Substructuring stability analysis in light of comprehensive transfer system dynamics

Real-time dynamic substructuring (RTDS) is an experimental technique that splits the structure under test into coupled parts that run in parallel. The structural component exhibiting unpredictable behaviour is tested in the laboratory while the remainder of the structure is modelled numerically. As the test proceeds, the dynamic force state at the physical–numerical interface is measured and a transfer system, usually a servo-hydraulic actuator or shaking table, is used to impose the commensurate response on the physical substructure. The integral dynamics of servo-hydraulic transfer systems can frustrate RTDS implementation by destabilising the system. Many have noted the deleterious stability implications of excessive phase lag in terms of a pure time-delay. However, because of the existence of magnitude variations and more complex phase characteristics, pure time-delay is too simple to represent the inherent nature of servo-hydraulic transfer systems. This paper considers RTDS stability in light of comprehensive transfer system dynamics. A transfer-function model of a servo-hydraulic transfer system is adopted and used to reflect the oversimplification of pure time-delay. The concept of gain margin is employed to reveal the drawbacks of the pure-delay based RTDS stability analyses. In order to overcome the drawbacks, a new method based on gain margin was developed. The comparative analyses demonstrate that the gain margin based method is tailored to predict the stability boundaries of a RTDS system incorporating comprehensive transfer system dynamics. The validity of the technique is verified experimentally through virtual and authentic RTDS system employing a shaking table. The performance of delay compensated shaking table RTDS is also assessed in perspective of stability.

[1]  Simon A Neild,et al.  Assessment of controller strategies for real-time dynamic substructuring of a lightly damped system , 2007 .

[2]  Guoshan Xu,et al.  Operator‐splitting method for real‐time substructure testing , 2006 .

[3]  Masayoshi Nakashima,et al.  Development of real‐time pseudo dynamic testing , 1992 .

[4]  Jun Guo,et al.  Control strategy for the substructuring testing systems to simulate soil-structure interaction , 2016 .

[5]  David J. Wagg,et al.  Control issues relating to real‐time substructuring experiments using a shaking table , 2005 .

[6]  Y. Namita,et al.  Real‐time hybrid experimental system with actuator delay compensation and its application to a piping system with energy absorber , 1999 .

[7]  Guang Li,et al.  Testing of dynamically substructured, base-isolated systems using adaptive control techniques , 2009 .

[8]  Feng Jin,et al.  Comparison of explicit integration algorithms for real-time hybrid simulation , 2015, Bulletin of Earthquake Engineering.

[9]  Martin S. Williams,et al.  Numerical Modeling of a Servohydraulic Testing System for Structures , 2001 .

[10]  Naresh K. Sinha,et al.  Modern Control Systems , 1981, IEEE Transactions on Systems, Man, and Cybernetics.

[11]  Gene H. Golub,et al.  Matrix computations (3rd ed.) , 1996 .

[12]  Qiang Wang,et al.  Real-time dynamic hybrid testing for soil–structure interaction analysis , 2011 .

[13]  M.I. Wallace,et al.  An adaptive polynomial based forward prediction algorithm for multi-actuator real-time dynamic substructuring , 2005, Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[14]  Kazuo Konagai,et al.  Simulation of nonlinear soil-structure interaction on a shaking table , 2002 .

[15]  Sung-Kyung Lee,et al.  Experimental implementation of a building structure with a tuned liquid column damper based on the real-time hybrid testing method , 2007 .

[16]  Joel P. Conte,et al.  Linear dynamic modeling of a uni‐axial servo‐hydraulic shaking table system , 2000 .

[17]  James M. Ricles,et al.  Stability and accuracy analysis of outer loop dynamics in real‐time pseudodynamic testing of SDOF systems , 2007 .

[18]  James M. Ricles,et al.  Stability analysis for real‐time pseudodynamic and hybrid pseudodynamic testing with multiple sources of delay , 2008 .

[19]  Juan Carrion,et al.  Model-Based Strategies for Real-Time Hybrid Testing , 2007 .

[20]  A. Blakeborough,et al.  Improved control algorithm for real‐time substructure testing , 2001 .

[21]  David J. Wagg,et al.  Stability analysis of real‐time dynamic substructuring using delay differential equation models , 2005 .

[22]  Toshihiko Horiuchi,et al.  A new method for compensating actuator delay in real–time hybrid experiments , 2001, Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences.

[23]  Takao Nishiumi,et al.  Hydraulic Control Systems: Theory And Practice , 2016 .

[24]  Feng Jin,et al.  Stability analysis of MDOF real‐time dynamic hybrid testing systems using the discrete‐time root locus technique , 2015 .

[25]  Laurent Larger,et al.  Subcritical Hopf bifurcation in dynamical systems described by a scalar nonlinear delay differential equation. , 2004, Physical review. E, Statistical, nonlinear, and soft matter physics.

[26]  David P Stoten,et al.  Adaptive control of dynamically substructured systems: The single-input single-output case , 2006 .

[27]  Ma Hua.  Effects on the Earthquake Simulation Caused by the Characteristics of the Specimen in the Shaking Table Tests-Part 1: Effects on the Stability of the System , 2010 .

[28]  Gene H. Golub,et al.  Matrix computations , 1983 .

[29]  James M. Ricles,et al.  Stability analysis of SDOF real‐time hybrid testing systems with explicit integration algorithms and actuator delay , 2008 .

[30]  Keh-Chyuan Tsai,et al.  Dual compensation strategy for real‐time hybrid testing , 2013 .