今日更新:International Journal of Solids and Structures 2 篇,International Journal of Plasticity 1 篇,Computer Methods in Applied Mechanics and Engineering 1 篇,Thin-Walled Structures 4 篇
Fracture analysis of multifunctional fiber-reinforced concrete using phase-field method
Sadighi Amirreza, Maghami Ebrahim, Khaneghahi Mohammad Houshmand, Kamireddi Divya, Rahmaninezhad Seyed Ali, Farnam Yaghoob (Amir), Sales Christopher, Schauer Caroline, Najafi Ahmad R.
doi:10.1016/j.ijsolstr.2023.112493
利用相场法分析多功能纤维增强混凝土的断裂情况
In this paper, a numerical analysis has been conducted to predict the fracture response of a novel type of fiber-reinforced concrete blocks, called “multi-functional fiber reinforced concretes” (MFRCs). In MFRCs, fibers have been coated with a shell. This will allow the structure to be used for multiple purposes, including concrete self-healing. This study is conducted utilizing phase-field fracture framework. The shell thickness and the ratio of fiber length to diameter are the geometrical parameters whose effects on the fracture resistance of the MFRCs have been analyzed. As choosing the right shell material is under investigation, in the next step of the study, in addition to the geometrical factors, different material mismatch cases for the critical energy release rate of the shell has been analyzed. Moreover, the application of two different fibers, polyester fiber and polypropylene fiber (with almost 10 times higher critical energy release rate), are looked into. All the structures undergo three loading conditions: tensile loading, compressive loading, and three-point bending. In order to judge what configuration performs best, the values of peak force and absorbed energy of each structure in each case study have been taken into consideration and compared with those of other structures. It was seen that the most favorable performance and configuration depend on the loading condition and also the material set. Under tension, MFRCs with the lowest fiber length to diameter ratio exhibit the highest peak force and absorbed energy in the case of polyester fiber. The same observation was made for all models and material sets under compressive loading. Under three-point bending loading condition, for the cases of polyester fiber, similar results were obtained as the lowest fiber length to diameter ratio showed the best mechanical response. Having said that, it must be mentioned that shell material had a dominant effect on the fracture response of the structure under this loading condition. Polypropylene fibers also managed to increase the peak forces in different loading conditions.
本文进行了数值分析,以预测一种新型纤维增强混凝土砌块的断裂响应,这种砌块被称为 "多功能纤维增强混凝土"(MFRCs)。在多功能纤维增强混凝土中,纤维被覆上一层外壳。这将使结构具有多种用途,包括混凝土自愈合。本研究利用相场断裂框架进行。研究分析了外壳厚度和纤维长度与直径之比这些几何参数对 MFRC 抗断裂性能的影响。由于正在研究如何选择合适的壳体材料,在下一步研究中,除了几何因素外,还分析了不同材料不匹配情况下壳体临界能量释放率的影响。此外,还研究了两种不同纤维的应用,即聚酯纤维和聚丙烯纤维(临界能量释放率几乎高出 10 倍)。所有结构都经历了三种加载条件:拉伸加载、压缩加载和三点弯曲。为了判断哪种结构性能最好,我们考虑了每个案例研究中每种结构的峰值力和吸收能量值,并与其他结构的峰值力和吸收能量值进行了比较。结果表明,最有利的性能和配置取决于加载条件和材料组合。在拉伸条件下,对于聚酯纤维,纤维长度与直径比最小的 MFRC 具有最高的峰值力和吸收能量。在压缩荷载下,所有模型和材料组都有相同的观察结果。在三点弯曲加载条件下,对于聚酯纤维,也得到了类似的结果,因为纤维长度与直径比最小的材料显示出最佳的机械响应。但必须指出的是,在这种加载条件下,壳体材料对结构的断裂响应有主要影响。在不同的加载条件下,聚丙烯纤维也能增加峰值力。
Coupling of Single-Layer Material Point Peridynamics and Finite Element Method for Analyzing the Fracture Behavior of Composite Laminates
Li F.S., Gao W.C., Liu W., Yang X.W.
doi:10.1016/j.ijsolstr.2023.112495
耦合单层材料点周向动力学和有限元法分析复合材料层压板的断裂行为
In this paper a novel method, Single-Layer Material Point (SLMP) Peridynamics is proposed to simulate in-plane problems of composite laminates using a single layer of material points. Assuming that there is no relative displacement between the layers of laminates, the Single-Layer Material Point Peridynamics doesn’t need to create multi-layer material points. To further improve the calculation efficiency, a coupling model of single-layer material point Peridynamics and finite element method (FEM) is then developed to simulate the damage initiation and evolution of the composite laminates. Linear elastic deformation problems are studied with the SLMP Peridynamic model and the coupling model respectively, and the results are compared with those of FEM. Damage initiation and evolution problems are also analyzed by the coupling model and the results are compared with those of experiments. It is demonstrated that the presented method is of high accuracy.
本文提出了一种新方法--单层材料点(SLMP)周向动力学,利用单层材料点模拟复合材料层压板的面内问题。假定层压板各层之间没有相对位移,单层材料点周向动力学不需要创建多层材料点。为了进一步提高计算效率,还开发了单层材料点 Peridynamics 与有限元法 (FEM) 的耦合模型,用于模拟复合材料层压板的损伤起始和演化。分别利用 SLMP Peridynamic 模型和耦合模型研究了线性弹性变形问题,并将结果与有限元法的结果进行了比较。耦合模型还分析了损伤的发生和演变问题,并将结果与实验结果进行了比较。结果表明,所提出的方法具有很高的精度。
Deformation mechanisms in a novel multiscale hetero-structured Mg alloy with high strength-ductility synergy
Wang Tong, Zha Min, Gao Yipeng, Wang Si-Qing, Jia Hai-Long, Wang Cheng, Wang Hui-Yuan
doi:10.1016/j.ijplas.2023.103766
新型多尺度异质结构镁合金的变形机制与高强度-电导率协同作用
Most of the high-strength Mg alloys exhibit poor ductility at room temperature. Architecturing appropriate heterostructure in metallic materials gives rise to the breakthrough of the inherent strength-ductility trade-off dilemma. Here, we prepared a novel multiscale hetero-structure in Mg-9Al-1Zn (AZ91) alloy, consisting of bimodal-structured center-region and fine-grained surface-layer, providing high strength and high ductility, i.e. yield strength of ∼303 MPa, tensile strength of ∼400 MPa, and elongation of ∼14.5%. The multiscale microstructural heterogeneities were induced via a simple rolling process that combines the advantages of both accumulative rolling bonding (ARB) and hard plate rolling (HPR). By utilizing quasi-in-situ electron backscattered diffraction (EBSD)-digital image correlation (DIC) characterizations combined with the determination of dislocation/disclination distributions, it has been found that diversified strain accommodation mechanisms are stimulated by the strain incompatibilities near hetero-interfaces in the multiscale hetero-structure. In particular, non-basal slips have been activated largely in both the bimodal-structured center-region and fine-grained surface-layer. Moreover, a unique slip trace distribution has been observed in the fine grains adjacent to the basal-oriented coarse grain. Such a strain accommodation can better coordinate local strain incompatibility among the hetero-interface. The uniaxial loading–unloading–reloading tensile loop tests demonstrate that the multiscale heterogeneities impart a pronounced hetero-deformation induced hardening during tensile deformation. Multiple deformation modes, including the non-Schmid and non-basal slips, have been activated substantially in the multiscale hetero-structured Mg alloy, effectively relaxing local stress concentration and achieving stable plastic flow at a high-stress state, which is beneficial to improving strain-hardening ability and strength-ductility synergy. Our work could shed light on designing and processing strong and ductile Mg alloys, by tailoring proper microstructural heterogeneity to activate cooperated accommodating deformation modes.
大多数高强度镁合金在室温下的延展性较差。在金属材料中构建适当的异质结构有助于突破固有的强度-延展性权衡困境。在此,我们在 Mg-9Al-1Zn (AZ91) 合金中制备了一种新型多尺度异质结构,由双峰结构中心区和细粒表层组成,具有高强度和高延展性,即屈服强度达 ∼303 MPa,抗拉强度达 ∼400 MPa,伸长率达 ∼14.5%。多尺度微观结构异质性是通过一种简单的轧制工艺诱导的,该工艺结合了累积轧制结合(ARB)和硬板轧制(HPR)的优点。通过利用准原位电子反向散射衍射(EBSD)-数字图像相关(DIC)特性分析与位错/偏斜分布测定相结合的方法,发现多尺度异质结构中异质界面附近的应变不相容性激发了多样化的应变容纳机制。特别是在双模结构的中心区域和细粒度表层,非基本滑移在很大程度上被激活。此外,在邻近基底导向粗粒的细粒中也观察到了独特的滑移痕迹分布。这种应变容纳可以更好地协调异质界面之间的局部应变不相容性。单轴加载-卸载-再加载拉伸循环试验表明,多尺度异质在拉伸变形过程中会产生明显的异质变形诱导硬化。在多尺度异质结构镁合金中,包括非施密德滑移和非基底滑移在内的多种变形模式被大量激活,有效地松弛了局部应力集中,实现了高应力状态下稳定的塑性流动,有利于提高应变硬化能力和强度-电导率协同效应。我们的研究工作可通过定制适当的微结构异质性来激活协同容纳变形模式,从而为设计和加工高强度、韧性镁合金提供启示。
Stabilized isogeometric formulation of the Stokes problem on overlapping patches
Wei Xiaodong, Puppi Riccardo, Antolin Pablo, Buffa Annalisa
doi:10.1016/j.cma.2023.116477
重叠斑块上斯托克斯问题的稳定等几何表述
We present a novel stabilized isogeometric formulation for the Stokes problem, where the geometry of interest is obtained via overlapping NURBS (non-uniform rational B-spline) patches, i.e., one patch on top of another in an arbitrary but predefined hierarchical order. All the visible regions constitute the computational domain, whereas independent patches are coupled through visible interfaces using Nitsche’s formulation. Such a geometric representation inevitably involves trimming, which may yield trimmed elements of extremely small measures (referred to as bad elements) and thus lead to the instability issue. Motivated by the minimal stabilization method that rigorously guarantees stability for trimmed geometries (Buffa et al., 2020), in this work we generalize it to the Stokes problem on overlapping patches. Central to our method is the distinct treatments for the pressure and velocity spaces: Stabilization for velocity is carried out for the flux terms on interfaces, whereas pressure is stabilized in all the bad elements. We provide a priori error estimates with a comprehensive theoretical study. Through a suite of numerical tests, we first show that optimal convergence rates are achieved, which consistently agrees with our theoretical findings. Second, we show that the accuracy of pressure is significantly improved by several orders using the proposed stabilization method, compared to the results without stabilization. Finally, we also demonstrate the flexibility and efficiency of the proposed method in capturing local features in the solution field. This contribution is dedicated to Thomas J.R. Hughes, as a tribute to his remarkable lifetime achievements.
我们针对斯托克斯问题提出了一种新颖的稳定等距计算方法,通过重叠 NURBS(非均匀有理 B-样条曲线)补丁获得相关几何图形,即一个补丁以任意但预定义的层次顺序重叠在另一个补丁之上。所有可见区域构成计算域,而独立的补丁则通过使用尼采公式的可见界面进行耦合。这种几何表示法不可避免地涉及到修剪,而修剪可能会产生量值极小的修剪元素(称为坏元素),从而导致不稳定问题。最小稳定法严格保证了修剪几何图形的稳定性(Buffa 等人,2020 年),受此启发,我们在本研究中将其推广到重叠斑块上的斯托克斯问题。我们方法的核心是对压力和速度空间的不同处理:速度稳定是针对界面上的通量项进行的,而压力稳定是针对所有坏元素进行的。我们通过全面的理论研究提供了先验误差估计。通过一系列数值测试,我们首先证明了达到了最佳收敛率,这与我们的理论研究结果一致。其次,我们表明,与不使用稳定方法的结果相比,使用所提出的稳定方法,压力的精确度显著提高了几个数量级。最后,我们还证明了所提方法在捕捉解场局部特征方面的灵活性和效率。谨以此文献给托马斯-休斯(Thomas J.R. Hughes),向他一生的卓越成就致敬。
Multi-level dynamic responses of blast-loaded orthogrid stiffened panels
Zhang Bei, Wang Huijie, Qi Zehao, Wang Hong, Tao Yanming, Li Ming, Fan Hualin
doi:10.1016/j.tws.2023.111241
爆破加载正交格栅加劲板的多级动态响应
In this study, the multi-level dynamic responses of the blast-loaded orthogrid stiffened panel (BOSP) is analyzed using the energy method. The dynamic response of the area of skin enclosed by the stiffeners can be considered as the combination of the overall deformation of the neural surface and the local deformation relative to the neural surface. The relevant vibration amplitude is calculated through the Lagrange principle. The theory is verified by the finite element method (FEM). Parametric analysis reveals the effect of the thickness of the skin and stiffener distribution on the dynamic response of BOSP. The anti-explosion theory of BOSP can help effectively predict the deflection, which can guide the ultra-lightweight design of BOSP.
本研究采用能量法分析了爆破加载正交格栅加劲板(BOSP)的多级动态响应。加劲板围成的表皮区域的动态响应可视为神经面整体变形和相对于神经面的局部变形的组合。相关的振动振幅是通过拉格朗日原理计算得出的。该理论通过有限元法(FEM)得到验证。参数分析揭示了表皮厚度和加强筋分布对 BOSP 动态响应的影响。BOSP 的防爆理论有助于有效预测挠度,从而指导 BOSP 的超轻设计。
An analytical solution for dynamics of cyclic thermomechanically loaded multi-layered filament-wound composite pipes in hygrothermal environment
Soleimani M., Gholami R., Alijani A., Ansari R.
doi:10.1016/j.tws.2023.111242
湿热环境中循环热机械加载多层丝状缠绕复合管道动力学的分析解决方案
In this study, an analytical solution is provided to present the stress and strain analyses of the multi-layered filament-wound composite (MLF-WC) pipes subjected to the cyclic internal pressure and cyclic thermal loading in hygrothermal environment. The MLF-WC pipe is made of anisotropic, homogeneous and linear elastic materials. It is assumed that the material properties are temperature-independent. Also, applied cyclic loadings are independent of the tangential and axial coordinates. Using the three-dimensional anisotropic elasticity, time-dependent analytical expressions are provided for the stresses, strains and displacements. The accuracy of present analytical approach and numerical results is verified by comparison with those given in literature. It is remarked that the developed analytical solution can be used for the dynamic analysis of functionally graded pipes and pressure vessels under the cyclic loadings. Moreover, through the numerical results, it is found that stacking sequence has a considerable effect on the distributions of shear strain and stress. Furthermore, for the MLF-WC pipe under simultaneous cyclic internal pressure and cyclic thermal loading, the mean amplitudes of the cyclic loadings have a significant effect on the sign of axial strain.
本研究提供了一种分析方法,用于分析多层丝状缠绕复合材料管道(MLF-WC)在湿热环境中承受循环内压和循环热负荷时的应力和应变。MLF-WC 管道由各向异性、均质和线性弹性材料制成。假设材料特性与温度无关。此外,施加的循环载荷与切向和轴向坐标无关。利用三维各向异性弹性,提供了与时间相关的应力、应变和位移分析表达式。通过与文献中给出的结果进行比较,验证了本分析方法和数值结果的准确性。结果表明,所开发的分析解决方案可用于循环载荷下功能分级管道和压力容器的动态分析。此外,通过数值结果还发现,堆叠顺序对剪切应变和应力的分布有相当大的影响。此外,对于同时承受循环内压和循环热荷载的 MLF-WC 管道,循环荷载的平均振幅对轴向应变的符号有显著影响。
Design method of axial compression stability for cross-section corrugated plate steel special-shaped column
Jiang Zi-qin, Niu Zi-yao, Zhang Ai-Lin, Liu Xue-chun
doi:10.1016/j.tws.2023.111243
截面波纹板钢异形柱轴向抗压稳定性设计方法
Obtaining a larger moment of inertia and overall stability with smaller material input, which is an effective way to improve the bearing capacity and reduce the self-weight of structural columns. This paper proposes a cross-section corrugated plate steel special-shaped column (CCSC), which is based on the optimization design idea of steel profiled-shaped column section, combined with the comprehensive consideration of the overall stability of steel structure column members, material use efficiency and building interior space utilization rate. The new CCSC is composed of three parts: core square steel pipe, corrugated plate, and flange plate. The high-out-of-plane stiffness characteristic of corrugated plate is utilized to improve the section rotation radius. The three parts above are coordinated to resist lateral load. The square steel pipe and flange plate are the main vertical bearing plates. The new special-shaped column can obtain a larger moment of inertia and overall stability with a smaller material input, thus improving the bearing capacity. Through the combination of theoretical analysis and numerical simulation, the overall stability of the axial compression of CCSC are analyzed, and the instability modes and failure modes of CCSC are revealed. The design method and suggestions for the stability of CCSC under axial compression are put forward. Then, the overall stability design and application suggestion based on conventional square steel tube is given. The results show that the stability design method of CCSC under axial compression can effectively judge the instability mode of CCSC and obtain the ultimate bearing capacity of the whole member. Compared with square steel tube columns with regularized slenderness ratio greater than 0.8 in structural design, the CCSC has obvious advantages in overall stability and steel consumption.
以较小的材料投入获得较大的惯性矩和整体稳定性,是提高结构柱承载力和减轻自重的有效途径。本文基于钢结构异形柱截面优化设计思想,结合钢结构柱构件整体稳定性、材料使用效率和建筑内部空间利用率等综合考虑,提出了一种截面波纹板钢异形柱(CCSC)。新型 CCSC 由核心筒方钢管、波纹板和翼缘板三部分组成。利用波纹板的高平面外刚度特性来提高截面旋转半径。上述三部分相互配合,共同抵抗侧向荷载。方钢管和翼缘板是主要的竖向承载板。新型异形柱能以较小的材料投入获得较大的惯性矩和整体稳定性,从而提高承载能力。通过理论分析和数值模拟相结合的方法,分析了 CCSC 轴向受压的整体稳定性,揭示了 CCSC 的失稳模式和失效模式。提出了轴向压缩下 CCSC 稳定性的设计方法和建议。然后,给出了基于常规方钢管的整体稳定性设计和应用建议。结果表明,轴向压缩下 CCSC 的稳定性设计方法能有效判断 CCSC 的失稳模式,并获得整个构件的极限承载力。与结构设计中规则化细长比大于 0.8 的方钢管柱相比,CCSC 在整体稳定性和用钢量方面具有明显优势。
Mechanical responses and energy absorption characteristics of a novel functionally graded voxel lattice structure
Xiao Sihang, Li Qi, Jia Heran, Wang Fei, Gao Jingjing, Lv Wenliang, Qi Junfeng, Duan Shengyu, Wang Panding, Lei Hongshuai
doi:10.1016/j.tws.2023.111244
新型功能分级体晶格结构的机械响应和能量吸收特性
Functionally graded lattice structures have attracted considerable interest owing to their superior mechanical performance compared to traditional uniform structures. In this paper, a novel voxel lattice unit cell with multiple symmetrical struts was designed, and graded lattice structures with variable densities were proposed. Quasi-static compression tests and numerical simulations were conducted to investigate mechanical responses, deformation modes, and energy absorption abilities. The results demonstrated that graded design enabled tunable deformation and a significant 20.3% increase in specific energy absorption compared to uniform structures. This study expands the design space of functionally graded lattice structures and highlights their significance in practice.
与传统的均匀结构相比,功能分级晶格结构具有更优越的机械性能,因而备受关注。本文设计了一种具有多个对称支杆的新型体素晶格单元单元,并提出了密度可变的梯度晶格结构。通过准静态压缩试验和数值模拟,研究了机械响应、变形模式和能量吸收能力。结果表明,与均匀结构相比,分级设计实现了可调变形,比能量吸收能力显著提高了 20.3%。这项研究拓展了功能分级晶格结构的设计空间,并凸显了其在实践中的重要意义。