【新文速递】2023年9月29日固体力学SCI期刊最新文章

今日更新：Mechanics of Materials 2 篇，Computer Methods in Applied Mechanics and Engineering 1 篇，Thin-Walled Structures 4 篇

Mechanics of Materials

A crystal plasticity model of Dynamic Strain Aging for a near-α Ti-alloy

Kazim Syed Mustafa, Prasad Kartik, Chakraborty Pritam

doi:10.1016/j.mechmat.2023.104814

用于近 α 钛合金的晶体塑性动态应变老化模型

Timetal-834, a near-α Ti-alloy, finds use in aeroengines due to its favorable properties. However, the alloy exhibits Dynamic Strain Aging (DSA) in the temperature range of 350-475 °C, that can cause it to fail early during service. As DSA is due to the micro-scale interaction between the diffusing solutes and mobile dislocations, a crystal plasticity model is developed in this work to capture this phenomenon. Additionally, the influence of the α (HCP) and β (BCC) laths of the transformed-β colony of this alloy on the DSA behavior is captured by using an equivalent model based on Taylor’s assumption. The effect of slip system dependent lath and colony size effect due to Burger’s Orientation Relation is also incorporated. Crystal plasticity finite element method simulations of polycrystalline domains, representative of Timetal-834, are performed for calibration and validation of the model using the available temperature dependent experimental data, and successfully capture the flow stress and DSA behavior. The strain rate dependency of DSA predicted by the model also shows an excellent agreement when compared with experimental data. Microstructural analysis of the simulations show that the orientation of grains/colonies have a strong influence on the aging time and hence the DSA response. Also, the initiation of DSA and frequency of serrated slip on the aligned systems of laths show differences due to dissimilar resistances and constraints on plastic flow. Overall, the model developed in this work can capture the microstructure dependent DSA and can be utilized for engineering of Timetal-834.

Timetal-834，一种近似于 α 钛合金，因其良好的性能而被用于航空发动机。然而，这种合金在 350-475 °C 的温度范围内会出现动态应变老化 (DSA)，导致其在使用过程中提前失效。由于 DSA 是由扩散溶质和移动位错之间的微尺度相互作用引起的，因此本研究建立了一个晶体塑性模型来捕捉这一现象。此外，还考虑了 α (HCP) 和 β β 通过使用基于泰勒假设的等效模型，可以捕捉到这种合金对 DSA 行为的影响。此外，还纳入了滑移系统相关板条的影响以及伯格方位关系导致的菌落大小影响。利用现有的温度相关实验数据，对 Timetal-834 的代表性多晶畴进行了晶体塑性有限元法模拟，以校准和验证模型，并成功捕捉了流动应力和 DSA 行为。与实验数据相比，模型预测的 DSA 应变速率依赖性也显示出极佳的一致性。模拟的微观结构分析表明，晶粒/菌落的取向对老化时间有很大影响，因此也会影响 DSA 响应。此外，由于塑性流动的阻力和约束条件不同，DSA 的启动和锯齿状滑移在排列整齐的板条系统上的频率也存在差异。总之，本研究开发的模型可以捕捉与微观结构相关的 DSA，并可用于 Timetal-834 的工程设计。

Design of partially covered bilayer thin film actuators

Peeketi Akhil Reddy, Swaminathan Narasimhan, Annabattula Ratna Kumar

doi:10.1016/j.mechmat.2023.104816

设计部分覆盖的双层薄膜致动器

One approach to create bending deformation using active materials is to fully cover a passive substrate with the active material. The active layer expands/contracts in response to an external stimuli, while, the passive layer doesn’t deform, thereby, generating a strain gradient through the thickness, and hence, bending. However, a recent experimental study [Pozo, M et al. ACS Appl. Mater. Interfaces, 13, 59381–59391 (2021).] showed that a partially covered (40%) bilayer deformed as much as the “standard” fully covered bilayer. To elucidate such a non-standard response of bilayers, we have developed an analytical model using the strain energy minimization. The developed model showed that the deformation of the bilayer may actually either increase or decrease or saturate with the increase in the coverage depending on the moduli ratio and the thickness ratio of the active and passive layers. Design strategies for actuators considering their curvature and bending stiffness are proposed based on the implications of the developed model. The present study also shows the potential for designing patterned actuators with multiple coverings (may have multiple active layers that are responsive to different stimuli) to realise different actuations based on the choice of the trigger from a single actuator creating multi-modal, multi-stimuli-responsive actuators.

使用活性材料产生弯曲变形的一种方法是用活性材料完全覆盖被动基底。活性层在外部刺 激下膨胀/收缩，而被动层不会变形，从而在厚度上产生应变梯度，进而产生弯曲。然而，最近的一项实验研究[Pozo, M et al. ACS Appl. Mater. Interfaces, 13, 59381-59391 (2021)。为了阐明双分子层的这种非标准响应，我们利用应变能最小化建立了一个分析模型。所建立的模型表明，双分子层的变形实际上可能随着覆盖率的增加而增大或减小或饱和，这取决于主动层和被动层的模量比和厚度比。根据所开发模型的含义，考虑到致动器的曲率和弯曲刚度，提出了致动器的设计策略。本研究还显示了设计具有多个覆盖层（可能有多个对不同刺 激做出响应的主动层）的图案致动器的潜力，从而根据从单个致动器中选择的触发器实现不同的致动，创造出多模式、多刺 激响应的致动器。

Computer Methods in Applied Mechanics and Engineering

Image-guided subject-specific modeling of glymphatic transport and amyloid deposition

Johnson Michael J., Abdelmalik Michael R.A., Baidoo Frimpong A., Badachhape Andrew, Hughes Thomas J.R., Hossain Shaolie S.

doi:10.1016/j.cma.2023.116449

以图像为指导的特定受试者血流传输和淀粉样蛋白沉积建模

The glymphatic system is a brain-wide system of perivascular networks that facilitate exchange of cerebrospinal fluid (CSF) and interstitial fluid (ISF) to remove waste products from the brain. A greater understanding of the mechanisms for glymphatic transport may provide insight into how amyloid beta (A β ) and tau agglomerates, key biomarkers for Alzheimer’s disease and other neurodegenerative diseases, accumulate and drive disease progression. In this study, we develop an image-guided computational model to describe glymphatic transport and A β deposition throughout the brain. A β transport and deposition are modeled using an advection–diffusion equation coupled with an irreversible amyloid accumulation (damage) model. We use immersed isogeometric analysis, stabilized using the streamline upwind Petrov–Galerkin (SUPG) method, where the transport model is constructed using parameters inferred from brain imaging data resulting in a subject-specific model that accounts for anatomical geometry and heterogeneous material properties. Both short-term (30-min) and long-term (12-month) 3D simulations of soluble amyloid transport within a mouse brain model were constructed from diffusion weighted magnetic resonance imaging (DW-MRI) data. In addition to matching short-term patterns of tracer deposition, we found that transport parameters such as CSF flow velocity play a large role in amyloid plaque deposition. The computational tools developed in this work will facilitate investigation of various hypotheses related to glymphatic transport and fundamentally advance our understanding of its role in neurodegeneration, which is crucial for the development of preventive and therapeutic interventions.

脑 glymphatic 系统是一个由血管周围网络组成的全脑系统，可促进脑脊液（CSF）和脑间质（ISF）的交换，清除脑内的废物。更深入地了解甘液转运的机制可能有助于深入了解淀粉样蛋白β（A β ）和 tau 凝聚物是阿尔茨海默病和其他神经退行性疾病的关键生物标志物，它们是如何积累并推动疾病进展的。在这项研究中，我们建立了一个图像引导的计算模型，以描述甘液运输和 A β 沉积。A β 运输和沉积模型采用平流扩散方程和不可逆淀粉样蛋白累积（损伤）模型相结合的方法。我们采用沉浸等距分析法，并使用流线型上风彼得罗夫-加勒金（SUPG）方法进行稳定，其中传输模型是使用从脑成像数据中推断出的参数构建的，从而形成一个考虑到解剖几何和异质材料特性的特定受试者模型。根据扩散加权磁共振成像（DW-MRI）数据构建了小鼠大脑模型内可溶性淀粉样蛋白运输的短期（30 分钟）和长期（12 个月）三维模拟。除了与示踪剂沉积的短期模式相匹配外，我们还发现 CSF 流速等传输参数在淀粉样斑块沉积过程中发挥着重要作用。这项工作中开发的计算工具将有助于研究与血流转运相关的各种假说，并从根本上促进我们对血流转运在神经变性中作用的理解，这对开发预防和治疗干预措施至关重要。

Thin-Walled Structures

Surface microtexturing design, laser-etching and adhesive failure of aluminum alloy single-lap-joint: Experiment and simulation

Jiang Shulan, Zhang Ao, Zhan Xiaobin, Jiang Hongyong

doi:10.1016/j.tws.2023.111237

铝合金单搭接接头的表面微纹理设计、激光蚀刻和粘合失效：实验与模拟

This study investigates the design and laser etching of surface microtextures on Al substrate to significantly improve the adhesive performance. Microstructures with different patterns were designed and fabricated. Also laser etching parameters such as etching power, line space and number of scans were thoroughly studied. The obtained microstructures exhibit excellent hydrophilicity, which is beneficial for the permeation of adhesives and formation of micromechanical interlocking. When testing the shear strength of the Al single-lap-joint, the results show great improvement compared with unetched specimens. In terms of the significance of laser parameters and textures on shear strength, power is the most significant, followed by number of scans, and finally line space and textures. The specimen designed with X-texture and etched by 20 W with scan space of 0.2 mm and number of 2 scans achieves the highest shear strength of 24 MPa and presents an improvement of 1225% in shear strength. In addition, multi-scale simulations were conducted to effectively demonstrate the interfacial bonding behavior and damage process of Al single-lap-joint. The proposed method shows great potential in improvement of bonding performance.

本研究探讨了如何在铝基材上设计和激光蚀刻表面微纹理，以显著提高粘合剂性能。研究人员设计并制作了具有不同图案的微结构。此外，还对激光蚀刻参数（如蚀刻功率、线间距和扫描次数）进行了深入研究。所获得的微结构具有极佳的亲水性，有利于粘合剂的渗透和微机械互锁的形成。与未蚀刻的试样相比，在测试铝单片接合处的剪切强度时，结果显示出很大的改善。就激光参数和纹理对剪切强度的影响而言，功率影响最大，其次是扫描次数，最后是线间距和纹理。采用 X 纹理设计的试样，在扫描空间为 0.2 毫米、扫描次数为 2 次、功率为 20 瓦的条件下进行蚀刻，其剪切强度最高，达到 24 兆帕，剪切强度提高了 1225%。此外，还进行了多尺度模拟，以有效证明铝单层接合的界面结合行为和破坏过程。所提出的方法在改善粘接性能方面显示出巨大的潜力。

Achieving high strength friction lap spot joints of carbon fiber reinforced thermosetting composite to aluminum alloy with additional thermoplastic interlayer

Xue C., Han S.C., Jiang C.Y., Wu L.H., Wang Q.Z., Xue P., Ni D.R., Xiao B.L., Ma Z.Y.

doi:10.1016/j.tws.2023.111239

利用附加热塑性中间膜实现碳纤维增强热固性复合材料与铝合金的高强度摩擦搭接点接头

The dissimilar materials of the 5182-aluminum alloy and continuous carbon fiber reinforced bismaleimide (CF-BMI) were joined by friction lap spot joining (FLSJ) directly and via the addition of the polyamide 6 (PA6) interlayer, and the effect of interlayer on the joining mechanism and the joint mechanical property was investigated. It was found that no effective joints were achieved by FLSJ directly, which was mainly attributed to the poor re-forming ability and liquidity of the thermosetting BMI, and its difficulty in reacting to metals. After the addition of the PA6 interlayer, the effective dissimilar joints were successfully realized by FLSJ. The maximum average tensile shear force of the joint reached 3.68 kN, with the average normal tensile shear strength of 20.9 MPa at the optimum parameter with the rotation rate of 2000rpm, dwell time of 7s, plunge depth of 0.7 mm and the PA6 interlayer of 0.3 mm. A new C-O-Al chemical bond was found at the interface of the PA6 interlayer and aluminum alloy, which was the result of the chemical reaction between the amide polar function of PA6 and surface oxide of aluminum alloy. The great increase in the joint strength by the addition of the PA6 interlayer was mainly attributed to the great reduction of the interface defects and the formation of the chemical bonding, as the result of the great improvement of the interface fluidity and chemical reaction ability of PA6. This study provides an effective way to achieve high strength metal/continuous carbon fiber reinforced thermosetting composite joints.

通过摩擦搭接点接触（FLSJ）直接接合和添加聚酰胺 6（PA6）中间膜接合 5182-铝合金和连续碳纤维增强双马来酰亚胺（CF-BMI）异种材料，研究了中间膜对接合机理和接合力学性能的影响。研究发现，直接使用 FLSJ 无法实现有效接合，这主要是由于热固性 BMI 的再成型能力和流动性较差，且难以与金属发生反应。在添加 PA6 中间膜后，FLSJ 成功实现了有效的异种连接。在转速为 2000rpm、停留时间为 7s、插入深度为 0.7 mm、PA6 中间层为 0.3 mm 的最佳参数下，接头的最大平均拉伸剪切力达到 3.68 kN，平均法向拉伸剪切强度为 20.9 MPa。在 PA6 夹层和铝合金的界面上发现了新的 C-O-Al 化学键，这是 PA6 的酰胺极性官能团和铝合金的表面氧化物发生化学反应的结果。加入 PA6 中间膜后，接头强度大大提高，这主要是由于 PA6 的界面流动性和化学反应能力大大提高，从而大大减少了界面缺陷并形成了化学键。这项研究为实现高强度金属/连续碳纤维增强热固性复合材料接头提供了一种有效途径。

Analytical and Finite Element Analyses on Axial Tensile Behaviour of Origami Bellows with Polygonal Cross-Section

Zhang Xinyi, Karagiozova Dora, Lu Guoxing, Durandet Yvonne, Wang Shenghai

doi:10.1016/j.tws.2023.111234

多边形截面折纸波纹管轴向拉伸行为的分析和有限元分析

The mechanical behaviour and energy absorption (EA) of origami bellows with polygonal cross-sections under quasi-static axial tension were numerically and theoretically investigated. The finite element analysis results showed that the plateau force increased with the number of polygon sides N, leading to increases in the mean tensile force (P m) and SEA. Two types of basic deployment elements during the tensile process of hexagonal cross-section bellows were defined in two deployment modes, namely non-rigid deployment mode I and non-rigid deployment mode II. The bellows exhibiting deployment mode II had approximately 60% greater SEA and P m than those exhibiting mode I. Theoretical predictions of the mean tensile force for each mode were derived based on a rigid, perfectly plastic material with superfolding elements. The predicted results showed reasonable agreement with the finite element analysis results in terms of force–displacement history and mean tensile force. This work reveals the fundamental mechanics involved and can facilitate design of origami bellows with optimized geometric and material parameters for desired EA behaviour.

对多边形截面折纸波纹管在准静态轴向拉力作用下的力学行为和能量吸收（EA）进行了数值和理论研究。有限元分析结果表明，高原力随多边形边数 N 的增加而增加，导致平均拉力（P m）和 SEA 的增加。六边形截面波纹管拉伸过程中的两种基本展开元素被定义为两种展开模式，即非刚性展开模式 I 和非刚性展开模式 II。根据带有超折叠元素的刚性完全塑性材料，对每种模式下的平均拉伸力进行了理论预测。在力-位移历史和平均拉伸力方面，预测结果与有限元分析结果显示出合理的一致性。这项研究揭示了其中涉及的基本力学原理，有助于设计具有优化几何参数和材料参数的折纸波纹管，以实现理想的 EA 行为。

Low-velocity impact performance of orthogonal grid reinforced CFRP-foam sandwich structure

Lv Hangyu, Shi Shanshan, Chen Bingzhi, Liu Ziping

doi:10.1016/j.tws.2023.111236

正交网格增强 CFRP 泡沫夹层结构的低速冲击性能

Orthogonal grid structures, which are widely used in engineering, are incorporated into the foam to form the grid reinforced core. However, the impact resistance of this type of sandwich structure varies with position. In this paper, the low-velocity impact performance of orthogonal grid reinforced CFRP-foam sandwich structure at different positions was investigated. The drop hammer low-velocity impact tests were conducted at 30 J, 50 J, and 80 J energy for the intersection, rib, and center positions, respectively, and the impact resistance of the three positions was further compared with the impact data. The test results showed that the intersection and rib exhibited fiber fracture and delamination of CFRP face and grid, as well as foam crushing and cracking. The center position showed face perforation and foam crushing. At the same impact energy, the intersection position had the strongest impact resistance, with an initial stiffness about 18% higher than that of the rib, and their peak load per unit mass was higher than that of CFRP-foam sandwich panels, and the center was the weakest. In addition, numerical simulations were performed which were in good agreement with the tests, and the damage processes at different stages were discussed. The lightweight, high impact resistant sandwich structure proposed can provide a reference for structural design.

工程中广泛使用的正交网格结构被纳入泡沫塑料中，形成网格加固夹芯。然而，这种夹层结构的抗冲击性能随位置的变化而变化。本文研究了正交网格增强 CFRP 泡沫夹层结构在不同位置的低速冲击性能。分别在交点、肋板和中心位置进行了能量为 30 J、50 J 和 80 J 的落锤低速冲击试验，并将三个位置的抗冲击性能与冲击数据进行了进一步比较。试验结果表明，交叉点和肋条位置出现纤维断裂、CFRP 面和网格分层以及泡沫破碎和开裂。中心位置则出现了面穿孔和泡沫破碎。在相同的冲击能量下，交叉点位置的抗冲击能力最强，其初始刚度比肋板高出约 18%，单位质量的峰值载荷也高于 CFRP 泡沫夹层板，而中心位置的抗冲击能力最弱。此外，还进行了数值模拟，结果与试验结果吻合，并讨论了不同阶段的破坏过程。所提出的轻质高抗冲击夹层结构可为结构设计提供参考。