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【新文速递】2024年7月24日复合材料SCI期刊最新文章

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

Composite Structures

Three-dimensional vibration analysis of multilayered composite and functionally graded piezoelectric plates and shells

S. Brischetto, D. Cesare

doi:10.1016/j.compstruct.2024.118413

多层复合材料和功能梯度压电板壳的三维振动分析

In the present paper, a coupled 3D exact electro-elastic shell model for Functionally Graded (FG) and composite piezoelectric structures is proposed. Primary variables of the electro-elastic model are the electric potential and the three displacement components. The model allows to evaluate the piezoelectric effect in terms of frequencies and vibration modes. Both closed and open circuit configurations are analyzed and compared. The 3D equilibrium equations and the 3D divergence electric displacement equation for spherical shells give the set of partial differential equations for the electro-elastic problem. The proposed model for spherical shells automatically degenerates into simpler models for plates and cylindrical shells via properly considerations on radii of curvature along in-plane directions. The orthogonal mixed curvilinear coordinates α, β and z are employed. The partial differential governing equations have constant coefficients considering fictitious layers and they are solved using the Navier harmonic form and the exponential matrix method. These features lead to an exact solution for simply-supported boundary conditions. Free vibration analyses are conducted and circular frequencies for the first three thickness vibration modes are computed. After a global assessment phase to verify the correctness of the developed model, new benchmarks are proposed: different thickness ratios and material configurations are investigated. The present work can be intended as a reference general solution for those scientists interested in the study of piezoelectric structures via 2D analytical and numerical formulations.

本文提出了功能梯度(FG)和复合压电结构的三维精确电弹性壳体耦合模型。电弹性模型的主要变量是电动势和三个位移分量。该模型可根据频率和振动模式评估压电效应。对闭路和开路配置进行了分析和比较。球壳的三维平衡方程和三维发散电位移方程给出了电弹性问题的偏微分方程组。通过适当考虑沿平面方向的曲率半径,所提出的球壳模型会自动退化为更简单的板壳和圆柱壳模型。模型采用了正交混合曲线坐标 α、β 和 z。考虑到虚构层,偏微分控制方程具有常数系数,并采用纳维谐波形式和指数矩阵法求解。这些特点导致了对简单支撑边界条件的精确求解。进行了自由振动分析,并计算了前三个厚度振动模式的圆周频率。经过全面评估阶段以验证所开发模型的正确性后,提出了新的基准:研究了不同的厚度比和材料配置。本研究成果可作为一般参考解决方案,供对通过二维分析和数值公式研究压电结构感兴趣的科学家参考。


Composites Part A: Applied Science and Manufacturing

Ultra-high temperature brazing of C/C using a simplified FeNiCrCu high-entropy alloy as filler

Xin Jiang, Guifeng Zhang, Kaiming Wang, Peng He

doi:10.1016/j.compositesa.2024.108370

 

采用简化FeNiCrCu高熵合金作为钎料进行C/C超高温钎焊

To increase remelting temperature of C/C brazed joint, a simplified FeNiCrCu high-entropy alloy (HEA) filler was designed in high-temperature brazing (HTB). The joint formation mechanism and fracture behavior were studied. The eutectic reaction of FeNiCrCu HEA with C/C could not occur, helping increase joint remelting temperature over HEA melting point (1334 °C). For the recommended parameter 1350 °C-2 min, C/C dissolution occurred well, and no defect was observed both at interface and within bond seam. The maximum shear strength was 24.2 MPa due to the high strength in-situ (Cr,Fe)3C2 reinforced the high plastic Cu-Ni-Fe(S.S.) matrix and intimate wavy interface. Cr existed only in M3C2 in bond seam, reducing both carbon content and CTE of bond seam. For higher temperature and longer time, excessive liquid carbon content resulted in the presence of large solidified carbon with defect at interface, joint shear strength decreased dramatically. These results provide a unique braze system for brazing carbon-based materials.

为了提高C/C钎焊接头的重熔温度,设计了一种简化的FeNiCrCu高熵合金(HEA)钎料用于高温钎焊(HTB)。研究了接头的形成机理和断裂行为。FeNiCrCu HEA与C/C的共晶反应不能发生,有助于提高接头重熔温度超过HEA熔点(1334 °C)。当推荐参数为1350 °C-2 min时,C/C溶解良好,界面和粘结缝内均未出现缺陷。高强度原位(Cr,Fe)3C2增强了高塑性Cu-Ni-Fe(S.S.)基体和紧密波状界面,最大抗剪强度为24.2 MPa。Cr仅存在于粘结缝的M3C2中,降低了粘结缝的含碳量和CTE。温度越高、时间越长,液态碳含量过高导致界面处存在较大的凝固碳缺陷,节理抗剪强度急剧下降。这些结果为钎焊碳基材料提供了一个独特的钎焊系统。


Design of polyimide/carbon nanotube@Ag@polyimide/graphene composite aerogel for infrared stealth and electromagnetic interference protection

Wuxuan Zheng, Hai Xie, Jinmei Li, Hao Yu, Zhangzhang Tang, Guangke Tian, Qihua Wang, Tingmei Wang

doi:10.1016/j.compositesa.2024.108371

 

聚酰亚胺/碳nanotube@Ag@聚酰亚胺/石墨烯复合气凝胶的红外隐身和电磁干扰防护设计

CHATGPT artificial intelligence is taking the world by storm, and countless electronic devices will generate massive amounts of electromagnetic interference (EMI). Hence, there is a pressing demand for materials exhibiting high thermal conductivity and superior EMI shielding effectiveness (SE). Thus, we construct a polyimide/carbon nanotube@Ag@polyimide/graphene (PCAPG) composite aerogel with porous, layered, and homogeneous structures in one, which provides a new idea for the multi-interface polarization interaction and special structure of anti-EMI materials. PCAPG has high thermal conductivity of ∼ 0.259 W (mK)-1 at 25 °C, excellent EMI SE of ∼ 90.28 dB and specific shielding effectiveness (SSE) of ∼ 940.42 dB cm3 g−1. The synergistic EMI attenuation mechanism of the PCAPG composite structure is analyzed using an aerogel unit. This composite aerogel provides a viable solution for infrared stealth, promoting heat dissipation from electronic components and reducing electromagnetic interference.

人工智能正在席卷全球,无数的电子设备将产生大量的电磁干扰(EMI)。因此,对具有高导热性和优异的电磁干扰屏蔽效能(SE)的材料有迫切的需求。因此,我们构建了一种集多孔、层状和均相结构于一体的聚酰亚胺/碳nanotube@Ag@聚酰亚胺/石墨烯(PCAPG)复合气凝胶,为抗电磁干扰材料的多界面极化相互作用和特殊结构提供了新的思路。PCAPG具有较高的热导率的 ∼ 25 0.259 W(可)1°C,优秀EMI SE ∼ 90.28 dB和具体的屏蔽效能(SSE)的 ∼ 940.42 dB立方厘米克−1。利用气凝胶装置分析了PCAPG复合结构的协同EMI衰减机理。这种复合气凝胶为红外隐身提供了可行的解决方案,促进了电子元件的散热,减少了电磁干扰。


Multifunctional, efficient, and durable composites of conductive PMIA/Ag membrane

Bai Jiang, Jianxun Shang, Faying Zhang, Na Li, Yan Wang, Zuming Hu, Junrong Yu

doi:10.1016/j.compositesa.2024.108372

多功能、高效、耐用的导电PMIA/Ag膜复合材料

Developing high-efficiency electromagnetic interference (EMI) shielding composite membranes along with additional functionalities to extend the application scenarios is highly desirable for the next generation electronic devices. Here, we report an ultrathin and flexible EMI shielding materials with sensitive Joule heating and outstanding infrared stealth performance was fabricated from poly-m-phenylene isophthalamide (PMIA) and Ag nanoparticles (AgNPs) through an innovation and simplicity method of electrospinning and electroless plating. Profiting from a continuous three-dimensional (3D) conductive network, the final membrane achieves an outstanding EMI shielding effectiveness (SE) of 100.51 dB (in X-band), a remarkable Joule heating properties with a fast thermal response and low driving voltage (<0.5V), and an outstanding infrared stealth with a low infrared emissivity (0.28). Meanwhile, the prepared composite membrane demonstrates stable EMI SE even after water washing, continuous bending, and heating treatment. This work integrates high-performance fiber PMIA, characterized by high heat resistance, flame retardancy, self-extinguishing properties, and chemical resistance, with functions such as EMI shielding, infrared stealth, and autonomous thermal management. It has great development potential if utilized in specialized combat uniforms under harsh conditions.

开发高效电磁干扰(EMI)屏蔽复合膜以及扩展应用场景的附加功能是下一代电子设备非常需要的。在这里,我们报道了一种超薄的柔性电磁干扰屏蔽材料,具有灵敏的焦耳加热和出色的红外隐身性能,由聚-间苯二胺(PMIA)和银纳米粒子(AgNPs)通过静电纺丝和化学镀的创新和简单的方法。得益于连续的三维(3D)导电网络,最终膜实现了100.51 dB (x波段)的出色EMI屏蔽效率(SE),具有快速热响应和低驱动电压(<0.5V)的卓越焦耳加热性能,以及具有低红外发射率(0.28)的出色红外隐身性能。同时,制备的复合膜在水洗、连续弯曲和加热处理后仍具有稳定的EMI SE。本工作集成了高性能PMIA纤维,具有高耐热性、阻燃性、自熄性和耐化学性,具有EMI屏蔽、红外隐身和自主热管理等功能。如果在恶劣条件下的特种作战制服中使用,具有很大的发展潜力。


Composites Part B: Engineering

Dynamically Crosslinked ECM-like Hydrogels Loaded with ROS-responsive Drug Nanoparticles for Treating Inflammation in Myocardial Infarction and Stroke

Zhicun Wang, Cheng Hu, Wen Zhang, Wenqi Liu, Shuyi He, Yang Liu, Li Yang, Yunbing Wang

doi:10.1016/j.compositesb.2024.111734

动态交联载ros反应药物纳米颗粒的类ecm水凝胶用于治疗心肌梗死和中风的炎症

Following a myocardial infarction (MI) or stroke, the excessive generation of reactive oxygen species (ROS) within a breaf timeframe may induce a pronounced inflammatory reaction, which exacerbates the progression of the disease. Thus, there is an urgent need to design a biomaterial to inhibit the inflammatory response associated with MI and stroke. In this study, we designed a reversible extracellular matrix (ECM)-like hydrogel via borate ester crosslinking, which responds to the inflammatory microenvironment affected by MI and stroke. At the same time, we developed a new type of loaded polymer nanoparticle (TK-DA) that can respond to ROS in ischemic regions and release the antiinflammatory drug dexamethasone. Ultimately, we integrated the nanoparticles and ECM-like hydrogel to fabricate a functional hydrogels.To verify the therapeutic effect of the functional hydrogel, we established two models of typical ischemic diseases, MI and stroke. The results showed that the hydrogel substantially reduced ROS levels and inflammation in vitro. Moreover, the results of the two in vivo animal models demonstrated that this functional hydrogel can effectively treat MI and stroke by suppressing inflammatory responses, mitigating apoptosis, and promoting neovascularization. In conclusion, the functional hydrogel strategy presents a universally applicable treatment approach for ischemic cardiovascular and cerebrovascular diseases, which are not limitted solely to the treatment of MI and stroke, but also hold future potential for clinical applications.

心肌梗死(MI)或中风后,呼吸时间内活性氧(ROS)的过量产生可能诱发明显的炎症反应,从而加剧疾病的进展。因此,迫切需要设计一种生物材料来抑制心肌梗死和脑卒中相关的炎症反应。在这项研究中,我们通过硼酸酯交联设计了一种可逆的细胞外基质(ECM)样水凝胶,该水凝胶对心肌梗死和中风影响的炎症微环境做出反应。同时,我们开发了一种新型负载聚合物纳米颗粒(TK-DA),它可以响应缺血区域的ROS并释放抗炎药物地塞 米松。最终,我们将纳米颗粒与类ecm水凝胶结合,制成功能性水凝胶。为了验证功能性水凝胶的治疗效果,我们建立了心肌梗死和脑卒中两种典型缺血性疾病模型。结果表明,水凝胶在体外显著降低ROS水平和炎症。此外,两种体内动物模型的结果表明,该功能性水凝胶可以通过抑制炎症反应、减轻细胞凋亡和促进新生血管形成来有效治疗心肌梗死和脑卒中。综上所述,功能性水凝胶策略是一种普遍适用于缺血性心脑血管疾病的治疗方法,它不仅局限于心肌梗死和脑卒中的治疗,而且具有未来临床应用的潜力。




来源:复合材料力学仿真Composites FEM
ACTSystemMAGNET振动断裂复合材料化学隐身电子UGUM焊接材料控制人工智能
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首次发布时间:2024-11-21
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【新文速递】2024年7月27日固体力学SCI期刊最新文章

今日更新:International Journal of Solids and Structures 2 篇,Journal of the Mechanics and Physics of Solids 2 篇,Mechanics of Materials 1 篇,Thin-Walled Structures 3 篇International Journal of Solids and StructuresA parametrized continuum constitutive model for reinforced thermoplastic composites with mechanically interlocked interfaceAnmol Kothari, Istemi B. Ozsoy, Gang Lidoi:10.1016/j.ijsolstr.2024.112994具有机械互锁界面的增强热塑性复合材料的参数化连续本构模型Reinforced thermoplastic composites (RTPC) exhibit weak interfacial strength due to the low surface energy of the polymer matrix. Recently, a concept of controlled mechanical interlocking was introduced that showed significant improvement in the interfacial shear strength with pure mechanical interlocking and no chemical bond/friction. In this paper, a parameterized continuum material model is developed through computational homogenization for an E-glass/polypropylene (PP) composite system with a mechanically interlocked interface. Such parametric models not only elucidate the effects of the microstructural parameters on the mechanical behavior of the material but also enables the optimization of the composite at the microstructure level.增强热塑性复合材料(RTPC)由于聚合物基体表面能低而表现出较弱的界面强度。最近,一种受控机械联锁的概念被引入,在纯机械联锁而没有化学键/摩擦的情况下,界面抗剪强度得到了显著提高。本文通过计算均质化,建立了具有机械互锁界面的e -玻璃/聚丙烯(PP)复合材料体系的参数化连续材料模型。这些参数化模型不仅阐明了微观结构参数对材料力学行为的影响,而且能够在微观结构水平上对复合材料进行优化。Constitutive description of distortional hardening in a TWIP steel: Addressing differential hardening under nonlinear strain pathsKang Wu, Chengchao Fang, Yong Sun, Jun Yangdoi:10.1016/j.ijsolstr.2024.113000 TWIP钢变形硬化的本构描述:处理非线性应变路径下的差异硬化The present study aims to describe the in-plane differential hardening behaviour of the twinning induced plasticity sheet metal TWIP980 under various stress states, including uniaxial tension, plane strain tension, and pure shear, particularly focusing on non-proportional loading conditions. The true stress–strain curves for each stress states were inversely obtained from their corresponding load–displacement curves and modeled using a differential hardening model that can accommodate all three stress states simultaneously on plastic work (density) contours. For non-proportional loading tests, oversize specimens were initially stretched under uniaxial tension up to a 10% pre-strain along the rolling, diagonal, and transverse directions, respectively. Subsequently, the three stress states were applied to subsize specimens cut from the deformed oversize specimens along the rolling direction. To describe the hardening behaviours during non-proportional loading, a homogeneous anisotropic hardening model was adopted and calibrated using two-step uniaxial tension tests. Subsequently, the differential hardening model was successfully incorporated into the homogeneous anisotropic hardening model to describe both the differential hardening and the strain path change-induced hardening behaviours under the two-step loadings, i.e., uniaxial tension to pure shear and uniaxial tension to plane strain tension. Both experimental and simulation results underscore the necessity to consider differential hardening under non-proportional loading conditions.本研究旨在描述双晶诱导塑性板材TWIP980在不同应力状态下的面内差异硬化行为,包括单轴拉伸、平面应变拉伸和纯剪切,特别关注非比例加载条件。每个应力状态下的真实应力-应变曲线由其对应的载荷-位移曲线反向获得,并使用微分硬化模型建模,该模型可以同时在塑性工作(密度)轮廓上容纳所有三种应力状态。对于非比例加载试验,超大试件在单轴拉伸下分别沿滚动、对角线和横向拉伸至10%的预应变。随后,将这三种应力状态应用于从变形的超大尺寸试样上沿轧制方向切割的亚尺寸试样。为了描述非比例加载时的硬化行为,采用均匀各向异性硬化模型,并采用两步单轴拉伸试验进行校准。随后,将差异硬化模型成功地纳入均匀各向异性硬化模型,以描述单轴拉伸到纯剪切和单轴拉伸到平面应变拉伸两步加载下的差异硬化和应变路径变化引起的硬化行为。实验和模拟结果都强调了在非比例加载条件下考虑差异硬化的必要性。Journal of the Mechanics and Physics of SolidsThe adjustable adhesion strength of multiferroic composite materials via electromagnetic loadings and shape effect of punchQing-Hui Luo, Yue-Ting Zhou, Yuxiao Yang, Shenghu Ding, Lihua Wangdoi:10.1016/j.jmps.2024.105794利用电磁载荷和冲头形状效应调节多铁复合材料的粘接强度Tunable and reversible dry adhesion possess great potential in a wide range of applications including transfer printing, climbing robots, wearable devices/electronics, and gripping in pick-and-place operations. Multiferroic composite materials offer new routines and approaches to achieve tunable adhesion due to their multi-field coupling effects. In this paper, the classical Johnson-Kendall-Roberts (JKR) adhesion model is extended to investigate the adhesive contact problem of a multiferroic composite half-space indented by an axisymmetric power-law shaped punch, whose shape index is denoted by n. The JKR-n adhesion models under the action of the power-law shaped punches with four different electromagnetic properties are set up by means of the total energy method. The explicit analytical expressions relating the indentation load and indentation depth to the contact radius are obtained, which can include the existing results in open literature as special cases. The generalized Tabor parameter and the interfacial adhesion strength applicable to multiferroic composite materials are defined. The effects of the shape index and the electromagnetic loadings on adhesion behaviors are revealed. It is found that both of them have prominent influences on the relationships among the indentation load, indentation depth and contact radius, the contact radius and indentation depth at self-equilibrium state, and the critical contact radius and indentation depth at pull-off moment. The pull-off force under the action of the conducting spherical punch subjected to non-zero electromagnetic loadings is dependent on material properties, which is different from the classical JKR result. More importantly, our analysis indicates that the pull-off force and the interfacial adhesion strength can be adjusted via altering the electromagnetic loadings and the shape index of the punch, which provides new approaches to achieve tunable adhesion.可调和可逆的干粘附在广泛的应用中具有巨大的潜力,包括转移印刷,攀爬机器人,可穿戴设备/电子产品,以及在拾取和放置操作中的抓取。多铁复合材料由于其多场耦合效应,为实现可调粘附提供了新的思路和方法。本文将经典的Johnson-Kendall-Roberts (JKR)粘接模型推广到研究形状指数为n的轴对称幂律型冲头压痕下多铁复合材料半空间的粘接接触问题。利用总能量法建立了四种不同电磁性能幂律型冲头作用下的JKR-n粘接模型。得到了压痕载荷和压痕深度与接触半径的显式解析表达式,作为特例可以包括公开文献中已有的结果。定义了适用于多铁复合材料的广义Tabor参数和界面粘接强度。揭示了形状指数和电磁载荷对粘接性能的影响。发现两者对压痕载荷、压痕深度与接触半径、自平衡状态下的接触半径与压痕深度、拉脱时刻临界接触半径与压痕深度之间的关系有显著影响。在非零电磁载荷作用下,导电球冲头的拉脱力取决于材料的性质,这与经典的JKR结果不同。更重要的是,我们的分析表明,拉拔力和界面粘附强度可以通过改变电磁载荷和冲头的形状指标来调节,这为实现可调粘附提供了新的途径。Pressurized membranes between walls: Thermodynamic process changes force and stiffnessPaul Lacorre, Louison Fiore, Jean-Marc Linares, Loïc Tadristdoi:10.1016/j.jmps.2024.105798 壁间加压膜:热力学过程改变了力和刚度Pressurized solids are ubiquitous in nature. Mechanical properties of biological tissues arise from cell turgor pressure and membrane elasticity. Flat contact between cells generate nonlinear forces. In this work, cells are idealized as pressurized elastic membranes in frictionless contact with one another. Contact forces are experimentally measured on rubber-like membranes and computed using finite element analysis (FEA). FEA matches experimental force-indentation relationships from small to large indentations. With the chosen dimensionless numbers, data gather on a master curve. The isobaric force exhibits a 4/3 power law over 1.5 decades of indentation. Forces for other thermodynamic processes (adiabatic, isothermal/osmotic and isochoric) are interpolated from isobaric data. Regarding stiffness, the isochoric process is superlinear contrary to the sublinear isobaric stiffness. Simple force-indentation relationships are given for each process.加压固体在自然界中无处不在。生物组织的力学特性是由细胞的膨胀压力和膜的弹性决定的。单元间的平面接触产生非线性力。在这项工作中,细胞被理想化为彼此无摩擦接触的加压弹性膜。实验测量了类橡胶膜上的接触力,并用有限元法计算了接触力。有限元分析从小到大的压痕匹配实验力-压痕关系。有了选定的无量纲数,数据就会在一条主曲线上收集。等压力在15年的压痕中呈现4/3幂律。其他热力学过程(绝热、等温/渗透和等时)的力由等压数据插值。在刚度方面,等压过程与次线性等压刚度相反是超线性的。给出了每个过程的简单力-压痕关系。Mechanics of MaterialsCarbon nanotubes as a basis of metamaterials and nanostructures: Crafting via design optimizationMarko Čanađija, Stefan Ivićdoi:10.1016/j.mechmat.2024.105105碳纳米管作为超材料和纳米结构的基础:通过设计优化制作Nanotruss structures made of carbon nanotubes are investigated in two conceptual applications: either as building blocks of metamaterials or for nanostructural applications. The nanotrusses are optimized for different purposes, including various loadings, boundary conditions, parameterizations, objectives and constraints used to formulate optimization problems. The procedure relies on a recently developed framework consisting of molecular dynamics simulations, neural networks and finite elements. This framework is now used in the design optimization of nanostructures and the performances of different popular heuristic optimization methods are compared. Five applications of nanotrusses made of carbon nanotubes are analyzed in detail to investigate the mechanical behavior of such structures and the efficiency of the optimizations. Besides an introductory example, the design of an energy trapping carbon nanotube nanotruss, an auxetic nanotruss, a cantilever nanotruss and the maximization of the compressive strength of a metamaterial are presented. It is shown that the exceptional mechanical properties of carbon nanotubes can indeed be exploited for the development of structures and materials with extraordinary mechanical properties. Although hampered by material and geometrical nonlinearity of the problem, most of the tested optimization methods have proven to be a good choice for the design of such materials and structures.由碳纳米管制成的纳米桁架结构在两个概念上的应用:作为超材料的构建块或用于纳米结构应用。纳米桁架针对不同的目的进行了优化,包括各种负载、边界条件、参数化、目标和约束,用于制定优化问题。该程序依赖于最近开发的由分子动力学模拟、神经网络和有限元组成的框架。该框架目前已用于纳米结构的设计优化,并比较了不同流行的启发式优化方法的性能。详细分析了碳纳米管纳米桁架的五种应用,研究了这种结构的力学性能和优化的效率。此外,还介绍了能量捕获型碳纳米管纳米桁架、辅助型纳米桁架、悬臂型纳米桁架以及超材料抗压强度最大化的设计方法。研究结果表明,碳纳米管优异的力学性能确实可以用于开发具有优异力学性能的结构和材料。虽然受到材料和几何非线性问题的限制,但大多数经过试验的优化方法已被证明是这类材料和结构设计的良好选择。Thin-Walled StructuresBehaviour, finite element modelling and design of flanged cruciform section steel columnsRuikai Dai, Behnam Behzadi-Sofiani, Spiridione Buhagiar, M. Ahmer Wadee, Leroy Gardnerdoi:10.1016/j.tws.2024.112268 法兰十字截面钢柱的性能、有限元建模与设计A study into the mechanical behaviour and design of flanged cruciform section steel members subjected to axial compression is presented herein. The mechanical behaviour of flanged cruciform section columns is first described, with particular emphasis on the newly developed approach for determining the elastic local buckling load for full flanged cruciform cross-sections. Existing experimental data on flanged cruciform section steel columns collected from the literature are then employed to validate numerical models developed within the finite element package ABAQUS. A comprehensive parametric study is subsequently conducted that encompasses a broad spectrum of cross-sectional geometries and global slenderness values. The mechanical behaviour and ultimate resistance of flanged cruciform section columns are shown to be dependent on not only the global slenderness, but also on the ratio of the elastic torsional to flexural buckling loads. The existing experimental data alongside the numerical parametric study results are employed to evaluate the resistance predictions provided in the current Eurocode 3 design codes, revealing a high level of conservatism. Finally, a new design approach for flanged cruciform section columns, suitable for incorporation into future revisions of Eurocode 3, is proposed which provides significantly improved accuracy and consistency in resistance predictions compared with the current provisions. A reliability analysis of the proposed design approach is conducted in accordance with the EN 1990 procedure, resulting in a recommended partial safety factor γ M1 = 1 . 0 .本文研究了十字形法兰型钢构件在轴压作用下的受力性能及设计。首先描述了法兰十字形截面柱的力学行为,特别强调了确定全法兰十字形截面弹性局部屈曲载荷的新方法。从文献中收集的法兰十字形截面钢柱的现有实验数据,然后用于验证在有限元软件包ABAQUS中开发的数值模型。随后进行了全面的参数化研究,包括广泛的横截面几何形状和整体长细比值。结果表明,法兰十字形截面柱的力学性能和极限抗力不仅与整体长细比有关,而且与弹性扭转载荷与弯曲屈曲载荷的比值有关。利用现有的实验数据和数值参数研究结果对现行欧洲规范3设计规范中提供的阻力预测进行了评估,显示出高度的保守性。最后,提出了一种新的法兰十字形截面柱的设计方法,适合纳入欧洲规范3的未来修订,与现行规定相比,该方法在阻力预测方面提供了显着提高的准确性和一致性。根据en1990程序对建议的设计方法进行可靠性分析,得出建议的部分安全系数γ M1 = 1。0。Flexible Roll Forming of surface developable profiles from Dual Phase steel.Achuth Sreenivas, Buddhika Abeyrathna, Bernard Rolfe, Matthias Weissdoi:10.1016/j.tws.2024.112271双相钢表面可展型材的柔性辊压成形。Flexible Roll Forming (FRF) can roll-form variable cross-sectional profiles for Electric Vehicle (EV) production however, a major limitation exists due to flange wrinkling while forming high-strength steels. Flange wrinkling can be eliminated by reducing the required level of membrane deformation in the longitudinal direction. Although reducing the severity of the profile&#39;s transitions minimises the strains, the overall complexity of the parts is also lowered. Origami-based developable profiles can be created from curved creased folding without membrane stretching or compression. In FRF, such types of profiles can be formed by combining a variation in width and depth over the length of the part. This study presents, for the first time, the analyses of forming a developable shape in a FRF operation. Firstly, analytical equations are applied to calculate the strains and forming stability of each pass which is followed by experimental FRF trials on two high-strength Dual Phase steels. Finally, Finite Element Analysis is used to investigate the forming behaviour of the two types of developable profiles. The experimental results show that the forming of one type of developable profile improves the shape, while the numerical analyses showed that an additional top-hat forming is required for the second profile type.柔性辊压成形(FRF)可以轧制出电动汽车(EV)生产的可变截面型材,但在成形高强度钢时存在法兰起皱的主要限制。可以通过降低纵向所需的膜变形水平来消除法兰起皱。虽然降低了型材过渡的严重程度,最大限度地减少了应变,但零件的整体复杂性也降低了。折纸为基础的可展轮廓可以创建从弯曲折痕折叠膜拉伸或压缩。在频响中,这种类型的轮廓可以通过结合零件长度上的宽度和深度变化来形成。本研究首次提出了在频响操作中形成可展开形状的分析。首先用解析方程计算了各道次的应变和成形稳定性,然后对两种高强度双相钢进行了频响试验。最后,采用有限元分析方法研究了两种可展开型材的成形行为。实验结果表明,一种可展开轮廓的成形可以改善形状,而数值分析表明,第二种轮廓需要额外的顶帽成形。Metamaterial design enabling simultaneous manipulation of Rayleigh and Love wavesJia Lou, Hui Fan, Jie Yang, Menghui Xu, Jianke Dudoi:10.1016/j.tws.2024.112273可以同时操纵瑞利波和洛夫波的超材料设计Studies on elastic metamaterials have expanded from manipulating bulk waves to surface waves, aiming to control the propagation of in-plane Rayleigh waves or anti-plane Love waves. Considering the coexistence of Rayleigh and Love waves in various scenarios, the objective of this study is to develop a metamaterial capable of simultaneously manipulating both types of waves. The proposed metamaterial consists of horizontal resonators with an oblique mounting angle relative to the wave propagation direction, as well as vertical resonators. Initially, analytical solutions for the dispersion of surface waves are derived, followed by Finite Element (FE) simulations to validate the analytically predicted dispersion and illustrate the corresponding wave modes, as well as the in-plane and out-of-plane displacement fields at specified frequencies. The present study reveals that the mounting angle of the horizontal resonators plays a crucial role in surface wave manipulation. By adjusting the mounting angle, three distinct objectives can be achieved: i) the attenuation of Rayleigh waves alone; ii) the independent attenuation of Rayleigh and Love waves, targeting different frequency ranges; and iii) the simultaneous attenuation of both Rayleigh and Love waves.弹性超材料的研究已经从控制体波扩展到控制面波,目的是控制面内瑞利波或反面洛夫波的传播。考虑到瑞利波和洛夫波在各种情况下的共存,本研究的目标是开发一种能够同时操纵两种波的超材料。所提出的超材料包括相对于波传播方向具有倾斜安装角的水平谐振器以及垂直谐振器。首先推导了表面波色散的解析解,然后进行了有限元模拟,验证了解析预测的色散,并说明了相应的波模,以及在指定频率下的面内和面外位移场。研究表明,水平谐振器的安装角度对表面波控制起着至关重要的作用。通过调整安装角度,可以实现三个不同的目标:1)瑞利波的单独衰减;ii)针对不同频率范围的瑞利波和洛夫波的独立衰减;瑞利波和洛夫波同时衰减。来源:复合材料力学仿真Composites FEM

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