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【新文速递】2024年4月11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,Journal of the Mechanics and Physics of Solids 3 篇,Mechanics of Materials 2 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 3 篇

International Journal of Solids and Structures

Data-driven probabilistic failure assessment curve based on similitude principle

Siyuan Li, Baoming Gong, Lianshuang Dai, Caiyan Deng, Xinjie Di

doi:10.1016/j.ijsolstr.2024.112819

基于相似原理的数据驱动概率失效评估曲线

In this study, based on the similarity in crack-tip fields between a pipeline structure and standardized single-edge notched tension (SE(T)) test specimen, a methodology using a data-driven machine learning technique is proposed to determine the specific failure assessment curves for full-scale pipeline girth welds. By considering constraint similitude and ductile tearing, the probabilistic failure assessment line obtained from SE(T) resistance curves with a 50% survival rate can provide the most accurate failure assessment, as validated using the experimental full-scale pipeline data in the literature, particularly for the zone dominated by ductile fracture. Moreover, Option 1 (in R6 terminology) fracture assessment curve of British Energy R6 approach, which corresponds to a 15% survival rate, is proven to be overly-conservative.

在这项研究中,基于管道结构与标准化单边缺口张力(SE(T))试样之间裂纹尖端场的相似性,提出了一种使用数据驱动的机器学习技术的方法来确定全尺寸管道环焊缝的具体失效评估曲线。通过考虑约束相似性和韧性撕裂,从SE(T)阻力曲线中获得的概率失效评估线具有50%的存活率,可以提供最准确的失效评估,并使用文献中的实验全尺寸管道数据进行验证,特别是对于以韧性断裂为主的区域。此外,英国能源公司R6方法的选项1 (R6术语)压裂评估曲线对应的存活率为15%,被证明过于保守。


Journal of the Mechanics and Physics of Solids

A novel continuum dislocation density field-based crystal plasticity theory

Qichao Ruan, Esteban P. Busso, Zhangchen Fan, Chao Ling, Dongfeng Li

doi:10.1016/j.jmps.2024.105643

一种新的连续位错密度场晶体塑性理论

In this work, a novel dislocation density field-based crystal plasticity formulation, that incorporates up-scaled continuum dislocation density fields to represent all possible characters of the dislocation density, is presented. The continuum dislocation field theory, formulated assuming large strain kinematics, is based on an all-dislocation concept, whereby individual dislocation density types are described as vector fields. The evolutionary behaviour of the dislocation density fields is defined in terms of a glide component derived from the classical general conservation law for dislocation density fields proposed originally by Kroner and Acharya, a rotation one given by the curl of the dislocation velocity vector as proposed originally by Ngan and co-workers, and a statistically stored dislocation source/sink component.The proposed formulation has been numerically implemented within the finite element method using a modified up-wind stabilisation approach, which results on eight extra independent nodal degrees of freedom per slip system, associated with the upscaled dislocation densities of pure edge and screw character. Furthermore, the required boundary conditions are simple: initial total dislocation density and dislocation flux or velocity, without the need for higher order boundary conditions. Full details of the numerical implementation of the crystal plasticity theory are given. The theory is then used to investigate classical boundary value problems involving 1D and 2D dislocation pile-ups, and the development of boundary layers in a deforming single crystal strip under constrained conditions. The main general understanding that emerges from the case studies is that, as either the dislocation pile-ups or the boundary layers develop with deformation, geometrically necessary dislocations are generated and lead to an overall behaviour that is size-dependent. Furthermore, it is shown that, in the absence of sources or sinks, which are statistically stored in nature, that total number of dislocations in the pile-up problems is preserved. The numerical predictions of the 1D pile-up and strip simple shear problems are in good agreement with published solutions.

在这项工作中,提出了一种新的基于位错密度场的晶体塑性公式,该公式包含了放大的连续位错密度场来表示位错密度的所有可能特征。连续位错场理论,假设大应变运动学,是基于全位错的概念,其中个别位错密度类型被描述为矢量场。位错密度场的演化行为定义为由Kroner和Acharya最初提出的位错密度场的经典一般守恒定律推导出的滑动分量,由Ngan和同事最初提出的位错速度矢量旋度给出的旋转分量,以及统计上存储的位错源/汇分量。所提出的公式已在有限元方法中使用改进的逆风稳定方法进行了数值实现,结果是每个滑移系统有8个额外的独立节点自由度,与纯边缘和螺旋特征的位错密度上升有关。此外,所需的边界条件很简单:初始总位错密度和位错通量或速度,不需要更高阶的边界条件。给出了晶体塑性理论的数值实现的全部细节。然后将该理论用于研究一维和二维位错堆积的经典边值问题,以及约束条件下变形单晶条中边界层的发展。从案例研究中得出的主要理解是,当位错堆积或边界层随着变形而发展时,会产生几何上必要的位错,并导致与尺寸相关的总体行为。此外,还表明,在不存在以统计方式储存在自然界中的源或汇的情况下,堆积问题中的位错总数是保留的。一维堆积和条形单剪问题的数值预测结果与已发表的结果吻合较好。


Spherical Indentation and Implementation of S3/P for Yield Stress Determination of Brittle Materials

B.L. Hackett, A.A. Wereszczak, E.G. Herbert, G.M. Pharr

doi:10.1016/j.jmps.2024.105645

球面压痕及S3/P法在脆性材料屈服应力测定中的应用

A mathematically transparent and robust experimental method has been developed to estimate the yield stress of brittle materials through the analysis of depth-sensing spherical indentation. Employing Hertzian contact mechanics, an elastically invariant ratio based on the simple equation S3/P=6REr2, (where S and P are contact stiffness and indentation load, respectively) has been derived that enables more accurate and confident determination of the transition from elastic to inelastic deformation; a transition that the yield stress dictates and represents. Using two diamond spheres with radii of 3.2 and 8.6 μm, the indentation test method and analyses are applied to two vitreous silicates: Corning's HPFS 7980® fused silica and Vitro's Starphire® soda-lime silicate. The estimated yield strengths are 8.15 GPa ± 2.5% for the fused silica and 6.1 GPa ± 3.3% for the soda-lime silicate, and both were independent of indenter radius. Verification of this new experimental method is demonstrated with an as-drawn titanium by showing equivalence of measured yield stress by its spherical indentation and that from uniaxial compression testing. This method will enable easier and more confident estimation of yield stress in brittle materials - a property that historically has been elusive to measure for these materials using common laboratory mechanical test methods.

通过对深度感应球形压痕的分析,开发出一种数学上透明且稳健的实验方法,用于估算脆性材料的屈服应力。利用赫兹接触力学,基于简单方程 S3/P=6REr2(其中 S 和 P 分别为接触刚度和压痕载荷)推导出一个弹性不变比率,从而能够更准确、更可靠地确定从弹性变形到非弹性变形的过渡;屈服应力决定并代表了这种过渡。使用两个半径分别为 3.2 和 8.6 μm 的金刚石球,将压痕测试方法和分析应用于两种玻璃硅酸盐: 康宁公司的 HPFS 7980® 熔融石英和 Vitro 公司的 Starphire® 碱石灰硅酸盐。熔融石英的屈服强度估计值为 8.15 GPa ± 2.5%,钠钙硅酸盐的屈服强度估计值为 6.1 GPa ± 3.3%,两者均与压头半径无关。通过球形压痕测量的屈服应力与单轴压缩试验测量的屈服应力相等,用拉伸钛验证了这一新的实验方法。这种方法将使脆性材料的屈服应力估算变得更容易、更有把握,而使用普通实验室机械测试方法一直难以测量这些材料的屈服应力。


Energy Quantification Framework for Underwater Explosive loading into PVC Foam Cladded Composite Plates

Piyush Wanchoo, Akash Pandey, Matthew Leger, James LeBlanc, Arun Shuka

doi:10.1016/j.jmps.2024.105646

聚氯乙烯泡沫包覆复合板水下爆炸载荷能量量化框架

This paper presents a novel approach for analyzing the effects of near-field underwater blast loading on composite marine structures. The operational requirements of these structures often expose them to blast or shock loading, which can lead to significant damage. The study focuses on the propagation of spherical blast waves and the subsequent secondary bubble collapse pulse that affects the structure under near-field underwater blast loading events. An analytical framework is developed to calculate the blast energies and structural energies during this complex loading event. The study further investigates the effect of applying a sacrificial cladding made of low-density closed-cell foam to the loading face of a composite panel. Experiments were conducted in a specialized facility to characterize the explosive-driven blast-loading and the subsequent interaction between the shock pressure front and the structure. Dynamic pressure measurements and high-speed imaging were utilized to capture the behavior of the composite panel under these extreme conditions. 3D digital image correlation was employed to analyze strain and deformation of the composite panel, while high-speed side view cameras captured the fluid-structure interaction during the blast and bubble collapse loading event. The results strongly indicate that the collapse of the explosion bubble is the dominant failure source in near-field underwater blast loadings. The analytical quantification of energy further corroborates the significant damaging effects of bubble collapse due to the buildup of after-flow energies during the bubble collapse duration. Furthermore, the inclusion of low-impedance elastic-plastic PVC foam cladding is shown to significantly mitigate the effect of blast loading on the composite structure.

本文提出了一种分析近场水下爆炸载荷对海洋复合材料结构影响的新方法。这些结构的操作要求经常使它们暴露在爆炸或冲击载荷下,这可能导致严重的损坏。研究了近场水下爆炸载荷作用下,球形爆炸波的传播及其产生的二次气泡崩塌脉冲对结构的影响。建立了一个分析框架,用于计算这种复杂加载事件下的爆炸能量和结构能量。本研究进一步探讨了在复合材料板的加载面上应用低密度闭孔泡沫牺牲包层的效果。在一个专门的设施中进行了实验,以表征炸药驱动的爆炸载荷以及随后的冲击压力前沿与结构之间的相互作用。动态压力测量和高速成像技术被用于捕捉复合材料板在这些极端条件下的行为。采用三维数字图像相关分析复合材料板的应变和变形,高速侧视摄像机捕捉爆炸和气泡崩塌加载过程中的流固耦合过程。结果表明,在近场水下爆炸载荷中,爆炸泡的破裂是主要的破坏源。能量的分析量化进一步证实了由于气泡破裂期间后流能量的积累,气泡破裂的破坏效应显著。此外,低阻抗弹塑性聚氯乙烯泡沫包层的加入可以显著减轻爆炸载荷对复合材料结构的影响。


Mechanics of Materials

An FFT based adaptive grid framework to represent non-singular dislocations

Rodrigo Santos-Güemes, Gonzalo Álvarez, Javier Segurado

doi:10.1016/j.mechmat.2024.105004

基于FFT的自适应网格框架表示非奇异位错

Non-singular theories aim at regularizing the unrealistic stress singularity around a dislocation line predicted by elasticity by spreading the Burgers vector around the core. The use of these approaches in discrete dislocation models or field dislocation mechanics require very fine discretization around the dislocation lines. FFT solvers commonly used in these problems rely on a regular grid which enforces the use of very fine discretizations or very small domains. In this work, a methodology is proposed to solve the boundary value problems associated with dislocation modeling using FFT with an adaptive grid which is refined around dislocation cores. The framework introduces a regular domain to compute Fourier derivatives mapped to a physical domain with more points concentrated the areas of interest. The linear differential operators involved are obtained by the product of the Fourier derivatives in the regular space and the Jacobian of the map defining the transformation between computational and physical domains. The periodic boundary value problem involved is transformed in a linear system that can be efficiently solved using Krylov solvers. The method for adaptive FFT grids is fully general and can be applied to any other micromechanical problem. It is demonstrated that the method allows to use several grid points within the core region of 2D and 3D dislocations even using coarse discretizations, allowing to resolve the non-singular stress fields within this region and also strongly reducing the numerical noise. Moreover, the method allows to preserve the accuracy of the results in fine meshes by reducing the grid spacing up to four times.

非奇异理论的目的是通过在核心周围扩散伯格矢量来正则化弹性预测的位错线周围不现实的应力奇异性。在离散位错模型或场位错力学中使用这些方法需要在位错线周围进行非常精细的离散化。在这些问题中通常使用的FFT求解器依赖于规则网格,它强制使用非常精细的离散化或非常小的域。在这项工作中,提出了一种方法来解决与位错建模相关的边值问题,该方法使用FFT和围绕位错核心进行细化的自适应网格。该框架引入了一个规则域来计算傅立叶导数映射到一个物理域,该物理域有更多的点集中在感兴趣的区域。所涉及的线性微分算子由正则空间中的傅里叶导数与定义计算域与物理域之间变换的映射的雅可比矩阵的乘积得到。将所涉及的周期边值问题转化为一个线性系统,该系统可以用克雷洛夫求解器有效地求解。自适应FFT网格的方法是完全通用的,可以应用于任何其他微力学问题。结果表明,该方法允许在二维和三维位错的核心区域内使用多个网格点,即使使用粗离散化,也可以解决该区域内的非奇异应力场,并且可以有效地降低数值噪声。此外,该方法通过将网格间距减少四倍,可以在精细网格中保持结果的准确性。


Multiscale Finite Element Analysis of Layer Interface Effects on Cracking in Semi-Flexible Pavements at different temperatures

Xing Cai, Prabin Kumar Ashish, Pai Zheng, Zhen Leng, Minghui Gong, Jun Yang

doi:10.1016/j.mechmat.2024.105008

不同温度下半柔性路面层界面开裂影响的多尺度有限元分析

This paper presents comprehensive research work on the crack initiation behavior of Semi Flexible Pavements (SFP) with the help of a one-way coupled multiscale modelling approach. The study focuses on elucidating the influence of layer interface conditions on potential cracking patterns under different temperature conditions. By integrating material properties at both local (mixture) and global (pavement) scales using a local de-homogenization approach, the interlocking effect was addressed within the asphalt binder's mesoscale properties. CT-image based mesostructure was employed to reconstruct the Representative Volume Element (RVE). Cohesive Zone Model (CZM) was utilized to simulate cracking initiation within the RVEs, with simulation results validated against practical engineering inspections. Additionally, a potential macroscopic failure index was introduced for SFP. It was found that the typical macroscopic failure indexes utilized for AC pavement may not be suitable for SFP due to the higher degree of heterogeneity. Analysis showed that SFP layer’s coarse aggregate and cement grout at the bottom may experience compressive stress, while asphalt binder beneath the tire load may face high tensile stresses. Regardless of the interface conditions, top-down cracking was found to be the dominating failure mode in SFP. Besides, the vulnerable area in bonded interface SFP shifts from under tire load to the adjacent area with the rise in pavement temperature, while bottom-up cracking may appear only in unbonded interface SFP under low temperature conditions. Subsequent analysis demonstrated that top-down cracking is prominent in bonded interface SFP, especially at higher temperatures, compared to unbonded interface SFP. It is expected that critical observations for SFP highlighted above will certainly help in understanding critical failure modes and, hence, designing and constructing durable SFP structures.

本文利用单向耦合多尺度建模方法对半柔性路面的起裂行为进行了全面的研究。重点研究了不同温度条件下层间界面条件对潜在裂纹形态的影响。通过使用局部去均质化方法整合局部(混合)和全局(路面)尺度的材料特性,在沥青粘合剂的中尺度特性中解决了联锁效应。采用基于ct图像的细观结构重构代表体元(Representative Volume Element, RVE)。利用内聚区模型(CZM)对RVEs内部的裂缝萌生进行了模拟,仿真结果与实际工程检测结果进行了对比验证。此外,还引入了SFP的潜在宏观失效指标。研究发现,由于AC路面具有较高的非均质性,其典型宏观破坏指标可能不适用于SFP。分析表明,SFP层底部的粗骨料和水泥浆料可能承受压应力,而轮胎荷载下的沥青粘结剂可能承受较高的拉应力。无论界面条件如何,自顶向下开裂都是SFP的主要破坏模式。此外,随着路面温度的升高,有粘结界面SFP的脆弱区域在轮胎荷载作用下向相邻区域移动,而只有在低温条件下无粘结界面SFP才会出现自下而上的开裂。随后的分析表明,与非粘合界面SFP相比,粘合界面SFP中自上而下的开裂非常突出,特别是在较高温度下。预计上述对SFP的关键观察将有助于理解关键失效模式,从而设计和建造耐用的SFP结构。


International Journal of Plasticity

Fatigue Life Estimation of Nickel-Based Single Crystal Superalloy with Different Inclined Film Cooling Holes: Initial Damage Quantification and Coupling of Damage-Fracture Mechanics Models

Fei Li, Zhixun Wen, Lei Luo, Zhufeng Yue, Ziqi Zang, Meng Li, Zhenwei Li, Yanchao Zhao

doi:10.1016/j.ijplas.2024.103967

不同斜膜冷却孔镍基单晶高温合金疲劳寿命估算:初始损伤量化及损伤-断裂力学模型耦合

Quantitative assessment of the initial damage state of a structure and fatigue life prediction on this basis, especially when it is sensitive to manufacturing quality, is crucial for both engineering application and material science. Traditional solutions based on fracture or damage mechanics either require precise constitutive relationships and cumbersome physical mechanism models or simply ignore the initial damage state. This study developed a novel equivalent initial flaw size (EIFS) quantitative evaluation method for film cooling holes in Nickel-based single crystal superalloy turbine blades to address the strong correlation between the initial damage in and fatigue life of the material. The temperature and stress field differences at the edges of holes with different inclination angles were simulated using a solid-liquid-gas three-phase level-set model and considered to represent the same initial damage. Next, the coupled damage–fracture mechanics model was used to achieve equivalent crack insertion, crack propagation, and fatigue life prediction based on the EIFS. The results indicate that this method can provide a highly robust EIFS distribution interval and that the crack geometry correction factor and EIFS distribution range are weakly correlated with the loading conditions (with an error within 2%). The EIFS-based fatigue life predictions demonstrated a notable degree of accuracy, with the majority of the predicted and experimental fatigue lives falling within a three-fold dispersion band and all predictions remaining confined within a five-fold dispersion band of the actual lifetime. These results represent a substantial advancement in accuracy compared to traditional damage mechanics predictions. Therefore, this study provides a powerful approach for evaluating the fatigue life of turbine blades considering the initial damage state and can be widely applied to guide drilling process optimization and blade fatigue analysis.

在此基础上定量评估结构的初始损伤状态和疲劳寿命预测,特别是当它对制造质量敏感时,对工程应用和材料科学都至关重要。基于断裂或损伤力学的传统解决方案要么需要精确的本构关系和繁琐的物理机制模型,要么简单地忽略初始损伤状态。针对镍基单晶高温合金涡轮叶片的初始损伤与疲劳寿命之间存在很强的相关性,提出了一种新的等效初始缺陷尺寸(EIFS)定量评价方法。采用固液气三相水平集模型模拟不同倾角孔边缘温度场和应力场的差异,认为它们代表相同的初始损伤。其次,采用损伤-断裂耦合力学模型,实现等效裂纹插入、裂纹扩展和疲劳寿命预测。结果表明,该方法能够提供一个鲁棒性较强的EIFS分布区间,且裂纹几何修正系数和EIFS分布范围与加载条件的相关性较弱(误差在2%以内)。基于eifs的疲劳寿命预测显示出显著的准确性,大多数预测和实验疲劳寿命落在三倍色散带内,所有预测都局限在实际寿命的五倍色散带内。与传统的损伤力学预测相比,这些结果在精度上取得了实质性的进步。因此,本研究为考虑初始损伤状态的涡轮叶片疲劳寿命评估提供了强有力的方法,可广泛应用于指导钻井工艺优化和叶片疲劳分析。


Thin-Walled Structures

Buckling and free vibration of grid-stiffened composite conical panels using Extended Kantorovich Method

M.M. Mobasheri Zafarabadi, M.M. Aghdam, Aurelio L. Araujo

doi:10.1016/j.tws.2024.111845

应用扩展Kantorovich法分析网格加筋复合材料锥形板的屈曲和自由振动

This paper develops very accurate closed-form solutions for buckling and free vibration of grid-stiffened composite conical panels using a semi-analytical method. On the base of first-order shear deformation theory (FSDT), the governing formulations are derived while an appropriate unit cell is used to derive the material properties of the lattice from their bulk properties. Multiple systems of ordinary differential equations (ODEs) are obtained by applying the Extended Kantorovich Method (EKM) to solve the governing system of partial differential equations (PDEs). The resulting ODEs are then solved using semi-analytical closed-form solutions to study buckling and free vibration of grid-stiffened panels. It is interesting to note that due to the general formulation of the conical panel, it is very easy to obtain other useful geometries including cylindrical panels, and even rectangular plates with general unit cell configurations. Regarding stability, fast convergence, and very low computing cost, the effectiveness of the proposed technique is investigated. The accuracy of the critical buckling loads and natural frequencies for various cases is studied which shows very good agreement in comparison with results obtained from the commercial finite element code ANSYS.

本文用半解析方法给出了网格加筋复合材料锥形板屈曲和自由振动的精确解。在一阶剪切变形理论(FSDT)的基础上,导出了控制公式,并采用适当的单元格从其体性质推导出晶格的材料性质。应用扩展Kantorovich方法求解偏微分方程控制系统,得到了多个常微分方程系统。然后用半解析闭式解求解得到的ode,以研究网格加筋板的屈曲和自由振动。有趣的是,由于锥形面板的一般公式,很容易获得其他有用的几何形状,包括圆柱形面板,甚至具有一般单元格配置的矩形板。从稳定性、收敛速度快、计算成本低等方面考察了该方法的有效性。对各种情况下的临界屈曲载荷和固有频率的精度进行了研究,与ANSYS商用有限元软件的计算结果吻合得很好。


3D equivalent Cauchy model for serrated re-entrant auxetic honeycombs based on variational asymptotic method

Yujie Zhou, Yifeng Zhong, Yilin Zhu, Rong Liu

doi:10.1016/j.tws.2024.111883

基于变分渐近方法的锯齿状可重入型辅助蜂窝三维等效Cauchy模型

The presence of serrated ligaments in the re-entrant auxetic honeycomb (abbreviated as serrated RAH) effectively enhances the stiffness while maintaining auxeticity in the re-entrant direction. To investigate its auxetic characteristics, a 3D equivalent Cauchy model (3D-ECM) was established using the variational asymptotic method. The unique aspect is that the engineering constants are obtained by homogenizing the representative unit-cell and then utilized in the 3D-ECM for global analysis. Subsequently, the resulting global responses are fed into the recovery relationships for localized field analysis. The accuracy of the 3D-ECM and the recovered local field distributions were confirmed by comparing them with the results obtained from the three-dimensional FE model (3D-FEM) and the experimental data collected from the 3D-printed specimen. The effects of the geometric parameters on the negative Poisson’s ratio and engineering constants were in-depth discussed. Specifically, an optimal value of 0.5 for the re-entrant ratio and d-value (corresponding to the re-entrant angle of 90 degree) yield maximum auxeticity and comparatively higher elastic moduli. In addition, the 3D-ECM greatly enhanced the computational efficiency without compromising the accuracy in predicting global behaviors and local field distributions. The unit-cell tailorability in the proposed model offers valuable guidance for optimizing the design of serrated RAHs.

再入辅助蜂窝(简称锯齿状RAH)中锯齿状韧带的存在有效地提高了刚度,同时保持了再入方向的辅助性。利用变分渐近方法建立了三维等效Cauchy模型(3D- ecm)。其独特之处在于,工程常数是通过均质化代表性的单元获得的,然后在3D-ECM中用于全局分析。随后,将得到的全局响应输入到恢复关系中,用于局部场分析。通过与三维有限元模型(3D-FEM)和3d打印试样的实验数据进行比较,验证了3D-ECM和恢复的局部场分布的准确性。深入讨论了几何参数对负泊松比和工程常数的影响。具体而言,重入比和d值(对应90度重入角)的最优值为0.5时,可获得最大的弹性模量和较高的弹性模量。此外,3D-ECM在不影响预测全局行为和局部场分布精度的情况下,大大提高了计算效率。该模型的单元可定制性为优化锯齿状结构的设计提供了有价值的指导。


Experiments and investigation of planar high-strength steel joints with additive manufacturing

Senbin Huang, Xiaowei Deng

doi:10.1016/j.tws.2024.111887

平面高强钢接头增材制造试验与研究

This paper investigates the application of high-strength steel in planar steel joints, specifically X-joints and T-joints, which are crucial connecting components in structural engineering, ensuring structural stability in buildings, bridges, and tower cranes. Conventional steel joints, mainly constructed from low-carbon steel, encounter challenges arising from the low ductility of high-strength steel and its strict welding criteria. The Solid Isotropic Material with Penalization (SIMP) method is employed to perform topology optimization on X-joints with different brace width to chord width ratios and T-joints, enabling the manufacturing of high-strength steel components through the Additive Manufacturing method (AM). The impact of different additive manufacturing orientations on material strength is tested, with results indicating improved mechanical properties when the loading direction is perpendicular to the normal direction of the additive manufacturing layer. Compression tests are conducted using 2D/3D Digital Image Correlation methods (2D/3D-DIC) alongside traditional measurement techniques. The results indicate that the stress distribution of the optimized joint is more rational, and the strength of the optimized joint has improved compared to the tubular joint. The optimized joint exhibits a more distinct load path and apparent failure mode. This optimized joint enables a uniform stress redistribution, enhancing ductility and achieving a strong-joint and weak-component structural mechanism that satisfies the serviceability limit state (SLS). In comparison to non-penetrative tubular joints, no significant cracks are observed under identical loading conditions.

本文研究了高强钢在平面钢节点中的应用,特别是x形节点和t形节点,它们是结构工程中至关重要的连接构件,保证了建筑、桥梁和塔吊的结构稳定性。传统钢接头主要由低碳钢构成,高强钢的低延展性和严格的焊接标准使其面临挑战。采用固体各向同性材料惩罚法(SIMP)对不同支宽弦宽比的x形接头和t形接头进行拓扑优化,实现了增材制造技术(AM)制造高强度钢构件。测试了不同增材制造方向对材料强度的影响,结果表明,当加载方向垂直于增材制造层的法线方向时,材料的力学性能得到改善。压缩测试使用2D/3D数字图像相关方法(2D/3D- dic)和传统测量技术进行。结果表明:优化后的接头应力分布更为合理,强度较钢管接头有所提高;优化后的节点具有更明显的荷载路径和破坏模式。优化后的接头实现了均匀的应力再分布,增强了延性,实现了满足使用极限状态(SLS)的强接头弱构件结构机制。与非渗透管接头相比,在相同的荷载条件下,没有观察到明显的裂缝。



来源:复合材料力学仿真Composites FEM
ACTMechanicalAdditiveSystemFlux振动疲劳断裂复合材料拓扑优化通用建筑增材海洋焊接裂纹理论爆炸材料多尺度
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首次发布时间:2024-11-14
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【新文速递】2024年4月1日固体力学SCI期刊最新文章

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To overcome the strength-ductility trade-off dilemma, we designed a kind of metallic layered composites (LCs) consisting of nano-grained Ni (grain size: 21-37 nm) and ultrafine nano-grained Ni-W (grain size: 8 nm) constituent layers with layer thickness ranging from microns to tens of nanometers. We found that the strength and ductility of Ni/Ni-W LCs can be simultaneously enhanced by decreasing the layer thickness. Interface-constrained grain growth in the Ni layers with an initial layer thickness of less than 1 μm enhances strain hardening ability. Thus, strain delocalization characterized by the formation of rectangular strain zones instead of crossed micro shear bands appears in the LCs. Based on the above mechanism, we obtained the optimum ratio of the layer thickness to the grain size for the nano-grained Ni layers as about 15:1, which corresponds to Ni0.25/Ni-W0.025 LCs with the highest tensile strength (1.9 GPa) and elongation to failure (5.5%). 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Changes to the design of welded joints in Eurocode 3 are currently proposed that affect the resistance and stiffness of the components associated with the column web panel. This paper presents an assessment of the design formulations included in the current Eurocode 3, part 1-8, and its forthcoming update in terms of stiffness and moment resistance, compared against a large parametric study of strong-axis beam-column welded joints for open sections carried out using validated sophisticated FE models. The results show that both the old and new Eurocode formulations provide a large scatter and no big differences between both methods. Additionally, the presence of axial force in the column shows a clear increase in the ratio between design resistance vs numerical resistance that, particularly in the case of transversally stiffened joints, may be unconservative.经过适当验证的高质量有限元 (FE) 模型与实验测试可以准确描述钢接头的载荷变形路径和应力状态,如今已被公认为 "实验结果"。目前,欧洲规范 3 对焊接接头的设计提出了修改建议,这将影响与柱腹板相关部件的阻力和刚度。本文介绍了对现行 Eurocode 3 第 1-8 部分及其即将更新的刚度和抗弯矩设计方案的评估,并与使用经过验证的复杂 FE 模型对开放截面的强轴梁-柱焊接接头进行的大型参数研究进行了比较。研究结果表明,新旧欧洲规范的计算方法存在较大差异,两种方法之间没有明显区别。此外,柱中轴向力的存在明显增加了设计阻力与数值阻力之间的比率,特别是在横向加固接头的情况下,这可能是不可靠的。Experimental and numerical investigation of through-diaphragm in H-shaped steel beam to CFST column connectionsYongHyun Cho, Fangying Wang, SooYeon Seo, KangSeok Lee, TaeSoo Kimdoi:10.1016/j.tws.2024.111852H 型钢梁与 CFST 柱连接中贯穿隔膜的实验和数值研究This research proposes a cruciform through-diaphragm (CTD) for an H-shaped steel beam to concrete-filled steel tubular (CFST) column and investigates its seismic performance experimentally and numerically. The proposed connection consists of through-plates passing through the aligned slots in the panel zone and end plates directly welded to an H-shaped steel beam. This connection eliminates welding inside the steel tube for installation of the diaphragm, while providing a reliable load path from the steel beam to the CFST column. The experimental program examined the connection hysteretic behaviors, including the moment-rotation response, ductility, initial stiffness, and energy dissipation capacity. The proposed connection shows stable hysteric behavior and good energy dissipation up to a story drift up to 4% and satisfies the AISC seismic provisions criteria for special moment connection. A finite element (FE) model was established and verified against the experimental results. The effects of concrete infill, steel tube column thickness, axial load ratio, and through-plate thickness on the hysteretic behavior of the proposed connection were investigated through parametric analysis of 24 FE models. This study provides the information on the optimized design parameters that ensures the stable seismic performance of the proposed connection that could be used in structural engineering practice.本研究提出了一种用于 H 型钢梁与混凝土填充钢管(CFST)柱的十字形贯穿隔膜(CTD),并对其抗震性能进行了实验和数值研究。拟议的连接由穿过面板区对齐槽的通板和直接焊接到 H 型钢梁上的端板组成。这种连接方式省去了在钢管内焊接安装隔膜的工序,同时提供了从钢梁到 CFST 柱的可靠载荷路径。实验程序检查了连接的滞后行为,包括力矩旋转响应、延展性、初始刚度和耗能能力。拟议的连接显示出稳定的滞回行为和良好的消能能力,可承受高达 4% 的楼层漂移,并满足 AISC 抗震规定中关于特殊弯矩连接的标准。建立了一个有限元(FE)模型,并根据实验结果进行了验证。通过对 24 个有限元模型进行参数分析,研究了混凝土填充、钢管柱厚度、轴向荷载比和通板厚度对拟议连接滞回行为的影响。这项研究提供了优化设计参数的信息,以确保所提连接具有稳定的抗震性能,可用于结构工程实践。来源:复合材料力学仿真Composites FEM

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