今日更新:International Journal of Solids and Structures 1 篇,Journal of the Mechanics and Physics of Solids 2 篇,Mechanics of Materials 1 篇,Thin-Walled Structures 6 篇
Mixed-mode fracture prediction of notched components using phase-field approach
Bahador Bahrami, Hossein Ahmadian, Mohmmad R. Mehraban, Majid R. Ayatollahi
doi:10.1016/j.ijsolstr.2024.113113
用相场法预测缺口构件的混合模式断裂
The application of the phase-field method (PFM) to brittle fracture for studying complex fracture phenomena has recently gained attention from researchers. However, there has been limited emphasis on predicting fracture loads for notched components. In this study, numerous phase-field simulations were conducted to compute the fracture load and crack initiation angle in brittle notched components under in-plane loading conditions. The accuracy of the results, verified against experimental data, demonstrates the PFM’s ability to precisely predict both fracture load and fracture initiation angle. Additionally, it has been demonstrated that Miehe’s spectral decomposition method provides more reliable results for notched Brazilian Disc specimens subjected to compressive loading than those obtained using Amor’s volumetric-deviatoric split method.
将相场法应用于脆性断裂研究复杂断裂现象近年来受到了研究人员的关注。然而,对缺口构件断裂载荷预测的重视程度有限。在本研究中,进行了大量的相场模拟,以计算平面内加载条件下脆性缺口构件的断裂载荷和裂纹起裂角。实验数据验证了结果的准确性,证明了PFM能够精确预测断裂载荷和破裂起裂角。此外,已经证明Miehe的光谱分解方法比Amor的体积偏差分裂方法提供了更可靠的结果,用于缺口巴西盘试件承受压缩载荷。
A theoretical framework for multi-physics modeling of poro-visco-hyperelasticity-induced time-dependent fracture of blood clots
Dongxu Liu, Nhung Nguyen, Tinh Quoc Bui, Luka Pocivavsek
doi:10.1016/j.jmps.2024.105913
多孔粘弹性诱导的血凝块时间依赖性断裂的多物理场建模理论框架
Fracture resistance of blood clots plays a crucial role in physiological hemostasis and pathological thromboembolism. Although recent experimental and computational studies uncovered the poro-viscoelastic property of blood clots and its connection to the time-dependent deformation behavior, the effect of these physical processes on clot fracture and the underlying fracture mechanisms are not well understood. This work aims to formulate a thermodynamically consistent, multi-physics theoretical framework for describing the time-dependent deformation and fracture of blood clots. This theory concurrently couples fluid transport through porous fibrin networks, non-linear visco-hyperelastic deformation of the solid skeleton, solid-fluid interactions, mechanical degradation of tissues, gradient enhancement of energy, and protein unfolding of fibrin molecules. The constitutive relations of tissue constituents and the governing equation of fluid transport are derived within the framework of porous media theory by extending non-linear continuum thermodynamics at large strains. A physics-based, compressible network model is developed for the fibrin network of blood clots to describe its mechanical response. The kinetic equations of the internal variables, introduced for describing the non-linear viscoelastic deformation, non-local damage driving force and protein unfolding, are formulated according to the thermodynamics principles by incorporating a non-equilibrium energy of fibrin networks, a gradient-enhanced energy, and a stretch-induced energy of fibrin molecules, respectively, into the total free energy density function. An energy-based damage model is developed to predict the damage and fracture of blood clots, and an evolving regularization parameter is proposed to limit the damage zone bandwidth. The proposed model is implemented into finite element code by writing subroutines and is experimentally validated using single-edge cracked clot specimens with different constituents. The fracture of blood clots subject to different loading conditions is simulated, and the mechanisms of clot fracture are systematically analyzed. Computational results show that this model can accurately capture the experimentally measured deformation and fracture. The viscoelasticity and fluid transport play essential roles in the fracture of blood clots under physiological loading.
血凝块的抗骨折性在生理性止血和病理性血栓栓塞中起着至关重要的作用。尽管最近的实验和计算研究揭示了血凝块的孔隙粘弹性特性及其与时间依赖性变形行为的联系,但这些物理过程对血凝块破裂的影响及其潜在的破裂机制尚未得到很好的理解。这项工作的目的是制定一个热力学一致的,多物理理论框架来描述血块的时间依赖性变形和断裂。该理论同时耦合了多孔纤维蛋白网络中的流体输送、固体骨架的非线性粘弹性变形、固体-流体相互作用、组织的机械降解、能量梯度增强和纤维蛋白分子的蛋白质展开。在多孔介质理论的框架下,通过扩展大应变下的非线性连续介质热力学,导出了组织组分的本构关系和流体输运的控制方程。一个基于物理的,可压缩的网络模型被开发为血凝块的纤维蛋白网络来描述其机械反应。根据热力学原理,将纤维蛋白网络的非平衡能量、梯度增强能量和拉伸诱导能量分别纳入总自由能密度函数,建立了描述非线性粘弹性变形、非局部损伤驱动力和蛋白质展开的内变量动力学方程。提出了一种基于能量的损伤模型来预测血凝块的损伤和断裂,并提出了一种演化正则化参数来限制损伤区带宽。该模型通过编写子程序实现到有限元代码中,并使用不同成分的单边裂凝块试样进行了实验验证。模拟了不同载荷条件下血凝块的断裂过程,系统分析了血凝块断裂的机理。计算结果表明,该模型能准确地捕捉到实验测量的变形和断裂。粘弹性和流体输运在生理负荷下的血凝块断裂中起着至关重要的作用。
Mechanics-informed, model-free symbolic regression framework for solving fracture problems
Ruibang Yi, Dimitrios Georgiou, Xing Liu, Christos E. Athanasiou
doi:10.1016/j.jmps.2024.105916
力学信息,无模型的符号回归框架,用于解决断裂问题
Data-driven methods have recently been introduced to address complex mechanics problems. While model-based, data-driven approaches are predominantly used, they often fall short of providing generalizable solutions due to their inherent reliance on pre-selected models. Model-free approaches, such as symbolic regression, hold promise for overcoming this limitation by extracting solutions directly from datasets. However, these approaches remain unexplored when dealing with high-dimensional fracture mechanics problems and require significant customization to be effective. In this work, we propose a new symbolic regression framework that integrates mechanics knowledge to enhance the ability to generalize solutions. This framework also includes a model-free variable separation scheme to decouple high-dimensional problems into simpler sub-problems with manageable complexity while preserving data fidelity. We demonstrate the advantages of this framework through two fracture mechanics problems, showing that it can potentially provide generalizable, analytical solutions to novel, easy-to-use fracture testing configurations.
数据驱动的方法最近被引入来解决复杂的力学问题。虽然主要使用基于模型的、数据驱动的方法,但由于它们固有地依赖于预先选择的模型,它们往往不能提供可推广的解决方案。无模型方法,如符号回归,有望通过直接从数据集中提取解决方案来克服这一限制。然而,这些方法在处理高维断裂力学问题时仍未被探索,并且需要大量定制才能有效。在这项工作中,我们提出了一个新的符号回归框架,它集成了力学知识,以提高推广解决方案的能力。该框架还包括一个无模型变量分离方案,用于将高维问题解耦为具有可管理复杂性的更简单的子问题,同时保持数据保真度。我们通过两个断裂力学问题证明了该框架的优势,表明它可以为新颖、易于使用的断裂测试配置提供可推广的分析解决方案。
Comprehensive analysis of wave interactions and resulting spall damage in layered heterogeneous medium under impact
Satyendra Pratap Singh, Harpreet Singh, Puneet Mahajan
doi:10.1016/j.mechmat.2024.105182
冲击作用下层状非均质介质中波浪相互作用及产生的小块损伤的综合分析
The effect of dynamic spall damage on the response of layered medium subjected to one-dimensional impact involving an impactor and a multi-layered target is investigated. The study examines the damage caused by elastic waves below the Hugoniot Elastic Limit (HEL) during impact events. Analytical expressions of stress and particle velocity derived from mass and momentum conservation principles are utilized to solve the wave interactions within the impactor-target system, considering reflections, transmissions, and wave interactions between layers. These analytical expressions, integrated into a computational framework, facilitate the monitoring of material responses following each wave interaction, thereby analysing the impact response of the layered medium. Wave interactions, resulting in tensile stresses, that can cause damage to the target have been identified. A strain-based damage initiation and evolution law is incorporated into the developed computer program to predict damage in each layer of a medium. Damage alters the medium’s impact behaviour by decreasing stress magnitude and inducing temporal delays in the response due to attenuated wave propagation speed. The occurrences of tensile stress are explored, analyzing spatial and temporal variations of multiple damage incidents within the layered medium. The tension at the interface between two layers can induce damage in one or both adjacent layers, leading to debonding between layers. The effect of damage on the impact response of the medium is analysed by comparing the results for the damaged and undamaged target scenarios. The impact behaviour of a single-layer and a multi-layer target obtained from the present model, in terms of stress and particle velocity, is verified through Finite Element simulations of the identical impact problems, where the damage evolution criterion is incorporated using a VUMAT subroutine. The outcomes derived from this study align closely with Finite Element (FE) results.
研究了动态碎裂损伤对层状介质受到冲击器和多层目标一维冲击时响应的影响。研究了冲击事件中低于Hugoniot弹性极限(HEL)的弹性波所造成的损伤。利用质量和动量守恒原理导出的应力和粒子速度的解析表达式,考虑反射、透射和层间波的相互作用,求解冲击器-目标系统内的波相互作用。这些解析表达式集成到一个计算框架中,便于监测每次波相互作用后的材料响应,从而分析层状介质的冲击响应。波的相互作用,导致拉伸应力,可以造成破坏的目标已经确定。将基于应变的损伤起裂和演化规律纳入计算机程序中,以预测介质各层的损伤。损伤通过降低应力大小和由于波传播速度衰减而引起响应的时间延迟来改变介质的冲击行为。探讨了拉应力的发生,分析了层状介质中多重损伤事件的时空变化。两层界面处的张力可引起相邻一层或两层的损伤,导致层间脱粘。通过比较目标损伤和未损伤两种情况下的结果,分析了损伤对介质冲击响应的影响。从该模型中获得的单层和多层目标在应力和粒子速度方面的冲击行为,通过对相同冲击问题的有限元模拟进行验证,其中使用VUMAT子程序将损伤演化准则纳入其中。本研究的结果与有限元(FE)结果密切相关。
Moment capacity of cold-formed steel channel beams with edge-stiffened and unstiffened elongated web holes
Dinesh Lakshmanan Chandramohan, Krishanu Roy, Zhiyuan Fang, Beulah Gnana Ananthi. G, James B.P. Lim
doi:10.1016/j.tws.2024.112605
边加筋和未加筋长腹板孔冷弯型钢槽钢的弯矩承载力
Cold-formed steel channel beams (CFSCB) often incorporate web holes to accommodate building services, but this reduces their moment capacity due to decreased web area. Recent studies have shown that a new type of edge-stiffened web holes can enhance moment capacity, especially for circular ones, and can now be extended to elongated web holes. However, there hasn't been research on the moment capacity of such CFSCB with elongated web holes. This paper uses finite element analysis (FEA) to examine the moment capacity and flexural behaviour of such beams with both elongated edge-stiffened web holes (EEH) and elongated unstiffened web holes (EUH). After validating the FEA models against experimental results available in the literature, a comprehensive parametric study involving 2160 FEA models was conducted. Results showed that CFSCB with EEH exhibited, on average, a 9% increase in moment capacity compared to those with EUH. Additionally, the parametric results were compared with the design capacities calculated from existing standards for CFSCB with unstiffened web holes. It was found that the current design equations for CFSCB with EUH were overly conservative by 9% and 66%, on average, for distortional or local buckling failure and lateral-torsional buckling failure, respectively. Consequently, modified Direct Strength Method (DSM) design equations were proposed to calculate the moment capacity of CFSCB with both EEH and EUH. Finally, a reliability analysis was conducted to assess the accuracy of the proposed design equations.
冷弯型钢槽梁(CFSCB)通常包含腹板孔以适应建筑服务,但由于腹板面积减少,这降低了它们的弯矩能力。最近的研究表明,一种新型的边加劲腹板孔可以提高弯矩承载力,特别是圆形腹板孔,现在可以扩展到细长腹板孔。然而,对这种带有细长腹板孔的CFSCB的弯矩承载力研究尚未见报道。本文采用有限元分析(FEA)来研究这类梁的弯矩承载力和抗弯性能,这两种梁都具有拉长的边缘加劲腹板孔(EEH)和拉长的未加劲腹板孔(EUH)。在将有限元模型与现有文献的实验结果进行验证后,对2160个有限元模型进行了全面的参数化研究。结果表明,加了EEH的CFSCB的弯矩容量比加了EUH的CFSCB平均增加了9%。此外,将参数计算结果与现有标准计算的无加劲腹板孔CFSCB设计承载力进行了比较。研究发现,对于扭曲或局部屈曲破坏,以及侧向扭转屈曲破坏,现有的含EUH CFSCB设计方程平均分别过于保守9%和66%。在此基础上,提出了修正的直接强度法(DSM)设计方程,用于计算具有EEH和EUH的CFSCB的弯矩承载力。最后,进行了可靠性分析,以评估所提出的设计方程的准确性。
Thermal performance analysis and optimization of air-supported membrane building envelope based on numerical simulation
Chengyang Huang, Yuying Sun, Hongyan Wang, Mingxin Pang, Wei Wang, Wenzhe Wei
doi:10.1016/j.tws.2024.112615
基于数值模拟的气支膜建筑围护结构热工性能分析与优化
Air-supported membrane (ASM) envelopes offer an effective solution for creating large interior spaces for buildings with lower energy consumption and carbon emissions. However, there is little research on the thermal performance of ASM envelopes, particularly regarding the natural convection within the air interlayer and its impact on thermal resistance. To address this gap, this study developed a numerical model of ASM envelopes and validated it through experiments. Subsequently, a numerical investigation was conducted to analyze natural convection and thermal resistance while considering factors such as indoor-outdoor temperature difference, membrane emissivity and air interlayer thickness. Results indicated that with the emissivity increased from 0.2 to 1, the thermal resistance of the air interlayer and the envelope decreased by 32.35% and 9.13%, respectively. Besides, the thickness of air interlayer also had evident effect on thermal resistance. When it increased from 5 mm to 35 mm, the thermal resistance of the air interlayer and the envelope increased by 156.19% and 14.74%, and further results in the heat transfer decreased by 13.85%. However, the convective heat transfer would remain constant when the thickness exceeded 35 mm. This study provided valuable reference for optimizing the design of ASM envelopes and accurately calculating their thermal resistance.
空气支撑膜(ASM)围护结构提供了一个有效的解决方案,为建筑创造更大的内部空间,降低能耗和碳排放。然而,关于ASM包膜热性能的研究很少,特别是关于空气夹层内的自然对流及其对热阻的影响的研究很少。为了解决这一差距,本研究开发了ASM包络的数值模型,并通过实验对其进行了验证。随后,在考虑室内外温差、膜发射率和空气层间厚度等因素的情况下,对自然对流和热阻进行了数值分析。结果表明,当发射率由0.2提高到1时,空气夹层和包络层的热阻分别降低了32.35%和9.13%。此外,空气夹层厚度对热阻也有明显的影响。当其由5 mm增大到35 mm时,空气夹层和包络层的热阻分别增大了156.19%和14.74%,换热量进一步减小了13.85%。然而,当厚度超过35 mm时,对流换热保持不变。该研究为ASM包壳优化设计和准确计算其热阻提供了有价值的参考。
Effect of elastic support on the vibration characteristics of mistuned coated blisks
Xianfei Yan, Wei Sun
doi:10.1016/j.tws.2024.112616
弹性支承对失谐涂覆圆盘振动特性的影响
Boundary conditions significantly affect the vibration characteristics of mechanical structures. Hard coatings are applied to reduce the vibration levels of blisks, and the modelling methods and vibration characteristics of mistuned coated blisks have been investigated under hard-support boundary conditions. However, the behavior of coated blisks under elastic support has not been previously studied. This paper presents a finite element model to simulate elastic support using two methods and develops reduced-order models to analyze coated blisks under elastic support. Furthermore, the effects of elastic support on the vibration characteristics of tuned, deterministic, and randomly mistuned blisks are investigated with a detailed discussion of the underlying mechanisms. The results indicate that elastic support has a notable impact on the natural frequencies and resonant responses at nodal diameters 1 and 2 in tuned-coated blisks. For deterministic mistuned blisks, the amplitude amplification factor varies in frequency-veering regions and frequency-intersecting regions with increasing support stiffness. Elastic support can reduce the forced responses of randomly mistuned blisks, and the well-known peak-value phenomenon is not observed in some cases based on statistical analyses.
边界条件对机械结构的振动特性影响很大。采用硬涂层来降低叶片振动水平,研究了在硬支撑边界条件下失谐涂层叶片的建模方法和振动特性。然而,涂层圆盘在弹性支撑下的行为尚未得到研究。本文提出了用两种方法模拟弹性支承的有限元模型,并建立了分析弹性支承下涂层圆盘的降阶模型。此外,弹性支承对调谐、确定性和随机失谐轮盘振动特性的影响进行了研究,并详细讨论了其潜在机制。结果表明,弹性支承对调谐包覆圆盘在节点直径1和2处的固有频率和共振响应有显著影响。对于确定性失谐轮盘,振幅放大因子在频率转向区和频率相交区随支承刚度的增加而变化。弹性支撑可以减小随机失谐圆盘的强迫响应,统计分析表明,在某些情况下没有观察到众所周知的峰值现象。
Mechanical behaviour of rigid-flexible combined structures: aluminium-inflated membrane beams for application in floating photovoltaic platform
Yunling Ye, Jin Gan, Weiguo Wu, Shan Wang, C. Guedes Soares
doi:10.1016/j.tws.2024.112628
刚柔组合结构的力学性能:用于浮式光伏平台的充气铝膜梁
This study aims to investigate the bending and failure behaviour of aluminium-inflated membrane beams for their applications in floating photovoltaic platforms. Four-point bending tests are conducted for a range of inflated pressures and two different deck heights to assess their effect on structural stiffness and ultimate bearing capacity. Meanwhile, the surface-based fluid cavity method is employed to develop the finite element model with the material properties determined by independent coupon-level tests. The bearing capacity of the aluminium-inflated membrane beam is positively correlated with the internal pressure and deck height. The midspan strain distribution is similar to those of the traditional four-point bending beam with the upper part undergoing compression and the lower part experiencing tension, however, the structural behaviour at the failure stage is different. Failure typically occurs due to localised depressions at the loading points on the aluminium deck, ultimately leading to structural failure. The numerical model closely matches the experimental data for the initial inflated and bending configurations, exhibiting a deviation of only 0.10% to 0.46% in diameter and 0.32% to 5.57% in equivalent bending stiffness. A parametric study shows that the loading properties of the beam are more sensitive to the internal pressure than the deck height and thickness.
本研究旨在研究用于浮动光伏平台的铝膨胀膜梁的弯曲和破坏行为。在充气压力范围和两种不同的甲板高度下进行四点弯曲试验,以评估其对结构刚度和极限承载能力的影响。同时,采用基于表面的流体腔法建立了基于独立耦合水平试验确定材料性能的有限元模型。充气铝膜梁的承载力与内压、桥面高度呈正相关。跨中应变分布与传统四点弯梁的上受压下受拉相似,但破坏阶段的结构行为不同。失效通常发生在铝制甲板上的加载点的局部凹陷,最终导致结构失效。数值模型与初始膨胀和弯曲构型的实验数据非常吻合,直径偏差仅为0.10% ~ 0.46%,等效弯曲刚度偏差仅为0.32% ~ 5.57%。参数化研究表明,梁的受力特性对内压的敏感性大于对桥面高度和厚度的敏感性。
Quasi-static crushing response of a novel triaxial isotropy mechanical metamaterial with dual-platform property
Runzhi Lu, Qian Zhang, Huizhong Zhang, Marco Meloni, Jian Feng, Jianguo Cai
doi:10.1016/j.tws.2024.112630
一种新型双平台三轴各向同性力学超材料的准静态破碎响应
A novel triaxial isotropy origami metamaterial with dual-platform is proposed by combining the tachi tubes and the honeycomb structures. Crushing responses of the hexahedral metamaterial under quasi-static compression load are investigated through experimental tests and numerical simulations. Experimental and numerical results reveal that the hexahedral metamaterial sample shows three deformation modes. Meanwhile, the numerical predictions of deformation modes and locations agree very well with the experimental results. Moreover, the effect of aspect ratio, thickness-to-span ratio, angle on the deformation mode, peak stress, plateau stress of different stages, and specific energy absorption (SEAM, SEAV) is investigated. Finally, the proposed metamaterial is compared with traditional honeycomb. The numerical results demonstrate that the SEAM of the hexahedral metamaterial is 90.6% of the traditional honeycomb in the Z-direction. However, during X/Y-direction compression, the energy absorption capacity of the hexahedral metamaterial is 13.0 and 12.2 times that of the traditional honeycomb, respectively.
提出了一种新型的三轴各向同性双平台折纸材料。通过实验和数值模拟研究了准静态压缩载荷作用下六面体超材料的破碎响应。实验和数值结果表明,六面体超材料试样呈现出三种变形模式。同时,数值预测的变形模式和变形位置与试验结果吻合较好。此外,还研究了纵横比、厚跨比、角度对变形模式、峰值应力、不同阶段的高原应力和比能吸收(SEAM, SEAV)的影响。最后,将该材料与传统蜂窝材料进行了比较。数值结果表明:六面体超材料在z方向上的SEAM是传统蜂窝的90.6%;然而,在X/ y方向压缩过程中,六面体超材料的能量吸收能力分别是传统蜂窝的13.0倍和12.2倍。
HSMAOA: An enhanced arithmetic optimization algorithm with an adaptive hierarchical structure for its solution analysis and application in optimization problems
Jingsen Liu, Jianggui Zhao, Yu Li, Huan Zhou
doi:10.1016/j.tws.2024.112631
HSMAOA:一种具有自适应层次结构的增强型算术优化算法,用于优化问题的解分析和应用
The Arithmetic Optimization Algorithm (AOA) has recently gained significant attention as a novel meta-heuristic algorithm. However, it faces challenges such as premature convergence and entrapment in local optima when addressing complex optimization problems. To overcome these limitations, this paper proposes an enhanced AOA, termed the Self-Adaptive Hierarchical Arithmetic Optimization Algorithm (HSMAOA). The proposed method integrates three key strategies: Firstly, a spiral-guided random walk mechanism is introduced to improve global search ability. Secondly, a novel adaptive hierarchy leader and follower mechanism is proposed, which establishes a complete multi-branch tree hierarchy with decreasing branching degrees within the population, thereby increasing information exchange among population individuals to escape local optima. Finally, a differential mutation strategy based on ranked selection is introduced to enhance candidate solution quality. HSMAOA's performance was evaluated on the CEC2022 test suite against some state-of-the-art algorithms. Results, including optimization accuracy analysis, convergence curves, and various statistical tests, demonstrate HSMAOA's superior optimization capability and robustness. In addition, tests on eight engineering structure optimization problems, including the pressure vessel design problem, the multiple disk clutch brake design problem, and the step-cone pulley problem, and so forth, further validate its effectiveness. Thus, HSMAOA shows strong competitiveness in complex optimization tasks and potential for a wide range of applications, and is an advantageous and promising alternative solution for optimization problems.
算术优化算法(AOA)作为一种新颖的元启发式算法,近年来受到了广泛的关注。然而,在处理复杂的优化问题时,它面临着过早收敛和陷入局部最优等挑战。为了克服这些限制,本文提出了一种改进的层次算法,称为自适应层次算法优化算法(HSMAOA)。该方法集成了三个关键策略:首先,引入螺旋引导随机行走机制,提高全局搜索能力;其次,提出了一种新的自适应层次leader和follower机制,该机制在种群内建立了分支度递减的完整多分支树层次结构,从而增加了种群个体间的信息交换,避免了局部最优;最后,提出了一种基于排序选择的差分突变策略,以提高候选解的质量。HSMAOA的性能在CEC2022测试套件上针对一些最先进的算法进行了评估。结果包括优化精度分析、收敛曲线和各种统计检验,证明了HSMAOA优越的优化能力和鲁棒性。此外,对压力容器设计问题、多盘离合器制动器设计问题、步锥滑轮问题等8个工程结构优化问题进行了试验,进一步验证了该方法的有效性。因此,HSMAOA在复杂优化任务中具有很强的竞争力和广泛的应用潜力,是一种具有优势和前景的优化问题替代解决方案。