首页/文章/ 详情

【新文速递】2023年10月28日固体力学SCI期刊最新文章

1天前浏览15

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

International Journal of Solids and Structures

A physically based strength prediction model for glass

Rudshaug Jonas, Aasen Karoline Osnes, Hopperstad Odd Sture, Børvik Tore

doi:10.1016/j.ijsolstr.2023.112548

基于物理的玻璃强度预测模型

The strength of glass has been a subject of great interest for more than one hundred years. Due to the stochastic nature of glass, governed by microscopical surface flaws, glass plates exhibit large variations in fracture strength. The aim of this work is to propose a new strength prediction model for glass, named the Glass Strength Prediction Model (GSPM) that captures the nature of fracture initiation in glass, spanning from rate dependence to size effects. We aim for the presented model to be applicable in modern design processes and provide a procedure to facilitate input parameter calibration for glass plates from different suppliers. GSPM is a Monte-Carlo based model that combines the theories of linear elastic fracture mechanics (LEFM) and sub-critical crack growth (SCG) to generate virtual tests on a representative sample of glass plates. The stress evolution in the glass plates is obtained from finite element (FE) simulations. The model results in representative fracture strength distributions that span the probable fracture initiation instances with respect to time, location and stress level. We also demonstrate how the GSPM can be used to trigger fracture in constitutive models applied in FE simulations. This feature provides the option to investigate scenarios including multiple glass plates with interdependent fracture initiation behavior. The GSPM displays great promise in terms of usability and prediction capacity. It is able to capture the fracture initiation behavior of glass plates of varying geometries exposed to load cases spanning from, e.g., quasi-static four-point bending to blast pressure. The model has the potential to reduce the number of physical experiments and numerical FE simulations in modern development processes of glass structures.

一百多年来,玻璃的强度一直是人们非常感兴趣的话题。由于玻璃具有随机性,受微观表面缺陷的影响,玻璃板的断裂强度变化很大。这项工作的目的是为玻璃提出一个新的强度预测模型,命名为玻璃强度预测模型(GSPM),该模型能捕捉玻璃断裂起始的性质,包括速率依赖性和尺寸效应。我们希望所提出的模型适用于现代设计流程,并提供一个程序,方便对来自不同供应商的玻璃板进行输入参数校准。GSPM 是一种基于蒙特卡洛的模型,它结合了线性弹性断裂力学(LEFM)和亚临界裂纹生长(SCG)理论,对玻璃板的代表性样本进行虚拟测试。玻璃板中的应力演变是通过有限元(FE)模拟获得的。该模型得出了具有代表性的断裂强度分布,这些分布在时间、位置和应力水平方面跨越了可能的断裂起始实例。我们还演示了如何利用 GSPM 在有限元模拟中应用的构成模型中触发断裂。该功能可用于研究包括具有相互依赖断裂起始行为的多块玻璃板在内的各种情况。就可用性和预测能力而言,GSPM 前景广阔。它能够捕捉不同几何形状的玻璃板在从准静态四点弯曲到爆炸压力等各种载荷情况下的断裂起始行为。在玻璃结构的现代开发过程中,该模型有望减少物理实验和数值 FE 模拟的数量。


Mechanics of Materials

Use of hardness, PIP and tensile testing to obtain stress-strain relationships for metals

Southern T.J.F., Campbell J.E., Fang C., Nemcova A., Bannister A., Clyne T.W.

doi:10.1016/j.mechmat.2023.104846

使用硬度、PIP 和拉伸测试获得金属的应力-应变关系

Both hardness testing and Profilometry-based Indentation Plastometry (PIP) can be used to obtain features of (tensile) stress-strain curves. The two tests are superficially similar, involving penetration (under a known load) of an indenter into the flat surface of a sample, followed by measurement of dimensional characteristics of the residual indent. The associated data handling procedures, however, are very different in the two types of test. Hardness numbers, which are commonly based on measurement of the lateral extent or depth of the indent, essentially give a semi-quantitative indication of the resistance to plastic deformation: going beyond this to infer features of the (nominal) stress-strain curve – notably the yield stress (YS) and Ultimate Tensile Stress (UTS) – can only be done via empirical correlations (often restricted to certain types of alloy). PIP testing, on the other hand, involves measurement of the complete indent profile, followed by (automated) iterative FEM modelling of the indentation, allowing the complete (true) stress-strain curve to be obtained. This paper covers application of both approaches to 12 different alloys, with inferred stress-strain characteristics being compared with those from tensile testing. Insights are provided relating to the very different levels of detail and reliability offered by the two procedures.

硬度测试和基于轮廓仪的压入塑性测量法(PIP)都可用于获取(拉伸)应力-应变曲线的特征。这两种测试表面上相似,都是将压头(在已知载荷下)插入样品的平面,然后测量残留压痕的尺寸特征。然而,这两种测试的相关数据处理程序却大相径庭。硬度值通常以测量压痕的横向范围或深度为基础,基本上是对塑性变形阻力的半定量指示:除此之外,要推断(标称)应力-应变曲线的特征,特别是屈服应力(YS)和极限拉伸应力(UTS),只能通过经验相关性来实现(通常仅限于某些类型的合金)。另一方面,PIP 测试涉及测量完整的压痕轮廓,然后对压痕进行(自动)迭代有限元建模,从而获得完整的(真实的)应力-应变曲线。本文介绍了这两种方法在 12 种不同合金中的应用,并将推断出的应力应变特性与拉伸试验得出的应力应变特性进行了比较。这两种方法所提供的详细程度和可靠性截然不同,本文对此进行了深入分析。


International Journal of Plasticity

Capturing the transition from diffuse to localised failure in constitutive modelling of partially saturated soils

Phan Dat Gia, Nguyen Giang D., Bui Ha H., Bennett Terry

doi:10.1016/j.ijplas.2023.103783

在部分饱和土壤的结构建模中捕捉从扩散到局部破坏的过渡过程

Localised failures in the form of shear band induce localised deformation and saturation within partially saturated soils. Inelastic responses mainly take place inside the shear band, while the zone outside it usually undergoes unloading processes with much smaller changes in deformation and saturation, as observed in several triaxial tests. The interaction between responses inside and outside shear bands governs the macro behaviour under effects of the hydromechanical coupling. This mechanism, along with properties of shear band (inclination, thickness) and the specimen size, are usually missing in existing classical models based on homogenous assumption. They are incorporated into our approach to correctly capture the post-localisation behaviour of partially saturated soils. In our proposed approach, enrichment terms for kinematics are used in the thermodynamics-based formulation to account for strong variations of hydromechanical responses (stress-strain, suction-saturation) outside and inside the shear band. The proposed formulation results in a size-dependent constitutive structure capable of describing the transition of behaviour from homogeneous to localised stages. The promising features of the proposed formulation are illustrated using data from drained triaxial tests.

在部分饱和的土壤中,剪切带形式的局部破坏会引起局部变形和饱和。非弹性反应主要发生在剪切带内部,而剪切带外部区域通常会经历卸载过程,变形和饱和度的变化要小得多,这在一些三轴试验中也能观察到。在水力机械耦合作用下,剪切带内外反应的相互作用决定了宏观行为。这种机制以及剪切带的特性(倾斜度、厚度)和试样尺寸,通常是现有基于同质假设的经典模型所缺乏的。我们的方法中加入了这些因素,以正确捕捉部分饱和土壤的后定位行为。在我们提出的方法中,基于热力学的公式中使用了运动学增量项,以考虑剪切带内外水力学响应(应力-应变、吸力-饱和度)的强烈变化。所提出的公式产生了一种与尺寸有关的构成结构,能够描述从均质阶段到局部阶段的行为转变。利用排水三轴试验的数据说明了所提公式的优点。


Thin-Walled Structures

Negative Stiffness Metamaterial with Directional Stability in Uniform Fields

Zhu Shaowei, Wang Jingzhe, Chen Liming, Liu Tao, Li Weiguo

doi:10.1016/j.tws.2023.111302

在均匀场中具有方向稳定性的负刚度超材料

Negative stiffness metamaterials have been widely studied due to their unusual properties and potential applications in shape reconfiguration, shock isolation, and reusable energy absorption, but their stability in fields has been less studied. In this work, a theoretical framework for determining the stability of negative stiffness metamaterials in a uniform field is established. More importantly, the concepts of directional stability and semi-directional stability are proposed for the metamaterials that have different stability in different field directions; metamaterials with different physical feature distributions are designed and prepared to achieve such ability, and the finite element simulation is used for theory verification and parameter study. The proposed metamaterial has the potential to be applied as field direction detectors and field-sensitive electrical relays.

负刚度超材料因其不同寻常的特性以及在形状重构、冲击隔离和可重复使用的能量吸收方面的潜在应用而被广泛研究,但对其在场内的稳定性研究较少。本研究建立了一个理论框架,用于确定负刚度超材料在均匀场中的稳定性。更重要的是,针对在不同场方向上具有不同稳定性的超材料,提出了定向稳定性和半定向稳定性的概念;设计并制备了具有不同物理特征分布的超材料来实现这种能力,并利用有限元模拟进行了理论验证和参数研究。所提出的超材料有望用作场方向探测器和场敏感电继电器。



来源:复合材料力学仿真Composites FEM
ACTMechanicalDeform断裂UGUM裂纹理论爆炸材料试验
著作权归作者所有,欢迎分享,未经许可,不得转载
首次发布时间:2024-11-03
最近编辑:1天前
Tansu
签名征集中
获赞 0粉丝 0文章 143课程 0
点赞
收藏
作者推荐

【新文速递】2023年10月12日复合材料SCI期刊最新文章

今日更新:Composite Structures 9 篇,Composites Part A: Applied Science and Manufacturing 1 篇,Composites Science and Technology 2 篇Composite StructuresHigh performance shape-adjustable structural lithium-ion battery based on hybrid fiber reinforced epoxy compositeMao Yu-Qin, Dong Guang-He, Fu Yu-Tong, Li Yuan-Qing, Huang Pei, Fu Shao-Yundoi:10.1016/j.compstruct.2023.117598基于混合纤维增强环氧树脂复合材料的高性能形状可调结构锂离子电池High performance shape-adjustable structural batteries with both excellent electrochemical performances and mechanical properties, and compatible with conventional batteries and composite processing techniques, are highly attractive for next generation electrical vehicles and electrical aircrafts. Herein, a high-performance structural lithium-ion battery composite (SLBC) is developed by encapsulating commercial-available battery core materials with hybrid fiber reinforced epoxy composite laminate shells, which can be assembled into desired irregular shapes with the conventional vacuum bagging technique. Firstly, the laminate shell layout with the combination of glass fiber woven fabric (GFWF) and carbon fiber woven fabric (CFWF) is designed and optimized. Meanwhile, a PET film is employed to wrap the battery core materials, which enables processing of the SLBC with liquid electrolyte in ambient condition. The SLBC obtained demonstrates both prominent mechanical (flexural strength of 211.7 MPa and flexural modulus of 7.7 GPa) and electrochemical properties (an initial discharge capacity of 98.5 mAh g-1 at 0.2 C, a high energy density of 314.5 Wh kg-1, and a good cycling performance) owing to the hybrid design of CFWF and GFWF as well as a sealed environment to guarantee the battery operate well. Impressively, the in-situ mechano-electrochemical measurements are assessed under the out-of-plane compressive stress and the flexural stress conditions. These results show that the SLBC under loading can maintain stable electrochemical performance even at a high out-of-plane compressive stress of 20 MPa and a high flexural stress of 150 MPa. Furthermore, the SLBC can also maintain the excellent discharge capacity when subjected to a high impact energy, which is promising in next generation electrical vehicles. Finally, the wave-like SLBC fabricated demonstrates the effectiveness in withstanding loads and driving electric fan simultaneously, which is promising in next generation electrical vehicles.可调整形状的高性能结构电池既具有优异的电化学性能和机械性能,又与传统电池和复合材料加工技术兼容,对下一代电动汽车和电动飞机极具吸引力。本文开发了一种高性能结构锂离子电池复合材料(SLBC),将商用电池芯材料与混合纤维增强环氧树脂复合材料层压板壳体封装在一起,可通过传统的真空装袋技术组装成所需的不规则形状。首先,设计并优化了玻璃纤维编织物(GFWF)和碳纤维编织物(CFWF)组合的层压外壳布局。同时,采用 PET 薄膜包裹电池芯材料,使 SLBC 能够在环境条件下与液态电解液一起加工。由于 CFWF 和 GFWF 的混合设计以及密封环境保证了电池的良好运行,因此获得的 SLBC 具有突出的机械性能(抗弯强度为 211.7 MPa,抗弯模量为 7.7 GPa)和电化学性能(0.2 C 下的初始放电容量为 98.5 mAh g-1,能量密度高达 314.5 Wh kg-1,循环性能良好)。令人印象深刻的是,在面外压缩应力和弯曲应力条件下对原位机械电化学测量进行了评估。这些结果表明,即使在 20 兆帕的高平面外压应力和 150 兆帕的高弯曲应力条件下,加载中的 SLBC 仍能保持稳定的电化学性能。此外,SLBC 在承受高冲击能量时也能保持出色的放电能力,这在下一代电动汽车中大有可为。最后,制造出的波浪状 SLBC 在承受负载的同时还能有效驱动电风扇,这在下一代电动汽车中大有可为。Influence of projectile physical state on ballistic energy absorption capacity of UHMWPE laminate: Experiment and SimulationHe Yemao, Jiao Yanan, Qing Zhou Johnny, Zhang Diantang, Lei Hongshuai, Chen Lidoi:10.1016/j.compstruct.2023.117607弹丸物理状态对超高分子量聚乙烯层压板弹道能量吸收能力的影响:实验与模拟This paper presents the influence of projectile physical state on ballistic energy absorption capacity of UHMWPE laminate. Specifically, standard fragment simulating projectile (FSP) and 7.62 mm × 39 mm mild steel core projectile (MSCP) are utilized to perforate two kinds of areal density laminate. Internal damage morphologies of post-impact laminate are characterized via X-ray computer tomography (CT). A sub-laminate discretization approach was used to establish numerical laminate model, and decoupling parametric studies of projectile state were performed. Results of ballistic tests show that ballistic energy absorption capacity of laminate depends on projectile state and laminate areal density. Multi scale damage morphologies analysis indicate that shear fracture and multi-layer delamination failure are the primary failure modes of post-impact laminate, which were in good agreement with simulation results. Results of parametric studies suggest that high-speed spin of projectile will cause torsional deformation of laminate.本文研究了弹丸物理状态对超高分子量聚乙烯层压板弹道能量吸收能力的影响。具体而言,本文使用标准碎片模拟弹丸(FSP)和 7.62 mm × 39 mm 低碳钢芯弹丸(MSCP)击穿两种等密度层压板。冲击后层压板的内部损伤形态通过 X 射线计算机断层扫描(CT)进行表征。采用子层压离散化方法建立了数值层压模型,并对弹丸状态进行了解耦参数研究。弹道试验结果表明,层压板的弹道能量吸收能力取决于弹丸状态和层压板的等密度。多尺度破坏形态分析表明,剪切断裂和多层分层破坏是冲击后层压板的主要破坏模式,这与模拟结果十分吻合。参数研究结果表明,弹丸的高速旋转会引起层压板的扭转变形。Multi-objective optimization for free vibration of L-shaped bi-functionally graded sandwich plates using an effective finite element method and non-dominated sorting genetic algorithm IIHoa Pham Quoc, Thanh Tran Trung, Zenkour Ashraf M., Nguyen-Thoi Trungdoi:10.1016/j.compstruct.2023.117622利用有效有限元法和非支配排序遗传算法 II 对 L 形双功能分级夹层板的自由振动进行多目标优化Free vibration analysis and multi-objective optimization for L-shaped bi-functionally graded sandwich (L-BFGSW) plates are studied in this work. The L-BFGSW plates are made of three layers including a ceramic core and two face-sheet layers made of two different functionally graded materials (FGMs). For free vibration analysis, an effective C1 finite element formulation based on Shi's third-order shear deformation plate theory (TSDT) is proposed. For solving the multi-objective optimization, the non-dominated sorting genetic algorithm II (NSGA-II) is utilized to execute the optimization-solving process to acquire Pareto-optimum solutions. These results demonstrate a clear solution for solving the trade-off relationship between the maximum of the first frequency and the minimum of the structural weight.本文研究了 L 型双功能梯度夹层板(L-BFGSW)的自由振动分析和多目标优化。L-BFGSW 板由三层组成,包括陶瓷芯层和由两种不同功能分级材料(FGM)制成的两层面板层。针对自由振动分析,提出了基于 Shi 的三阶剪切变形板理论(TSDT)的有效 C1 有限元公式。为解决多目标优化问题,利用非支配排序遗传算法 II(NSGA-II)执行优化求解过程,以获得帕累托最优解。这些结果表明,在解决第一频率最大值和结构重量最小值之间的权衡关系时,有一个明确的解决方案。Parametric theoretical prediction of elastic properties and strength of fine weave pierced C/C compositesYao Tianlei, Li Diansen, Jiang Leidoi:10.1016/j.compstruct.2023.117614细织穿孔 C/C 复合材料弹性性能和强度的参数理论预测This paper developed a parametric model of fine weave pierced carbon/carbon (FWPCC) composites based on the structural relationship of actual sample information. The elastic constants and compressive strengths of FWPCC composites with various Z-directional yarn contents were parametrically investigated. The developed theoretical prediction model agreed well with the experimental data. The parametric prediction results found Z-directional modulus of FWPCC composites with 6K Z-directional yarns increased by 88.21% compared to FWPCC composites with 1K Z-directional yarns; X/Y-directional modulus decreased by 17.32%; Z-directional compressive strength increased by 337.33%; X/Y-directional compressive strength only decreased by 6.12%. The accuracy of the two failure criteria (Hoffmann, Hashin failure criterion) used for the model was compared. The accuracy of the model prediction using Hashin failure criterion was better than that of the Hoffmann criterion. The predicted results using Hashin criterion also showed that under Z-directional compressive loading, the composite failure was mainly the compressive failure of the Z-directional yarns; under X/Y-directional compressive loading, the composite failure was mainly the compressive failure of the fibers in the bending section in the X/Y-directional yarns. The developed theoretical model was of great significance for the engineering application of C/C composite.本文基于实际样品信息的结构关系,建立了细织穿孔碳/碳(FWPCC)复合材料的参数模型。对不同 Z 向纱线含量的 FWPCC 复合材料的弹性常数和抗压强度进行了参数化研究。所建立的理论预测模型与实验数据吻合良好。参数预测结果发现,与使用 1K Z 向纱的 FWPCC 复合材料相比,使用 6K Z 向纱的 FWPCC 复合材料的 Z 向模量增加了 88.21%;X/Y 向模量降低了 17.32%;Z 向抗压强度增加了 337.33%;X/Y 向抗压强度仅降低了 6.12%。比较了模型使用的两种失效准则(霍夫曼失效准则和哈辛失效准则)的准确性。采用 Hashin 失效准则的模型预测准确性优于 Hoffmann 准则。使用 Hashin 准则预测的结果还表明,在 Z 向压缩载荷作用下,复合材料的破坏主要是 Z 向纱线的压缩破坏;在 X/Y 向压缩载荷作用下,复合材料的破坏主要是 X/Y 向纱线弯曲部分纤维的压缩破坏。所建立的理论模型对 C/C 复合材料的工程应用具有重要意义。In-plane crashing behavior and energy absorption of re-entrant honeycomb reinforced by arched ribsZou Zhen, Xu Fengxiang, Niu Xiaoqiang, Fang Tengyuan, Jiang Zhoushundoi:10.1016/j.compstruct.2023.117615用拱肋加固的重入式蜂窝材料的平面内碰撞行为和能量吸收Arched structures have increased in importance over the last few years due to their high efficiency in bearing loads. This paper introduces arched ribs to the classical re-entrant honeycomb (RH) as reinforced structures, and then its energy absorption is improved by simultaneously utilizing the reinforced structures and the auxetic deformation of RHs. Herein, the in-plane crashing response of reinforced RHs (RRH) under different impact velocities is investigated with finite element methods verified against the quasi-static compression experiment of 3D-printed RRH specimens. By introducing arched structures, the deformation of RHs becomes more stable and regular, and two plateau stresses are produced in the stress-strain curves of RRHs. Benefiting from the stacking deformation of RRHs and pure compression characteristic of catenary arches, the second plateau stress of all-reinforced RHs (ARH) is 3.8 times higher than the first one. Two plateau stresses of ARHs are derivated theoretically with a relative error of less than 7%. Furthermore, a parametric study is performed to explore the effect of impact velocities, thicknesses, and the height of arched ribs on the crashing response of RRHs. The present investigation paves a new way toward strengthening the energy absorption of conventional honeycombs.在过去几年中,弧形结构因其高效的承载能力而日益受到重视。本文在经典的重入式蜂窝(RH)中引入了弧形肋作为增强结构,然后通过同时利用增强结构和 RH 的辅助变形来提高其能量吸收能力。本文采用有限元方法研究了不同撞击速度下增强型 RH(RRH)的平面内碰撞响应,并通过三维打印的 RRH 试样的准静态压缩实验进行了验证。通过引入弧形结构,RRH 的变形变得更加稳定和规则,并且在 RRH 的应力-应变曲线中产生了两个高原应力。得益于 RRH 的堆积变形和导管拱的纯压缩特性,全增强 RH(ARH)的第二个高原应力是第一个应力的 3.8 倍。从理论上推导出 ARH 的两个高原应力,其相对误差小于 7%。此外,还进行了参数研究,以探讨冲击速度、厚度和拱肋高度对 RRH 碰撞响应的影响。本研究为加强传统蜂窝的能量吸收能力铺平了新的道路。Investigation on tearing damage of CFRP circular cell honeycomb in end-face grindingDong Zhigang, Wang Zhenjia, Tian Junchao, Kang Renke, Bao Yandoi:10.1016/j.compstruct.2023.117616端面磨削中 CFRP 圆形蜂窝的撕裂损伤研究CFRP circular cell honeycomb has promising applications in the aerospace field due to its excellent mechanical properties. However, a large number of periodically distributed tearing damages severely restrict the high-quality machining of CFRP circular cell honeycomb. This paper investigates the formation mechanism of tearing damages during end-face grinding of CFRP circular cell honeycomb and proposes suppression strategies. In this paper, a maximum undeformed chip thickness model considering tearing damage distribution is developed, and the evolution behavior of tearing damage is studied by combining the material removal process and grinding force. The grinding force and maximum tearing damage depth in different grinding conditions are analyzed. The results show that the formation of tearing damage in the cut-in stage is related to the weak stiffness of thin walls and the radial grinding force. The radial grinding force and maximum tearing depth can be altered by changing the maximum undeformed chip thickness which can be adjusted for different grinding speeds, feed rates, and offset ratios. The low-damage machining of CFRP circular cell honeycomb can be achieved by using a large offset ratio and variable feed rate.CFRP 圆孔蜂窝材料因其优异的机械性能在航空航天领域有着广阔的应用前景。然而,大量周期性分布的撕裂损伤严重制约了 CFRP 循环蜂窝材料的高质量加工。本文研究了 CFRP 圆孔蜂窝材料端面磨削过程中撕裂损伤的形成机理,并提出了抑制策略。本文建立了考虑撕裂损伤分布的最大未变形切屑厚度模型,并结合材料去除过程和磨削力研究了撕裂损伤的演变行为。分析了不同磨削条件下的磨削力和最大撕裂损伤深度。结果表明,切入阶段撕裂损伤的形成与薄壁的弱刚度和径向磨削力有关。径向磨削力和最大撕裂深度可通过改变最大未变形切屑厚度来改变,而最大未变形切屑厚度可根据不同的磨削速度、进给量和偏置比进行调整。通过使用大偏移比和可变进给率,可实现 CFRP 圆形蜂窝材料的低损伤加工。3D printing microlattice interpenetrating phase composites for energy absorption, damage resistance, and fracture toughnessGuo Xiao, Hu Yuwei, Li Xinwei, Ying Hsi Fuh Jerry, Feng Lu Wendoi:10.1016/j.compstruct.2023.117617三维打印微晶格互穿相复合材料,实现能量吸收、抗损伤和断裂韧性Under external load, lightweight cellular solids are often associated with localized deformation that would lead to their catastrophic failure. Cellular solids are thus often infilled with a soft secondary material, constituting interpenetrating phase composites. Owing to highly interconnected porous architectures and controllable smooth surfaces, the triply periodic minimal surface structures based on interpenetrating phase composites are investigated in this paper. Samples are fabricated via polyjet multi-material printing, with the hard material taking on the primitive lattice and the soft material taking on its inverse. Quasi-static compression and three-point bending tests were performed on the fabricated composites. Results show that the combination of high stiffness, strength, and prolonged smooth plateau stress endows the composites to be promising for lightweight materials and energy absorbers. The designed composites can exhibit an excellent fracture toughness of 0.51MPa•m1/2. Moreover, the designed interpenetrating architectures and stiff-contrast materials intrinsically control the strengthening and toughening mechanisms. The findings presented here demonstrate the potential to obtain enhanced mechanical properties by combining the advantages of the multi-material printing technique and interpenetrated design.在外部载荷作用下,轻质蜂窝状固体往往会产生局部变形,从而导致灾难性的破坏。因此,蜂窝状固体通常会填充柔软的辅助材料,构成互穿相复合材料。由于具有高度互联的多孔结构和可控的光滑表面,本文研究了基于互穿相复合材料的三周期最小表面结构。样品是通过 polyjet 多材料打印技术制作的,其中硬质材料采用原始晶格,软质材料采用其反晶格。对制作的复合材料进行了准静态压缩和三点弯曲试验。结果表明,高刚度、高强度和长期平稳的高原应力使这种复合材料有望成为轻质材料和能量吸收器。所设计的复合材料的断裂韧性高达 0.51MPa-m1/2。此外,所设计的互穿结构和刚性对比材料从本质上控制了增强和增韧机制。本文的研究结果表明,结合多种材料打印技术和穿插设计的优势,有可能获得更高的机械性能。Comments on “Sigmoid functionally graded plates embedded on Winkler-Pasternak foundation: Free vibration analysis by dynamic stiffness method” [Compos. Struct. 288 (2022) 115400]Kumar Raj, Jana Prasundoi:10.1016/j.compstruct.2023.117619关于 "嵌入 Winkler-Pasternak 地基上的西格玛功能分层板:用动态刚度法进行自由振动分析" [Compos.As comments to the paper in Composite Structures 288 (2022) 115400, the present article shows that the mathematical formulation presented for the vibration analysis of sigmoid functionally graded (S-FGM) plates resting on elastic foundation is not correct in its present form. It is shown that the incorrect formulation has resulted in considerable error in the reported results of the paper. In this note, possible mistakes of the mathematical formulation of the paper have been identified, and corrections are proposed.作为对《复合材料结构》(Composite Structures)288 (2022) 115400 号期刊论文的评论,本文指出,针对弹性地基上的西格码功能分级(S-FGM)板振动分析所采用的数学公式目前并不正确。结果表明,不正确的公式导致本文报告的结果存在相当大的误差。本说明指出了论文数学表述中可能存在的错误,并提出了修正建议。Study of the transverse strain effect on the Fiber Bragg Grating Sensor (FBGS) response with polyimide coating under experimental biaxial testsMartínez Vicente J.L, González-Gallego M, Ramírez F Terroba, Frövel M, Cela J.J Lópezdoi:10.1016/j.compstruct.2023.117621在实验性双轴测试中研究横向应变对带有聚酰亚胺涂层的光纤布拉格光栅传感器 (FBGS) 响应的影响The aim of this research work is to study the behaviour of Fiber Bragg Grating (FBG) sensors to interpret their response more accurately in a structural monitoring system. In the presence of a complex stress state, a structure is subjected to strain fields in multiple directions simultaneously and the sensors used for its structural monitoring are affected as well. However, the traditional procedure to calibrate FBG sensors consists of uniaxial tensile tests to calculate a strain sensitivity factor (K) that relates the sensor response to the strain measured during the test. In this study, a polyimide coated FBG sensor is embedded in a cruciform composite specimen to analyse its response to biaxial strain states. The experimental methodology has consisted of carrying out a campaign of biaxial tests on this specimen in which the longitudinal strain (εx) has been kept constant and the transverse strain (εy) has been varied by means of a triaxial testing machine to reproduce different plane stress states. Biaxial tests have allowed to study experimentally the influence of the εy on the longitudinal measurement of the FBG sensor and therefore on the calibration procedure. Finally, the experimental results obtained in both uniaxial and biaxial tests have been compared to the strain-optic theory.这项研究工作的目的是研究光纤布拉格光栅(FBG)传感器的行为,以更准确地解释其在结构监测系统中的响应。在复杂的应力状态下,结构会同时受到多个方向的应变场影响,用于结构监测的传感器也会受到影响。然而,校准 FBG 传感器的传统方法是通过单轴拉伸试验来计算应变灵敏度系数(K)该系数将传感器的响应与测试过程中测得的应变联系起来。本研究将聚酰亚胺涂层 FBG 传感器嵌入十字形复合材料试样中,分析其对双轴应变状态的响应。实验方法包括对该试样进行一系列双轴测试,其中纵向应变 (εx) 保持不变,横向应变 (εy) 通过三轴试验机变化,以再现不同的平面应力状态。通过双轴测试,可以在实验中研究ε y 的影响。εy 对 FBG 传感器纵向测量的影响,因此也影响了校准过程。最后,将单轴和双轴测试中获得的实验结果与应变光学理论进行了比较。Composites Part A: Applied Science and ManufacturingMagnetic field vertically aligned Co-MOF-74 derivatives/polyacrylamide hydrogels with bifunction of excellent electromagnetic wave absorption and efficient thermal conduction performancesCai Jingyu, Zhao Hao, Liu Huan, Wei Yifeng, Zheng Zongrui, Zhang Chunni, Xiao Longqiang, Zhao Rui, Hou Linxidoi:10.1016/j.compositesa.2023.107832磁场垂直排列的 Co-MOF-74 衍生物/聚丙烯酰胺水凝胶具有优异的电磁波吸收和高效的热传导双重性能Developing dual-function materials with efficient electromagnetic wave absorption and good thermal conductivity to achieve excellent packaging of devices has considerable appeal in modern electronic devices. Co-MOF-74 derivatives/polyacrylamide bifunctional gels (PAM-x) were synthesized by magnetic field assisted technique and in situ radical polymerization. PAM-x showed a minimum reflection loss (RLmin) of -51.6 dB and a maximum effective absorption bandwidth (EAB) of 5.73 GHz at a low filler loading of 5wt%. The magnetic nanoparticles in the MOF derivatives orient the fillers in the polymer matrix under the action of the magnetic field to form an ordered thermal conductivity path, which improves the thermal conductivity perpendicular to the plane direction and helps to promote rapid heat transfer. This work highlights the potential of MOF derivatives/polymers as bifunctional gels, and also provides a reference for the trade-off between electromagnetic wave absorption and thermal conductivity.开发具有高效电磁波吸收和良好导热性能的双功能材料,以实现出色的器件封装,在现代电子设备中具有相当大的吸引力。利用磁场辅助技术和原位自由基聚合法合成了 Co-MOF-74 衍生物/聚丙烯酰胺双功能凝胶(PAM-x)。在填充量为 5wt% 时,PAM-x 的最小反射损耗 (RLmin) 为 -51.6 dB,最大有效吸收带宽 (EAB) 为 5.73 GHz。在磁场的作用下,MOF 衍生物中的磁性纳米粒子使聚合物基体中的填料定向,形成有序的导热路径,从而提高了垂直于平面方向的导热率,有助于促进快速传热。这项工作凸显了 MOF 衍生物/聚合物作为双功能凝胶的潜力,同时也为电磁波吸收和导热性之间的权衡提供了参考。Composites Science and TechnologyMechanically robust, flexible hybrid tactile sensor with microstructured sensitive composites for human-cyber-physical systemsLi Zefu, Wang Shuo, Ding Wenxuan, Chen Yonglin, Chen Meng, Zhang Shujie, Liu Zhuangjian, Yang Weidong, Li Yandoi:10.1016/j.compscitech.2023.110303 采用微结构敏感复合材料的机械坚固柔性混合触觉传感器,适用于人体--计算机--物理系统Advances in human-cyber-physical system (HCPS) requires multiple and multimodal sensory network to address the challenge of human-machine relationships, posing substantial potential for human health monitoring and human-centric smart manufacturing. However, combining electrical sensitivity and mechanical robustness of flexible sensors with simple device structure is still challenging. This work presents a flexible porous bimodal pressure sensor (PBPS) by fabricating 3D microstructured sensitive porous carbon-nanotubes composites (PCNC). The multi-layered PBPS can offer the ability to switch between piezoresistive and piezocapacitive sensing modes without altering the device structure, enhancing mechanical stability of device under loading/unloading cycles. This versatility allows for the detection of hardness discrimination, grabbing sensing, and dynamic human physiological signal recognition, which possess superior pressure sensing performances with a high sensitivity (0.1059 kPa−1 in piezoresistive mode, 0.2054 kPa−1 in capacitive mode), wide measuring range (0–25 kPa), rapid response time (<130 ms in piezoresistive mode, <55 ms in piezocapacitive mode), and long-term durability (>3000 cycles). Furthermore, we proposed mechanical constitutive model to elucidate the sensing mechanism of microstructured PCNC by 3D micro-CT based modeling and experimental data. Finally, we employed multiple PBPSs as sensing elements to real-time monitor 3D printing processing stress, structure assembling stress, and human physiology signals in HCPS, indicating the potential applications of PBPS ranging from monitoring human health to facilitating intelligent manufacturing.人类-网络-物理系统(HCPS)的发展需要多种多模态传感网络来应对人机关系的挑战,这为人类健康监测和以人为本的智能制造带来了巨大潜力。然而,如何将柔性传感器的电灵敏度和机械鲁棒性与简单的设备结构相结合仍是一项挑战。本研究通过制造三维微结构敏感多孔碳纳米管复合材料(PCNC),提出了一种柔性多孔双模压力传感器(PBPS)。多层 PBPS 能够在不改变器件结构的情况下在压阻和压电容传感模式之间切换,从而增强了器件在加载/卸载循环下的机械稳定性。这种多功能性可用于检测硬度辨别、抓取感应和动态人体生理信号识别,具有卓越的压力传感性能,灵敏度高(压阻模式为 0.1059 kPa-1,电容模式为 0.2054 kPa-1),测量范围宽(0-25 kPa),响应时间快(压阻模式小于 130 毫秒,压电模式小于 55 毫秒),长期耐用(大于 3000 次循环)。此外,我们还提出了力学组成模型,通过基于三维微计算机断层扫描的建模和实验数据,阐明了微结构 PCNC 的传感机制。最后,我们采用多个 PBPS 作为传感元件,实时监测 HCPS 中的 3D 打印加工应力、结构装配应力和人体生理信号,这表明 PBPS 具有从监测人体健康到促进智能制造的潜在应用价值。New recyclable and self-healing elastomer composites using waste from toner cartridgesUtrera-Barrios S., Martínez M.F., Mas-Giner I., Verdejo R., López-Manchado M.A., Hernández Santana M.doi:10.1016/j.compscitech.2023.110292 利用硒鼓废料制成的新型可回收和自愈合弹性体复合材料Product recycling reintroduces what is discarded as waste and minimizes the environmental impact on our society. Among the different types of waste from electrical and electronic equipment, toner recycling often falls short, downcycling plastic components. This study introduces an innovative approach in which waste parts from toner cartridges are valorized to develop (recyclable and) self-healing elastomeric composite materials. The synergy between carboxylated nitrile rubber (XNBR) as the elastomeric phase and high-impact poly (styrene) (HIPS) as the thermoplastic phase derived from toner cartridge waste was explored and optimized. This combination resulted in the creation of a thermoplastic elastomer exhibiting robust mechanical properties and self-healing capabilities with a tensile strength of 6.6 ± 0.2 MPa and a temperature-driven mechanical recovery of 100%. Furthermore, the capacity of toner powder, an integral component of waste, to act as a reinforcing filler was confirmed, with a 50% increase in mechanical strength compared with the unfilled composite. Moreover, an increase in toner content (up to 20 phr) resulted in an optimal balance between tensile strength and self-healing capacity, surpassing the traditional antagonism between these properties. As a result, this research opens a new pathway in the field of self-healing composites and suggests a practical and environmentally friendly approach for managing electronic waste, effectively supporting the principles of Circular Economy.产品回收利用可以将废弃物重新回收利用,最大限度地减少对社会环境的影响。在电气和电子设备产生的各类废物中,墨粉盒的回收利用往往不足,塑料部件的循环利用率较低。本研究介绍了一种创新方法,即利用硒鼓中的废弃部件来开发(可回收和)自愈合弹性复合材料。研究探索并优化了羧基丁腈橡胶(XNBR)作为弹性体相与高抗冲聚苯乙烯(HIPS)作为热塑性相之间的协同作用。这种组合造就了一种热塑性弹性体,它具有强大的机械性能和自愈能力,拉伸强度为 6.6 ± 0.2 兆帕,温度驱动的机械恢复能力为 100%。此外,废料中不可或缺的墨粉粉末作为增强填料的能力也得到了证实,与未填充的复合材料相比,其机械强度提高了 50%。此外,墨粉含量的增加(最多 20phr)使拉伸强度和自愈能力达到了最佳平衡,超越了这两种性能之间的传统对立关系。因此,这项研究为自愈合复合材料领域开辟了一条新的道路,并为管理电子废弃物提出了一种实用、环保的方法,有效地支持了循环经济原则。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