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Influence of the vertical seismic component on the response of continuous RC bridges 竖向地震分量对连续 RC 桥梁响应的影响
IF 4.4 2区 工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-10-04 DOI: 10.1016/j.compstruc.2024.107558
Germán Nanclares, Oscar Curadelli, Daniel Ambrosini
This paper investigates the influence of vertical seismic accelerations on the seismic response of RC bridges through numerical simulations using an enhanced non-linear numerical model. Results confirm that the incorporation of vertical accelerations, either through actual records or scaled horizontal records, can considerably modify the seismic response and the collapse mechanism. In the case of actual vertical records, the vertical component significantly contributes to premature structural deterioration, intensifying demand and accelerating failure mechanisms. On the other hand, the study underscores the inadequacy of using scaled horizontal records to represent vertical accelerations, as suggested by some seismic codes, as it not only distorts seismic response evaluation but also alters failure modes. The analysis of vertical vibration reveals higher displacements, increasing flexural demand on the deck, and leading to a progressive loss of vertical support at the central column. The research establishes the need to accurately account for vertical seismic accelerations in bridge design evaluations, as their impact on structural response and failure mechanisms cannot be underestimated. The work highlights the importance of a highly detailed 3D numerical model in assessing traditional parameters and capturing complex collapse mechanisms arising from material and geometric nonlinearities.
本文通过使用增强型非线性数值模型进行数值模拟,研究了垂直地震加速度对 RC 桥梁地震响应的影响。结果证实,通过实际记录或按比例水平记录加入垂直加速度,可显著改变地震响应和倒塌机制。在实际垂直记录的情况下,垂直分量对结构过早恶化、需求增加和加速破坏机制有显著作用。另一方面,该研究强调了按照某些地震规范的建议,使用按比例缩放的水平记录来表示垂直加速度的不足之处,因为这不仅会扭曲地震反应评估,还会改变破坏模式。对垂直振动的分析显示了更高的位移,增加了对甲板的抗弯要求,并导致中央支柱逐渐失去垂直支撑。这项研究证明了在桥梁设计评估中准确考虑垂直地震加速度的必要性,因为它们对结构响应和破坏机制的影响不容低估。这项研究强调了高度详细的三维数值模型在评估传统参数以及捕捉材料和几何非线性引起的复杂倒塌机制方面的重要性。
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引用次数: 0
A quadrilateral inverse plate element for real-time shape-sensing and structural health monitoring of thin plate structures 用于薄板结构实时形状传感和结构健康监测的四边形反演板元素
IF 4.4 2区 工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-10-03 DOI: 10.1016/j.compstruc.2024.107551
Ihtisham Khalid , Zahid Ahmed Qureshi , Haris Ali Khan , Selda Oterkus , Erkan Oterkus
The inverse finite element method (iFEM) emerged as a powerful tool in shape-sensing and structural health monitoring (SHM) applications with distinct advantages over existing methodologies. In this study, a quadrilateral inverse-plate element is formulated via a sub-parametric approach using bi-linear and non-conforming cubic Hermite basis functions for engineering structures, which can be modeled as thin plates. Numerical validation involves dense and assumed sparse sensor arrangements for in-plane, out-of-plane, and mixed general loading conditions. iFEM analysis reveals efficient monotonic convergence to analytical and high-fidelity finite element reference solutions. After successful numerical validation, defect detection analysis is performed considering minute geometric discontinuities and structural stiffness reduction because of latent subsurface defects under tensile and transverse loading conditions. The inverse formulation successfully resolves the presence of simulated defects under a sparse sensor arrangement. The proposed inverse-plate element is accurate in the full-field reconstruction of shape-sensing profiles and reliable in defect identification and quantification in thin plate structures.
反有限元法(iFEM)是形状传感和结构健康监测(SHM)应用中的一种强大工具,与现有方法相比具有明显优势。在本研究中,通过一种子参数方法,使用工程结构的双线性和非正规立方赫米特基函数,制定了四边形反向板元素,可将其建模为薄板。数值验证涉及平面内、平面外和混合一般加载条件下的密集和假定稀疏传感器布置。iFEM 分析显示出与分析和高保真有限元参考解的高效单调收敛性。在成功进行数值验证后,考虑到拉伸和横向加载条件下潜伏的次表面缺陷导致的微小几何不连续性和结构刚度降低,进行了缺陷检测分析。在传感器稀疏布置的情况下,反演公式成功地解决了模拟缺陷的存在。所提出的反板元素在形状传感剖面的全场重建方面非常精确,在薄板结构的缺陷识别和量化方面也非常可靠。
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引用次数: 0
The Hellan–Herrmann–Johnson and TDNNS methods for linear and nonlinear shells 线性和非线性壳的 Hellan-Herrmann-Johnson 和 TDNNS 方法
IF 4.4 2区 工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-10-03 DOI: 10.1016/j.compstruc.2024.107543
Michael Neunteufel , Joachim Schöberl
In this paper we extend the recently introduced mixed Hellan–Herrmann–Johnson (HHJ) method for nonlinear Koiter shells to nonlinear Naghdi shells by means of a hierarchical approach. The additional shearing degrees of freedom are discretized by H(curl)-conforming Nédélec finite elements entailing a shear locking free method. By linearizing the models we obtain in the small strain regime linear Kirchhoff–Love and Reissner–Mindlin shell formulations, which reduce for plates to the originally proposed HHJ and TDNNS methods for Kirchhoff–Love and Reissner–Mindlin plates, respectively. By interpolating the membrane strains into the so-called Regge finite element space we obtain locking-free arbitrary order shell methods. Additionally, the methods can be directly applied to structures with kinks and branched shells. Several numerical examples and experiments are performed validating the excellent performance of the proposed shell elements.
在本文中,我们通过分层方法将最近推出的用于非线性 Koiter 壳的混合 Hellan-Herrmann-Johnson (HHJ) 方法扩展到非线性 Naghdi 壳。额外的剪切自由度由 H(curl)-conforming Nédélec 有限元离散化,这意味着一种无剪切锁定方法。通过对模型进行线性化处理,我们得到了小应变机制下的线性基尔霍夫-洛夫和赖斯纳-明德林壳公式,对于板材,这两种公式分别简化为最初提出的基尔霍夫-洛夫和赖斯纳-明德林板材的 HHJ 和 TDNNS 方法。通过将膜应变插值到所谓的 Regge 有限元空间,我们得到了无锁定任意阶壳方法。此外,这些方法还可直接应用于具有扭结和分支壳体的结构。几个数值示例和实验验证了所提出的壳元素的卓越性能。
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引用次数: 0
Jacobi-Ritz method for dynamic analysis of functionally graded cylindrical shell with general boundary conditions based on FSDT 基于 FSDT 的雅各比-里兹法对具有一般边界条件的功能分级圆柱壳进行动态分析
IF 4.4 2区 工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-09-26 DOI: 10.1016/j.compstruc.2024.107552
Jiawei Xu, Cong Gao, Haichao Li, Fuzhen Pang, Jiajun Zheng, Tianyi Hang
This study introduces the vibration behavior of uniform functionally graded (FG) cylindrical shells by Jacobi-Ritz method. The first-order shear deformation theory (FSDT) and domain decomposition method (DDM) are used to establish the theoretical model. The complex constraint of FG cylindrical shells is realized by using artificial springs. The Jacobi orthogonal polynomials combined with Fourier series can be expanded to denote the admissible displacement field of the structure. Finally, the Rayleigh-Ritz method has been adopted to solve the behavior of free vibration and forced vibration. The transient vibration behavior of FG cylindrical shells is solved in accordance with Newmark-β integration method. For verify the validity of Jacobi-Ritz method, the convergence study is carried out, and the calculation results of FG cylindrical shells with various influencing factors such as boundary conditions, material parameters, excitation load forms and geometric dimensions are given, and the FEM results and published literature are compared. The computation show that the method has high precision and can supply theoretical basis for vibration control of FG cylindrical shell. This study introduces the vibration behavior of uniform functionally graded (FG) cylindrical shells by Jacobi-Ritz method. The first-order shear deformation theory (FSDT) and domain decomposition method (DDM) are used to establish the theoretical model. The complex constraint of FG cylindrical shells is realized by using artificial springs. The Jacobi orthogonal polynomials combined with Fourier series can be expanded to denote the admissible displacement field of the structure. Finally, the Rayleigh-Ritz method has been adopted to solve the behavior of free vibration and forced vibration. The transient vibration behavior of FG cylindrical shells is solved in accordance with Newmark-β integration method. For verify the validity of Jacobi-Ritz method, the convergence study is carried out, and the calculation results of FG cylindrical shells with various influencing factors such as boundary conditions, material parameters, excitation load forms and geometric dimensions are given, and the FEM results and published literature are compared. The computation show that the method has high precision and can supply theoretical basis for vibration control of FG cylindrical shell.
本研究采用 Jacobi-Ritz 方法介绍了均匀功能分级(FG)圆柱壳的振动行为。采用一阶剪切变形理论(FSDT)和域分解法(DDM)建立理论模型。利用人工弹簧实现了 FG 圆柱壳的复杂约束。雅可比正交多项式结合傅里叶级数可以展开表示结构的容许位移场。最后,采用 Rayleigh-Ritz 方法求解自由振动和强迫振动行为。FG 圆柱壳的瞬态振动行为采用 Newmark-β 积分法求解。为验证 Jacobi-Ritz 方法的有效性,进行了收敛性研究,给出了 FG 圆柱壳在边界条件、材料参数、激励载荷形式和几何尺寸等不同影响因素下的计算结果,并将有限元计算结果与已发表的文献进行了比较。计算结果表明,该方法精度高,可为 FG 圆柱壳的振动控制提供理论依据。本研究采用 Jacobi-Ritz 方法介绍了均匀功能分级(FG)圆柱壳的振动行为。采用一阶剪切变形理论(FSDT)和域分解法(DDM)建立理论模型。利用人工弹簧实现了 FG 圆柱壳的复杂约束。雅可比正交多项式结合傅里叶级数可以展开表示结构的容许位移场。最后,采用 Rayleigh-Ritz 方法求解自由振动和强迫振动行为。FG 圆柱壳的瞬态振动行为采用 Newmark-β 积分法求解。为验证 Jacobi-Ritz 方法的有效性,进行了收敛性研究,给出了 FG 圆柱壳在边界条件、材料参数、激励载荷形式和几何尺寸等不同影响因素下的计算结果,并将有限元计算结果与已发表的文献进行了比较。计算结果表明,该方法精度高,可为 FG 圆柱壳的振动控制提供理论依据。
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引用次数: 0
A simultaneous shape and topology optimization approach of shell structures based on isogeometric analysis and density distribution field 基于等距分析和密度分布场的壳体结构形状和拓扑结构同步优化方法
IF 4.4 2区 工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-09-26 DOI: 10.1016/j.compstruc.2024.107550
Zhao Zhang , Hao Yu , Hengan Wu , Qingpeng Chen
This paper presents a novel simultaneous shape and topology optimization approach of shell structures based on isogeometric analysis and density distribution field. In the optimization approach, Non-Uniform Rational B-Splines (NURBS) technology is utilized to describe the geometry and material distribution of the shell structures. The coordinates and densities of the NURBS control points are utilized as design variables to simultaneously optimize the shape and topology of shell structures. The proposed approach offers significant advantages, including ease of implementation, seamless integration with CAD models, high efficiency, and smooth, clear boundaries. Two representative examples are performed to demonstrate the effectiveness of the proposed approach. The optimized configurations are compared with other works and commercial software results.
本文提出了一种基于等几何分析和密度分布场的新型壳体结构同步形状和拓扑优化方法。在优化方法中,非均匀有理 B-样条曲线(NURBS)技术被用来描述壳体结构的几何形状和材料分布。NURBS 控制点的坐标和密度被用作设计变量,以同时优化壳体结构的形状和拓扑结构。所提出的方法具有显著的优势,包括易于实施、与 CAD 模型无缝集成、效率高以及边界平滑清晰。我们通过两个具有代表性的实例来证明所提方法的有效性。优化后的配置与其他作品和商业软件的结果进行了比较。
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引用次数: 0
Grammar-based generation of strut-and-tie models for designing reinforced concrete structures 基于语法生成用于设计钢筋混凝土结构的支撑和拉杆模型
IF 4.4 2区 工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-09-25 DOI: 10.1016/j.compstruc.2024.107549
Karin L. Yu , Michael A. Kraus , Eleni Chatzi , Walter Kaufmann
Reinforced concrete structures featuring discontinuity regions are complex to design and often susceptible to errors linked to numerical analysis methods. For such structural design problems, strut-and-tie models offer a simple, intuitive and safe design method based on the lower bound theorem of plasticity. Although intuitive, the derivation of strut-and-tie models requires nonnegligible effort and a certain degree of expertise to navigate the highdimensional design space. The automated generation of strut-and-tie models is nontrivial with existing optimisation-based methods, which struggle with accounting for fabrication aspects or incorporating user adaptations.
This paper presents a novel grammar-based approach for generating practical strut-and-tie models by representing them as graphs and constructing a graph grammar. It consists of rules customised to consider engineering judgement, significantly reducing the dimensionality of the design space. The sequential application of such rules allows for human-computer interaction and aids engineers in decision-making, while being kept in the loop. Parsing four common design examples from the literature demonstrates the efficacy of this approach. The developed designs are more practical compared with existing optimisation-based suggestions. This interpretable grammar-based approach closely follows the intuitive decision-making process of practising structural engineers, which could be adapted to support further structural engineering design tasks.
具有不连续区域的钢筋混凝土结构设计复杂,而且经常容易受到数值分析方法误差的影响。对于此类结构设计问题,支撑-拉杆模型提供了一种基于塑性下界定理的简单、直观和安全的设计方法。虽然直观,但推导支撑-拉杆模型需要不可忽略的努力和一定程度的专业知识,才能在高维设计空间中游刃有余。通过现有的基于优化的方法,自动生成支撑和拉杆模型并非易事,因为这些方法很难考虑到制造方面或用户的适应性。本文提出了一种基于语法的新方法,通过将其表示为图形并构建图形语法,生成实用的支撑和拉杆模型。它由考虑工程判断而定制的规则组成,大大降低了设计空间的维度。这些规则的顺序应用允许人机交互,并帮助工程师做出决策,同时使其处于环路中。对文献中四个常见设计实例的解析证明了这种方法的有效性。与现有的基于优化的建议相比,所开发的设计更加实用。这种基于语法的可解释方法与实际结构工程师的直观决策过程密切相关,可用于支持更多的结构工程设计任务。
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引用次数: 0
A method for static analysis of multistage cyclic structure based on group theory and two-stage Guyan reduction 基于群论和两阶段圭安还原法的多级循环结构静态分析方法
IF 4.4 2区 工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-09-24 DOI: 10.1016/j.compstruc.2024.107548
Dongdong Xie , Yonggang Zheng , Bo Wang , Shengli Xu , Yongfeng Sui , Qiang Gao
Considering the non-negligible multistage coupling effect of stages in multi-stage cyclic structure, such as bladed disk systems in aircraft turbo engines, a method is established for the static analysis of multistage cyclic structures. A special coordinate system is established based on the structural characteristics of the multistage cyclic structure. In this coordinate system, the sectors of a given disk have the same position; therefore, the stiffness matrices of any sector of the same disk are identical. Then, based on a two-stage Guyan reduction, the internal degrees of freedom (DOFs) of the disks are condensed and the number of DOFs corresponding to the full structure is reduced to that corresponding to the interdisk structures. Furthermore, group theory and the properties of the block circulant matrix are used to significantly reduce the computational cost of the two-stage Guyan reduction. Compared to the analysis of the full finite element model, the proposed method introduces no approximation. The main advantages of the proposed method are its high accuracy, high efficiency, and less demand on computational resources. Numerical examples demonstrate the accuracy and efficiency of the proposed method.
考虑到多级循环结构(如飞机涡轮发动机中的叶盘系统)中各级不可忽略的多级耦合效应,建立了多级循环结构的静力分析方法。根据多级循环结构的结构特点,建立了一个特殊的坐标系。在该坐标系中,给定圆盘的扇区具有相同的位置;因此,同一圆盘的任何扇区的刚度矩阵都是相同的。然后,根据两阶段吉安缩减法,对圆盘的内部自由度(DOFs)进行压缩,将与完整结构相对应的 DOFs 数量减少到与盘间结构相对应的 DOFs 数量。此外,利用群论和分块圆周矩阵的特性,可以大大降低两阶段 Guyan 简化的计算成本。与全有限元模型分析相比,所提出的方法不引入近似值。所提方法的主要优点是精度高、效率高、对计算资源的需求少。数值实例证明了所提方法的准确性和高效性。
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引用次数: 0
Stabilization and improvement of the convergence of hybrid-Trefftz stress elements for plate bending analysis 板弯曲分析中混合特雷弗茨应力元素收敛性的稳定和改进
IF 4.4 2区 工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-09-23 DOI: 10.1016/j.compstruc.2024.107519
J.A. Teixeira de Freitas , C. Tiago , E.M.B.R. Pereira
The polynomial boundary basis usually applied in the implementation of hybrid-Trefftz stress elements for plate bending is extended to render its rate of convergence insensitive to the shear-to-bending stiffness ratio of the plate. The boundary basis is also extended to improve the accuracy of the element in the modelling of boundary layer effects and of singular stress fields caused by wedge effects. Numerical testing problems are selected to illustrate and validate the effect of the proposed extensions on the stabilization and improvement of finite element solutions. The solutions modelling boundary layer effects in Mindlin-Reissner plates are used to recover the equivalent shear and corner force concepts of the Kirchhoff plate bending model.
扩展了通常用于板弯曲混合特雷弗茨应力元素的多项式边界基础,使其收敛速度对板的剪切弯曲刚度比不敏感。此外,还扩展了边界基础,以提高元素在模拟边界层效应和楔形效应引起的奇异应力场时的精度。我们选择了一些数值测试问题来说明和验证所提出的扩展对稳定和改进有限元求解的影响。模拟 Mindlin-Reissner 板中边界层效应的解法用于恢复基尔霍夫板弯曲模型的等效剪力和角力概念。
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引用次数: 0
Uncertainty quantification of acoustic metamaterial bandgaps with stochastic material properties and geometric defects 具有随机材料特性和几何缺陷的声学超材料带隙的不确定性量化
IF 4.4 2区 工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-09-23 DOI: 10.1016/j.compstruc.2024.107511
Han Zhang , Rayehe Karimi Mahabadi , Cynthia Rudin , Johann Guilleminot , L. Catherine Brinson
Acoustic metamaterials are a subject of increasing study and utility. Through designed combinations of geometries with material properties, acoustic metamaterials can be built to arbitrarily manipulate acoustic waves for various applications. Despite the theoretical advances in this field, however, acoustic metamaterials have seen limited penetration into industry and commercial use. This is largely due to the difficulty of manufacturing the intricate geometries that are integral to their function and the sensitivity of metamaterial designs to material batch variability and manufacturing defects. Capturing the effects of stochastic material properties and geometric defects requires empirical testing of manufactured samples, but this can quickly become prohibitively expensive with higher precision requirements or with an increasing number of input variables. This paper demonstrates how uncertainty quantification techniques, and more specifically the use of polynomial chaos expansions and spectral projections, can be used to greatly reduce sampling needs for characterizing acoustic metamaterial dispersion curves. With a novel method of encoding geometric defects in a 1D, interpretable, resolution-independent way, our uncertainty quantification approach allows for both stochastic material properties and geometric defects to be considered simultaneously. Two to three orders of magnitude sampling reductions down to 100 and 101 were achieved in 1D and 7D input space scenarios, respectively. Remarkably, this reduction in sampling was possible while preserving accurate output probability distributions of the metamaterial performance characteristics (bandgap size and location).
声学超材料的研究和应用日益广泛。通过设计几何形状与材料特性的组合,声学超材料可以任意操纵声波,应用于各种领域。尽管在这一领域取得了理论上的进步,但声学超材料在工业和商业应用中的渗透却十分有限。这主要是由于难以制造与其功能密不可分的复杂几何形状,以及超材料设计对材料批次变化和制造缺陷的敏感性。要捕捉随机材料特性和几何缺陷的影响,需要对制造的样品进行经验测试,但随着精度要求的提高或输入变量数量的增加,这种测试很快就会变得昂贵得令人望而却步。本文展示了如何利用不确定性量化技术,特别是多项式混沌展开和频谱投影,来大大减少表征声学超材料频散曲线的采样需求。我们的不确定性量化方法采用了一种新颖的方法,以一维、可解释、与分辨率无关的方式对几何缺陷进行编码,可同时考虑随机材料特性和几何缺陷。在 1D 和 7D 输入空间情况下,采样率分别降低了 2 至 3 个数量级,达到 ∼100 和 ∼101。值得注意的是,在减少采样的同时,还保留了超材料性能特征(带隙尺寸和位置)的精确输出概率分布。
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引用次数: 0
On thermomechanical problems in a topology optimisation method based on non-uniform rational basis spline entities 基于非均匀有理基样条实体的拓扑优化方法中的热力学问题
IF 4.4 2区 工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-09-23 DOI: 10.1016/j.compstruc.2024.107530
Elisabetta Urso, Marco Montemurro
This paper presents a new method to deal with thermomechanical topology optimisation (TO) problems based on a pseudo-density algorithm reformulated in the context of Non Uniform Rational Basis Spline (NURBS) entities. Specifically, a NURBS entity is used to represent the topological descriptor, providing an implicit filtering effect thanks to the local support propriety. The problem is formulated in the most general case of inhomogeneous Neumann-Dirichlet boundary conditions and design-dependent thermal sources and thermomechanical loads. In this context, a study on the combined effect of design-dependent heat sources, thermomechanical loads and applied forces and displacements on the optimal topologies is carried out. Furthermore, the influence of the penalisation schemes involved in the definition of the stiffness matrix, conductivity matrix, thermal loads and thermal sources on the optimised topology is investigated through a wide campaign of sensitivity analyses. Finally, sensitivity analyses are also conducted to investigate the influence of the integer parameters of the NURBS entity on the optimised solution. The effectiveness of the approach is tested on 2D and 3D benchmark problems.
本文介绍了一种处理热力学拓扑优化(TO)问题的新方法,该方法基于在非均匀有理基样条(NURBS)实体背景下重新制定的伪密度算法。具体来说,NURBS 实体用于表示拓扑描述符,并通过局部支持特性提供隐式过滤效果。该问题是在不均匀 Neumann-Dirichlet 边界条件和设计相关的热源和热机械负载的最一般情况下提出的。在此背景下,研究了与设计相关的热源、热机械载荷以及外加力和位移对最优拓扑结构的综合影响。此外,还通过广泛的敏感性分析,研究了定义刚度矩阵、传导矩阵、热负荷和热源时所涉及的惩罚方案对优化拓扑结构的影响。最后,还进行了敏感性分析,以研究 NURBS 实体的整数参数对优化解决方案的影响。该方法的有效性在二维和三维基准问题上进行了测试。
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引用次数: 0
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