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An overview of hybrid simulation implementations in NEES projects

ENGINEERING STRUCTURES 2013年第Nov.期56卷 1439-1451页

作者： Shao, Xiaoyun Griffith, Chelsea Western Michigan Univ Dept Civil & Construct Engn Kalamazoo MI 49009 USA

Hybrid simulation is an advanced structural seismic experimental method that combines experimental physical models with analytical numerical models;its versatility and capability of simulating seismic response of large-scale specimens make it particularly applicable to the general civil structural systems. Hybrid simulation has been applied to over twenty George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) projects. This paper provides an overview of hybrid simulation implementations used in these projects based on the shared project data available at the NEEShub project warehouse. A brief introduction of hybrid simulation methods is firstly presented. Then hybrid simulation implementations in NEES projects are discussed in detail, including experimental substructural materials and scaling, substructural partition, hybrid simulation framework, integration algorithms, real-time hydraulic compensations, and verifications and applications of hybrid simulation results. The paper concludes that hybrid simulation is an effective, reliable and economic experimental method in earthquake engineering but requires further development to provide more realistic structural responses and validated general hybrid simulation procedure for broader application. Published by Elsevier Ltd.

关键词： Hybrid simulation NEES projects Seismic experimentation integration algorithm Real-time compensation

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FORMULATION AND SOLUTION OF INVERSE SPAGHETTI PROBLEM - APPLICATION TO BEAM DEPLOYMENT DYNAMICS

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AIAA JOURNAL 1993年第2期31卷 339-347页

作者： DOWNER, JD PARK, KC UNIV COLORADO DEPT AEROSP ENGN SCI BOULDER CO 80309 USA

A finite element model of the dynamics of axially moving, highly flexible beams is presented. The model is based on a geometrically nonlinear beam formulation that allows for large overall motions. To account for the varying length of a deploying beam, a moving finite element reference grid is incorporated within the nonlinear beam formulation such that the number of finite element nodes remains fixed and the finite element length is allowed to vary. Hamilton's law is used to formulate the equations of motion, and a transient integration solution procedure is derived from a space-time finite element discretization of the Hamiltonian variational principle. Computational results of the methodology are presented for a planar inverse-spaghetti problem.

关键词： Finite Element Approximation Elastic Deformation Bernoulli Euler Beam Theory Transverse Shear integration algorithm Cantilever Beam Young's Modulus Large Space Structures Piezoelectric Materials Beam Kinematics

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New constraint stabilization technique for dynamic systems with nonholonomic constraints

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 1999年第3期22卷 497-499页

作者： Wu, SD Chiou, JC Yang, JY Natl Chiao Tung Univ Dept Elect & Control Engn Hsinchu 300 Taiwan

A new constraint stabilization technique based on the velocity correction method is proposed for solving multibody dynamic systems with nonholonomic constraints. By propagating the velocity errors into a nonholonomic constraint equation, a modified velocity vector is obtained that consists of a constraint Jacobian matrix and the original calculated velocity. The present method does not require one to choose parameters that greatly affect the performance in simulating MBD systems. A computational procedure based on this finding is developed to suppress the constraint violation during the process of numerical integration. (AIAA)

关键词： Numerical integration integration algorithm Numerical Simulation Convex Optimization Energy Conservation Aircraft Control Control Surfaces Linear Mapping Heading Angle Robot Arms

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Stability analysis of Baumgarte constraint stabilization technique in multibody dynamic systems

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 1999年第1期22卷 160-162页

作者： Chiou, JC Yang, JY Wu, SD Natl Tsing Hua Univ Dept Elect & Control Engn Hsinchu 300 Taiwan

A guideline for determining the stabilization parameters of the Baumgarte technique is developed. The guideline, based on the stability limits of the numerical algorithms used and the chosen integration step size, is used to systematically determine the stabilization parameter. A crank-mechanism problem is considered as a numerical example. Numerical results indicate that the proposed guideline yields a more accurate and robust solution than arbitrarily determined parameters in simulating multibody dynamic systems. (AIAA)

关键词： Probability Density Functions integration algorithm Numerical algorithms Numerical integration Variable Structure System Holonomic Constraints Robot Arms Viscosity

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Inverse dynamics of aircraft via reduced-order shooting methods

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2002年第6期25卷 1158-1162页

作者： Bernelli-Zazzera, F Cappello, G Mantegazza, P Politecn Milan Dept Aerosp Engn I-20158 Milan Italy

The inverse simulation of a military trainer aircraft is treated. The inverse simulation problem requires the determination of control inputs that will make a set of specified states follow a prescribed trajectory. The method proposed here allows an arbitrary combination of very general path and dynamics constraints, and, at the same time, it optimizes a defined performance index. The method departs from the classical approach for trajectory optimization based on direct transcription. It arises from the concept of combining collocation and direct transcription and has the advantage of minimizing the number of variables and constraints involved in the numerical optimization with special regard to the equality constraints deriving from the direct transcription. This minimization of constraints and variables allowed the study of the inverse problem of the aircraft, including the dynamics of the actuators, on a personal computer, in a reasonable time, and without the need of using any specialized sparse optimization tool. It has been shown that the use of direct methods avoids both the explicit specification of, and the analytical conditions for, the Lagrange multipliers and the analytical differentiation of constraints on the path and on the state, thus making it simpler to use tabulated aeromechanics databases. (Author)

关键词： Trainer Aircraft Numerical Optimization Trajectory Optimization Mathematical Models Ailerons Numerical integration Inverse Problems Sequential Quadratic Programming Angle of Attack integration algorithm

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The Phase-to-Ground Fault Locating Method for the Wind Farm Transmission Line With the Single End Transient Information

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IEEE ACCESS 2024年 12卷 115286-115295页

作者： He, Jianan Niu, Jian Li, Lei Liu, Zibo Liu, Haitao Huang, Ying Zhang, Xu Wang, Erqing Luo, Meiling State Grid Ningxia Elect Power Co Ltd Elect Power Sci Res Inst Yinchuan 750011 Peoples R China State Grid Ningxia Elect Power Co Ltd Yinchuan Power Supply Co Yinchuan 750001 Peoples R China China Univ Min & Technol Beijing Sch Mech & Elect Engn Beijing 100083 Peoples R China

The fault characteristics of large-capacity wind farms affect the sensitivity of transmission-line protection, resulting in protection devices refusing to operate or mal-operate. A phase-to-ground fault-locating method with single-end transient information for wind farm transmission lines was proposed in this study. The proposed method employs a time-domain transient quantity integration equation matrix with the transmission line equivalent resistance, inductance, and fault path resistance to solve the fault location. The effectiveness of the scheme was evaluated using Real-Time Lab (RTLAB). The impact of factors such as the fault resistance, location, and distributed capacitance is considered. Under different fault locations, the distance measurement error of the proposed algorithm is within 3%, and there is no rejection or mal-operation. The results demonstrate that the proposed algorithm is characterized by high speed and reliability.

关键词： Transient analysis Wind farms Resistance Location awareness Transmission line measurements Protection Distance measurement Fault location Fault locating wind farm integration algorithm single end information

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Numerical studies of hyperplasticity with single, multiple and a continuous field of yield surfaces

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INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS 2003年第10期27卷 837-858页

作者： Einav, I Puzrin, AM Houlsby, GT Univ Western Australia Ctr Offshore Fdn Syst Nedlands WA 6009 Australia Georgia Inst Technol Sch Civil & Environm Engn Atlanta GA 30332 USA Univ Oxford Dept Engn Sci Oxford OX1 3PJ England

The development of a new constitutive model would normally require a new procedure to be established for derivation of the incremental response. However, for models generated within the framework of hyperplasticity (using single, multiple or continuous yield surfaces), this derivation can be carried out using standard procedures. In this paper we present first the unified incremental response for a model using a single internal variable for general loading conditions. Next, we develop and explore three different numerical techniques for implementation of this procedure. One of the approaches, which seems superior, is extended to the multi-surface hyperplastic formulation. Finally, to allow integration of continuous hyperplastic models within the same multi-surface hyperplastic setting, the issue of discretization of the continuous field of yield surfaces is addressed. Copyright (C) 2003 John Wiley Sons, Ltd.

关键词： hyperplasticity multi-surface hyperplasticity continuous hyperplasticity incremental response integration algorithm yield-surface(s) drift

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Novel analytical solutions of stochastic Ginzburg- Landau equation driven by Wiener process via the improved modified extended tanh function method

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ALEXANDRIA ENGINEERING JOURNAL 2023年 72卷 269-274页

作者： Alhojilan, Yazid Ahmed, Hamdy M. Qassim Univ Coll Sci Dept Math POB 6644 Buraydah 51452 Saudi Arabia El Shorouk Acad Higher Inst Engn Dept Phys & Engn Math Cairo Egypt

In this manuscript, the improved modified extended tanh integration technique is imple-mented to investigate the exact solutions of stochastic Ginzburg-Landau model driven by Wiener process which appeared in various fields of chemistry, mathematics and physics. Many types of stochastic wave solutions are raised such as hyperbolic stochastic solutions, trigonometric stochastic solutions, Weierstrass elliptic stochastic solutions and Jacobi elliptic stochastic solutions. Moreover, 3D and 2D graphical representations are depicted to show the effect of the multiplicative noise on the propagated waves. The results reveal that as the noise level increases, the wave degrades. The wave is distorted when r P 1. In addition, the 3D graphical representation show that the propa-gated wave is flattered when the noise strength is increased. These solutions may be applicable in various applications in applied science. The proposed method is efficient, direct and powerful. (c) 2023 THE AUTHORS. Published by Elsevier BV on behalf of Faculty of Engineering, Alexandria University This is an open access article under the CC BY-NC-ND license (http://***/ licenses/by-nc-nd/4.0/).

关键词： Wave solutions integration algorithm Stochastic system Nonlinear equations

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INFLUENCE OF GEOMETRIC NONLINEARITIES IN THE DYNAMICS OF FLEXIBLE TREELIKE STRUCTURES

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 1989年第6期12卷 830-837页

作者： IDER, SK AMIROUCHE, FML Illinois University Chicago

A comprehensive computer algorithm used in the dynamic analysis of multibody systems is presented. The procedures developed combine Kane's equations, the strain energy, and modal analysis to describe the elastic bodies. The equations of motion are expressed in a form in which their coefficients are based on the partial velocity and partial angular velocity arrays and are easily coded for computers. The nonlinear geometric stiffness matrix is developed for three-dimensional beams that account for the couplings between the deformation components having significant effects in high-speed systems. The method presented in this paper is tailored for structures with variable cross-sectional beam elements such as spacecraft antennae, helicopter rotor blades, robot systems, and mechanisms. The effects of rotary inertia as well as shear deformation are automatically included into the equations of motion. A method for obtaining the shape function matrix consisting of assumed dynamic modes is also presented. In addition, the preceding formulations are used in a simulation of a space- based robotic manipulator, and the results are compared with those obtained by Kane et al. (Author)

关键词： Stiffness Matrices Elastic Deformation Multibody System integration algorithm Robotic Manipulators Helicopter Rotor Dynamic Analysis Spacecraft Antennas Robots Material Properties

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Stability analysis of MDOF real-time dynamic hybrid testing systems using the discrete-time root locus technique

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EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS 2015年第2期44卷 221-241页

作者： Zhu, Fei Wang, Jin-Ting Jin, Feng Chi, Fu-Dong Gui, Yao Tsinghua Univ State Key Lab Hydrosci & Engn Beijing 100084 Peoples R China Yunnan Huaneng Lancang River Hydropower Co Ltd Kunming 650011 Peoples R China

The time delay resulting from the servo hydraulic systems can potentially destabilize the real-time dynamic hybrid testing (RTDHT) systems. In this paper, the discrete-time root locus technique is adopted to investigate the delay-dependent stability performance of MDOF RTDHT systems. Stability analysis of an idealized two-story shear frame with two DOFs is first performed to illustrate the proposed method. The delay-dependent stability condition is presented for various structural properties, time delay, and integration time steps. Effects of delay compensation methods on stability are also investigated. Then, the proposed method is applied to analyze the delay-dependent stability of a single shaking table RTDHT system with an 18-DOF finite element numerical substructure, and corresponding RTDHTs are carried out to verify the theoretical results. Furthermore, the stability behavior of a finite element RTDHT system with two physical substructures, loaded by twin shaking tables, is theoretically and experimentally investigated. All experimental results convincingly demonstrate that the delay-dependent stability analysis on the basis of the discrete-time root locus technique is feasible. Copyright (c) 2014 John Wiley & Sons, Ltd.

关键词： real-time dynamic hybrid testing delay-dependent stability discrete-time root locus integration algorithm delay compensation method

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