【新文速递】2023年10月26日固体力学SCI期刊最新文章

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今日更新：Thin-Walled Structures 4 篇

Thin-Walled Structures

Dimension reduction model for sandwich panels with novel triangular chiral honeycomb using variational asymptotic method

Jie You, Yifeng Zhong, Hui Yuan, Evrard Irakoze Alain

doi:10.1016/j.tws.2023.111297

采用变异渐近法的新型三角形手性蜂窝夹芯板尺寸缩减模型

The triangular chiral (Tri-Chi) honeycomb is a novel negative Poisson’s ratio structure, featuring fully triangular cells inspired by the anti-tetra chiral design. This work aims to reveal the deformation mechanisms of the Tri-Chi honeycomb and employs the variational asymptotic method to determine the effective plate properties of sandwich panels with Tri-Chi honeycombs (i.e., SP-TCH). Based on this, a 2D dimension reduction model (2D-DRM) is developed, and the warping functions are solved through asymptotic analysis of the leading terms in the energy functional. Comparative analysis with the 3D FE model demonstrates that the 2D-DRM exhibited maximum errors of only 6.83% and 2.93% respectively in analyzing tension-bending coupling behavior and natural frequency, with the computational efficiencies being improved by 54.6-fold and 32.3-fold, respectively. Furthermore, the parameter analysis indicate that the structural stiffness and natural frequencies of SP-TCH were higher than those of stiffened triangle honeycomb sandwich panel with the same dimensions and materials. The facesheet layup design had a significant impact on the equivalent stiffness and vibration characteristics, whereas the included angle had a significant influence on the Poisson’s ratio of the Tri-Chi core layer, leading to a reversal from a negative to a positive ratio as the included angle increased.

三角形手性（Tri-Chi）蜂窝是一种新型负泊松比结构，其特点是全三角形单元的设计灵感来自反四手性设计。本研究旨在揭示 Tri-Chi 蜂窝的变形机理，并采用变异渐近法确定带有 Tri-Chi 蜂窝的夹芯板（即 SP-TCH）的有效板特性。在此基础上，建立了二维降维模型（2D-DRM），并通过对能量函数中的前导项进行渐近分析来求解翘曲函数。与三维 FE 模型的对比分析表明，二维-DRM 在分析拉弯耦合行为和固有频率时的最大误差分别仅为 6.83% 和 2.93%，计算效率分别提高了 54.6 倍和 32.3 倍。此外，参数分析表明，SP-TCH 的结构刚度和固有频率高于相同尺寸和材料的加劲三角蜂窝夹芯板。面片层叠设计对等效刚度和振动特性有显著影响，而包含角对三菱形芯层的泊松比有显著影响，导致随着包含角的增大，泊松比由负转正。

Structural Response of Monolithic and Multi-stacked AA2014-T6 Sheet Specimens Subjected to Shock Loading

Yadav Kuldeep, Pandouria Anoop Kumar, Bhagoria Palak, Bharadwaj Muddu Rahul, Tiwari Vikrant

doi:10.1016/j.tws.2023.111293

单片和多层 AA2014-T6 板材试样在冲击载荷下的结构响应

Experimental and numerical investigation of the shock response of AA2014-T6 sheets is presented in the current study. A double-stage shock loading apparatus is utilized to load the simply supported specimens under the shock loading. The experiments are performed on two different sheet thicknesses i.e., 1 mm and 2 mm. The spatial out-of-plane displacement of the specimens is obtained using 3D digital image correlation (DIC) technique. ABAQUS/Explicit is utilized for finite element (FE) modelling and simulating the shock loading event. A modified loading function is incorporated in the FE model to approximate the change in the specimen loading area and shock loading magnitude for the deformable specimens. The experimentally and numerically obtained out-of-plane displacement of the specimens are compared and agreement between both is quantified using Russell error technique. A series of experiments are conducted to investigate the effect of change in shock loading magnitude on the deformation phenomenon and corresponding energy dissipation. Alloy sheet of 2 mm thickness is observed to be better shock resistant than 1 mm sheet as the plastic dissipation energy per unit mass is higher for 2 mm thick sheet. Additionally, the shock behaviour of layered targets is also investigated for effective thicknesses of 2 mm and 3 mm. The performance of monolithic sheet of 2 mm is observed to be better than layered configuration of (1+1) mm. For the effective thickness of 3 mm, the order of decreasing shock performance is observed as (2+1) mm, (1+2) mm, and (1+1+1) mm.

本研究对 AA2014-T6 板材的冲击响应进行了实验和数值研究。利用双级冲击加载装置对冲击加载下的简支撑试样进行加载。实验在两种不同厚度的板材（即 1 毫米和 2 毫米）上进行。试样的空间平面外位移是通过三维数字图像相关（DIC）技术获得的。ABAQUS/Explicit 用于有限元（FE）建模和模拟冲击加载事件。在有限元模型中加入了修改后的加载函数，以近似反映试样加载区域的变化和可变形试样的冲击加载幅度。对实验和数值得出的试样平面外位移进行比较，并使用罗素误差技术量化两者之间的一致性。进行了一系列实验来研究冲击加载幅度的变化对变形现象和相应能量耗散的影响。观察发现，厚度为 2 毫米的合金板材的抗冲击性能优于厚度为 1 毫米的板材，因为厚度为 2 毫米的板材单位质量的塑性耗散能量更高。此外，还研究了有效厚度为 2 毫米和 3 毫米的分层目标的抗冲击性能。观察发现，2 毫米整体板材的性能优于 (1+1) 毫米的分层结构。有效厚度为 3 毫米时，冲击性能依次为 (2+1) 毫米、(1+2) 毫米和 (1+1+1) 毫米。

Effect of global stiffness on the force response of thin GFRP reinforced concrete slabs subjected to impact loading

JIN Liu, ZHAO Xinyu, ZHANG Renbo, XIA Maoxin, ZHENG Min, DU Xiuli

doi:10.1016/j.tws.2023.111300

整体刚度对承受冲击荷载的 GFRP 钢筋混凝土薄板受力响应的影响

The purpose of present study is to investigate the effect of global stiffness on the force response of thin GFRP reinforced concrete slabs simply supported by steel beams under drop-weight impact. Considering the strain rate effect of GFRP bars and concrete materials, a numerical model of GFRP-RC slabs was established and verified. The dynamic equilibrium relationship of the impact force, reaction force and inertial force was analyzed and intuitively explained from the velocity and displacement. Meanwhile, the effects of the global stiffness by varying the slab length, slab thickness and reinforcement ratio on the acceleration distribution, characteristic value of impact force and reaction force, failure pattern, displacement distribution and energy dissipation were evaluated in more detail. Eventually, the semi-empirical formulas considering key parameters were proposed to predict the reaction force time history of simply-supported RC/FRP-RC slabs under drop hammer impact. The results show that the effect of the slab stiffness by varying the slab length and thickness on the reaction force is significant, while the influence of reinforcement ratio is not obvious. The effect of global stiffness of the slab on the plateau value of the reaction force is similar to that on the plateau value of the impact force. The effect of the slab stiffness by varying the slab thickness and reinforcement ratio on the displacement is obvious, while varying the slab length hardly affects the deformation. The fitting equation considering key parameters can predict the simplified reaction force time history of simply-supported RC/FRP-RC slabs under impact loading. However, more experimental validation and extensive parametric studies are needed to improve their accuracy and applicability.

本研究的目的是探讨全局刚度对落重冲击下由钢梁简支的 GFRP 钢筋混凝土薄板受力响应的影响。考虑到 GFRP 钢筋和混凝土材料的应变率效应，建立并验证了 GFRP-RC 板的数值模型。分析了冲击力、反作用力和惯性力的动态平衡关系，并从速度和位移方面进行了直观解释。同时，通过改变板长、板厚和配筋率，详细评估了整体刚度对加速度分布、冲击力和反作用力特征值、破坏模式、位移分布和能量耗散的影响。最后，提出了考虑关键参数的半经验公式来预测落锤冲击下简单支撑 RC/FRP-RC 板的反力时间历程。结果表明，通过改变板的长度和厚度，板的刚度对反力的影响很大，而配筋率的影响不明显。板的整体刚度对反力高原值的影响与对冲击力高原值的影响相似。通过改变板厚和配筋率，板刚度对位移的影响非常明显，而改变板长对变形几乎没有影响。考虑关键参数的拟合方程可以预测简支 RC/FRP-RC 板在冲击荷载作用下的简化反力时间历程。然而，要提高其准确性和适用性，还需要更多的实验验证和广泛的参数研究。

Optimization of Interleaved Structures with Amorphous Halloysite Nanotubes for Superior Performance of CFRP Pipes in Various Environmental Conditions

Kumar Sanjay, Park Ye-Rim, Kim Yun-Hae

doi:10.1016/j.tws.2023.111301

优化非晶霍洛石纳米管交错结构，提高 CFRP 管材在各种环境条件下的性能

The carbon fiber-reinforced polymer (CFRP) pipes are extensively used in various industrial sectors and are routinely exposed to diverse environmental conditions, making it imperative to enhance their performance and durability. To address this need, our study investigates the effects of incorporating amorphous halloysite nanotubes (A-HNTs) in different layers of five distinct layer arrangements on the bending and pipe stiffness properties of interleaved CFRP flat (F) and cylindrical (C) structures under various environmental conditions. Notably, the maximum moisture absorption rate of carbon/epoxy composites (A3), encompassing all layers of epoxy modified with A-HNTs, was 190% lower than that of carbon/epoxy (E3) composites containing unmodified epoxy resin in all layers. Furthermore, F(A3) exhibited the highest flexural strength at 3141 MPa among all composites tested. A-HNTs significantly improved pipe stiffness, with C(A3) exhibiting remarkable stiffness enhancements of 314% after moisture absorption and 268% after drying compared to C(E3). The composite C(E2A1), which included a bottom layer of epoxy modified with A-HNTs, also demonstrated significant stiffness enhancements of 308% after moisture exposure and 290% after drying, compared to C(E3). Consequently, we recommend the use of A3 and E2A1 composites for industrial applications.

碳纤维增强聚合物（CFRP）管道广泛应用于各个工业领域，经常暴露在各种环境条件下，因此必须提高其性能和耐用性。为了满足这一需求，我们的研究调查了在不同的环境条件下，将无定形哈洛来石纳米管（A-HNTs）加入五种不同的层排列的不同层中，对交错碳纤维增强聚合物扁平（F）和圆柱（C）结构的弯曲和管道刚度性能的影响。值得注意的是，碳/环氧复合材料（A3）的最大吸湿率比所有层都含有未改性环氧树脂的碳/环氧复合材料（E3）低 190%，而所有层都含有 A-HNT 改性环氧树脂的碳/环氧复合材料（A3）的最大吸湿率比 A-HNT 改性环氧树脂的碳/环氧复合材料（E3）低 190%。此外，在所有测试的复合材料中，F（A3）的抗弯强度最高，达到 3141 兆帕。A-HNT 显著提高了管道刚度，与 C(E3) 相比，C(A3) 在吸湿后的刚度提高了 314%，在干燥后的刚度提高了 268%。与 C(E3) 相比，复合材料 C(E2A1) 的吸湿后刚度提高了 308%，干燥后提高了 290%；复合材料 C(E2A1) 的底层是用 A-HNTs 改性的环氧树脂，吸湿后刚度提高了 308%，干燥后提高了 290%。因此，我们建议在工业应用中使用 A3 和 E2A1 复合材料。

来源：复合材料力学仿真Composites FEM

【新文速递】2023年10月28日固体力学SCI期刊最新文章

今日更新：International Journal of Solids and Structures 1 篇，Mechanics of Materials 1 篇，International Journal of Plasticity 1 篇，Thin-Walled Structures 1 篇International Journal of Solids and StructuresA physically based strength prediction model for glassRudshaug Jonas, Aasen Karoline Osnes, Hopperstad Odd Sture, Børvik Toredoi:10.1016/j.ijsolstr.2023.112548基于物理的玻璃强度预测模型The strength of glass has been a subject of great interest for more than one hundred years. Due to the stochastic nature of glass, governed by microscopical surface flaws, glass plates exhibit large variations in fracture strength. The aim of this work is to propose a new strength prediction model for glass, named the Glass Strength Prediction Model (GSPM) that captures the nature of fracture initiation in glass, spanning from rate dependence to size effects. We aim for the presented model to be applicable in modern design processes and provide a procedure to facilitate input parameter calibration for glass plates from different suppliers. GSPM is a Monte-Carlo based model that combines the theories of linear elastic fracture mechanics (LEFM) and sub-critical crack growth (SCG) to generate virtual tests on a representative sample of glass plates. The stress evolution in the glass plates is obtained from finite element (FE) simulations. The model results in representative fracture strength distributions that span the probable fracture initiation instances with respect to time, location and stress level. We also demonstrate how the GSPM can be used to trigger fracture in constitutive models applied in FE simulations. This feature provides the option to investigate scenarios including multiple glass plates with interdependent fracture initiation behavior. The GSPM displays great promise in terms of usability and prediction capacity. It is able to capture the fracture initiation behavior of glass plates of varying geometries exposed to load cases spanning from, e.g., quasi-static four-point bending to blast pressure. The model has the potential to reduce the number of physical experiments and numerical FE simulations in modern development processes of glass structures.一百多年来，玻璃的强度一直是人们非常感兴趣的话题。由于玻璃具有随机性，受微观表面缺陷的影响，玻璃板的断裂强度变化很大。这项工作的目的是为玻璃提出一个新的强度预测模型，命名为玻璃强度预测模型（GSPM），该模型能捕捉玻璃断裂起始的性质，包括速率依赖性和尺寸效应。我们希望所提出的模型适用于现代设计流程，并提供一个程序，方便对来自不同供应商的玻璃板进行输入参数校准。GSPM 是一种基于蒙特卡洛的模型，它结合了线性弹性断裂力学（LEFM）和亚临界裂纹生长（SCG）理论，对玻璃板的代表性样本进行虚拟测试。玻璃板中的应力演变是通过有限元（FE）模拟获得的。该模型得出了具有代表性的断裂强度分布，这些分布在时间、位置和应力水平方面跨越了可能的断裂起始实例。我们还演示了如何利用 GSPM 在有限元模拟中应用的构成模型中触发断裂。该功能可用于研究包括具有相互依赖断裂起始行为的多块玻璃板在内的各种情况。就可用性和预测能力而言，GSPM 前景广阔。它能够捕捉不同几何形状的玻璃板在从准静态四点弯曲到爆炸压力等各种载荷情况下的断裂起始行为。在玻璃结构的现代开发过程中，该模型有望减少物理实验和数值 FE 模拟的数量。Mechanics of MaterialsUse of hardness, PIP and tensile testing to obtain stress-strain relationships for metalsSouthern T.J.F., Campbell J.E., Fang C., Nemcova A., Bannister A., Clyne T.W.doi:10.1016/j.mechmat.2023.104846使用硬度、PIP 和拉伸测试获得金属的应力-应变关系Both hardness testing and Profilometry-based Indentation Plastometry (PIP) can be used to obtain features of (tensile) stress-strain curves. The two tests are superficially similar, involving penetration (under a known load) of an indenter into the flat surface of a sample, followed by measurement of dimensional characteristics of the residual indent. The associated data handling procedures, however, are very different in the two types of test. Hardness numbers, which are commonly based on measurement of the lateral extent or depth of the indent, essentially give a semi-quantitative indication of the resistance to plastic deformation: going beyond this to infer features of the (nominal) stress-strain curve – notably the yield stress (YS) and Ultimate Tensile Stress (UTS) – can only be done via empirical correlations (often restricted to certain types of alloy). PIP testing, on the other hand, involves measurement of the complete indent profile, followed by (automated) iterative FEM modelling of the indentation, allowing the complete (true) stress-strain curve to be obtained. This paper covers application of both approaches to 12 different alloys, with inferred stress-strain characteristics being compared with those from tensile testing. Insights are provided relating to the very different levels of detail and reliability offered by the two procedures.硬度测试和基于轮廓仪的压入塑性测量法（PIP）都可用于获取（拉伸）应力-应变曲线的特征。这两种测试表面上相似，都是将压头（在已知载荷下）插入样品的平面，然后测量残留压痕的尺寸特征。然而，这两种测试的相关数据处理程序却大相径庭。硬度值通常以测量压痕的横向范围或深度为基础，基本上是对塑性变形阻力的半定量指示：除此之外，要推断（标称）应力-应变曲线的特征，特别是屈服应力（YS）和极限拉伸应力（UTS），只能通过经验相关性来实现（通常仅限于某些类型的合金）。另一方面，PIP 测试涉及测量完整的压痕轮廓，然后对压痕进行（自动）迭代有限元建模，从而获得完整的（真实的）应力-应变曲线。本文介绍了这两种方法在 12 种不同合金中的应用，并将推断出的应力应变特性与拉伸试验得出的应力应变特性进行了比较。这两种方法所提供的详细程度和可靠性截然不同，本文对此进行了深入分析。International Journal of PlasticityCapturing the transition from diffuse to localised failure in constitutive modelling of partially saturated soilsPhan Dat Gia, Nguyen Giang D., Bui Ha H., Bennett Terrydoi:10.1016/j.ijplas.2023.103783在部分饱和土壤的结构建模中捕捉从扩散到局部破坏的过渡过程Localised failures in the form of shear band induce localised deformation and saturation within partially saturated soils. Inelastic responses mainly take place inside the shear band, while the zone outside it usually undergoes unloading processes with much smaller changes in deformation and saturation, as observed in several triaxial tests. The interaction between responses inside and outside shear bands governs the macro behaviour under effects of the hydromechanical coupling. This mechanism, along with properties of shear band (inclination, thickness) and the specimen size, are usually missing in existing classical models based on homogenous assumption. They are incorporated into our approach to correctly capture the post-localisation behaviour of partially saturated soils. In our proposed approach, enrichment terms for kinematics are used in the thermodynamics-based formulation to account for strong variations of hydromechanical responses (stress-strain, suction-saturation) outside and inside the shear band. The proposed formulation results in a size-dependent constitutive structure capable of describing the transition of behaviour from homogeneous to localised stages. The promising features of the proposed formulation are illustrated using data from drained triaxial tests.在部分饱和的土壤中，剪切带形式的局部破坏会引起局部变形和饱和。非弹性反应主要发生在剪切带内部，而剪切带外部区域通常会经历卸载过程，变形和饱和度的变化要小得多，这在一些三轴试验中也能观察到。在水力机械耦合作用下，剪切带内外反应的相互作用决定了宏观行为。这种机制以及剪切带的特性（倾斜度、厚度）和试样尺寸，通常是现有基于同质假设的经典模型所缺乏的。我们的方法中加入了这些因素，以正确捕捉部分饱和土壤的后定位行为。在我们提出的方法中，基于热力学的公式中使用了运动学增量项，以考虑剪切带内外水力学响应（应力-应变、吸力-饱和度）的强烈变化。所提出的公式产生了一种与尺寸有关的构成结构，能够描述从均质阶段到局部阶段的行为转变。利用排水三轴试验的数据说明了所提公式的优点。Thin-Walled StructuresNegative Stiffness Metamaterial with Directional Stability in Uniform FieldsZhu Shaowei, Wang Jingzhe, Chen Liming, Liu Tao, Li Weiguodoi:10.1016/j.tws.2023.111302在均匀场中具有方向稳定性的负刚度超材料Negative stiffness metamaterials have been widely studied due to their unusual properties and potential applications in shape reconfiguration, shock isolation, and reusable energy absorption, but their stability in fields has been less studied. In this work, a theoretical framework for determining the stability of negative stiffness metamaterials in a uniform field is established. More importantly, the concepts of directional stability and semi-directional stability are proposed for the metamaterials that have different stability in different field directions; metamaterials with different physical feature distributions are designed and prepared to achieve such ability, and the finite element simulation is used for theory verification and parameter study. The proposed metamaterial has the potential to be applied as field direction detectors and field-sensitive electrical relays.负刚度超材料因其不同寻常的特性以及在形状重构、冲击隔离和可重复使用的能量吸收方面的潜在应用而被广泛研究，但对其在场内的稳定性研究较少。本研究建立了一个理论框架，用于确定负刚度超材料在均匀场中的稳定性。更重要的是，针对在不同场方向上具有不同稳定性的超材料，提出了定向稳定性和半定向稳定性的概念；设计并制备了具有不同物理特征分布的超材料来实现这种能力，并利用有限元模拟进行了理论验证和参数研究。所提出的超材料有望用作场方向探测器和场敏感电继电器。来源：复合材料力学仿真Composites FEM