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【新文速递】2023年11月9日固体力学SCI期刊最新文章

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今日更新:Mechanics of Materials 1 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 6 篇

Mechanics of Materials

Elucidating the impact of microstructure on mechanical properties of phase-segregated polyurea: Finite element modeling of molecular dynamics derived microstructures

Yang Steven J., Rosenbloom Stephanie I., Fors Brett P., Silberstein Meredith N.

doi:10.1016/j.mechmat.2023.104863

阐明微观结构对相分离聚脲机械性能的影响:分子动力学衍生微观结构的有限元建模

Phase-segregated polyureas (PU) have received considerable interest due to their use as tough, impact-resistant coatings. Polyureas are favored for these applications due to their mechanical strain rate sensitivity and energy dissipation. Predicting and tailoring the mechanical response of PU remains challenging due to the complex interaction between its elastomeric and glassy phases. To elucidate the role of PU microstructure on its mechanical properties, we developed a finite element modeling framework in which each phase is represented by a volume fraction within a representative volume element (RVE). Critically, we used separate constitutive models to describe the elastomeric and glassy phases. We developed a plasticity-driven breakdown process in which we model the glassy phase disaggregating into a new phase. The overall contribution of each phase at a material point is determined by their respective volume fractions within the RVE. We applied our modeling methods to two compositions of PU with differing elastomeric segment lengths derived from oligoether diamines, Versalink P650 and P1000. Our simulations show that a combination of microstructural differences and elastomeric phase properties accounts for the difference in mechanical response between P650 and P1000. We show our model’s ability to predict PU behavior in various loading conditions, including low-rate cyclic loading and monotonic loading over a wide range of strain rates. Our model produces microstructure transformations that mirror those indicated by small-angle X-ray scattering (SAXS) experiments. Fourier transform analysis of our RVEs reveals glassy phase fibrillation due to deformation, a finding consistent with SAXS experiments.

相分离聚脲(PU)由于可用作坚韧的抗冲击涂层而备受关注。聚氨酯因其机械应变速率敏感性和能量耗散性而受到这些应用的青睐。由于聚氨酯的弹性体相和玻璃相之间存在复杂的相互作用,因此预测和定制聚氨酯的机械响应仍然具有挑战性。为了阐明聚氨酯微观结构对其机械性能的影响,我们开发了一个有限元建模框架,其中每个相都由代表体积元素(RVE)中的体积分数来表示。重要的是,我们使用不同的构成模型来描述弹性体相和玻璃相。我们开发了一种塑性驱动的分解过程,其中我们模拟了玻璃相分解为新相的过程。各相在材料点的总体贡献由它们在 RVE 中各自的体积分数决定。我们将建模方法应用于低聚醚二胺(Versalink P650 和 P1000)制成的两种具有不同弹性段长度的聚氨酯成分。模拟结果表明,P650 和 P1000 的机械响应差异是由微观结构差异和弹性体相特性共同造成的。我们展示了我们的模型在各种加载条件下预测聚氨酯行为的能力,包括低速率循环加载和大范围应变速率下的单调加载。我们的模型所产生的微观结构变化与小角 X 射线散射(SAXS)实验所显示的结果一致。对我们的 RVE 进行的傅立叶变换分析揭示了玻璃相因变形而产生的纤维化,这一发现与 SAXS 实验一致。


International Journal of Plasticity

Towards a reliable nanohardness-dose correlation of ion-irradiated materials from nanoindentation tests: A case study in proton-irradiated vanadium.

Chen Shang, Yuan Jiuxi, Wang Shumin, Mei Luyao, Yan Jiaohui, Li Lei, Zhang Qiuhong, Zhu Zhixi, Lv Jin, Xue Yunfei, Dou Yankun, Xiao Xiazi, Guo Xun, Jin Ke

doi:10.1016/j.ijplas.2023.103804

通过纳米压痕测试实现离子辐照材料的可靠纳米硬度-剂量相关性:质子辐照钒案例研究。

Nanoindentation has been commonly used for evaluating the hardening effects of ion-irradiated materials. Nonetheless, establishing a reliable correlation between the hardness and irradiation dose is never trivial, due to not only the intrinsic analytical challenges of this technique, such as size effects, pile-up effects, etc., but also the fact that the irradiation dose is usually uneven inside the stress volume under the indenter, especially near the depth of dose peak. In the present work, the hardening in pure V irradiated with 1 MeV proton at various fluences is investigated by using nanoindentation tests, combined with the characterization of both irradiation defects and dislocations of the indented material. Under the cross-sectional indentation, we demonstrate that the nanohardness-dose correlation can be unified from the samples irradiated to different fluences and at different depths on each sample, as long as the lateral spanning of indenter is carefully considered. Crystal-plasticity finite-element-modeling simulation results can well describe the measured hardening-dose correlation, as well as the observed features on the change in strained fields and pile-up effects after irradiations. Moreover, the measured hardness is further corrected for the dose-dependent pile-up based on the surface profiling, and the indentation size effects based on surface indentation tests for deeper indentation depth, to reach a reliable connection between the hardening effects and the irradiation dose. Furthermore, microstructural characterization of the indented materials shows the pinning of dislocation by irradiation defects and the sweeping of those defects during dislocation migration. Molecular dynamics results suggest that the drag of loops by edge dislocations might cause the annihilation or aggregation of small loops, which could be responsible for the lower density but the larger size of irradiation loops in the strained region.

纳米压痕常用于评估离子辐照材料的硬化效应。然而,要在硬度和辐照剂量之间建立可靠的相关性绝非易事,这不仅是由于该技术固有的分析难题,如尺寸效应、堆积效应等,还由于辐照剂量在压头下的应力体积内通常是不均匀的,尤其是在剂量峰值深度附近。在本研究中,通过纳米压痕试验,结合辐照缺陷和压痕材料位错的表征,研究了在不同通量下用 1 MeV 质子辐照的纯 V 的硬化情况。在横截面压痕下,我们证明了只要仔细考虑压头的横向跨度,就能从每个样品上的不同通量和不同深度的辐照中统一出纳米硬度与剂量的相关性。晶体塑性有限元模型模拟结果可以很好地描述测量到的硬化-剂量相关性,以及观察到的辐照后应变场变化和堆积效应特征。此外,还根据表面轮廓分析进一步校正了与剂量相关的堆积效应,并根据表面压痕测试进一步校正了压痕深度的压痕尺寸效应,从而在硬化效应与辐照剂量之间建立了可靠的联系。此外,压痕材料的微观结构特征显示了辐照缺陷对位错的钉扎作用,以及位错迁移过程中对这些缺陷的扫描。分子动力学结果表明,边缘位错对环状体的拖拽可能导致小环状体的湮灭或聚集,这可能是应变区辐照环状体密度较低但尺寸较大的原因。


Thin-Walled Structures

Energy absorption characteristics of aluminum foam-filled corrugated tube under axial compression loading

Yan Song, Jiang Yi, Deng Yueguang, Cai Yunlong

doi:10.1016/j.tws.2023.111333

铝泡沫填充波纹管在轴向压缩载荷下的能量吸收特性

To improve the energy absorption characteristics of thin-walled structures and reduce the initial peak compression force and load fluctuation, a novel aluminum foam-filled corrugated tube was proposed in this study. Finite element model validated by quasi-static compression experiments was adopted to investigate the crashworthiness performances of aluminum foam-filled corrugated tubes and their combined energy-absorbing structures. The effects of structure parameters including corrugation radius, wall thickness, corrugation length and corrugation radius increments on axial compression characteristics were investigated through finite element analysis. The results showed that compared with aluminum foam-filled straight tubes, the initial peak compression force of aluminum foam filled corrugated tube was reduced by 22.87%, the compression force efficiency was increased by 6.69% and the load fluctuation was reduced by 17.94%. The smaller the values of corrugation radius, wall thickness and corrugation length, the smaller the initial peak compression force; Because the corrugation radius had a great effect on the peak compression force, the order that the corrugations were compressed into folds can be controlled by designing the corrugation radius; In view of the peak and valley values of compression force, an innovative combination of single tubes with different △H was obtained, which had better energy absorption performance. Compared with a single aluminum foam-filled corrugated tube, the compression force efficiency of the combined structure (△H: 0-5-10) was increased by 18.15% and the load fluctuation was reduced by 33.60%. The research results can provide a reference for the design and optimization of energy-absorbing devices.

为了改善薄壁结构的能量吸收特性,降低初始峰值压缩力和载荷波动,本研究提出了一种新型铝泡沫填充波纹管。采用经准静态压缩实验验证的有限元模型,研究了泡沫填充铝波纹管及其组合吸能结构的耐撞性能。通过有限元分析研究了波纹半径、壁厚、波纹长度和波纹半径增量等结构参数对轴向压缩特性的影响。结果表明,与泡沫铝填充直管相比,泡沫铝填充波纹管的初始峰值压缩力降低了 22.87%,压缩力效率提高了 6.69%,载荷波动降低了 17.94%。波纹半径、壁厚和波纹长度的值越小,初始峰值压缩力越小;由于波纹半径对峰值压缩力的影响很大,因此可以通过设计波纹半径来控制波纹被压缩成褶皱的顺序;根据压缩力的峰值和谷值,创新性地得到了不同△H 的单管组合,具有更好的能量吸收性能。与单一的铝泡沫填充波纹管相比,组合结构(△H:0-5-10)的压缩力效率提高了 18.15%,载荷波动降低了 33.60%。研究结果可为吸能装置的设计和优化提供参考。


Simulation of SMA-based engineering applications considering large displacement and rotation, thermomechanical coupling and partial phase transformation

Kundu Animesh, Banerjee Atanu

doi:10.1016/j.tws.2023.111338

考虑到大位移和旋转、热机械耦合和部分相变的基于 SMA 的工程应用模拟

Shape memory alloys (SMAs) undergo large recoverable deformation due to their inherent diffusionless martensitic phase transformation. Two factors need to be taken into account to incisively emulate the behaviour of SMA based structures: (i) consideration of large displacement and rotation (LDR) effect, and (ii) capturing the consequence of transformation induced material level coupling. In this study, both these effects are apprehended by extending the infinitesimal strain-based constitutive model of SMA as proposed by Lagoudas et al. (2012), assuming small elastic strain but with finite inelastic strain. To preclude any spurious stress generation out of large rotation, the Jaumann stress rate is used, and incremental objectivity for finite rotation between two successive time instants is conserved by rotating the strain increment and spin tensor to the rotation-independent mid-point configuration following Hughes-Winget (Hughes and Winget, 1980) algorithm. In addition, the contribution of thermoelastic and latent heat evolved during transformation is taken into consideration in the thermal equilibrium equation. Moreover, the effect of partial phase transformation yielding minor hysteresis loop has also been captured. The equilibrium equation is expressed in the current configuration following the Updated Lagrangian formulation. The mechanical and thermal equilibrium equations are solved concurrently in block matrix form using the Newton–Raphson (NR) iterative technique, considering the coupling terms resulting from the phase transformation. The efficacy and robustness of the developed finite element model are corroborated through various practical applications of SMA-based members, e.g., SMA ring, SMA-actuated beam, morphing of corrugated airfoil, orthodontic palatal expander, compliant gripper, undergoing LDR while subjected to different thermomechanical loading conditions. The combined effects of LDR along with thermomechanical coupling yield a stiffening behaviour during loading and sluggish response at the time of thermal recovery.

形状记忆合金(SMA)由于其固有的无扩散马氏体相变,会产生较大的可恢复变形。要准确模拟基于 SMA 的结构行为,需要考虑两个因素:(i) 考虑大位移和旋转 (LDR) 效应;(ii) 捕获转化诱导的材料级耦合的后果。在本研究中,通过扩展 Lagoudas 等人(2012 年)提出的基于无穷小应变的 SMA 构成模型,假设弹性应变较小,但非弹性应变有限,从而理解了这两种效应。为了排除大旋转产生的任何虚假应力,使用了 Jaumann 应力率,并按照 Hughes-Winget 算法(Hughes 和 Winget,1980 年)将应变增量和自旋张量旋转到与旋转无关的中点配置,从而保持了两个连续时间点之间有限旋转的客观增量。此外,热平衡方程还考虑了转化过程中产生的热弹性和潜热。此外,还考虑了部分相变产生小滞后环的影响。平衡方程是按照最新的拉格朗日公式在当前配置中表示的。考虑到相变产生的耦合项,采用牛顿-拉斐森(NR)迭代技术,以块矩阵形式同时求解机械平衡方程和热平衡方程。通过各种基于 SMA 的实际应用,如 SMA 环、SMA 驱动梁、波纹翼面变形、正畸腭部扩张器、顺应式夹具等,证实了所开发有限元模型的有效性和稳健性,并在不同的热机械加载条件下进行 LDR。LDR 与热机械耦合的综合效应导致加载期间的僵化行为和热恢复时的迟缓响应。


Effect of high-frequency induction weld seam on the deformation of M1700 ultra-high strength steel shell structures considering residual tensile stress

Yang Fan, Wen Tong, Wang Qiufeng, Zhang Longzhu, Liu Hailong, Zhou Yang

doi:10.1016/j.tws.2023.111340

考虑残余拉应力的高频感应焊缝对 M1700 超高强度钢壳结构变形的影响

The feasible cold forming procedure to massively manufacture ultra-high strength steel (UHSS) light-weighting profiles so far in industrial fields consists of roll forming, welding, cutting and bending. To reveal the role the high-frequency induction weld (HFIW) line plays in the subsequent plastic forming, a serials of deliberately designed collapse tests of the shell structures taken from M1700 roof rail pillar with a wall-thickness of 2 mm and triangle cross-section were conducted. Real geometries and inhomogeneous material properties of the weld seam and heat-affected zone (HAZ), together with the residual tensile stresses within the weld seam after HFIW, were fully considered in the numerical simulation. The Brozoo's modified CL damage model and Oyane damage model were employed and compared. The results show that the deformation resistance of the shell structures is modified by the material accumulation around the HFIW seams during the collapse tests. The cracks mainly occur within the critical HAZ outside the tube and the temper softening zone inside the tube under the action of softening effect in the HAZ of M1700 steel. The residual tensile stresses increase the crack probability of weld seams. The predicting accuracy of fracture location of the Oyane damage model is higher than that of the Brozoo's modified CL damage model.

迄今为止,在工业领域大规模制造超高强度钢(UHSS)轻质型材的可行冷成型程序包括辊压、焊接、切割和弯曲。为了揭示高频感应焊接(HFIW)线在后续塑性成形中的作用,我们对取自 M1700 车顶轨支柱的壁厚为 2 毫米、横截面为三角形的壳体结构进行了一系列特意设计的坍塌试验。数值模拟充分考虑了焊缝和热影响区(HAZ)的实际几何形状和不均匀材料特性,以及高频无缝焊接后焊缝内的残余拉应力。采用了 Brozoo 修正的 CL 损伤模型和 Oyane 损伤模型,并进行了比较。结果表明,在坍塌试验过程中,壳体结构的抗变形能力受到 HFIW 焊缝周围材料堆积的影响。在 M1700 钢 HAZ 软化效应的作用下,裂纹主要出现在管外临界 HAZ 和管内回火软化区。残余拉应力增加了焊缝的裂纹概率。Oyane 损伤模型对断裂位置的预测精度高于 Brozoo 修正的 CL 损伤模型。


Graphene/h-BN hybrid van der Waal structures with high strength and flexibility: a nanoindentation investigation

Yang Youzhe, Ma Jun, Yang Jie, Zhang Yingyan

doi:10.1016/j.tws.2023.111341

 

具有高强度和柔韧性的石墨烯/h-BN 混合范德华结构:纳米压痕研究

Two-dimensional nanomaterials, such as graphene and h-BN have been widely used as reinforcing fillers for polymer-based impact protection materials, phase change materials (PCM) or thermal interface materials (TIM) due to its exceptional high mechanical strength and high thermal conductivity. But the mechanical properties of graphene/h-BN (GBN) van der Waals (vdW) heterostructures remain largely unexplored. Herein we carry out intensive nanoindentation tests on GBN by using molecular dynamics simulations as well as finite element analysis to investigate its mechanical properties, its fracture mechanisms as well as the effective manipulation techniques for force and deformation. Compared with its homogeneous counterparts (pure graphene or pure h-BN), the heterogenous GBN possess excellent performance in resisting bending deformation in terms of the indentation load and depth. The size-dependent performance of GBN can be effectively manipulated by hydrogenation in the middle graphene and layer number, except the composition diffusion interface. This comprehensive study confirms that the high strength and high flexibility of GBN endow it with great potential in the applications of impact protection and thermal management in PCM and TIM.

石墨烯和 h-BN 等二维纳米材料因其卓越的高机械强度和高导热性,已被广泛用作聚合物基抗冲击保护材料、相变材料 (PCM) 或热界面材料 (TIM) 的增强填料。但是,石墨烯/h-BN(GBN)范德华(vdW)异质结构的机械性能在很大程度上仍未得到探索。在此,我们通过分子动力学模拟和有限元分析,对 GBN 进行了密集的纳米压痕测试,以研究其力学性能、断裂机制以及力和变形的有效操控技术。与同质材料(纯石墨烯或纯 h-BN)相比,异质 GBN 在抵抗弯曲变形方面具有优异的性能,包括压痕载荷和深度。除成分扩散界面外,GBN 的尺寸性能可通过中间石墨烯和层数的氢化得到有效控制。这项综合研究证实,GBN 的高强度和高柔韧性使其在 PCM 和 TIM 的抗冲击保护和热管理方面具有巨大的应用潜力。


Experimental study on S700 T-stub in heating and cooling during fire

Dhamane Shravani, Mushahary Suman Kumar, Singh Konjengbam Darunkumar

doi:10.1016/j.tws.2023.111342

S700 T 型管在火灾中加热和冷却的实验研究

In this paper, experimental investigations were carried out to assess the strength of S700 steel material and T-stub made from S700 steel in heating and cooling during fire with an emphasis on cooling stage fire (decreasing temperature). T-stub is a simple idealization of tension zone in bolted connection as T-shaped joint. In total, 17 coupons were tested in room temperature, growth (growing/ increasing temperature), cooling and postfire phases. It was observed from the tensile test data, that the growth phase properties were not similar as the cooling phase properties, however, about 90% of strength regained at the end of cooling phase, (i.e., in postfire specimens). 22 T-stubs of two geometric configurations were tested for axial capacity in heating and cooling during fire. In both the geometric configuration, the mode of failure at room temperature changed to other modes at elevated temperatures. The mode of failure at elevated temperature depended on the relative strength of T-stub and the bolts. The experimental results were compared with existing codal provisions – Eurocode 3 and AISC 360. It was found that the Eurocode prediction was close to the experimental results, while AISC prediction was highly conservative, which might be attributed to the non-consideration of bolt strength (proportionate reduction in strength due to fire) directly during the strength prediction.

本文进行了实验研究,以评估 S700 钢材料和由 S700 钢制成的 T 型管在火灾期间加热和冷却时的强度,重点是冷却阶段火灾(温度降低)。T 形管是将螺栓连接中的拉伸区简单理想化为 T 形连接。共有 17 个试样在室温、增长(温度增长/升高)、冷却和火灾后阶段进行了测试。从拉伸试验数据中可以看出,增长阶段的特性与冷却阶段的特性并不相似,但在冷却阶段结束时(即熄火后试样),强度恢复了约 90%。对两种几何结构的 22 根 T 形管进行了火灾期间加热和冷却轴向承载力测试。在这两种几何结构中,室温下的失效模式在高温下会转变为其他模式。高温下的破坏模式取决于 T 形柱和螺栓的相对强度。实验结果与现有的规范条款--Eurocode 3 和 AISC 360 进行了比较。结果发现,Eurocode 的预测结果与实验结果接近,而 AISC 的预测结果则非常保守,这可能是由于在强度预测过程中没有直接考虑螺栓强度(火灾导致强度按比例降低)。


Mechanical design and energy absorption performances of novel plate-rod hybrid lattice structures

Cui Zhuang, Zhao Jiayun, Xu Rong, Ding Yuanyuan, Sun Zhengping

doi:10.1016/j.tws.2023.111349

新型板棒混合晶格结构的机械设计和能量吸收性能

Hybrid lattice structures, integrating diverse structural components from fundamental lattice topologies, have attracted significant attention for their exceptional mechanical properties encompassing elastic modulus, yield stress, and energy absorption. To amalgamate the lightweight characteristics of rod structures with the robust mechanical properties of plate structures, a novel plate-rod hybrid lattice (PRHL) with controllable geometrical parameters and higher energy absorption was proposed and fabricated via the Selective Laser Sintering technique. In the PRHL design, the hybrid rod structure, interlinked with the center of each surface of the semi-open Octet plate lattice (SOPL), mutually provides support and deformation constraints. To identify the mechanical properties of PRHL, quasi-static uniaxial compression tests of PRHL samples sintered by Polylactic Acid powder were carried out. In comparison to SOPL, the newly proposed PRHL demonstrates an approximate 13.4% improvement in initial crush stress and an 18.5% increase in specific energy absorption capacity. Furthermore, numerical simulations incorporating the effect of printing orientation were performed to analyze the deformation mechanism of the PRHL structures. The present study also underscores the capacity to fine-tune the mechanical properties of PRHLs by regulating the plate thickness, rod diameter and excavated hole diameter.

混合晶格结构集成了基本晶格拓扑结构中的各种结构组件,因其包括弹性模量、屈服应力和能量吸收在内的优异机械性能而备受关注。为了将杆状结构的轻质特性与板状结构的坚固机械特性相结合,我们提出了一种几何参数可控、能量吸收能力更强的新型板杆混合晶格(PRHL),并通过选择性激光烧结技术进行了制造。在 PRHL 设计中,混合杆结构与半开放式八面体板晶格(SOPL)每个表面的中心相互连接,相互提供支撑和变形约束。为了确定 PRHL 的机械性能,对用聚乳酸粉末烧结的 PRHL 样品进行了准静态单轴压缩试验。与 SOPL 相比,新提出的 PRHL 的初始压应力提高了约 13.4%,比能量吸收能力提高了 18.5%。此外,还结合印刷方向的影响进行了数值模拟,以分析 PRHL 结构的变形机制。本研究还强调了通过调节板厚、杆直径和挖孔直径来微调 PRHL 机械性能的能力。



来源:复合材料力学仿真Composites FEM
ACTMechanicalDeform断裂UGUM焊接裂纹材料分子动力学控制试验螺栓
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【新文速递】2023年11月11日复合材料SCI期刊最新文章

今日更新:Composite Structures 3 篇,Composites Part A: Applied Science and Manufacturing 4 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇Composite StructuresPullout behavior of recycled macro fibers in the cementitious matrix: analytical model and experimental validationYUAN Hong, FAN Y.C., YOU X.M., FU Bing, ZOU Q.Q.doi:10.1016/j.compstruct.2023.117690水泥基质中再生大纤维的拉拔行为:分析模型和实验验证A novel mechanical recycling method has been recently developed in the authors’ group for processing waste glass fiber-reinforced polymer (GFRP) composites into macro fibers, which are then incorporated into concrete to produce green fiber-reinforced concrete (FRC). The present study has been conducted for facilitating the characterization of the tensile properties of macro fiber reinforced concrete (MFRC). A trilinear bond-slip model based on the shear-lag theory has first been refined by introducing a slip coefficient to consider different slip behaviors at the final pullout stages. Such a refined trilinear bond-slip model is suitable for describing the bond-slip behavior of the recycled macro fibers embedded in the cementitious matrix. The bond parameters are obtained through an inverse analysis, in which an improved particle swarm optimization algorithm (PSO) is used. The predicted force-end slip curves are compared with the pullout test results, and a good agreement is observed counterparts with the integral absolute error (IAE) ranging from 3.05%-5.52%, demonstrating the feasibility of the proposed analytical model. A parametric study is finally conducted to examine the sensitivity of different parameters including the fiber geometries and bond properties on the pullout behavior of the macro fibers.作者的研究小组最近开发了一种新的机械回收方法,用于将废玻璃纤维增强聚合物(GFRP)复合材料加工成大纤维,然后将其融入混凝土中,生产出绿色纤维增强混凝土(FRC)。本研究的目的是分析大纤维增强混凝土(MFRC)的拉伸特性。基于剪切滞后理论的三线性粘结滑移模型首先通过引入滑移系数进行了改进,以考虑最后拉拔阶段的不同滑移行为。这种改进后的三线粘结滑移模型适用于描述嵌入水泥基质中的再生大纤维的粘结滑移行为。粘结参数是通过反分析获得的,其中使用了改进的粒子群优化算法(PSO)。将预测的力端滑移曲线与拉拔测试结果进行比较,发现两者之间存在很好的一致性,其积分绝对误差(IAE) 在 3.05%-5.52% 之间,证明了所提分析模型的可行性。最后还进行了参数研究,以检验不同参数(包括纤维几何形状和粘结性能)对宏纤维拉拔行为的敏感性。Ti-PEEK interpenetrating phase composites with minimal surface for property enhancement of orthopedic implantsXie Haiqiong, Chen Junjie, Liu Fei, Wang Rui, Tang Yichuan, Wang Yiru, Luo Tao, Zhang Kaifei, Cao Jiandoi:10.1016/j.compstruct.2023.117689 具有最小表面的 Ti-PEEK 互穿相复合材料,用于提高骨科植入物的性能Bioinspired interpenetrating phase composites (IPCs) present a promising strategy for augmenting the mechanical properties of materials, thereby synergistically enhancing the strength and fracture toughness of orthopedic implants. In this study, Ti6Al4V-PEEK IPCs were fabricated by pressing molten PEEK into additively manufactured Ti6Al4V scaffolds designed using minimal surface structures. The mutual spatial interpenetration and strong binding between Ti and PEEK were confirmed through CT detection and SEM analyses, revealing the presence of continuous constituents within biomimetic architectures. Due to interpenetration promoting interaction and efficient stress transfer of the two phases, IPCs enhances toughness and energy absorption by over 291% and 309% respectively while maintaining bone-compatible elastic modulus and higher strength. The mechanisms underlying stress dispersion, crack propagation resistance, and prolonged stress plateau period of IPCs were investigated through the utilization of digital image correlation (DIC) and finite element simulation techniques. Among the various types of IPCs investigated, Gyroid IPCs exhibit superior comprehensive mechanical properties, thereby facilitating the development of customized IPCs aimed at ensuring long-term stability in orthopedic implantation scenarios.受生物启发的互穿相复合材料(IPC)是增强材料力学性能的一种有前途的策略,可协同增强骨科植入物的强度和断裂韧性。在这项研究中,通过将熔融的 PEEK 压入采用最小表面结构设计的添加式制造的 Ti6Al4V 支架中,制造出了 Ti6Al4V-PEEK IPC。通过 CT 检测和 SEM 分析证实了 Ti 和 PEEK 之间的空间互穿和强结合,揭示了生物仿生结构中存在连续的成分。由于相互渗透促进了两相之间的相互作用和有效应力传递,IPCs 在保持骨兼容弹性模量和更高强度的同时,韧性和能量吸收分别提高了 291% 和 309%。通过利用数字图像相关(DIC)和有限元模拟技术,研究了 IPCs 的应力分散、抗裂纹扩展和应力高原期延长的机理。在所研究的各种类型的 IPC 中,Gyroid IPC 表现出更优越的综合机械性能,从而促进了定制 IPC 的开发,以确保骨科植入应用中的长期稳定性。Nonlinear electromechanical bending of bi-modular piezoelectric laminated beamsZeng Shan, Yu Zhiyong, Wang Fei, Wang Kaifa, Wang Baolindoi:10.1016/j.compstruct.2023.117718双模块压电叠层梁的非线性机电弯曲In this paper, the nonlinear electromechanical bending of a bi-modular piezoelectric laminated beam is studied based on the principle of minimum potential energy and the Adomian decomposition method. The different tensile-compressive Young’s modulus of the core and piezoelectric layers, and the different tensile-compressive piezoelectric coefficients are considered. The electromechanical governing equations and related boundary conditions are obtained by using the principle of minimum potential energy. The deflection, neutral layer and interlaminar stresses of the beam are solved by the Adomian decomposition method and the iterative method, and verified by the finite element model and Galerkin's method. Results show that the applied voltage and the bi-modular characteristics affect the position of the neutral layer and the interlaminar stresses. Compared with the bi-modular properties of the core layer, the influences of the bi-modular properties of the piezoelectric layer on the neutral layer are relatively unobvious. In addition, the interlaminar stresses between the piezoelectric layer and core layer can be increased or decreased, depending on the relative magnitude of the applied voltage ratio and the bi-modular ratio. The results obtained are helpful for the analysis of the electromechanical coupling mechanism and design of piezoelectric composites and structures with bi-modular characteristics.本文基于最小势能原理和 Adomian 分解法研究了双模块压电层叠梁的非线性机电弯曲。考虑了芯层和压电层不同的拉伸-压缩杨氏模量以及不同的拉伸-压缩压电系数。利用最小势能原理得到了机电控制方程和相关边界条件。采用 Adomian 分解法和迭代法求解了梁的挠度、中性层和层间应力,并通过有限元模型和 Galerkin 方法进行了验证。结果表明,外加电压和双模块特性会影响中性层的位置和层间应力。与芯层的双模块特性相比,压电层的双模块特性对中性层的影响相对不明显。此外,压电层与芯层之间的层间应力可以增加或减少,这取决于外加电压比和双模态比的相对大小。所获得的结果有助于分析机电耦合机制和设计具有双模块特性的压电复合材料和结构。Composites Part A: Applied Science and ManufacturingAnisotropy Behavior of Liquid Metal Elastomer Composites with Both Enhanced Thermal Conductivity and Crack Resistance by Direct Ink WritingXu Peihua, Zhu Lida, Zhao Zixu, Yang Zhichao, Ning Jinsheng, Xue Pengsheng, Lu Haodoi:10.1016/j.compositesa.2023.107890通过直接油墨写入法增强导热性和抗裂性的液态金属弹性体复合材料的各向异性行为Liquid metal elastomer composites (LMEC) have broad application prospects in flexible devices, but the research on the basic processes of DIW for LMEC and the properties of DIW-ed LMEC is lacking. In this study, liquid metal (LM) is added to silicone elastomers such as Polydimethylsiloxane (PDMS), and the effect of LM volume fraction on ink rheology is investigated. Results show that the storage modulus of ink is lower than its loss modulus, which is not conducive to self-support formation. Therefore, fluorination is adopted to treat the silicon dioxide substrate used, thereby reducing the deformation rate of the printed structure to below 110%. The results of properties show that the crack resistance and thermal conductivity of soft elastomers increase with the LM volume fraction. Additionally, the tensile properties of PDMS printed via DIW exhibit significant anisotropy parallel and perpendicular to the scanning direction, and that the addition of LM droplets reduces the anisotropy. And with the increase of curing temperature and LM droplet size, the stretchability of DIW-ed LMEC in both directions decreases, but only LMEC samples cured at 140℃ exhibit significant anisotropy. This study provides guidance pertaining to the basic process and printing directions for the application of DIW in the manufacture of LMEC equipment.液态金属弹性体复合材料(LMEC)在柔性设备中具有广阔的应用前景,但有关液态金属弹性体复合材料 DIW 的基本工艺以及 DIW 后液态金属弹性体复合材料性能的研究却十分缺乏。本研究将液态金属(LM)添加到聚二甲基硅氧烷(PDMS)等有机硅弹性体中,并研究了 LM 体积分数对油墨流变性的影响。结果表明,油墨的存储模量低于其损耗模量,不利于自支撑的形成。因此,采用氟化处理所用的二氧化硅基底,从而将印刷结构的变形率降低到 110% 以下。性能结果表明,软弹性体的抗裂性和导热性随 LM 体积分数的增加而提高。此外,通过 DIW 印刷的 PDMS 的拉伸性能在平行和垂直于扫描方向上表现出明显的各向异性,而添加 LM 液滴则会降低这种各向异性。随着固化温度和 LM 液滴大小的增加,DIW 印刷的 LMEC 在两个方向上的拉伸性都会降低,但只有在 140℃ 下固化的 LMEC 样品才会表现出明显的各向异性。这项研究为在 LMEC 设备制造中应用 DIW 的基本工艺和印刷方向提供了指导。Evolutionary Algorithm-Based Integrated Design of Material-Structural Microwave Absorption Using Material ExtrusionZhang Yuhui, Shan Mengtong, Lei Han, Zhao Pengzhen, Yu Chen, Huang Yixingdoi:10.1016/j.compositesa.2023.107891基于进化算法的材料-结构微波吸收综合设计(材料挤压法The development of electromagnetic wave absorbing materials and structures holds significant importance in fields such as aerospace and electronic communications. Traditional absorbing coatings have poor mechanical load-bearing capacity and struggle to meet the requirements of lightweight applications. On the other hand, the research on lossy dielectric absorbers is limited by process constraints, making it difficult to fabricate complex configurations, thereby greatly restricting their broadband absorption performance. In this study, a functional absorbing composite filament was developed using material extrusion technique. A magnetic lossy four-layer gradient honeycomb metastructure was designed, which enables effective absorption in the frequency range of 6.09-37.18 GHz within a thickness of 16 mm. The effective absorption bandwidth covers 81.82% in the frequency range of 2-40 GHz. This broadband absorbing design achieves the integration of material functionality and structural design by additive manufacturing, enabling effective absorption across a broad frequency range.电磁波吸收材料和结构的开发在航空航天和电子通信等领域具有重要意义。传统的吸波涂层机械承载能力差,难以满足轻质应用的要求。另一方面,有损电介质吸收体的研究受到工艺限制,难以制造复杂的结构,从而大大限制了其宽带吸收性能。本研究利用材料挤压技术开发了一种功能性吸波复合丝。设计了一种磁性损耗四层梯度蜂窝结构,在厚度为 16 毫米的范围内实现了 6.09-37.18 GHz 频率范围内的有效吸收。在 2-40 GHz 频率范围内,有效吸收带宽达到 81.82%。这种宽带吸收设计通过增材制造实现了材料功能与结构设计的整合,从而实现了宽频率范围内的有效吸收。Hybrid assembly based on nanomaterial reinforcement for multifunctionalized skin-like flexible sensorsLv Xiaohua, Ling Yufei, Tang Kaiyou, Qiao Changyu, Fu Lihua, Xu Chuanhui, Lin Baofeng, Wei Yendoi:10.1016/j.compositesa.2023.107892基于纳米材料加固的混合组件,用于多功能类肤柔性传感器Currently, the inferior mechanical strength, weak environmental adaptability, and limited functionality of conductive hydrogel significantly impede its potential application in wearable sensors. Here, ''hard'' acrylic bentonite (AABT) intercalated nanostructures and silver-modified polydopamine (PDA@Ag) particles are encapsulated in a ''soft'' polyacrylic acid matrix in a water/glycerol binary solvent system. This strategy successfully realized the high matched skin modulus (58 kPa), high stress (371 kPa) and strain (1025%). The PDA@Ag particles retains rich phenolic hydroxyl groups imitating mussel to provide strong adhesion (29.12 kPa). These particles also give the hydrogel long time antibacterial properties (3 days), while demonstrating excellent biosafety. The introduction of a binary system of water/glycerol effectively suppresses the evaporation and crystallization of water, thereby maintaining sensing performance above 82% even under extreme conditions. This hydrogel achieves integrated applications of multifunctionality and multi-environmental adaptability, providing a new idea for the development of next-generation skin-like hydrogel sensors.目前,导电水凝胶的机械强度低、环境适应性弱、功能有限,这些都严重阻碍了其在可穿戴传感器中的潜在应用。在这里,"硬 "丙烯酸膨润土(AABT)插层纳米结构和银改性聚多巴胺(PDA@Ag)颗粒被封装在水/甘油二元溶剂体系中的 "软 "聚丙烯酸基质中。这种策略成功实现了高匹配表皮模量(58 kPa)、高应力(371 kPa)和应变(1025%)。PDA@Ag 颗粒保留了仿贻贝的丰富酚羟基,提供了强大的粘附力(29.12 kPa)。这些颗粒还赋予了水凝胶长效抗菌特性(3 天),同时表现出卓越的生物安全性。水/甘油二元体系的引入有效抑制了水的蒸发和结晶,因此即使在极端条件下也能保持 82% 以上的传感性能。这种水凝胶实现了多功能和多环境适应性的综合应用,为开发下一代类皮肤水凝胶传感器提供了新思路。Dual-modulus 3D Printing Technology for Magnetorheological Metamaterials-Part II: Negative Regulation Theory and ApplicationLou Congcong, Liu Bing, Cao Xufeng, Gao Liang, Xuan Shouhu, Deng Huaxia, Gong Xinglongdoi:10.1016/j.compositesa.2023.107893磁流变超材料的双模量三维打印技术--第二部分:负调控理论与应用Metamaterials are artificially structured periodic materials that have remarkable property of wave attenuation in bandgaps. However, metamaterials with adjustable and low-frequency bandgap are still challenge in traditional method. In this work, a novel magnetorheological metamaterial (MRM) with negative regulation and low-frequency bandgaps was fabricated by dual-modulus 3D printing technology. The bandgaps of negative regulation MRM were analyzed theoretically by using the mass-spring model. As a result, the starting frequency of bandgap reduced by 37.6% and ending frequency increased by 47.8% under external magnetic field. Moreover, the propagation characteristics of longitudinal wave in negative regulation MRM were also studied and the results indicated that the stiffnesses were magnetic-related, and the bandgap can be tuned substantially under external magnetic field. This work presented a negative regulation MRM that the bandgap was broadened and moved to lower frequency under the external magnetic field, showing a great potential in the field of vibration isolation.超材料是一种人工结构的周期性材料,在带隙中具有显著的波衰减特性。然而,具有可调低频带隙的超材料仍然是传统方法的挑战。在这项工作中,利用双模量三维打印技术制作了一种具有负调控和低频带隙的新型磁流变超材料(MRM)。利用质量弹簧模型对负调节超材料的带隙进行了理论分析。结果表明,在外加磁场作用下,带隙的起始频率降低了 37.6%,终止频率提高了 47.8%。此外,还研究了负调压磁共振中纵波的传播特性,结果表明刚度与磁有关,带隙在外加磁场作用下可大幅调整。这项研究提出了一种负调控磁共振,其带隙在外加磁场的作用下被拓宽并向低频移动,在隔振领域显示出巨大的潜力。Composites Part B: EngineeringRecycled carbon fiber potential for reuse in carbon fiber/PA6 composite partsJeantet Louis, Regazzi Arnaud, Perrin Didier, Pucci Monica Francesca, Corn Stéphane, Quantin Jean-Christophe, Ienny Patrickdoi:10.1016/j.compositesb.2023.111100 再生碳纤维在碳纤维/PA6 复合材料部件中的再利用潜力Pyrolysis reclaiming is the most promising process to treat high volumes of composite waste with an advantageous carbon footprint. This paper aims to compare pyrolysis reclaimed carbon fibers (RCF) to virgin sized fibers (VF) and de-sized fibers (VFT) in their capability to bond to a polyamide 6 matrix. Micromechanical tensile testing of single fiber samples of the three fiber types was conducted. A minor reduction in tensile strength and an unchanged elastic modulus of the RCF compared to VF was observed. Scanning electron microscopy and atomic force microscopy scans were used to evaluate the morphology of the fibers. To evaluate the surface energy of the fibers, tensiometric testing was conducted. RCF showed a better adhesion capability compared to VFT through higher total surface energy. Moreover, X-ray spectrophotometry scans highlighted a higher proportion of functional groups at the RCF surface compared to VFT. Finally, pull-out tests underlined a decrease of the interfacial shear strength of RCF and VFT by 35 % compared to VF. Overall, this study’s results further the understanding of the impact of the pyrolysis reclaiming process on RCF mechanical and adhesion properties.热解再生是处理大量复合材料废料的最有前途的工艺,同时还具有良好的碳足迹。本文旨在比较热解再生碳纤维(RCF)与原生尺寸纤维(VF)和去尺寸纤维(VFT)与聚酰胺 6 基质的粘合能力。对三种纤维的单纤维样品进行了微机械拉伸测试。与 VFT 相比,RCF 的拉伸强度略有降低,弹性模量保持不变。扫描电子显微镜和原子力显微镜扫描用于评估纤维的形态。为了评估纤维的表面能,还进行了张力测试。与 VFT 相比,RCF 通过更高的总表面能显示出更好的粘附能力。此外,X 射线分光光度扫描显示,与 VFT 相比,RCF 表面的官能团比例更高。最后,拉出试验表明,与 VF 相比,RCF 和 VFT 的界面剪切强度降低了 35%。总之,这项研究的结果进一步加深了人们对热解再生工艺对 RCF 机械和粘附性能影响的理解。Composites Science and TechnologyA simple rheological method for the experimental assessment of the fiber percolation threshold in short fiber biocompositesVitiello Libera, Salzano de Luna Martina, Ambrogi Veronica, Filippone Giovannidoi:10.1016/j.compscitech.2023.110345 用于实验评估短纤维生物复合材料纤维渗流阈值的简单流变学方法The identification of the percolation threshold (Φc) in short fiber composites is a challenging problem in Composite Science. Above Φc the fibers form a continuous network that causes substantial changes in mechanical and transport properties. Besides, percolation of natural fibers in biodegradable polymer matrices allows water and other pro-degradative species to access the inner parts of the material from the external environment, accelerating biodegradation. Whether such a speeding up is desired or not, assessing Φc in composites is of utmost importance. Unfortunately, natural fibers are not conductive and exhibit highly variable shape and physical properties. This prevents the use of many experimental and theoretical approaches for the estimate of Φc. Here we propose an original rheological approach borrowed from the viscoelastic modelling of polymer nanocomposites. The method was applied to two systems made of poly(lactic acid) filled with hemp or kenaf fibers (average length <500 μm, average length-to-diameter ratio <5). The estimate of Φc (∼10.1 and 19.5 vol% for the hemp- and kenaf-based composite, respectively) required a single set of simple linear viscoelastic measurements, and the computed values were in good agreement with those obtained through time-consuming (measurement times >3 weeks) dielectric spectroscopy analyses (∼10.1 and 18.5 vol%).确定短纤维复合材料中的渗流阈值(Φc)是复合材料科学中一个具有挑战性的问题。超过 Φc 时,纤维会形成连续的网络,从而导致机械和传输性能发生重大变化。此外,天然纤维在可生物降解聚合物基质中的渗滤作用可使水和其他促降解物质从外部环境进入材料内部,从而加速生物降解。无论是否希望加速降解,评估复合材料中的Φc 都至关重要。遗憾的是,天然纤维并不导电,而且其形状和物理性质变化很大。这使得许多实验和理论方法无法用于估算 Φc。在此,我们从聚合物纳米复合材料的粘弹性建模中借鉴了一种独创的流变学方法。我们将该方法应用于由聚乳酸填充麻纤维或槿麻纤维(平均长度小于 500 μm,平均长径比小于 5)制成的两个系统。只需进行一组简单的线性粘弹性测量,即可估算出Φc(麻基和槿麻基复合材料的Φc分别为 10.1 ∼ 10.1 和 19.5 vol%),计算值与耗时(测量时间大于 3 周)的介电光谱分析结果(Φc 为 10.1 ∼ 10.1 和 18.5 vol%)十分吻合。来源:复合材料力学仿真Composites FEM

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