今日更新：International Journal of Solids and Structures 1 篇，Mechanics of Materials 1 篇，International Journal of Plasticity 2 篇，Thin-Walled Structures 4 篇International Journal of Solids and StructuresEnergy absorption of Kresling pattern thin-walled structures with pre-folded patterns and graded stiffnessXiaolei Wang, Haibo Qu, Buqin Hu, Haoqian Wang, Wenju Liu, Sheng Guodoi:10.1016/j.ijsolstr.2024.113057具有预折叠图样和梯度刚度的Kresling薄壁结构的能量吸收Traditional thin-walled structures are widely employed in several energy-absorbing engineering fields, and origami patterns inspire novel structures with unique functionalities in this area. In this study, we explore energy-absorbing effects of origami-inspired thin-walled structures from perspective of the predicted stability of the Kresling origami. Our research utilizes finite element analysis and experimental validation to evaluate and contrast the energy-absorbing effects of the Kresling origami-inspired thin-walled structures (KOI-TWSs) with a traditional hexagonal thin-walled structure (HTWS). The results indicate that introducing the Kresling origami pattern into the thin-walled structure to obtain geometric defects (pre-folded pattern) and graded stiffness, and their effects are reflected in improving the buckling deformation stability or reducing the initial peak force. These effects depend on the predicted stability of the Kresling origami and are intuitively reflected in the geometric parameters. On the other hand, the reusability of materials is worth considering for improving the energy absorption of the thin-walled structures. These works provide new contents and perspectives for the KOI-TWSs.传统薄壁结构广泛应用于吸能工程领域，折纸图案激发了具有独特功能的新型结构。在本研究中，我们从Kresling折纸的预测稳定性角度探讨了折纸启发薄壁结构的吸能效应。本研究利用有限元分析和实验验证对Kresling折纸薄壁结构(KOI-TWSs)和传统六边形薄壁结构(HTWS)的吸能效果进行了评价和对比。结果表明，在薄壁结构中引入Kresling折纸图案可获得几何缺陷(预折叠图案)和梯度刚度，其作用体现在提高屈曲变形稳定性或降低初始峰值力上。这些影响取决于克雷斯林折纸的预测稳定性，并直观地反映在几何参数中。另一方面，为了提高薄壁结构的吸能，材料的可重复使用性值得考虑。这些工作为KOI-TWSs提供了新的内容和视角。Mechanics of MaterialsCorrelation between the ratio between the tensile and shear yield strength on porosity evolution in isotropic ductile materialsKarl R. Knaak, Oana Cazacu, Benoit Revil-Baudarddoi:10.1016/j.mechmat.2024.105150各向同性韧性材料抗拉屈服强度与抗剪屈服强度之比与孔隙度演化的关系In this paper, we investigate the dilatational response of porous solids with matrix plastic behavior governed by Cazacu (2018) yield criterion that involves both invariants of the stress deviator, the relative weight of these invariants being described by a parameter . This parameter depends only on the ratio between the shear and tensile strengths; for = 0, = and the von Mises criterion is recovered. For both compressive and tensile loadings, FE unit-cell simulations were conducted at fixed stress triaxialities and various ordering of the principal stresses, namely loadings such that = 0 and axisymmetric loadings such that > 0 and < 0, respectively. Irrespective of the material’s ratio, there is a combined effect of the sign of the mean stress and on the dilatational response. The value of the ratio dictates the rate at which the porosity evolves. Under axisymmetric tensile loadings, for a material with < the rate of void growth is faster than for a porous von Mises material, the reverse holds true for a material with > . For axisymmetric compressive loadings, the larger is the ratio of the material, the slower is the rate at which porosity closes. For loadings at = 0 materials with < exhibit slower rate of void growth or void collapse than for axisymmetric loadings, the opposite being true for materials with > .在本文中，我们研究了具有基体塑性行为的多孔固体的膨胀响应，该响应受Cazacu(2018)屈服准则的约束，该准则涉及应力偏差的两个不变量，这些不变量的相对权重由参数描述。该参数仅取决于剪切强度与拉伸强度之比;为= 0，=，恢复von Mises判据。对于压缩和拉伸加载，有限元单元格模拟分别在固定应力三轴性和不同主应力顺序下进行，即加载= 0和轴对称加载> 0和< 0。无论材料的比例如何，平均应力的符号和膨胀响应都有共同的影响。比值的值决定了孔隙度演化的速率。在轴对称拉伸载荷下，孔隙生长速率<的材料比多孔的von Mises材料更快，而>的材料则相反。对于轴对称压缩载荷，材料的比例越大，孔隙率闭合的速度越慢。对于= 0加载，<的材料表现出比轴对称加载更慢的空穴生长或空穴塌陷速率，>的材料则相反。International Journal of PlasticityTailoring Mechanical Properties of Pearlitic Steels through Size Regulation of Multiscale Microstructures: Experiments and SimulationsXutao Huang, Yinping Chen, Jianjun Wang, Wenxin Wang, Gang Lu, Sixin Zhao, Qian Li, Yujie Liu, Chunming Liudoi:10.1016/j.ijplas.2024.104110 珠光体钢多尺度显微组织尺寸调节的机械性能:实验与模拟Pearlitic steels possess excellent mechanical properties due to their multiscale microstructures, yet this configuration introduces complex size and interface effects, impeding the elucidation of their microscopic deformation mechanisms. In this study, a predictive framework that combines a high-resolution reconstruction algorithm with a strain gradient crystal plasticity model was developed to investigate the relationship between local deformation behaviors in nodules, colonies, and lamellae of various sizes and their mechanical properties. This approach effectively reconstructs the multiscale structure of pearlite and accurately tracks the dynamic mechanical responses. The integrated experimental and computational findings highlight the critical role of microstructure size in regulating strain delocalization and dislocation dynamics, which, through strain partitioning and interface density, are vital for optimizing mechanical properties. Notably, a decrease in lamellar spacing and nodule size significantly enhances both strength and toughness, while smaller nodules and colonies promote increased plasticity. Finally, a dual-parameter Hall-Petch equation incorporating lamellar spacing and nodule size is introduced, enabling precise quantification of the impact of all microstructures in pearlite on mechanical properties with robust predictive capabilities.珠光体钢由于其多尺度微观结构而具有优异的力学性能，但这种结构引入了复杂的尺寸和界面效应，阻碍了其微观变形机制的阐明。本研究开发了一个结合高分辨率重建算法和应变梯度晶体塑性模型的预测框架，以研究不同尺寸的结核、菌落和片层的局部变形行为与其力学性能之间的关系。该方法有效地重建了珠光体的多尺度结构，准确地跟踪了动态力学响应。综合实验和计算结果强调了微观结构尺寸在调节应变离域和位错动力学方面的关键作用，这些作用通过应变分配和界面密度对优化力学性能至关重要。值得注意的是，减少片层间距和结核尺寸可显著提高强度和韧性，而较小的结核和集落可提高塑性。最后，引入了包含片层间距和结核尺寸的双参数Hall-Petch方程，可以精确量化珠光体中所有微观结构对力学性能的影响，并具有强大的预测能力。Atomistic analysis of the mechanisms underlying irradiation-hardening in Fe–Ni–Cr alloysA. Ustrzycka, F.J. Dominguez-Gutierrez, W. Chromińskidoi:10.1016/j.ijplas.2024.104118Fe-Ni-Cr合金辐照硬化机理的原子分析This work presents a comprehensive examination of the physical mechanisms driving hardening in irradiated face-centered cubic FeNiCr alloys. The evolution of irradiation-induced defects during shear deformation is modeled by atomistic simulations through overlapping cascade simulations, where the nucleation and evolution of dislocation loops is validated by transmission electron microscopy images obtained from irradiated FeNiCr alloys using tandem accelerator. The effect of different shear rates on the microstructure of irradiated materials with a specific focus on the changes in the density of voids and dislocation loops induced by irradiation was analyzed. Additionally, the fundamental interaction processes between single irradiation-induced defects contributing to irradiation hardening, such as voids and dislocation loops in the alloy are explained. The analysis at atomic level indicates that both the dislocation loops and the voids exhibit strengthening effects. Furthermore, the nanometric voids are much stronger obstacles than dislocation loops of comparable size. The mechanism of cutting the voids leads to an increase of voids density and thus contributes to an increase in irradiation hardening. The mechanism of collapse of small voids into dislocation loops leads to decrease of voids density and at the same time increase of loops density. The coupling effect between the density of voids and dislocation loops is determined. Finally, the novel, physical mechanisms-based model of irradiation hardening and dislocation-radiation defect reaction kinetics are developed, which consider the mechanisms of void cutting, void shrink and void collapse to dislocation loop.这项工作提出了一个全面的物理机制驱动硬化在辐照面心立方FeNiCr合金。在剪切变形过程中，辐照诱导缺陷的演变通过重叠级联模拟的原子模拟来模拟，其中位错环的成核和演变通过使用串联加速器从辐照FeNiCr合金中获得的透射电子显微镜图像来验证。分析了不同剪切速率对辐照材料微观结构的影响，重点分析了辐照引起的空洞和位错环密度的变化。此外，还解释了导致辐照硬化的单一辐照缺陷(如合金中的空洞和位错环)之间的基本相互作用过程。在原子水平上的分析表明，位错环和空洞都表现出强化作用。此外，纳米级的空洞比同等尺寸的位错环具有更强的障碍。切割孔洞的机制导致孔洞密度增加，从而导致辐照硬化的增加。小孔洞坍缩成位错环的机制导致孔洞密度减小，同时导致位错环密度增大。确定了孔隙密度与位错环之间的耦合效应。最后，建立了基于物理机制的辐照硬化和位错-辐射缺陷反应动力学模型，该模型考虑了空穴切削、空穴收缩和空穴坍缩到位错环的机理。Thin-Walled StructuresTheoretical study of extracting modal frequencies and hinge joint stiffness for thin-walled assembled multi-girder bridges from 3D vehicleBaoquan Wang, Yan Zeng, Dongming Fengdoi:10.1016/j.tws.2024.112429薄壁拼装多梁桥三维车辆模态频率和铰节点刚度提取的理论研究This paper presents a theoretical framework for extracting the modal frequencies of thin-walled assembled multi-girder bridges (AMGBs), which are widely adopted in small- and medium-span highway bridges, using the dynamic response of a three-dimensional (3D) moving vehicle. For the first time, closed-form solutions for the responses of the bridge and contact point (CP) are derived when the test vehicle passes through the AMGB. Based on the derived CP response, a guiding procedure for retrieving the modal frequency and hinge joint stiffness of the bridge is proposed. The correctness of the analytical solutions for the CP response and the reliability of the bridge frequency identification are verified through numerical examples. Additionally, the robustness of the proposed technique is examined under various influence factors. The results show that maintaining a moderate vehicle speed can balance the accuracy and efficiency of the bridge frequency identification. The damping of vehicle tires has a small effect on frequency extraction using the CP response, while an increase in bridge damping ratio diminishes the visibility of its frequencies. Nevertheless, for the investigated bridge damping ratios, the effectiveness remains satisfactory, as the first four frequencies still being discernible. The residual contact response of the front and rear wheels can effectively eliminate the masking effect of pavement roughness, thereby enhancing the frequency extraction effect. Furthermore, the proposed method exhibits strong robustness against measurement noise.本文提出了一种基于三维运动车辆动力响应的薄壁拼装多梁桥模态频率提取的理论框架。薄壁拼装多梁桥在中小跨公路桥梁中得到广泛应用。首次推导了试验车辆通过AMGB时桥梁和接触点(CP)响应的封闭解。基于推导出的CP响应，提出了一种检索桥梁模态频率和铰节点刚度的指导程序。通过算例验证了CP响应解析解的正确性和桥梁频率识别的可靠性。此外，在各种影响因素下检验了所提出技术的鲁棒性。结果表明，保持适度车速可以平衡桥梁频率识别的准确性和效率。车辆轮胎阻尼对利用CP响应提取频率的影响较小，而桥梁阻尼比的增加会降低其频率的可见性。然而，对于所研究的桥梁阻尼比，有效性仍然令人满意，因为前四个频率仍然是可识别的。前后轮残余接触响应可以有效消除路面粗糙度的掩蔽效应，从而增强频率提取效果。此外，该方法对测量噪声具有较强的鲁棒性。Seismic performance of ultra-high performance concrete-filled FRP tube composite columns reinforced with SFCBs: Test and modelingZhiwen Zhang, Ashraf Ashour, Wenjie Gedoi:10.1016/j.tws.2024.112430sfcb加固超高性能FRP混凝土筒复合柱抗震性能试验与建模To reduce residual deformation and address corrosion issues, this paper introduces a novel type of composite columns, utilizing ultra-high performance concrete (UHPC)-filled fiber reinforced polymer (FRP) tubes (UHPC-FFT) and reinforced with steel-FRP composite bars (SFCBs). The seismic performance of the proposed SFCB-reinforced UHPC-FFT composite columns was evaluated through pseudo-static experiments and numerical analysis in comparison with those of traditional composite columns. Results indicated that the UHPC-FFT composite columns reinforced with SFCB exhibited larger energy dissipation compared with those reinforced with either steel or FRP bars. Increasing the axial compression ratio from 0.15 to 0.25 enhance load-bearing capacity but reduces ductility and energy dissipation. Increasing the yield strength of internal steel bar of SFCBs can improve the load-bearing capacity and deformation of the columns without affecting the ductility, initial stiffness, and stiffness degradation rate. Increasing the elastic modulus of out-wrapped FRP of SFCBs enhanced the seismic performance of UHPC-FFT composite columns but could lead to premature failure due to FRP rupture. It is recommended to set an elastic modulus for the outer FRP wrap at 55 GPa for optimal seismic performance in UHPC-FFT composite columns.为了减少残余变形和解决腐蚀问题，本文介绍了一种新型的复合柱，利用超高性能混凝土(UHPC)填充纤维增强聚合物(FRP)管(UHPC- fft)和钢-FRP复合筋(SFCBs)加固。通过拟静力试验和数值分析，与传统组合柱的抗震性能进行了比较，评价了所提出的sfcb - UHPC-FFT组合柱的抗震性能。结果表明:SFCB加筋的UHPC-FFT组合柱比钢筋和FRP筋的组合柱耗能更大;将轴压比由0.15提高到0.25，可提高承载能力，但会降低延性和耗能。提高sfcb内钢筋屈服强度可以在不影响延性、初始刚度和刚度退化率的情况下提高柱的承载能力和变形量。提高sfcb外包FRP的弹性模量，提高了UHPC-FFT复合柱的抗震性能，但可能导致FRP断裂而过早破坏。为使UHPC-FFT复合柱抗震性能最佳，建议将FRP外膜弹性模量设置为55gpa。Local buckling and capacities of stainless steel hexagonal hollow sections under axial compressionYukai Zhong, Ke Jiang, Andi Su, Jiyang Fu, Airong Liu, Ou Zhaodoi:10.1016/j.tws.2024.112431不锈钢六角形空心截面在轴压作用下的局部屈曲和承载力This paper presents experimental and numerical investigations into the local buckling behaviour and capacities of stainless steel hexagonal hollow sections. A testing programme, including tensile coupon tests, initial local geometric imperfection measurements and fifteen stub column tests, was firstly carried out. The key test results, including failure loads, load–end shortening curves and failure modes, were reported. Subsequently, a numerical modelling programme was conducted, where finite element models were developed and validated against the test results and then used to conduct parametric studies to generate additional numerical data. The obtained test and numerical data were used to evaluate the relevant local buckling design rules specified in the European code, American specification and ASCE standard. The evaluation results revealed that the slenderness limits, as defined in the European code and American specification, were generally accurate and safe when used for cross-section classification of stainless steel hexagonal hollow sections, while the ASCE slenderness limit was unsafe. The European code and American specification resulted in overall accurate and consistent cross-section compression resistance predictions, but the predictions for non-slender cross-sections were conservative and scattered, due to the neglect of material strain hardening. The ASCE standard led to overall scattered and relatively conservative cross-section compression resistance predictions, but also with some unsafe predictions for those intermediate cross-section sizes due mainly to the unsafe slenderness limit. Finally, a revised ASCE design approach was proposed and shown to result in more accurate predictions of cross-section classification and resistances.本文对不锈钢六角空心截面的局部屈曲行为和屈曲能力进行了实验和数值研究。首先进行了一套测试程序，包括张轴试验、初始局部几何缺陷测量和15根短柱试验。报告了主要试验结果，包括破坏荷载、荷载-端缩短曲线和破坏模式。随后，进行了数值模拟程序，其中开发了有限元模型，并根据测试结果进行验证，然后用于进行参数研究，以生成额外的数值数据。利用所获得的试验和数值数据，对欧洲规范、美国规范和ASCE标准中有关的局部屈曲设计规则进行了评价。评价结果表明，欧洲规范和美国规范定义的长细限值用于不锈钢六角形空心截面分类时，总体上是准确和安全的，而ASCE长细限值则不安全。欧洲规范和美国规范对截面抗压抗力的预测总体上是准确一致的，但对非细长截面的预测由于忽略了材料的应变硬化而较为保守和分散。ASCE标准对截面抗压性能的预测总体上较为分散和保守，但对中间截面尺寸的预测也存在一定的不安全，主要是由于长细限值的不安全。最后，提出了一种改进的ASCE设计方法，并证明该方法可以更准确地预测截面分类和阻力。Fatigue test and evaluation of U-rib butt welds in orthotropic steel decksDengke Zhang, Chuang Cui, Shijin Qiu, Qinghua Zhang, Ye Ludoi:10.1016/j.tws.2024.112432正交各向异性钢甲板u形肋对接焊缝疲劳试验与评价U-rib butt weld cracking is one of the most typical fatigue failure modes of orthotropic steel decks (OSDs), which directly endangers the safety of bridges. Since the on-site quality of butt welds is difficult to guarantee, manufacturing defects are an important factor affecting fatigue performance. A full-scale OSD section specimen was manufactured with a real process, and the force characteristics and fatigue stress history of U-rib butt welds were investigated, and the fatigue crack growth characteristics were analyzed. A finite element model (FEM) was developed to extract the structural stress components of typical failure modes, and the equivalent structural stress method was used to quantify the effect of manufacturing defect sizes on the failure modes and fatigue life of U-rib butt welds. The results showed that the fatigue strength of U-rib butt welds was evaluated to be 125.1 MPa (corresponding to 4.6 million load cycles) using the equivalent structural stress method. When the radius of defect R < 1.25 mm, the fatigue cracking mode is weld toe cracking; when R > 1.25 mm, the fatigue cracking mode is internal defect cracking, which has a significant effect on the fatigue life.u型肋对接焊缝开裂是正交各向异性钢桥面最典型的疲劳破坏形式之一，直接危及桥梁的安全。由于对接焊缝的现场质量难以保证，制造缺陷是影响疲劳性能的重要因素。采用真实工艺制作了全尺寸OSD截面试样，研究了u肋对接焊缝的受力特性和疲劳应力历史，并分析了其疲劳裂纹扩展特征。建立有限元模型，提取典型失效模式的结构应力分量，采用等效结构应力法量化制造缺陷尺寸对u肋对接焊缝失效模式和疲劳寿命的影响。结果表明:采用等效结构应力法计算u肋对接焊缝的疲劳强度为125.1 MPa(对应460万次载荷循环);当缺陷半径R < 1.25 mm时，疲劳开裂方式为焊趾开裂;当R > 1.25 mm时，疲劳开裂方式为内部缺陷开裂，对疲劳寿命影响显著。来源：复合材料力学仿真Composites FEM
