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Damage calculation method for prestressed thin-walled aqueducts subjected to water pressure blasting 预应力薄壁渡槽水压爆破损伤计算方法

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2024-10-25 DOI: 10.1016/j.tws.2024.112627

Tao Peng , Gaohui Wang , Wenbo Lu , Ming Chen , Peng Yan

In recent years, the blast resistance of hydraulic structures under explosion loads has attracted more and more attention. The damage calculation method of prestressed aqueducts subjected to blasting load is still a complicated problem. For this purpose, the theory of computation of the water pressure blasting is introduced and the formula for calculating the charge weight of the water pressure blasting is presented. The accuracy of the Coupled Eulerian-Lagrangian (CEL) algorithm of the underwater explosion model is verified by the previous experiment. Then, a fully coupled three-dimensional numerical model of a prestressed aqueduct is established to acquire the dynamic performances and failure mechanisms of the prestressed aqueduct subjected to water pressure blasting. The influence of the prestress and pull rod on nonlinear dynamic performances and failure modes of a prestressed aqueduct subjected to water pressure blasting are discussed. Finally, based on the wave and material mechanics, a method of calculation for the prestressed aqueduct subjected to water pressure blasting is presented. The accuracy of the suggested method is validated by the damage mode of the prestressed aqueduct subjected to water pressure blasting under various TNT weights. The analysis results show that the proposed method can satisfy the relationship between the damage characteristics of the prestressed aqueduct to water pressure blasting and various TNT weights. 1.5 kg TNT is insufficient to completely shatter the prestressed aqueduct, while 3.5 kg TNT can cause a perfect crushing effect. 7.5 kg TNT will result in excessive fragmentation of the prestressed aqueduct and inefficient utilization of the explosive energy. The proposed damage calculation method can provide significant support for explosion analysis of the prestressed thin-walled aqueduct structure.

近年来，水工结构在爆炸荷载作用下的抗爆性能越来越受到人们的关注。预应力渡槽在爆破荷载作用下的破坏计算方法仍是一个复杂的问题。为此，介绍了水压爆破的计算理论，提出了水压爆破装药重量的计算公式。水下爆破模型的欧拉-拉格朗日（CEL）耦合算法的准确性通过之前的实验得到了验证。然后，建立了预应力渡槽的全耦合三维数值模型，以获取预应力渡槽在水压爆破作用下的动态性能和破坏机理。讨论了预应力和拉杆对水压爆破下预应力渡槽非线性动态性能和破坏模式的影响。最后，基于波动力学和材料力学，提出了水压爆破下预应力渡槽的计算方法。通过不同 TNT 重量下预应力渡槽遭受水压爆破的破坏模式，验证了所提方法的准确性。分析结果表明，所提出的方法能够满足预应力渡槽在水压爆破下的破坏特征与不同 TNT 重量之间的关系。1.5 千克 TNT 不足以完全击碎预应力渡槽，而 3.5 千克 TNT 则可造成完美的击碎效果。7.5 公斤 TNT 会导致预应力渡槽过度破碎，爆炸能量得不到有效利用。所提出的破坏计算方法可为预应力薄壁渡槽结构的爆炸分析提供重要支持。

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引用次数: 0

Buckling behaviour of high-strength retrofitted steel sections manufactured through post heat-treatment processes 通过后热处理工艺制造的高强度改造型钢的屈曲性能

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2024-10-24 DOI: 10.1016/j.tws.2024.112626

Shadiya Jamshiyas , Konstantinos Skalomenos , Yang Ma , Marios Theofanous

High-strength steel is increasingly popular in construction for its strength-to-weight ratio, which lowers the self-weight of structures and reduces transportation, erection, and foundation costs. Induction hardening (IH) process which involves rapid heating and cooling of the material leads to microstructural changes which enhance the hardness and strength of conventional steel, elevating it to the level of High Strength (HS) steel. This study reports an extensive investigation on the buckling response and design of IH post-treated structural steel Circular Hollow Sections (CHS). It includes tensile coupon tests, microstructural analyses, initial geometric imperfection measurements, and residual stress evaluations to determine the effects of IH treatment on CHS. Column buckling tests were conducted, and a numerical model was developed and validated against the experimental results which was utilised to study systematically the effect of imperfections. The findings suggest that the magnitude of the imperfections in IH steel sections doubled compared to the non-treated condition, whilst there was a minimal impact on the residual stresses. A comprehensive parametric study was performed using finite element models to study the structural response of IH steel CHS columns over a large range of global slendernesses and allow the assessment of the buckling curves specified in EN 1993–1–1. It was concluded that the buckling curve a (imperfection factor, α=0.21) specified in EN 1993–1–1 provides the best buckling load predictions for the IH steel CHS columns, the response of which is superior to that of their virgin counterparts, despite the increased imperfections caused by the heat-treating process.

高强度钢以其强度重量比降低了结构自重，减少了运输、安装和地基成本，在建筑领域越来越受欢迎。感应淬火（IH）工艺涉及材料的快速加热和冷却，会导致微观结构变化，从而提高传统钢材的硬度和强度，使其达到高强度（HS）钢材的水平。本研究报告对 IH 后处理结构钢圆形空心型钢 (CHS) 的屈曲响应和设计进行了广泛调查。它包括拉伸试样测试、微观结构分析、初始几何缺陷测量和残余应力评估，以确定 IH 处理对 CHS 的影响。进行了立柱屈曲试验，开发了一个数值模型，并根据试验结果进行了验证，利用该模型系统地研究了缺陷的影响。研究结果表明，与未处理的情况相比，IH 钢截面的缺陷程度增加了一倍，而对残余应力的影响却微乎其微。使用有限元模型进行了全面的参数研究，以研究 IH 钢 CHS 柱在较大的整体细长度范围内的结构响应，并对 EN 1993-1-1 中规定的屈曲曲线进行评估。研究得出的结论是，EN 1993-1-1 中规定的屈曲曲线 a（不完美系数，α=0.21）为 IH 钢 CHS 柱提供了最佳屈曲载荷预测，尽管热处理过程导致不完美增加，但其响应优于原始同类产品。

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引用次数: 0

CVAE-based inverse design of two-dimensional honeycomb pentamode metastructure for acoustic cloaking 基于 CVAE 的用于声隐形的二维蜂巢五模元结构反设计

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2024-10-24 DOI: 10.1016/j.tws.2024.112623

Gen Li, Lihua Tang, Vladislav Sorokin, Shaohua Wang

In this work, a method for inverse design of two-dimensional honeycomb pentamode metastructures (HPM) based on the Conditional Variational Auto-Encoder (CVAE) is proposed to achieve acoustic cloaking. The parameter distribution of the perfect acoustic cloak with two-dimensional cylindrical Kohn-Shen-Vogelius-Weinstein (KSVW) mapping is first derived. The CVAE model framework is then established along with its loss function in terms of the design parameters of the HPM. The inverse design performance of the deep generative model is evaluated using a large number of random test samples based on finite element simulations, showing that the equivalent mechanical parameters obtained from inverse design are highly consistent with the target parameters of the perfect acoustic cloak. For the HPM cloak design given by the trained deep generative model, the total scattering cross section (TSCS) is significantly reduced as compared to the case without a cloak, thereby demonstrating the effectiveness of the CVAE-based inverse design of acoustic cloak.

本文提出了一种基于条件变异自动编码器（CVAE）的二维蜂窝五模隐身结构（HPM）反向设计方法，以实现声隐身。首先推导了具有二维圆柱 Kohn-Shen-Vogelius-Weinstein (KSVW) 映射的完美声隐形的参数分布。然后，根据 HPM 的设计参数建立了 CVAE 模型框架及其损失函数。在有限元模拟的基础上，使用大量随机测试样本对深度生成模型的反设计性能进行了评估，结果表明反设计获得的等效机械参数与完美声学隐形衣的目标参数高度一致。对于训练有素的深度生成模型给出的 HPM 斗篷设计，与没有斗篷的情况相比，总散射截面（TSCS）显著减小，从而证明了基于 CVAE 的声学斗篷反设计的有效性。

引用次数: 0

A multiscale Gaussian expansion method for low-frequency multimodal damping analysis of variable stiffness acoustic black hole beams 用于变刚度声学黑洞梁低频多模态阻尼分析的多尺度高斯扩展方法

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2024-10-23 DOI: 10.1016/j.tws.2024.112619

Wei Li , Huabing Wen , Junhua Guo

To address the issues of slow convergence and poor accuracy in existing dynamics methods caused by non-uniform variable cross-sections and layered material stiffness variations in variable stiffness acoustic black hole structure (VSABH). A multiscale Gaussian expansion method (MSGEM) is proposed in this paper. The structural dimensions are taken into account, and the structural parameters of multiple shape functions are adaptively selected based on stiffness and cross-sectional variation parameters. This results in the formation of shape function groups of various scales, which in turn creates the matrix of multi-scale Gaussian function groups. The feature information of the displacement field is realized to be extracted from multiple scales, and the fitting error of MSGEM to the displacement field of VSABH beam is within 2.02 %. The missing solution of eigenfrequency of Gaussian expansion method is avoided, and the modal vibration patterns are basically matched, which verifies the validity of MSGEM. Meanwhile, the advantages of low-frequency multimodal vibration reduction of VSABH beams are highlighted from several aspects, and the trend of the adjustment of the vibration reduction characteristics of VSABH beams by different parameters is clarified, which provides valuable design guidance for ABH metamaterials oriented to low-frequency vibration reduction.

为了解决变刚度声学黑洞结构（VSABH）中不均匀的变截面和分层材料刚度变化所导致的现有动力学方法收敛慢和精度低的问题。本文提出了一种多尺度高斯扩展方法（MSGEM）。该方法考虑了结构尺寸，并根据刚度和截面变化参数自适应地选择多个形状函数的结构参数。这就形成了不同尺度的形状函数组，进而创建了多尺度高斯函数组矩阵。实现了从多个尺度提取位移场的特征信息，MSGEM 对 VSABH 梁位移场的拟合误差在 2.02% 以内。避免了高斯展开法特征频率解的缺失，模态振型基本匹配，验证了 MSGEM 的有效性。同时，从多个方面凸显了 VSABH 梁低频多模态减振的优势，阐明了不同参数对 VSABH 梁减振特性的调节趋势，为面向低频减振的 ABH 超材料提供了有价值的设计指导。

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引用次数: 0

A four-node inverse curved shell element coupling MITC method for deformation reconstruction of plate and shell structures 用于板壳结构变形重建的四节点反向曲面壳元素耦合 MITC 方法

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2024-10-23 DOI: 10.1016/j.tws.2024.112598

Xiao Xiao, Shishun Zhang, Jianping Xuan, Tielin Shi

In the field of structural deformation monitoring, the inverse finite element method (iFEM) has significant engineering value as a structural health monitoring technique that provides timely and reliable warnings for shell structures. However, existing inverse finite elements are mainly based on first-order shear deformation theory and kirchhoff–love theory, which are not suitable for deformation reconstruction in plate and shell structures of arbitrary thickness. This study integrates iFEM with the Mixed Interpolation of Tensorial Components (MITC) method to develop a novel four-node quadrilateral inverse curved shell element, named iMICS(inverse Mixed Interpolation Curved Shell)4, aimed at enhancing the accuracy and efficiency of deformation reconstruction in complex plate and shell structures. The method uses the MITC4 shell element as the kinematic framework and applies the least squares variational principle to achieve deformation reconstruction, effectively alleviating shear and membrane locking issues across structures of varying thickness. Numerical examples validate the superior performance of the iMICS4 element, demonstrating its promising application prospects.

在结构变形监测领域，反有限元法（iFEM）作为一种结构健康监测技术，能为壳体结构提供及时可靠的预警，具有重要的工程价值。然而，现有的反有限元主要基于一阶剪切变形理论和基尔霍夫-洛夫理论，不适合任意厚度板壳结构的变形重建。为了提高复杂板壳结构变形重建的精度和效率，本研究将 iFEM 与张量成分混合插值（MITC）方法相结合，开发了一种新型的四节点四边形反弯壳元素，命名为 iMICS（inverse Mixed Interpolation Curved Shell）4。该方法使用 MITC4 壳体元素作为运动学框架，应用最小二乘变分原理实现变形重建，有效缓解了不同厚度结构的剪切和膜锁定问题。数值实例验证了 iMICS4 元素的卓越性能，展示了其广阔的应用前景。

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引用次数: 0

Kinematics and dynamics characteristics of a double-ring truss deployable antenna mechanism based on triangular prism deployable unit 基于三角棱柱可展开单元的双环桁架可展开天线机构的运动学和动力学特性

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2024-10-22 DOI: 10.1016/j.tws.2024.112608

Bo Han , Yuanzhi Zhou , Meng Han , Xiaoyu Hu , Yundou Xu , Jiantao Yao

In order to effectively improve the single-ring truss deployable antenna mechanism due to the large aperture caused by the problem with low structural strength and low-profile accuracy, a series of double-ring truss deployable antenna mechanisms (DRTDAM) are proposed with constant height during folding and deployment process. First, a variety of DRTDAMs are proposed based on tetrahedral units and their topologies are analyzed. Secondly, degree-of-freedom (DOF) characteristics of DRTDAM proposed in this paper are analyzed based on the screw theory and screw-constrained topological graphs and based on this, the kinematic characteristics of DRTDAM is investigated. Thirdly, the dynamics of the whole DRTDAM is built with Newton-Euler equations of multi-rigid body system. Finally, the correctness of above analysis is verified through dynamics analysis software ADAMS and numerical analysis software MATLAB, and the principle prototype is produced to verify the correctness of DOF analysis. The mechanism proposed in this paper enriches the configuration of DRTDAM, and the process of kinematic characterization method is clear and simple, which is meaningful for the research in space complex mechanism.

为了有效改善单环桁架可展开天线机构因大孔径造成的结构强度低、外形精度低等问题，提出了一系列在折叠和展开过程中高度不变的双环桁架可展开天线机构（DRTDAM）。首先，提出了多种基于四面体单元的 DRTDAM，并对其拓扑结构进行了分析。其次，基于螺钉理论和螺钉约束拓扑图分析了本文提出的 DRTDAM 的自由度（DOF）特性，并在此基础上研究了 DRTDAM 的运动学特性。第三，利用多刚体系统的牛顿-欧拉方程建立了整个 DRTDAM 的动力学模型。最后，通过动力学分析软件 ADAMS 和数值分析软件 MATLAB 验证了上述分析的正确性，并制作了原理样机来验证 DOF 分析的正确性。本文提出的机构丰富了DRTDAM的配置，运动学表征方法过程清晰、简单，对空间复杂机构的研究具有重要意义。

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引用次数: 0

Study on the buckling behavior of aluminum alloy sheets - before and after repaired with composite patches 铝合金板材屈曲行为研究--复合材料修补前后

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2024-10-22 DOI: 10.1016/j.tws.2024.112614

Xin Li , Anbiao Zhong , Jiale Zhang , Weilin Dong , Ruoqin Xiong , Heng Zhang , Xiaoliang Geng , Lei Huang , Jun Liu

In this paper, the compressive buckling behavior of aluminum alloy plates with an elliptical hole of various sizes is investigated. In order to improve the stability of these thin plates, T700/QY8911 composite laminate is used as a patch to repair the hole. The study included an analysis of the critical and post-critical behaviour using experimental and numerical methods. Experiments focus on buckling loads, post-buckling behavior and the relationship between sizes of holes and buckling load. Meanwhile, the buckling load and buckling mode are determined by finite element analysis, using linear analysis of eigenvalue problems modes, and then, the nonlinear analysis of structures with initiated geometrically imperfection is carried out, studying its post-buckling behavior, damage behavior and transfer of load. The results show that the buckling load of the open-hole specimen is related to size of opening. The existence of patch has a significant influence on stress distribution, and the buckling capability of repaired specimens is noticeably improved to the plate without a hole. And the compression experimental results are consistent with the numerical results, revealing that the developed finite element model of the structure is correct.

本文研究了带有不同大小椭圆孔洞的铝合金薄板的压缩屈曲行为。为了提高这些薄板的稳定性，使用了 T700/QY8911 复合材料层压板作为修补孔的补片。研究包括使用实验和数值方法分析临界和临界后行为。实验的重点是屈曲载荷、屈曲后行为以及孔洞尺寸与屈曲载荷之间的关系。同时，通过有限元分析确定屈曲载荷和屈曲模式，使用特征值问题模式的线性分析，然后对具有初始几何缺陷的结构进行非线性分析，研究其屈曲后行为、破坏行为和载荷传递。结果表明，开孔试样的屈曲载荷与开孔尺寸有关。补丁的存在对应力分布有显著影响，修复后试样的屈曲能力明显优于无孔试样。压缩实验结果与数值结果一致，表明所建立的结构有限元模型是正确的。

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引用次数: 0

Boosting tree with bootstrap technique for pre-stress design in cable dome structures 采用引导技术的提升树用于缆索穹顶结构的预应力设计

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2024-10-22 DOI: 10.1016/j.tws.2024.112611

Yutao He , Jiamin Guo , Huan Ping , MingLiang Zhu , Weigang Chen , Guangen Zhou

Tensegrity structures, known for their rigidity derived from feasible pre-stresses, present unique challenges in structural engineering. Traditional force-finding methods, though comprehensive, rely heavily on intricate matrix computations, making them computationally intensive and often uncomfortable for considering external loads in practical engineering scenarios. This paper introduces a novel approach to compute pre-stresses in cable dome structures by integrating machine learning and probability theory, collectively termed the boosting tree with bootstrap technique (BTWBT). This method reduces the sample size to as few as 100 per iteration, while improving computational efficiency by randomly generating internal forces. By reframing the force determination as an inverse problem, it ensures that structural displacement converges to zero under feasible pre-stresses. The effectiveness of BTWBT is demonstrated across three distinct cable dome structures: the Geiger dome, Kiewitt dome, and rotating hyperboloid cable dome. Results show that BTWBT achieves the preset displacement requirement (maximum nodal displacement below 0.01 mm) with fewer iterations and reduced computational cost compared to traditional machine learning methods. BTWBT's capability to manage complex structural configurations with minimal data, while incorporating random internal force generation ranges, highlights its potential as a superior alternative for force determination in tensegrity structures.

张拉结构的刚度来源于可行的预应力，这给结构工程带来了独特的挑战。传统的测力方法虽然全面，但严重依赖于复杂的矩阵计算，因此计算量大，在实际工程场景中考虑外部荷载时往往不那么得心应手。本文介绍了一种通过整合机器学习和概率论来计算缆索穹顶结构预应力的新方法，统称为带引导技术的提升树（BTWBT）。该方法可将每次迭代的样本量减少到 100 个，同时通过随机产生内力提高计算效率。通过将力的确定重构为一个逆问题，它确保了结构位移在可行的预应力下趋近于零。BTWBT 的有效性在三种不同的缆索穹顶结构中得到了验证：盖革穹顶、凯威特穹顶和旋转双曲面缆索穹顶。结果表明，与传统的机器学习方法相比，BTWBT 以更少的迭代次数和更低的计算成本达到了预设位移要求（最大节点位移低于 0.01 毫米）。BTWBT 能够用最少的数据管理复杂的结构配置，同时结合随机内力生成范围，这突出表明它有潜力成为张拉结构力确定的最佳替代方法。

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引用次数: 0

Nonlinear finite element formulation for thin-walled conical shells 薄壁锥形壳的非线性有限元计算公式

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2024-10-22 DOI: 10.1016/j.tws.2024.112617

Saher Attia , Magdi Mohareb , Samer Adeeb

This study presents a novel finite element formulation to predict the geometrically nonlinear response of conical shells under a wide range of practical loading conditions. The formulation expresses the discretized equilibrium equations in terms of the first Piola-Kirchhoff stress tensor and its conjugate gradient of the virtual displacements, is based on the kinematics of Love-Kirchhoff thin shell theory and the Saint-Venant-Kirchhoff constitutive model, and captures the follower effect of pressure loading. The formulation takes advantage of the axisymmetric nature of the shell geometries by adopting a Fourier series to characterize the displacement distributions along the circumferential direction while using Hermitian interpolation along the meridional direction. Comparisons with general shell models show the accuracy of the formulation under various loading conditions with a minimal number of degrees of freedom, resulting in a significant computational efficiency compared to conventional general-purpose shell solutions.

本研究提出了一种新的有限元计算方法，用于预测锥壳在各种实际加载条件下的几何非线性响应。该公式用第一皮奥拉-基尔霍夫应力张量及其虚拟位移的共轭梯度来表示离散平衡方程，以 Love-Kirchhoff 薄壳理论的运动学和 Saint-Venant-Kirchhoff 构成模型为基础，并捕捉了压力加载的随动效应。该公式利用了壳体几何的轴对称性质，采用傅里叶级数来描述沿圆周方向的位移分布，同时沿经线方向使用赫米特插值法。与一般壳体模型的比较表明，该公式在各种载荷条件下都能以最少的自由度实现精确计算，与传统的通用壳体解决方案相比，计算效率显著提高。

引用次数: 0

A novel machine learning framework for impact force prediction of foam-filled multi-layer lattice composite structures 用于泡沫填充多层晶格复合结构冲击力预测的新型机器学习框架

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2024-10-21 DOI: 10.1016/j.tws.2024.112607

Jiye Chen , Yufeng Zhao , Hai Fang , Zhixiong Zhang , Zheheng Chen , Wangwang He

Numerical simulations can provide valuable insights for the optimization of design and operational management; however, they are often impractical and computationally intensive. Machine learning methods are appealing to these problems due to their sufficient efficiency and accuracy. In this study, a novel framework for predicting the impact responses of foam-filled multi-layer lattice composite structures (FMLCSs) was proposed by combining the accurate finite element (FE) analyses, surrogate models, fast Fourier transform (FFT) method, and inverse FFT (IFFT) method. Firstly, reliable FM models were established to simulate the crashworthiness of the five FMLCSs under impact loading, including an analysis of energy transformation. Subsequently, surrogate models, namely radial basis function (RBF), polynomial response surface (PRS), Kriging (KRG), and back propagation neural network (BPNN), combined with methods of FFT and IFFT, were employed to predict the impact force-time series of the FMLCSs. More than 1000 frequency points were employed for each type of FMLCS, and all the R-square (R²) values of the established surrogate models exceeded 0.95, indicating that the proposed framework accurately predicted the impact duration and impact responses in the frequency domain. In addition, parameter sensitivity analysis revealed that a high peak impact force was accompanied by a short impact duration. Moreover, increasing the lattice-web height resulted in a significant increase in the impact duration.

数值模拟可以为优化设计和运营管理提供有价值的见解；然而，数值模拟往往不切实际，而且计算密集。机器学习方法具有足够的效率和准确性，因此对这些问题很有吸引力。本研究结合精确的有限元（FE）分析、代用模型、快速傅立叶变换（FFT）方法和反FFT（IFFT）方法，提出了预测泡沫填充多层晶格复合材料结构（FMLCS）冲击响应的新框架。首先，建立了可靠的 FM 模型来模拟五种 FMLCS 在冲击载荷下的耐撞性，包括能量转换分析。随后，采用径向基函数（RBF）、多项式响应面（PRS）、Kriging（KRG）和反向传播神经网络（BPNN）等代用模型，结合 FFT 和 IFFT 方法，预测了 FMLCS 的冲击力-时间序列。每种类型的 FMLCS 都采用了超过 1000 个频率点，所建立的代用模型的 R-square（R2）值都超过了 0.95，表明所提出的框架能准确预测频域内的冲击持续时间和冲击响应。此外，参数敏感性分析表明，峰值冲击力大，冲击持续时间短。此外，增加格网高度会显著增加冲击持续时间。

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引用次数: 0