An improved equivalent force control algorithm for hybrid seismic testing of nonlinear systems

Wang, Zhen; Wu, Bin; Xu, Guoshan; Bursi, Oreste S.

doi:10.1002/stc.2076

Cited by 7 publications

(6 citation statements)

References 26 publications

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“…Real-time hybrid simulation (RTHS) is a versatile and cost-effective method for dynamic performance evaluation of structures and has received increasing attention in recent years [1][2][3][4][5][6][7][8][9]. This method divides the investigated structure into two parts, namely the experimental substructure (ES), which often exhibits a complicated nonlinear performance and is loaded experimentally in a laboratory, and the numerical substructure (NS), which can be simulated by a computer.…”

Section: Background and Motivationmentioning

confidence: 99%

“…The control accuracy of the shake table is a significant challenge. Unlike the RTHS using actuators, where various delay compensation and actuator control strategies are available [2,6,11,12,44], only a few schemes have been investigated for STST. Further, STST requires stringent control strategies for specimens with acceleration-dependent behaviors; the acceleration responses of the loading system are extremely sensitive to disturbances.…”

Section: Background and Motivationmentioning

confidence: 99%

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Shaking Table Substructure Testing Based on Three-Variable Control Method with Velocity Positive Feedback

Wang

Bao

et al. 2020

Applied Sciences

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To improve the experimental accuracy and stability of shaking table substructure testing (STST), an explicit central difference method (CDM) and a three-variable control method (TVCM) with velocity positive feedback (VPF) are proposed in this study. First, the explicit CDM is presented for obtaining an improved control accuracy of the boundary conditions between the numerical and experimental substructures of STST. Compared with the traditional CDM, the proposed method can provide explicit control targets for displacement, velocity, and acceleration. Furthermore, a TVCM-VPF is proposed to improve the control stability and accuracy for loading the explicit control targets of displacement, velocity, and acceleration. The effectiveness of the proposed methods is validated by experiments on a three-story frame structure with a tuned liquid damper loaded on an old shaking table originally designed with the traditional displacement control mode. The experimental results show that the proposed explicit CDM works well, and the response rate and control accuracy of the shaking table are significantly improved with the contribution of the TVCM-VPF compared with those of the traditional proportional integral derivative (PID) controller. This indicates the advantage of the proposed TVCM-VPF over the traditional PID for STST. A comparison between the traditional shaking table test and STST shows that when the latter is based on the TVCM-VPF, it exhibits an excellent performance in terms of the stability and accuracy of displacement and an acceptable performance in terms of the acceleration accuracy.

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Section: Background and Motivationmentioning

confidence: 99%

Section: Background and Motivationmentioning

confidence: 99%

Shaking Table Substructure Testing Based on Three-Variable Control Method with Velocity Positive Feedback

Wang

Bao

et al. 2020

Applied Sciences

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“…Using a numerical integration algorithm to analyze and solve the motion equation is the precondition for conducting an RTHS, 3–6 which can be divided into explicit and implicit categories. The actuator usually uses a proportional–integral–differential (PID) control algorithm to adjust its performance.…”

Section: Introductionmentioning

confidence: 99%

“…Currently, researchers using RTHS mostly focus on single members or plane specimens as experimental substructures 4,5,11,14,16–19 . For large‐scale space frame structures, there are not many real‐time tests 20 .…”

Section: Introductionmentioning

confidence: 99%

Real‐time hybrid simulation of a space substructure based on high‐strength steel composite Y‐eccentrically braced frames

Yan

et al. 2021

Struct Control Health Monit

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Summary Real‐time hybrid simulation (RTHS) is a novel structural seismic test method that has good application prospects. The applicability of RTHS for large‐scale space frame structures is further investigated in this study based on high‐strength steel composite Y‐eccentrically braced frames (Y‐HSS‐EBFs). First, an RTHS system was established, which included OpenSees, OpenFresco, an xPC‐Target, and an electrohydraulic servo control system. An adaptive feedforward delay compensator based on displacement prediction was introduced. Then, a shaking table test model of a three‐story Y‐HSS‐EBF was taken as the prototype, the third‐story frame with the strongest nonlinear performance was taken as the experimental substructure, and the remaining two stories were taken as the numerical substructure in order to perform the RTHS. The results of the RTHS were compared with those obtained in a purely numerical model and a shaking table test, and the stability of the RTHS system was analyzed. The results indicate that the RTHS results are in good agreement with the numerical simulation results and that RTHS can be used to obtain results similar to the ones obtained using the shaking table. In the typical seismic testing frequencies and the mass distribution ranges of the substructures, the RTHS system displayed good stability and reliability and was able to effectively evaluate the seismic performance of large‐scale space frame structures.

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“…The reason is that the restoring force behavior is generally path dependent . Vast researches have been conducted to resolve the deficiencies of explicit and implicit methods for hybrid simulation and make these methods suitable for a wide range of structural systems . Among these improvements, operator splitting (OS) method has been the most popular, and also very effective for hybrid simulation, because its implementation is nearly as easy as explicit methods, and it is more accurate and stable .…”

Section: Introductionmentioning

confidence: 99%

Reliable nonlinear hybrid simulation using modified operator splitting technique

Zakersalehi

Tasnimi

Ahmadizadeh

2018

Struct Control Health Monit

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One of the main challenges of hybrid simulation is developing integration methods that not only provide accurate and stable results but also are compatible with the hybrid simulation circumstances. This paper presents a novel enhanced integration technique for hybrid simulation termed "modified operator splitting" (MOS) method. The main aim of the MOS technique is to improve the precision of the operator splitting (OS) method by reducing the corrector step length, where initial stiffness is utilized instead of actual stiffness. For this purpose, a new algorithm is proposed, which makes a more precise estimation of the predictor displacement; thus minimizes the effect of the corrective procedure. As a result, a higher percentage of the restoring force is based on actual experimental behavior rather than being approximated, which finally leads to a very precise and reliable integration method, especially for nonlinear hybrid simulations. Performance of the MOS method is evaluated by the following: (a) Analytical studies, (b) numerical simulations, and (c) hybrid simulation. The accuracy analysis for a wide range of structures and ductility levels demonstrates the superior precision of MOS over OS, especially for severe nonlinearities and larger Δt/T 0 . In terms of stability, it is shown that for practical applications of civil engineering problems, MOS provides stable results. Furthermore, the application of MOS to hybrid simulation not only again verifies its higher precision over OS, but also shows that MOS minimizes the accumulation of errors during the test; the characteristic that is desirable for a method applied to feedback systems such as hybrid simulation.

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An improved equivalent force control algorithm for hybrid seismic testing of nonlinear systems

Cited by 7 publications

References 26 publications

Shaking Table Substructure Testing Based on Three-Variable Control Method with Velocity Positive Feedback

Shaking Table Substructure Testing Based on Three-Variable Control Method with Velocity Positive Feedback

Real‐time hybrid simulation of a space substructure based on high‐strength steel composite Y‐eccentrically braced frames

Reliable nonlinear hybrid simulation using modified operator splitting technique

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