分离损伤准则框架下,建立了能够准确预测载荷响应和断裂行为的数值模型。结果表明,带水平触发装置的圆管吸能较高(0.98% ~ 15.62%)。带倾斜触发器的圆管具有较高的破碎负荷效率(12.16% ~ 22.97%)。材料的损伤状态变得可控,主要表现为纤维轴向的拉伸和压缩损伤。为阐明其强化机理,研究了触发器典型结构参数对其耐撞性的影响。研究发现,增大槽宽可以有效降低峰值荷载。最后,分析并揭示了CFRP管的可控失效原理。结果证实了该触发机构的有效性。来源:复合材料力学仿真Composites FEM

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