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Three-Dimensional Numerical Realization And Application Of Collapsible Loess Constitutive Model Considering Initial Water Content

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GEOTECHNICAL AND GEOLOGICAL ENGINEERING 2025年第1期43卷 1-19页

作者： Weng, Xiaolin Hou, Lele Li, Xuancong Li, Zejie Zhou, Rongming Changan Univ Sch Highway Xian 710064 Peoples R China China Railway 11 Bur Grp Co Ltd Xian Construct Branch Xian 710000 Peoples R China Henan Polytech Univ Sch Energy Sci & Engn Jiaozuo 454000 Peoples R China

The structural evolution of loess under load and humidification plays an important role in the safety evaluation of engineering in loose area. A simplified constitutive model is developed by incorporating the structural composition of collapsible loess in this paper. The user defined material subroutine (UMAT) of this model is programmed using an improved Euler integration algorithm with error control. A stress correction technique is incorporated in the UMAT subroutine to improve the computational accuracy and efficiency. Comparisons between UMAT subroutine simulation results, existing experimental results and result from the MATLAB program shows the validity and stability of this UMAT subroutine. Examples of three-dimensional square foundation and pit excavation using the UMAT subroutine is analysed, the simulation results demonstrates its reliability in capturing the general features of the wetting collapse for collapsible loose. These results can provide reference for the secondary development of relevant critical state models and offer a new approach for the engineering application of constitutive models for collapsible loess.

关键词： Collapsible loess Initial water content Structure Constitutive model Stress correction integration algorithm

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Enhancing keyphrase extraction from academic articles using section structure information

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SCIENTOMETRICS 2025年第4期130卷 2311-2343页

作者： Zhang, Chengzhi Yan, Xinyi Zhao, Lei Zhang, Yingyi Nanjing Univ Sci & Technol Dept Informat Management Nanjing Peoples R China Soochow Univ Dept Arch & E Govt Suzhou Peoples R China

The exponential increase in academic papers has significantly increased the time required for researchers to access relevant literature. Keyphrase extraction (KPE) offers a solution to this situation by enabling researchers to efficiently retrieve relevant literature. The current study on KPE from academic articles aims to improve the performance of extraction models through innovative approaches using Title and Abstract as input corpora. However, the semantic richness of keywords is significantly constrained by the length of the abstract. While full-text-based KPE can address this issue, it simultaneously introduces noise, which significantly diminishes KPE performance. To address this issue, this paper utilized the structural features and section texts obtained from the section structure information of academic articles to extract keyphrase from academic papers. The approach consists of two main parts: (1) exploring the effect of seven structural features on KPE models, and (2) integrating the extraction results from all section texts used as input corpora for KPE models via a keyphrase integration algorithm to obtain the keyphrase integration result. Furthermore, this paper also examined the effect of the classification quality of section structure on the KPE performance. The results show that incorporating structural features improves KPE performance, though different features have varying effects on model efficacy. The keyphrase integration approach yields the best performance, and the classification quality of section structure can affect KPE performance. These findings indicate that using the section structure information of academic articles contributes to effective KPE from academic articles. The code and dataset supporting this study are available at https://***/yan-xinyi/SSB_KPE.

关键词： Keyphrase extraction Section structure information Academic articles integration algorithm

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A TRACK CORRELATION algorithm FOR MULTISENSOR integration

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 1987年第2期10卷 166-171页

作者： KOSAKA, M MIYAMOTO, S IHARA, H Hitachi Ltd. Systems Development Laboratory Kawasaki Japan

A track correlation algorithm in a multi-sensor integration system for a surveillance mission is proposed. The performance of such track correlation processing is strongly dependent not only on the target state estimation error distribution but also on the target spatial density distribution. Therefore, a track correlation problem is formulated as the likelihood ratio test problem which can take both target state estimation error distribution and target state spatial density distribution into consideration. From this formulation, the correlation algorithm for on-line processing is derived by modifications and approximations. Through analytical evaluations and simulation studies, it is shown that the proposed algorithm, is superior to the conventional nearest neighbor algorithm.

关键词： Sensor Systems Kalman Filter Gaussian White Noise Cartesian Coordinate System integration algorithm Newton Raphson Method RADAR SONAR

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Comparison of explicit integration algorithms for real-time hybrid simulation

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BULLETIN OF EARTHQUAKE ENGINEERING 2016年第1期14卷 89-114页

作者： Zhu, Fei Wang, Jin-Ting Jin, Feng Gui, Yao Tsinghua Univ State Key Lab Hydrosci & Engn Beijing 100084 Peoples R China Changjiang Inst Survey Planning Design & Res Wuhan 430010 Peoples R China

Real-time hybrid simulation (RTHS) combines physical experimentation with numerical simulation to evaluate dynamic responses of structures. The inherent characteristics of integration algorithms change when simulating numerical substructures owing to the response delay of loading systems in physical substructures. This study comprehensively investigates the effects of integration algorithms on the delay-dependent stability and accuracy of multiple degrees-of-freedom RTHS systems. Seven explicit integration algorithms are considered;and the discrete-time root locus technique is adopted. It is found that the stability of RTHS system is mainly determined by the time delay rather than the integration algorithms, whereas its accuracy mainly depends on the accuracy characteristic of the applied integration algorithm itself. An unconditionally stable integration algorithm cannot always guarantee good stability performance;and the inherent accuracy or numerical energy dissipation of integration algorithms should be taken into account in RTHSs. These theoretical findings are well verified by RTHSs.

关键词： Real-time hybrid simulation integration algorithm Delay-dependent stability and accuracy Delay compensation Discrete-time root locus

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Unconditionally stable time-step-integration algorithms based on Hamilton's principle

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AIAA JOURNAL 2000年第8期38卷 1453-1464页

作者： Fung, TC Nanyang Technol Univ Sch Civil & Struct Engn Singapore 639798 Singapore

Unconditionally stable time-step-integration algorithms derived from Hamilton's principle are presented. The corresponding constrained variations are assumed to be in the form of Sigma alpha(k)tau(k)(1 - T) to ensure vanishing variations at the ends of a time interval. The initial conditions are strongly enforced in the formulation. The order of accuracy can be 2n - 1 or 2n, where n is the number of unknown variables. The ultimate spectral radii of the algorithms can be controlled directly. The approximate solutions are in fact equivalent to the generalized Pade approximations for linear second-order differential equations. Hence, Hamilton's principle can be used to construct unconditionally stable higher-order-accurate time-step-integration algorithms directly as well, provided the appropriate constrained variations are used.

关键词： integration algorithm Second Order Differential Equations Critical Damping Ratio Lagrange Multipliers Kinetic Energy Hu Washizu Principle Linear Interpolation Solid Mechanics Modal Analysis Cramers Rule

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Efficiency improvement of unified implicit relaxation/time integration algorithms

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AIAA JOURNAL 1999年第1期37卷 125-128页

作者： Fujii, K Inst Space & Astronaut Sci Space Trasportat Res Div Sagamihara Kanagawa 2298510 Japan

Discusses the development of relaxation-type algorithms and the improvement in efficiency by adopting the lower-upper-symmetric Gauss-Seidel (LU-SGS) and the lower-upper alternating direction implicit (LU-ADI). Formul... 详细信息

关键词： integration algorithm Freestream Mach Number Vortex Structure Angle of Attack Reynolds Averaged Navier Stokes Rockets Turbulence Models Computational Fluid Dynamics NACA 0012 Continuity Equation

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Stability analysis of SDOF real-time hybrid testing systems with explicit integration algorithms and actuator delay

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EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS 2008年第4期37卷 597-613页

作者： Chen, Cheng Ricles, James M. Lehigh Univ Dept Civil & Environm Engn ATLSS Res Ctr Bethlehem PA 18015 USA

Real-time hybrid testing is a method that combines experimental substructure(s) representing component(s) of a structure with a numerical model of the remaining part of the structure. These substructures are combined with the integration algorithm for the test and the servo-hydraulic actuator to form the real-time hybrid testing system. The inherent dynamics of the servo-hydraulic actuator used in real-time hybrid testing will give rise to a time delay, which may result in a degradation of accuracy of the test, and possibly render the system to become unstable. To acquire a better understanding of the stability of a real-time hybrid test with actuator delay, a stability analysis procedure for single-degree-of-freedom structures is presented that includes both the actuator delay and an explicit integration algorithm. The actuator delay is modeled by a discrete transfer function and combined with a discrete transfer function representing the integration algorithm to form a closed-loop transfer function for the real-time hybrid testing system. The stability of the system is investigated by examining the poles of the closed-loop transfer function. The effect of actuator delay on the stability of a real-time hybrid test is shown to be dependent on the structural parameters as well as the form of the integration algorithm. The stability analysis results can have a significant difference compared with the solution from the delay differential equation, thereby illustrating the need to include the integration algorithm in the stability analysis of a real-time hybrid testing system. Copyright (C) 2007 John Wiley & Sons, Ltd.

关键词： hybrid testing real time integration algorithm stability actuator delay discrete transfer function closed loop

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Automatic differentiation of numerical integration algorithms

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MATHEMATICS OF COMPUTATION 1999年第226期68卷 717-731页

作者： Eberhard, P Bischof, C Univ Stuttgart Inst Mech B D-70550 Stuttgart Germany Rhein Westfal TH Aachen D-52056 Aachen Germany

Automatic differentiation (AD) is a technique for automatically augmenting computer programs with statements for the computation of derivatives. This article discusses the application of automatic differentiation to numerical integration algorithms for ordinary differential equations (ODEs), in particular, the ramifications of the fact that AD is applied not only to the solution of such an algorithm, but to the solution procedure itself. This subtle issue can lead to surprising results when AD tools are applied to variable-stepsize, variable-order ODE integrators. The computation of the final time step plays a special role in determining the computed derivatives. We investigate these issues using various integrators and suggest constructive approaches for obtaining the desired derivatives.

关键词： .integrators typically system parameters AD tools AUTOMATIC DIFFERENTIATION computation of derivatives desired derivatives integration algorithm

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DYNAMIC ADAPTIVE SELECTION OF integration algorithmS WHEN SOLVING ODE-S

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BIT 1982年第3期22卷 361-367页

作者： WOLFBRANDT, A Dept. KYEB ASEA 72183 Västerås Sweden

The specific area of stiffness detection has traditionally required user interaction. This paper presents an attempt to switch dynamically between stiff and non-stiff algorithms.

关键词： Computational Mathematic Specific Area User Interaction integration algorithm Adaptive Selection

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integration algorithms Based on Drucker-Prager Criterion and Application in Slope Stability Analysis

Integration Algorithms Based on Drucker-Prager Criterion and...

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The Second International Symposium on Constitutive Modeling of Geomaterials:Advances and New Applications(IS-Model 2012)

作者： Yuanwei Pan Yaoru Liu Jingjuan Qian Qiang Yang State Key Laboratory of Hydroscience and Engineering Tsinghua University

ISBN: (纸本)9783642328138

＜正＞In this paper,an incremental analysis method of perfect elasto-plastic constitutive relation based on Drucker-Prager criteria is adopted in nonlinear finite element computation,which is of first-order accuracy and unconditional stable. This method converges for either small load steps or large load *** method was embedded into a 3D nonlinear FEM software named TFINE and applied to stability analysis of Dagangshan high *** theoretical analysis and numerical example show that the method is suitable for limit analysis and can achieve high accuracy to large load increment.

关键词： integration algorithm analytic solution slope stability

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