【新文速递】2024年2月25日固体力学SCI期刊最新文章

今日更新：International Journal of Solids and Structures 1 篇，Thin-Walled Structures 5 篇International Journal of Solids and StructuresHomogenization of 3D laminated micro-structures including bending effectsİzzet Özdemirdoi:10.1016/j.ijsolstr.2024.112723包括弯曲效应在内的三维层状微结构均质化In this paper, a homogenization method which captures intrinsic size effect associated with fiber diameter is revisited and adapted for three-dimensional laminated micro-structures. Based on a unit-cell composed of matrix and reinforcement layers, enhanced deformation gradients varying through the thickness, are introduced with the aid of an additional kinematic variable reflecting the difference between the homogenized and constituent level deformation gradients. In the current work, as opposed to the original formulation, higher order terms are preserved for both phases and therefore bending stiffness of the matrix phase can be taken into account as well. The formulation is implemented within the commercial finite element solver Abaqus through user element (UEL) subroutine considering a finite strain hyperelastic response for the reinforcement layers and a von Mises type hyper-elastoplastic one for the matrix phase. An explicitly discretized unit-cell with varying reinforcement phase fraction, layer inclination angle and layer thicknesses are used as a reference to assess the predictive capabilities of the homogenized model and the significance of bending stiffness of the phases. Similarly, explicitly discretized model of a beam type structure with a crossed lamellar micro-structure is used to evaluate the performance of the homogenized model under more general, non-periodic boundary conditions. The findings of both cases support the effectiveness of the homogenized model.本文重新探讨了一种捕捉与纤维直径相关的内在尺寸效应的均质化方法，并将其应用于三维层状微结构。基于由基体层和增强层组成的单元格，借助反映均质化变形梯度和成分层变形梯度之间差异的附加运动变量，引入了随厚度变化的增强变形梯度。在目前的工作中，与原始公式不同的是，两个阶段都保留了高阶项，因此基体阶段的弯曲刚度也可以考虑在内。考虑到加固层的有限应变超弹性响应和基体相的 von Mises 型超弹性响应，该公式通过用户单元 (UEL) 子程序在商用有限元求解器 Abaqus 中实现。一个明确离散化的单元单元具有不同的加固相分数、层倾角和层厚度，用来评估均质化模型的预测能力和各相弯曲刚度的重要性。同样，我们还使用了具有交叉层状微结构的梁式结构的显式离散模型，以评估均质化模型在更一般的非周期性边界条件下的性能。这两种情况的研究结果都证明了均质化模型的有效性。Thin-Walled StructuresCompressive Behaviour of Locally Corroded Steel Tubular Members under Eccentric LoadsThong M. Pham, Ee-Fang Ong, Tung T. Tran, Yan Zhuge, Khuong L. Nguyen, Long Nguyen-Minhdoi:10.1016/j.tws.2024.111742偏心荷载下局部腐蚀钢管构件的抗压行为This paper investigated the compressive behaviour of locally corroded steel tubular members under both concentric and eccentric loads, revealing insights into the effects of corrosion thickness and patch angle on failure and buckling behaviour. A direct relationship between corrosion thickness and structural integrity was found in this study, highlighting the significant impact of corrosion on the columns. Moreover, the patch angle's influence on buckling and failure modes emphasises the role of geometric considerations in evaluating these members. Notably, an evident linear reduction in loading capacity occurs as the patch angle increases, irrespective of loading conditions, underscoring the need to account for geometric factors. In addition, even minor eccentricities lead to a substantial decrease in the compressive capacity, further emphasizing the vulnerability of corroded structures. By comparing the effects of corroded patch angle and depth on capacity reduction, the study underscores a steeper reduction gradient with patch angle. The established linear relationships between volume loss due to corrosion damage, centroid shifted distance, and ultimate compressive load capacity provide valuable insights for capacity prediction. Moreover, this study evaluates the applicability of conventional prediction methods like AS 4100:2020, which tends to overestimate critical load capacity for locally patch-corroded members. As an alternative, a proposed formula is presented, exhibiting enhanced accuracy with lower errors compared to existing models.本文研究了局部腐蚀钢管构件在同心和偏心载荷作用下的抗压行为，揭示了腐蚀厚度和补丁角度对破坏和屈曲行为的影响。研究发现，腐蚀厚度与结构完整性之间存在直接关系，凸显了腐蚀对支柱的重大影响。此外，贴片角度对屈曲和失效模式的影响强调了几何因素在评估这些构件中的作用。值得注意的是，无论加载条件如何，随着贴片角度的增大，加载能力都会出现明显的线性下降，这强调了考虑几何因素的必要性。此外，即使是微小的偏心也会导致抗压能力大幅下降，这进一步强调了腐蚀结构的脆弱性。通过比较腐蚀斑块角度和深度对承载力降低的影响，研究强调了随着斑块角度的增加，承载力降低的梯度也会增加。腐蚀损伤导致的体积损失、中心偏移距离和极限抗压承载力之间的线性关系为承载力预测提供了宝贵的见解。此外，本研究还评估了 AS 4100:2020 等传统预测方法的适用性，这些方法往往会高估局部斑块腐蚀构件的临界承载能力。作为一种替代方法，本研究提出了一种拟议公式，与现有模型相比，该公式精度更高、误差更小。Multi-scale simulation of residual stress and deformation of large-size hollow parts fabricated by laser-based powder bed fusionKun Li, Ming Zhang, Yaqing Hou, Yingjie Wu, Chen Ji, Jianhao He, Peng Jin, Daijian Wu, Liang Zhudoi:10.1016/j.tws.2024.111743基于激光的粉末床熔融技术对大尺寸空心零件的残余应力和变形进行多尺度模拟Hollow structures are widely used in aerospace, automotive, and other fields. Laser-based powder bed fusion (LB-PBF) enables the fabrication of complex parts. However, residual stresses and deformations present challenges for manufacturing high-quality components. This study proposes a modified inherent strain method (MISM) coupled with shear strain and dynamic mechanical properties to capture the asymmetric deformation behavior of the parts. The asymmetric deformation behavior was verified by two typical geometric structure parts, which demonstrated the generality of the phenomenon. The excellent agreement between the experimental and predicted results proved the validity of the extended model. Based on the asymmetric deformation, the effect of different geometries on the stresses was investigated. The results showed that the geometry of the parts affects the stress distribution and magnitude. The proposed numerical model can accurately predict the stress components of the parts, which is helpful to further investigate crack extension and damage in complex thin-walled parts.中空结构广泛应用于航空航天、汽车和其他领域。激光粉末床熔融技术（LB-PBF）可以制造复杂的部件。然而，残余应力和变形是制造高质量部件的挑战。本研究提出了一种改进的固有应变方法（MISM），结合剪切应变和动态机械性能来捕捉零件的非对称变形行为。两个典型的几何结构零件验证了非对称变形行为，证明了这一现象的普遍性。实验结果与预测结果的良好一致性证明了扩展模型的有效性。在非对称变形的基础上，研究了不同几何结构对应力的影响。结果表明，零件的几何形状会影响应力的分布和大小。所提出的数值模型可以准确预测零件的应力分量，有助于进一步研究复杂薄壁零件的裂纹扩展和损伤。Nonlocal strain gradient analysis of honeycomb sandwich nanoscale platesP. Phung-Van, H. Nguyen-Xuan, P.T. Hung, M. Abdel-Wahab, Chien H. Thaidoi:10.1016/j.tws.2024.111746蜂窝夹层纳米板的非局部应变梯度分析Honeycomb structures, which are known for being lightweight and stiff, are still being researched and developed. They have been used in a wide range of industries, but their full potential has not yet been realized. In this study, a novel computational approach for exploring the size-dependent behaviors of auxetic honeycomb sandwich nanoplates is developed. The proposed approach employs a nonlocal strain-gradient isogeometric analysis integrating the influences of nonlocality and strain gradient into the nanoplate structures. The sandwich nanoplate consists of a core layer featuring an auxetic honeycomb with a negative Poisson's ratio, complemented by two outer skin layers reinforced with graphene nanoplatelets (GNPs). This configuration not only achieves exceptional lightweight characteristics through the utilization of auxetic honeycomb cells but also enhances structural stiffness by incorporating GNPs into the skin layers. The material properties of the core layer are determined using cellular cell formulas, while the reinforcement of the two outer skin layers with GNPs is calculated using the modified Halpin-Tsai model. Numerous numerical examples are conducted to investigate the influence of various parameters on the frequencies of the auxetic honeycomb sandwich nanoplates. Notably, the geometrical dimensions of the auxetic honeycomb cells and the nonlocal and length scale parameters emerge as significant influencers on the results. As the first analysis of honeycomb structures at small dimensions, our findings stand as valuable benchmarks for future analyses.蜂窝结构以重量轻、刚度大而著称，目前仍在研究和开发中。它们已被广泛应用于各行各业，但其潜力尚未得到充分发挥。本研究开发了一种新型计算方法，用于探索辅助蜂窝夹层纳米板的尺寸相关行为。该方法采用非局部应变梯度等几何分析，将非局部性和应变梯度的影响整合到纳米板结构中。夹层纳米板由一个具有负泊松比的辅助蜂窝芯层和两个用石墨烯纳米板（GNPs）加固的外表层组成。这种结构不仅通过利用辅助蜂窝单元实现了优异的轻质特性，还通过在表皮层中加入 GNPs 增强了结构刚度。芯层的材料特性是通过蜂窝单元公式确定的，而使用 GNPs 加固两个外表层则是通过改进的 Halpin-Tsai 模型计算的。通过大量数值示例研究了各种参数对辅助蜂窝夹层纳米板频率的影响。值得注意的是，辅助蜂窝单元的几何尺寸以及非局部和长度尺度参数对结果产生了重要影响。作为对小尺寸蜂窝结构的首次分析，我们的研究结果为未来的分析提供了宝贵的基准。Progressive Collapse Analysis on Modular Steel Construction Based on a Simplified Joint ModelLiang Zong, Wanquan Fang, Yichi Zhang, Jian Cuidoi:10.1016/j.tws.2024.111733基于简化连接模型的模块化钢结构渐进式坍塌分析Modular steel construction (MSC), as a kind of highly prefabricated assembly building, has the advantages of high industrialization, perfect energy saving and great being environmentally friendly. Due to the special characteristics of its detail construction, there is an urgent need to study its progressive collapse resistance performance. Based on the experimental and refined simulating results, a simplified model of inter-module connection was proposed and shown to be accurate enough for capturing the collapse properties of the MSC by comparing with a sub-structure push-down test. Then the collapse responses of a typical four-story, nine-span MSC under different local failure conditions were intensively studied using the proposed model. The MSC survived in the local failure scenarios of the side-columns, the corner-columns or even the mid-modular unit. However, in the scenario of side-modular unit failure, the inter-module connections of all four stories were damaged due to excessive overturning moments, leading to the collapse of the span where the unit fails. Nevertheless, the rest part of MSC still did not collapse. Therefore, it can be concluded that the modular steel construction with inter-module connections by bolts and shear keys has good performance on progressive collapse resistance. Moreover, further research into this type of inter-module connection would be worthwhile.装配式钢结构（MSC）作为一种高度预制的装配式建筑，具有工业化程度高、节能效果好、非常环保等优点。由于其细部构造的特殊性，迫切需要对其抗逐步倒塌性能进行研究。在实验和精细模拟结果的基础上，提出了模块间连接的简化模型，并通过与下部结构推倒试验的比较，证明该模型足以准确捕捉 MSC 的倒塌特性。然后，利用所提出的模型深入研究了典型的四层九跨 MSC 在不同局部破坏条件下的坍塌响应。在边柱、角柱甚至中间模块单元的局部破坏情况下，MSC 都能幸存下来。然而，在侧模块单元失效的情况下，由于倾覆力矩过大，所有四层楼的模块间连接都遭到破坏，导致单元失效的跨度坍塌。尽管如此，多层模块结构的其余部分仍然没有倒塌。因此，可以得出结论，采用螺栓和剪力键进行模块间连接的模块化钢结构在抗渐进式倒塌方面具有良好的性能。此外，这种模块间连接方式值得进一步研究。Post-Fire Compressive Behavior of CFRP Stirrups Reinforced CFST Columns: Experimental Investigation and Calculation ModelsMing-Xiang Xiong, Taoyuan Ren, Peng Zhou, Minfeng Yang, Wei Gong, Huawei Lidoi:10.1016/j.tws.2024.111747CFRP 直箍筋加固 CFST 柱的火灾后抗压行为：实验研究与计算模型This paper investigates the post-fire compressive behavior of CFST columns reinforced with CFRP strip stirrups. CFRP materials possess higher tensile strength than steel, making them promising candidates to enhance the ductility of high strength concrete when properly confined. However, direct exposure to fire leads to burning and rapid loss of tensile capacity in CFRP materials. To mitigate this, the study explores embedding CFRP stirrups in concrete to provide additional confinement besides the steel tube which prevents fire penetration through concrete cracks and protects the CFRP stirrups. Through experimental tests and comparisons with steel stirrups reinforced counterparts, it was observed that the CFRP stirrups, even after heating, still provided confinement to the concrete core as the overlapping joints of the strips remained intact. The failure mode observed in the CFRP stirrups was the rupture of FRP, rather than debonding of overlapping joints. Additionally, the use of CFRP stirrups led to reduced concrete temperatures and significantly higher unit enhancement in residual load-bearing capacity for the CFST columns compared to steel stirrups. Practical calculation models were developed to estimate the historical maximum temperatures and residual load-bearing capacity of the CFRP stirrups reinforced CFST columns, regardless of whether high strength or normal strength concrete was used. The calculated values demonstrated good agreement with experimental results. This study provides valuable insights into the performance of CFRP stirrups reinforced CFST columns under post-fire conditions, highlighting their potential as effective fire-resistant and structurally efficient solutions in civil engineering applications.本文研究了用 CFRP 带箍筋加固的 CFST 柱的火灾后抗压行为。CFRP 材料比钢材具有更高的抗拉强度，因此在适当限制的情况下，有望增强高强度混凝土的延展性。然而，直接暴露在火中会导致 CFRP 材料燃烧并迅速丧失抗拉能力。为了缓解这一问题，本研究探讨了在混凝土中嵌入 CFRP 箍筋，以提供钢管以外的额外约束，从而防止火灾通过混凝土裂缝渗透并保护 CFRP 箍筋。通过实验测试以及与钢箍筋加固的同类产品进行比较，发现 CFRP 箍筋即使在加热后，由于条带的重叠接缝保持完好无损，仍能为混凝土核心提供约束。在 CFRP 箍筋中观察到的失效模式是 FRP 破裂，而不是重叠接缝脱开。此外，与钢箍筋相比，使用 CFRP 箍筋可降低混凝土温度，并显著提高 CFST 柱的单位剩余承载力。我们开发了实用的计算模型来估算 CFRP 箍筋加固 CFST 柱的历史最高温度和剩余承载力，无论使用的是高强度混凝土还是普通强度混凝土。计算值与实验结果显示出良好的一致性。这项研究为了解 CFRP箍筋加固 CFST 柱在火灾后条件下的性能提供了宝贵的见解，凸显了其在土木工程应用中作为有效的耐火和结构高效解决方案的潜力。来源：复合材料力学仿真Composites FEM