Test Rehearsal Methods for Quasi Static and Real-Time Hybrid Simulations


Abstract eng:
Over the last decade, the popularity of the hybrid simulation testing method has significantly increased and the testing method has been extensively adopted by the research community to conduct experimental earthquake and multi-hazard studies. While hybrid simulation provides a versatile, realistic and cost-effective method for simulating seismic response experimentally, test specimens and test setups have also become increasingly more complicated and therefore more costly. During a hybrid test, the command for the test control system is provided by a numerical analysis model based upon experimental feedback signals from the test specimen. Due to the nature of servo hydraulic test systems, which inherently include system delays and sensor noise, there is always discrepancy between command and feedback signals. Because these experimental errors, especially the systematic errors, are fed back to the numerical analysis model, they can accumulate during the solution process and cause a hybrid test to go unstable. As a consequence, the costly test specimens and possibly even the test setups can be damaged due to these incorrect loading histories. Thus, it is critical to have test methods available that can rehearse, meaning virtually simulate the different portions of a hybrid simulation, prior to the real hybrid test. This paper introduces several test rehearsal methods for quasi-static and real-time hybrid simulation, where an increasing number of parts of the overall hybrid testing system are being included in the virtual simulation. 1) FE adapter element method In this method, the FEAdapter experimental control feature in OpenFresco is being used to connect the hybrid analysis model with a test specimen that is being simulated in a Finite Element Analysis (FEA) software. A wide range of FEA software can be used to simulate the test specimen and it can be used to simulate both quasi static and real-time hybrid simulations. This test rehearsal method provides the means to verify that the hybrid model has been setup correctly, appropriate analysis parameters have been selected, and all of the OpenFresco components have been correctly defined. 2) Calculation channels in MTS Flextest software The MTS Calculation Channel feature can be used to model the specimen, servo valve behavior, system delay, and sensor noise. The resulting signals from these calculations can be used in control and also output as valve drive signals. The virtual system runs in real-time according to the system clock rate. Combined with a hybrid model, the Calculation Channel functionality provides an effective way to simulate a hybrid test. This method is typically used for quasi static hybrid simulations. 3) Model test system in Simulink and run it on target PC Simulink is used to model the physical test system. The model is compiled and downloaded into a target PC and then run in real-time. Since Simulink is a powerful analysis tool, complicated specimen properties, system delay, sensor noise, and other experimental errors can be modeled accurately. This method can be used in both quasi static and real-time hybrid simulations. Each test rehearsal method is illustrated through an example. By using proper test rehearsal methods, real hybrid tests have a much better opportunity to be successful. Incorporating such rehearsal techniques in a testing program can save valuable time and money by mitigating risk and improving overall accuracy.

Contributors:
Conference Title:
Conference Title:
16th World Conference on Earthquake Engineering
Conference Venue:
Santiago (CL)
Conference Dates:
2017-01-09 / 2017-01-13
Rights:
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 Record created 2017-01-18, last modified 2017-01-18


Original version of the author's contribution as presented on USB, paper 3288.:
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