今日更新:International Journal of Solids and Structures 1 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 6 篇
Investigation of dynamic contact between cold spray particles and substrate based on 2D SPH method
Dai Zhen, Xu Fei, Wang Jiayi, Wang Lu
doi: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。
Wavy Interface Enables Extra Strengthening in an Additively Manufactured High-Entropy Alloy with Mortise-Tenon Architecture
Bai Yunjian, Li Yadong, Wang Yun-jiang, Zhang Kun, Jiang Quanyu, Liu Zishang, Hu Zheng, Wei Bingchen
doi: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。
Very Low-Cycle Fatigue Failure Behaviours of Pipe Elbows under Displacement-Controlled Cyclic Loading
Hong Jin Nye, Kim Jin Weon, Lee Dae Yong, Lee Jong-Min, Kim Yun-Jae
doi: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 Environment
Bodurtha Nidhi Mehta, Kishore Shyamal, Salazar Christopher J., Shukla Arun
doi: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 damage
Zhao Zhongwei, Liu Jiaxing, Zhao Bingzhen, Jin Zeyuan, Jian Xiangyang, Zhang Ni
doi: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 coupling
Wang Peiyan, Chen Yongshun, Pei Runa, Lian Chenchen, Zhang Ke, Zhou Yinhua
doi: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 welding
Dutta Ananta, Pal Surjya K, Panda Sushanta K
doi: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 panels
Jiang Jin-Liang, Ge Lu-Qi, Yang Xiong, Yu Chao-Qun, Tong Jing-Zhong, Tong Gen-Shu
doi: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。