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【新文速递】2023年11月13日固体力学SCI期刊最新文章

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今日更新:International Journal of Solids and Structures 1 篇,Mechanics of Materials 1 篇,International Journal of Plasticity 2 篇,Thin-Walled Structures 2 篇

International Journal of Solids and Structures

3D-printed highly stretchable curvy sandwich metamaterials with superior fracture resistance and energy absorption

Hamzehei Ramin, Bodaghi Mahdi, Wu Nan

doi:10.1016/j.ijsolstr.2023.112570

3d打印高拉伸弯曲夹层超材料,具有优异的抗断裂性和能量吸收

This paper focuses on the potential of curvy mechanical metamaterials to show how topological design can significantly enhance fracture toughness along the in-plane and out-of-plane (through-depth) directions. The conventional re-entrant unit cell is first reformulated by introducing local curvy ligaments and then additively manufactured by three-dimensional (3D) printing to form a center/edge-notch lattice metamaterial. The new conceptual design provides multi-stiffness unit cells, helping to control stress distribution within a structure under tensile load, specifically in the vicinity of the notches where stress concentrations occur. In other words, curvy unit cells are capable of arresting and blunting the notch under tensile loads and toughening the metamaterials. The crack tip opening displacement (CTOD) method calculates the fracture toughness. Not only can the fracture of lattice metamaterials be controlled along the in-plane direction by replacing unit cells in the sensitive parts of the metamaterials, but a new assembly method is also proposed. This offers that different thin plates of metamaterials with different layouts can be sandwiched to control out-of-plane fracture propagation (through-depth propagation of opening mode fracture) for the first time in fracture mechanics. This novel sandwiching method offers a multi-step fracture and significantly improves the fracture behavior of the lattice metamaterials from brittle to ductile by taking advantage of multiple through-thickness thin plates instead of considering one thick specimen. A detailed analysis of the effects of the ligament curvature value on the fracture behavior is presented. The results reveal that the more curvature, the more extension (ductility) will be realized, but too large curvature design can provide lower energy absorption capacity.

本文关注弯曲机械超材料的潜力,以展示拓扑设计如何显著提高沿面内和面外(穿过深度)方向的断裂韧性。首先通过引入局部弯曲韧带来重新构造传统的可重入单元格,然后通过三维(3D)打印进行增材制造,形成中心/边缘缺口晶格超材料。新的概念设计提供了多刚度单元,有助于控制拉伸载荷下结构内的应力分布,特别是在应力集中的缺口附近。换句话说,弯曲单元胞能够在拉伸载荷下阻止和钝化缺口,并使超材料增韧。裂纹尖端开度位移(CTOD)法计算断裂韧性。通过替换超材料敏感部位的单元胞,不仅可以沿面内方向控制晶格超材料的断裂,而且还提出了一种新的装配方法。这在断裂力学中首次提出了将不同布局的超材料薄片夹在夹层中,以控制面外断裂扩展(开口模式断裂的纵深扩展)。这种新型的夹夹方法利用多个贯穿厚度的薄板而不是单一的厚试样,提供了多步断裂,显著改善了晶格超材料从脆性到延性的断裂行为。详细分析了韧带曲率值对断裂行为的影响。结果表明,曲率越大,可实现的延展性越大,但曲率过大会降低结构的吸能能力。


Mechanics of Materials

An infill-based approach towards stiffer auxetic lattices: Design and study of enhanced in-plane elastic properties

Acharya Antu, Muthkani Vikram, DasGupta Anirvan, Jain Atul

doi:10.1016/j.mechmat.2023.104849

一种基于填充的更硬塑性格的方法:增强面内弹性性能的设计与研究

Mechanical metamaterials have tunable material properties, and the architecture of such materials can be tuned to impart Negative Poisson's Ratio (NPR). However, architected lattices typically have low stiffness. In the current study, the filler-based and infill-based strategies for creating auxetic lattices with enhanced stiffness are proposed and demonstrated. Analytic expressions for different in-plane elastic properties of the sinusoidal re-entrant honeycomb (SRH) lattice are developed. Finite element models are validated using data from published literature and analytic models. Using validated FE modelling, parametric studies involving infill patterns and filler materials in the SRH lattices are undertaken to find combinations leading to enhanced stiffness with minor loss in auxeticity. The possibility of attaining a massive increment in stiffness than that of the empty lattices, while retaining significant auxeticity (Poisson's ratio < −1), is demonstrated, which is a key outcome of this work. Using the proposed approach, high stiffness has been achieved in case of both non-auxetic infill-based (NAIB) and auxetic infill-based (AIB) while retaining NPR is established. Further studies have confirmed that the AIB lattices exhibit much higher stiffness compared to all the other lattices. Finally, the proposed approach is benchmarked against four published approaches towards generating stiff lattices with NPR. When compared with existing approaches, it is found that the strategies proposed in this paper perform better; for the same NPR, the proposed approaches lead to lattices with higher stiffness, and conversely, for the same normalised stiffness higher auxeticity is achieved. Implementation of the proposed approaches can be realized using in-built infill capabilities of prevalent additive manufacturing 3D printing technologies. New opportunities to enhance the capabilities of the existing technology are also indicated.

机械超材料具有可调谐的材料特性,并且这种材料的结构可以调谐以赋予负泊松比(NPR)。然而,结构格通常具有低刚度。在目前的研究中,提出并证明了基于填料和基于填料的策略来创建具有增强刚度的补充晶格。建立了正弦重入蜂窝(SRH)晶格面内弹性特性的解析表达式。有限元模型使用已发表的文献和分析模型的数据进行验证。使用经过验证的有限元模型,对SRH晶格中的填充模式和填充材料进行了参数化研究,以找到既能增强刚度又能减少弹性的组合。证明了在保持显著的弹性(泊松比 < −1)的同时,获得比空晶格大量增加刚度的可能性,这是本工作的关键成果。采用本文提出的方法,在保持非补强填充(NAIB)和补强填充(AIB)的同时,获得了高刚度。进一步的研究证实,与所有其他晶格相比,AIB晶格具有更高的刚度。最后,本文提出的方法与四种已发表的用NPR生成刚性格子的方法进行了基准测试。通过与已有方法的比较,发现本文提出的策略具有更好的效果;对于相同的NPR,所提出的方法导致晶格具有更高的刚度,相反,对于相同的归一化刚度,获得更高的奇异性。所提出的方法可以使用流行的增材制造3D打印技术的内置填充功能来实现。还指出了提高现有技术能力的新机会。


International Journal of Plasticity

Discrete dislocation dynamics simulations of 〈 a 〉 -type prismatic loops in zirconium

Roig Daniel Hortelano, Kumar Rakesh, Balint Daniel S., Tarleton Edmund

doi:10.1016/j.ijplas.2023.103802

锆中< a >型棱柱环的离散位错动力学模拟

Neutron irradiation of zirconium alloys in light water nuclear reactors generates nano-scale defects in the form of vacancy and interstitial 〈 a 〉 -type prismatic loops which lie in prismatic planes of the sample. The dynamics of idealised conservative rectangular 〈 a 〉 -type prismatic loops have been investigated for a range of loop lengths in the framework of linear isotropic elasticity. Three-dimensional dislocation dynamics (DD) simulations of a dislocation-loop interaction have been performed to investigate the dislocation-loop interaction mechanism. For this purpose, a mobility law developed for hexagonally close-packed materials has been implemented and described in detail. Analytical and numerical calculations have been performed to obtain expressions for the restoring force and angular stability of prismatic loops. These analyses have been used to inform a 2.5D discrete dislocation plasticity (DDP) model in order to emulate realistic prismatic loop physics and improve irradiation hardening simulations. From the 2.5D DDP prismatic loop analyses, it has been observed that the stable angle of smaller sized loops is less sensitive to external stresses compared to that of larger loops, which may have implications for the mechanisms of irradiation hardening. Furthermore, initial 2.5D single-slip simulations predict that prismatic loops cause significantly elevated flow stress that increases with increasing loop density in accord with experimental observations, and that the restraining effect of the out-of-plane loop segments (the restoring force) plays an important role in the strengthening caused by loops.

在轻水核反应堆中中子辐照锆合金会在样品的棱柱面产生空位和间隙< >型棱柱环的纳米级缺陷。在线性各向同性弹性框架下,研究了理想保守矩形< a >型棱柱环在一定长度范围内的动力学。为了研究位错-环相互作用机理,对位错-环相互作用进行了三维位错动力学模拟。为此,对六边形密装材料的迁移率规律进行了实现和详细描述。通过解析和数值计算,得到了棱柱环的恢复力和角稳定性表达式。这些分析已被用于2.5D离散位错塑性(DDP)模型,以模拟真实的棱柱环物理并改进辐照硬化模拟。从2.5D DDP柱形环的分析中可以观察到,与大环相比,小环的稳定角对外部应力的敏感性较低,这可能与辐照硬化的机制有关。此外,初始2.5D单滑移模拟预测,棱柱形环引起的流动应力显著升高,且流动应力随环密度的增加而增加,与实验结果一致,并且面外环段的抑制作用(恢复力)在环引起的强化中起重要作用。


Anisotropic damage and frictional poroplastic modelling of quasi-brittle rocks in a combined homogenization/thermodynamics framework

Zhu Qi-Zhi, Yuan Shuang-Shuang, Shao Jian-Fu

doi:10.1016/j.ijplas.2023.103789

准脆性岩石的各向异性损伤与摩擦孔塑性模型

Hydromechanical coupling is one of the essential theoretical and practical issues in rock mechanics and rock engineering. In geological context, it is critically important to incorporate the effect of pore pressure into the constitutive equations with full account of cracking-induced material anisotropies and friction-related plastic deformation. Focus here is put on poromechanical formulations for quasi-brittle rocks weakened by microcracks and saturated with pore fluid pressure. The linear homogenization method applied to derive the effective properties and system free energy is combined with the irreversible thermodynamics and the problem decomposition. Constitutive derivations include the determination of the system free energy, state equations associated with and evolution laws of the internal variables, closed-form failure criterion, etc.. Inherent coupling between anisotropic unilateral damage, friction-induced plastic deformation and the fluid pressure constitutes one of significant novelties of the work. Continuities required for the total free energy, macroscopic stress and the global porosity are guaranteed at any opening-closure transition of cracks. Through strength and deformation coupling analyses, the effects of fluid pressure on material strength and deformation are elucidated and also validated by experiments we performed upon a sandstone.

流体力学耦合是岩石力学和岩石工程中重要的理论和实践问题之一。在地质环境中,将孔隙压力的影响纳入本构方程并充分考虑材料的各向异性和摩擦相关的塑性变形是至关重要的。本文重点讨论了受微裂纹削弱、孔隙流体压力饱和的准脆性岩石的孔隙力学公式。采用线性均匀化方法推导有效性质和系统自由能,并结合不可逆热力学和问题分解。本构推导包括系统自由能的确定、与内变量相关的状态方程及其演化规律、闭式破坏准则等。各向异性单侧损伤、摩擦引起的塑性变形和流体压力之间的内在耦合是这项工作的重要创新之一。总自由能、宏观应力和整体孔隙率在裂纹的任何开闭过渡段都能保证连续性。通过强度和变形耦合分析,阐明了流体压力对材料强度和变形的影响,并通过砂岩试验进行了验证。


Thin-Walled Structures

Experimental characterization and modeling of cylindrical CFRP structures under quasi-static multiaxial loading conditions

Duda Szymon, Smolnicki Michał, Stabla Paweł, Zielonka Paweł, Osiecki Tomasz, Gao Chao, Lesiuk Grzegorz

doi:10.1016/j.tws.2023.111364

准静态多轴加载条件下圆柱形CFRP结构的实验表征与建模

An experimental and numerical investigation of the cylindrical carbon fiber reinforced polymer (CFRP) structures under various loads including tension/torsion loading conditions has been conducted. Various boundary conditions and parameters were taken into account to check the impact of the shear component to obtain the result. The nonlinear shear model proposed by Chang has been implemented to take into account the softening effect of the stress-strain curve caused by damage accumulation. The computational model of the thin-walled tubes contains the geometrical architecture of the material, such as interweaving, which are characteristic of the parts made by filament winding technology. The studies were preceded by preliminary tests of the individual components to predict elastic properties based on the Abolin'sh micromechanical approach. The strength parameters were empirically delivered on the basis of the experimental results and used to determine the failure of the structure. The accuracy of the calibrated nonlinear shear model was validated using strain gauges and digital image correlation techniques. The strain distribution obtained from FEA was compared with that of the optical method. The damage distribution provided by FEA is exhibited in a similar manner to the real one captured by DIC. The proposed model provides a precise prediction of the CFRP tubes under quasi-static loading conditions proven by the experiments.

对圆柱形碳纤维增强聚合物(CFRP)结构在不同载荷条件下(包括拉伸/扭转载荷)进行了试验和数值研究。考虑了各种边界条件和参数,对剪切分量的影响进行了校核,得到了结果。采用Chang提出的非线性剪切模型,考虑了损伤累积对应力-应变曲线的软化作用。薄壁管的计算模型包含了材料的几何结构,如交织,这是长丝缠绕技术制造的零件所具有的特征。在研究之前,对各个部件进行了初步测试,以预测基于Abolin'sh微力学方法的弹性性能。在试验结果的基础上,经验地给出了强度参数,并用于确定结构的破坏程度。利用应变片和数字图像相关技术验证了校正后的非线性剪切模型的准确性。将有限元法得到的应变分布与光学法得到的应变分布进行了比较。有限元分析得到的损伤分布与DIC捕捉到的真实损伤分布具有相似的表现方式。该模型对CFRP管在准静态载荷条件下的受力情况进行了较精确的预测,并得到了试验的验证。


Seismic Behaviors of CFT Frame-Four-corner Bolted Connected Buckling-Restrained Steel Plate Shear Walls Using ALC/RAC Panels

Du Yansheng, Mohammed Amer, Chen Zhihua, Al-Haaj Mohammed, Huang Jin

doi:10.1016/j.tws.2023.111365

ALC/RAC板CFT框架-四角螺栓连接抗屈曲钢板剪力墙的抗震性能

A Frame-Buckling Restrained Steel Plate Shear Walls (BRSPSWs) system has been designed, featuring a steel plate connected to frame elements, to withstand lateral loads like seismic or wind forces. This system incorporates recycled aggregate concrete (RAC) to create concrete-filled and concrete panels, promoting eco-friendly and sustainable construction materials. Two single-span, two-floor specimens were tested under cyclic quasi-static load. A four-corner bolted connection was used to connect the steel plate to the square concrete-filled steel tubes (CFTs) column and H-section beam, minimizing the potential deformation of the frame elements produced by the tension field of the steel plate after high-order bucking. The steel plate was sandwiched using either autoclaved lightweight concrete (ALC) or RAC panels. The study analyzed failure modes, load-displacement responses, and characteristic capacities. Test results inferred that BRSPSWs exhibited favorable cyclic behavior, with similar failure modes observed using both ALC and RAC panels. The buckling of steel plates was reduced, and the type of restrained panels had a negligible impact on buckling. Consequently, ALC panels can effectively replace RAC panels. Furthermore, bearing capacities and yield stiffness were primarily determined by the bolted connection forms. A finite element (FE) modeling was developed using ABAQUS software and validated against test results. This FE modeling method successfully simulated failure modes and load-displacement curves. Parametric analyses were conducted and revealed that bearing capacity and yield stiffness positively correlated with steel plate thickness, bolt diameter, and the number of bolts but negatively correlated with the axial compression ratio. In contrast, the panel thickness and span length had a minor impact due to shear deformation in the bolted connection. Based on the test results and parametric studies, an equation for the yield-bearing capacity of BRSPSWs was proposed and verified.

一种框架屈曲约束钢板剪力墙(brspsw)系统已经被设计出来,其特点是钢板连接到框架元件上,可以承受地震或风力等侧向载荷。该系统采用再生骨料混凝土(RAC)来制造混凝土填充和混凝土板,促进生态友好和可持续的建筑材料。两个单跨、两层试件在循环准静力荷载作用下进行了试验。钢板与方钢管混凝土柱和h型梁之间采用四角螺栓连接,最大限度地减少了高阶屈曲后钢板张力场对框架构件产生的潜在变形。钢板夹在蒸压轻质混凝土(ALC)或RAC面板上。研究分析了破坏模式、荷载-位移响应和特征能力。试验结果表明,brspsw具有良好的循环性能,在ALC和RAC面板上观察到相似的破坏模式。钢板屈曲减小,约束板类型对屈曲的影响可以忽略不计。因此,ALC面板可以有效地取代RAC面板。此外,承载能力和屈服刚度主要取决于螺栓连接形式。利用ABAQUS软件建立了有限元模型,并与试验结果进行了对比验证。该有限元建模方法成功地模拟了破坏模式和荷载-位移曲线。参数分析结果表明,承载力和屈服刚度与钢板厚度、螺栓直径和螺栓数量呈正相关,与轴压比呈负相关。相比之下,由于螺栓连接中的剪切变形,面板厚度和跨距长度的影响较小。在试验结果和参数研究的基础上,提出并验证了brspsw的产量承载能力方程。



来源:复合材料力学仿真Composites FEM
ACTMechanicalAdditiveOpticalSystem断裂非线性光学建筑增材裂纹理论材料控制试验螺栓
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【新文速递】2023年10月12日固体力学SCI期刊最新文章

今日更新:International Journal of Solids and Structures 1 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 6 篇International Journal of Solids and StructuresInvestigation of dynamic contact between cold spray particles and substrate based on 2D SPH methodDai Zhen, Xu Fei, Wang Jiayi, Wang Ludoi:10.1016/j.ijsolstr.2023.112520基于二维 SPH 方法的冷喷颗粒与基底之间的动态接触研究In cold spray, the study of the dynamic contact between the particle and the substrate in the high-velocity impact is essential during particle deposition. To entirely reveals the dynamic contact process, the SPH (Smoothed Particle Hydrodynamics) method is applied to virtual experiments to avoid the time-consuming and high costs in real experiments due to scale. In particular, an interface force model is proposed to completely describe the dynamic contact between the cold spray particles (CS particles) and substrate, which has the ability to eliminate the unphysical SPH particle penetration, rebounding phenomenon, and insufficient momentum transfer. The variation of the steady mean temperature of the CS particle surface with the initial velocity is analyzed and the critical velocity of particle deposition is successfully predicted. Furthermore, the effect of particle shapes on the deposition is discussed, which shows that the circular particles are more favourable to be deposited than the elliptical ones. The cold spray SPH model with the novel dynamic contact developed in this paper is in favor of understanding the mechanism of CS particles deposition and guiding the cold spray processes in a certain extent.在冷喷雾中,研究颗粒沉积过程中颗粒与基体在高速冲击下的动态接触至关重要。为了完全揭示动态接触过程,我们将 SPH(平滑粒子流体力学)方法应用于虚拟实验,以避免真实实验中因规模而产生的耗时和高成本。特别是提出了一种界面力模型来完整描述冷喷粒子(CS 粒子)与基体之间的动态接触,该模型能够消除 SPH 粒子穿透、反弹现象和动量传递不足等非物理性问题。分析了 CS 粒子表面的稳定平均温度随初始速度的变化,并成功预测了粒子沉积的临界速度。此外,还讨论了颗粒形状对沉积的影响,结果表明圆形颗粒比椭圆形颗粒更有利于沉积。本文建立的带有新型动态接触的冷喷 SPH 模型有助于理解希尔思粒子沉积的机理,并在一定程度上指导冷喷过程。International Journal of PlasticityWavy Interface Enables Extra Strengthening in an Additively Manufactured High-Entropy Alloy with Mortise-Tenon ArchitectureBai Yunjian, Li Yadong, Wang Yun-jiang, Zhang Kun, Jiang Quanyu, Liu Zishang, Hu Zheng, Wei Bingchendoi:10.1016/j.ijplas.2023.103777波浪形界面使具有榫卯结构的快速成型高熵合金得到额外强化Laminated structures have the potential to enhance the performance of high-entropy alloys (HEAs) by providing intriguing interface strengthening. However, laminated HEA designs is uncommon due to the challenges posed by the relatively poor machinability of HEAs. In this study, we successfully fabricate a CoCrNi-Fe50Mn30Co10Cr10 laminated HEA using additive manufacturing technique, incorporating a unique Mortise-Tenon architecture within the alloy. The laminated HEA introduces a novel wavy-shaped interface alongside the conventional flat-shaped interfaces. Tensile tests reveal that the laminated HEA exhibits an exceptional combination of strength and ductility. The measured yield strength exceeds the predicted value based on the rule-of-mixture principle by approximately 36.5%. This enhancement is attributed to the extra strengthening resulting from the local chemical variation near the heterogeneous interfaces. Interestingly, the wavy-shaped interface has a larger local-chemical-variation zone than the flat-shaped interface, which can trigger more strong interface-dislocation interactions and therefore remarkable strengthening. The Mortise-Tenon architecture not only provides extra interface strengthening, surpassing the yield strength of the two monolithic HEAs, but also preserves the excellent work hardening ability in the early stage of deformation, enabling reasonable ductility. Remarkably, the interface strengthening is comparable in magnitude to dislocation strengthening, contributing to approximately 23% of the overall yield strength. These findings highlight the potential of laminated HEA designs and the associated interface strengthening as promising strategies for enhancing mechanical performance.层压结构通过提供耐人寻味的界面强化,有可能提高高熵合金(HEA)的性能。然而,由于高熵合金的可加工性相对较差,因此层压高熵合金设计并不常见。在本研究中,我们利用快速成型技术成功制造出了 CoCrNi-Fe50Mn30Co10Cr10 层状 HEA,并在合金中加入了独特的榫卯结构。除了传统的扁平界面外,层压 HEA 还引入了新颖的波浪形界面。拉伸测试表明,层压 HEA 具有出色的强度和延展性。测得的屈服强度比基于混合原则的预测值高出约 36.5%。这种增强归因于异质界面附近的局部化学变化产生的额外强化。有趣的是,波浪形界面的局部化学变化区大于扁平界面,这可能会引发更强的界面-异位相互作用,从而产生显著的强化作用。榫卯结构不仅提供了额外的界面强化,超过了两种整体式 HEA 的屈服强度,而且在变形早期保留了出色的加工硬化能力,实现了合理的延展性。值得注意的是,界面强化的程度与位错强化相当,约占整体屈服强度的 23%。这些发现凸显了层状 HEA 设计和相关界面强化作为提高机械性能的有效策略的潜力。Thin-Walled StructuresVery Low-Cycle Fatigue Failure Behaviours of Pipe Elbows under Displacement-Controlled Cyclic LoadingHong Jin Nye, Kim Jin Weon, Lee Dae Yong, Lee Jong-Min, Kim Yun-Jaedoi:10.1016/j.tws.2023.111261位移控制循环加载下管道弯头的极低循环疲劳失效行为In this study, quasi-static very low-cycle fatigue tests were conducted on pipe elbows at room temperature to investigate the effects of the pipe thickness, internal pressure, and material on the failure behaviours under large-amplitude cyclic loads. Three types of elbow specimens comprising two different materials and two different pipe thicknesses were used in the tests. Elbow specimens were subjected to displacement-controlled, fully reversed, in-plane mode cyclic bending with and without internal pressure. All specimens failed due to through-wall cracking of which the location and orientation depend only on the pipe thickness regardless of the internal pressure and elbow material. For thin-walled elbows of Schedule 40, the axial crack at flank was developed, whereas for thick-walled elbows of Schedule 160, the circumferential crack at intrados. The number of cycles to failure decreased with increasing internal pressure in thin-walled elbows. However, the effect of internal pressure on the number of cycles to failure was negligible in thick-walled elbows. Regardless of internal pressure level, stainless steel elbows were more resistant to failure, compared with carbon steel elbows of identical dimensions. Finally, the strain-based evaluation model considering the void growth and shrinkage effect was applied to predict fatigue failure location and cycles. Two parameters in the model, the multi-axial fracture strain locus and void shrinkage ratio, were determined from monotonic tensile test data and the fatigue life curve of the material. The predicted crack initiation site and orientation were consistent with experimental finding. For all cases, the predicted failure cycles were less but overall close to experimental data.本研究在室温下对弯管进行了准静态极低循环疲劳试验,以研究管道厚度、内部压力和材料对大振幅循环载荷下失效行为的影响。试验中使用了三种弯管试样,包括两种不同的材料和两种不同的管道厚度。弯管试样在有内压和无内压的情况下受到位移控制、完全反向、平面内模式的循环弯曲。所有试样都因穿壁开裂而失效,开裂的位置和方向仅取决于管道厚度,与内部压力和弯头材料无关。对于附表 40 的薄壁弯头,在侧面出现轴向裂纹,而对于附表 160 的厚壁弯头,在内侧出现周向裂纹。薄壁弯头的失效循环次数随着内部压力的增加而减少。然而,在厚壁弯头中,内部压力对失效循环次数的影响可以忽略不计。与相同尺寸的碳钢弯头相比,无论内压水平如何,不锈钢弯头的抗破坏能力都更强。最后,基于应变的评估模型考虑了空隙增长和收缩效应,用于预测疲劳失效位置和周期。模型中的两个参数,即多轴向断裂应变位置和空隙收缩率,是根据单调拉伸试验数据和材料的疲劳寿命曲线确定的。预测的裂纹起始位置和方向与实验结果一致。在所有情况下,预测的破坏周期都较少,但总体上接近实验数据。Dynamic Instability of Reinforced Hollow Cylinders in a Confined Underwater EnvironmentBodurtha Nidhi Mehta, Kishore Shyamal, Salazar Christopher J., Shukla Arundoi:10.1016/j.tws.2023.111263封闭水下环境中加固空心圆柱体的动态不稳定性An experimental investigation was conducted to understand the collapse mechanisms of internally ring stiffened aluminum cylinders under uniform hydrostatic loading in a confined underwater environment. The implosion of ring stiffened cylinders was studied using a combination of high-speed photography and 3D Digital Image Correlation (DIC). The results show that as stiffener thickness is decreased, the collapse of the structure transitions from two segments collapsing in mode III with the stiffener serving as boundary separating the segments to one uniform mode II collapse where the ring stiffener collapses with the structure. Furthermore, in the cases with two collapses, the behavior of the structure can be described as approaching that of two cylinders divided by a simply-supported boundary condition at the location of the stiffener. The ring thickness also affects the collapse pressure of the cylinder, radial velocity during collapse at the location of the ring stiffener, and dwell time between the collapse of two sections in cases with two collapses.为了了解内环加固铝制圆柱体在密闭水下环境中承受均匀静水压力时的坍塌机理,我们进行了一项实验研究。采用高速摄影和三维数字图像相关(DIC)相结合的方法,对环形加劲圆柱体的内爆进行了研究。结果表明,随着加劲件厚度的减小,结构的坍塌会从以模式 III 形式坍塌的两段(加劲件作为分隔两段的边界)过渡到以模式 II 形式坍塌的一段(环形加劲件与结构一起坍塌)。此外,在有两个坍塌的情况下,结构的行为可描述为接近于两个圆柱体的行为,在加劲件的位置被一个简单支撑边界条件分割。环厚度还会影响圆柱体的坍塌压力、环形加强筋位置处坍塌过程中的径向速度,以及两段坍塌情况下两段坍塌之间的停留时间。Shear capacity of corrugated steel plates with a random corrosion damageZhao Zhongwei, Liu Jiaxing, Zhao Bingzhen, Jin Zeyuan, Jian Xiangyang, Zhang Nidoi:10.1016/j.tws.2023.111264具有随机腐蚀损伤的波纹钢板的抗剪能力Corrugated steel plates have been utilized widely in engineering structures, such as underground utility tunnels, web of steel beams, underground pipelines, and shear walls. The influence of corrosion on the buckling capacity of corrugated steel plates differs from that of flat steel plates. A numerical model of corrugated steel plates with random corrosion is initially established and validated using theoretical results. The influence of pitting corrosion on the shear capacity of corrugated steel plates is investigated through stochastic numerical analysis. The influences of geometric parameters, including pitting size, plate thickness, and corroded thickness, on the shear capacity of randomly corroded steel plates are also investigated. In addition, the changing trend of shear capacity along with mass loss ratio is derived.波纹钢板已广泛应用于工程结构中,如地下公用设施隧道、钢梁腹板、地下管道和剪力墙。腐蚀对波纹钢板屈曲能力的影响不同于平板钢板。初步建立了随机腐蚀波纹钢板的数值模型,并利用理论结果进行了验证。通过随机数值分析研究了点蚀对波纹钢板抗剪能力的影响。同时还研究了点蚀尺寸、钢板厚度和腐蚀厚度等几何参数对随机腐蚀钢板剪切能力的影响。此外,还得出了剪切能力随质量损失率的变化趋势。Buckling and post-buckling analysis of composite wing box under loads with torsion-bending couplingWang Peiyan, Chen Yongshun, Pei Runa, Lian Chenchen, Zhang Ke, Zhou Yinhuadoi:10.1016/j.tws.2023.111266复合材料翼盒在扭转-弯曲耦合载荷下的屈曲和屈曲后分析In this paper, a mathematical model for the effect of different torsion-bending ratios on buckling and failure loads under complex operating conditions was proposed, and the buckling, post-buckling and failure behavior and mechanism of carbon fiber composite wing box were studied by combining experiments and simulations. A high-precision computational simulation model was established by considering detailed bolt arrangement information, as well as damage and failure of composite materials. The predicted buckling loads, failure loads, and damage modes are in good agreement with the experimental results. The results show that, under the condition of constant bending moment, as the torque increases, the linear strain of the box section remains consistent, while the shear strain increases significantly, leading to a change in the buckling mode and failure distribution. When the torsion-bending ratio is less than 2.0, the loading form of the structure is greatly affected by the torque. On the contrary, the buckling and failure loads are exponentially close to the pure torsional state. The mathematical model and simulation model in this study can provide an important reference for the structural design and failure mechanism analysis of large composite wing boxes.本文提出了复杂工况下不同扭弯比对屈曲和失效载荷影响的数学模型,并通过实验和模拟相结合的方法研究了碳纤维复合材料翼盒的屈曲、后屈曲和失效行为及机理。通过考虑详细的螺栓布置信息以及复合材料的损伤和失效,建立了高精度的计算仿真模型。预测的屈曲载荷、破坏载荷和破坏模式与实验结果十分吻合。结果表明,在弯矩恒定的条件下,随着扭矩的增加,箱形截面的线性应变保持一致,而剪切应变则显著增加,从而导致屈曲模式和破坏分布发生变化。当扭弯比小于 2.0 时,结构的加载形式受扭矩影响较大。相反,屈曲载荷和破坏载荷则以指数形式接近于纯扭转状态。本研究的数学模型和仿真模型可为大型复合材料翼盒的结构设计和失效机理分析提供重要参考。A novel method of fabricating aluminium honeycomb core by friction stir weldingDutta Ananta, Pal Surjya K, Panda Sushanta Kdoi:10.1016/j.tws.2023.111262用搅拌摩擦焊制造铝蜂窝芯的新方法Aluminium honeycomb structure has been recognized as an exceptional lightweight energy absorber in transportation, construction and aerospace industries. An innovative fabrication method based on friction stir welding is proposed to enhance the crashworthiness property of aluminium honeycomb and address the challenges with conventional fabrication methods. Moreover, a lab-scale fixture is designed to demonstrate the feasibility of the suggested method for industrial use. Various fabricated honeycombs with different core heights and cell counts are subjected to quasi-static flatwise compression tests to investigate their crushing characteristics. The crashworthiness parameters like yield stress, average plateau stress, specific energy absorption are analysed and compared with theoretically predicted crushing strength. The failure mode of the structure is also discussed, showing the influence of non-optimal welding parameters. Experimental results indicate that average crush force and specific energy absorption do not differ significantly with cell count and core height. The specimens under flatwise compression fold with plastic hinges symmetrically positioned without any rupture of the weld. Specific compression property of the fabricated honeycomb has been compared with other aluminium honeycombs fabricated using other methods, which favours the friction stir welded honeycomb over the other conventional counterparts.铝蜂窝结构已被公认为运输、建筑和航空航天工业中一种特殊的轻质能量吸收器。本文提出了一种基于搅拌摩擦焊的创新制造方法,以增强铝蜂窝结构的防撞性能,并解决传统制造方法所面临的挑战。此外,还设计了一个实验室规模的夹具,以证明所建议的方法在工业应用中的可行性。对不同芯高和单元数的各种蜂窝进行了准静态平向压缩试验,以研究其破碎特性。分析了屈服应力、平均高原应力、比能量吸收等耐压参数,并与理论预测的压溃强度进行了比较。此外,还讨论了结构的破坏模式,显示了非最佳焊接参数的影响。实验结果表明,平均压碎力和比能量吸收与细胞数和芯材高度没有显著差异。扁平压缩下的试样以塑料铰链对称折叠,焊缝没有断裂。与其他方法制造的铝蜂窝相比,搅拌摩擦焊接蜂窝具有更好的压缩性能。Analytical and numerical studies on flexural resistance of fold-fastened multi-cellular steel panelsJiang Jin-Liang, Ge Lu-Qi, Yang Xiong, Yu Chao-Qun, Tong Jing-Zhong, Tong Gen-Shudoi:10.1016/j.tws.2023.111265 折叠固定多孔钢板抗弯性能的分析和数值研究Fold-fastened multi-cellular steel panel (FMSP) is a novel type of cold-formed steel (CFS) built-up member, which is manufactured by connecting multiple FMSP cells. When connecting these cells, folded regions can be formed by lapping the FMSPs cells end to end, and indentations are used as fasteners during the manufacturing process. In this study, the flexural resistance of FMSPs was numerically and analytically investigated. Firstly, the refined finite element (FE) models were developed to simulate the flexural behavior of FMSPs. The accuracy of FE modeling method was validated by comparing the numerical results with experimental results obtained from the published literature about these investigations for CFS built-up members in terms of their moment capacities, moment-deflection curves and failure modes. Then, substantial parametric analyses involving a total of 105 different FE models of FMSPs were carried out to study the effects of steel thickness and strength, cellular dimension, width of fold-fastened regions and indented spacing on the flexural behavior of FMSPs. Finally, a sectional analysis based on the effective width method (EWM) was adopted to predict the ultimate flexural resistance of FMSPs. The results revealed that steel thickness and web plate depth have a great effect on the flexural behavior of FMSPs, while there was little influence on the ultimate load in other parameters. Moreover, the decrease in both width-to-thickness ratio and aspect ratio will lead to better ductile behavior for FMSPs. In addition, the EWM adopted in this study can agree well with the FE results, achieving better predicting results compared with other methods; therefore, this method is valid and well fits the practical needs.折叠固定多孔钢板(FMSP)是一种新型冷弯型钢(CFS)建筑构件,通过连接多个 FMSP 单元来制造。在连接这些单元时,可通过端对端搭接 FMSP 单元形成折叠区域,并在制造过程中使用压痕作为紧固件。本研究对 FMSP 的抗弯强度进行了数值和分析研究。首先,建立了精细的有限元(FE)模型来模拟 FMSP 的抗弯行为。通过将数值结果与已发表的文献中有关 CFS 建筑构件的弯矩承载力、弯矩-挠度曲线和破坏模式的实验结果进行比较,验证了 FE 建模方法的准确性。然后,对总共 105 个不同的 FE 模型进行了大量参数分析,以研究钢材厚度和强度、蜂窝尺寸、折叠固定区域宽度和缩进间距对 FMSP 抗弯行为的影响。最后,采用基于有效宽度法(EWM)的断面分析预测了 FMSP 的极限抗弯强度。结果表明,钢板厚度和腹板深度对 FMSP 的抗弯行为有很大影响,而其他参数对极限荷载的影响很小。此外,宽厚比和长宽比的减小会使 FMSP 具有更好的延展性。此外,本研究采用的 EWM 与 FE 结果吻合度较高,与其他方法相比能获得更好的预测结果;因此,该方法是有效的,非常符合实际需要。来源:复合材料力学仿真Composites FEM

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