A General-Purpose Platform for Hybird Simulation with Model Updating
Kung-Juin Wang1, Ming-Chieh Chuang1, Chao-Hsien Li1, Pu-Yuan Chin2,
Keh-Chyuan Tasi2
1 National Center for Research on Earthquake Engineering
200, Sec. 3, Xinghai Rd., Taipei, Taiwan
kjwang@narlabs.org.tw
mcchuang@narlabs.org.tw
chli@narlabs.org.tw
2 Department of Civil Engineering, National Taiwan University
1, Sec. 4, Roosvelt Rd., Taipei, Taiwan
r04521207@ntu.edu.tw
kctsai@ntu.edu.tw
Abstract. A flexible C++ structural testing platform was developed in National Center for Research on Earthquake Engineering (NCREE), Taiwan to support general structural testing, including traditional hybrid simulation. This paper describes the research effort in which the said platform was used to integrate a finite element program (Platform of Inelastic Structural Analysis for 3D Systems, PISA3D) and a six-degree-of-freedom (DOF) testing facility (multi-axial testing system, MATS) in NCREE to conduct a series of hybrid simulation tests on a full-scale specimen of steel panel damper in a 3-dimensional 6-storey moment resisting frame subjected to earthquake excitation of two perpendicular directions. To increase the simulation fidelity, it employed a number of advanced testing technologies and simulation techniques including (1) fast data transmission using Shared Common Random Access Memory Network (SCRAMNet) to link two actuator controllers such that command and specimen responses can be smoothly transmitted between PISA3D and MATS, (2) techniques of external control that allowed imposing accurate target deformation on the specimen despite the presence of the imperfect specimen boundary conditions, (3) an online model updating scheme that learned the mechanical properties from the specimen responses while the test was on the fly and then accordingly adjusted those properties of other related numerical elements in the numerical structural model. Among the 12 DOF’s of the specimen, four (responses of the two strong axes: in-plane translation and rotation) participated in the hybrid simulation using real resisting force measured from the test, four (responses of the two weak axes: out-of-plane translation and rotation) participated in the simulation using elastic computation, and the rest four (twisting and shortening) were chosen not to participate in the hybrid simulation. Frictions of the testing facility included in the resisting force measurement were estimated and eliminated using numerical models. Two integration algorithms (Newmark average acceleration method and operator splitting method) were employed and their behaviours were studied. Finally, most of the implementation mentioned above (except the part of model updating) was achieved without any software hard coding in the developed testing platform. The test result well agreed with that obtained from the numerical analysis and thus validated the related testing technologies described in this paper.
Keywords: hybrid simulation, model updating, Internet, finite element, steel, experiment.
