Characterization and real‐time hybrid simulation testing of rolling pendulum isolation bearings with different surface treatments

Vargas, Braulio A. Covarrubias; Harvey, P. Scott; Cao, Liang; Ricles, James M.; Al‐Subaihawi, Safwan; Vega, Esteban Villalobos

doi:10.1002/eqe.3694

Cited by 4 publications

(1 citation statement)

References 27 publications

(55 reference statements)

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“…The experimental substructure, the proof-of-concept specimen in the lab, is selected as the subsystem of unknown performance that is desired to be explored for further studies. Examples of specimens investigated using RTHS are often selected due to the rate dependence of the materials such as rubber bearings by Yuan et al (2017), structural behavior such as nonlinearities in connections of steel members by Castaneda et al (2015), rate-dependent damping devices such as MR dampers by Friedman et al (2015), active inerters by Chen and Chen (2023), or isolation systems such as rolling pendulums in Covarrubias Vargas et al (2022). To realize the benefits of RTHS, the transfer system that generates the displacement between the numerical and experimental substructures needs to be designed for effective tracking.…”

Section: Introductionmentioning

confidence: 99%

Conditional adaptive time series compensation and control design for multi-axial real-time hybrid simulation

Aguila,

Li,

Palacio-Betancur

et al. 2024

Front. Built Environ.

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The structural performance of critical infrastructure during extreme events requires testing to understand the complex dynamics. Shake table testing of buildings to evaluate structural integrity is expensive and requires special facilities that can allow for the construction of large-scale test specimens. An attractive alternative is a cyber-physical testing technique known as Real-Time Hybrid Simulation (RTHS), where a large-scale structure is decomposed into physical and numerical substructures. A transfer system creates the interface between physical and numerical substructures. The challenge occurs when using multiple actuators connected with a coupler (i.e., transfer system) to create translation and rotation at the interface. Tracking control strategies aim to reduce time delay errors to create the desired displacements that account for the complex dynamics. This paper proposes two adaptive control methodologies for multi-axial real-time hybrid simulations that improve capabilities for a higher degree of coupling, boundary, complexity, and noise reduction. One control method integrates the feedback proportional derivative integrator (PID) control with a conditional adaptive time series (CATS) compensation and inverse decoupler. The second proposed control method is based on a coupled Model Predictive Control (MPC) with the CATS compensation. The performance of the proposed methods is evaluated using the virtual multi-axial benchmark control problem consisting of a steel frame as the experimental substructure. The transfer system consists of a coupler that connects two hydraulic actuators generating the translation and rotation acting at the joint. Through sensitivity analysis, parameters were tuned for the decoupler components, CATS compensation, and the control design for PID, LQG, and MPC. Comparative results among different control methods are evaluated based on performance criteria, including critical factors such as reduction in the time delay of bothactuators. The research findings in this paper improve the tracking control systems for the multi-axial RTHS of building structures subjected to earthquake loading. It provides insight into the robustness of the proposed tracking control methods in addressing uncertainty and improves the understanding of multiple output controllers that could be used in future cyber-physical testing of civil infrastructure subjected to natural hazards.

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Section: Introductionmentioning

confidence: 99%

Conditional adaptive time series compensation and control design for multi-axial real-time hybrid simulation

Aguila,

Li,

Palacio-Betancur

et al. 2024

Front. Built Environ.

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Real‐time hybrid simulation of structural systems with soil‐foundation interaction effects using neural networks

Al‐Subaihawi,

Ricles,

Quiel

et al. 2024

Earthq Engng Struct Dyn

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Real‐time hybrid simulation (RTHS) involves dividing a structural system into numerical and experimental substructures. The experimental substructure is challenging to model analytically and is therefore modeled physically in the laboratory. Analytical substructures are conventionally modeled using the finite element method. The two substructures are kinematically linked, and the governing equations of motion are solved in real‐time. Thus, the state determination of the analytical substructure needs to occur within the timestep, which is of the order of a few milliseconds. All structural systems are supported by a soil‐foundation system and any evaluation of the efficacy of response modification devices placed in the structure should consider soil‐foundation structure interaction (SFSI) effects. SFSI adds compliance to a structural system, thereby altering the natural frequencies. Additionally, nonlinear behavior in the soil can result in residual deformations in the foundation and structure, as well as provide added damping. These effects can occur under both wind and earthquake loading. To overcome the barrier of the large computational effort required to model SFSI effects in real‐time using the conventional finite element approach, a neural network (NN) model is combined with an explicit‐based analytical substructure and experimental substructure with dampers to create a framework for performing RTHS with SFSI effects. The framework includes a block of long‐short term memory (LSTM) layers that is combined with a parallel rectified linear unit (ReLU) to form a NN model of the soil‐foundation system. RTHS of a tall 40‐story steel building equipped with nonlinear viscous dampers and subjected to a windstorm are performed to illustrate the framework. It was found that a number of factors have an effect on the quality of RTHS results. These include: (i) the discretization of the wind loading into bins of basic wind speed; (ii) the extent of the NN model training as determined by the root mean square error (RMSE); (iii) noise in the restoring forces produced by the NN model and its interaction with the integration algorithm; and, (iv) the bounding of outliers of the NN model's output. Guidelines for extending the framework for the RTHS of structures subjected to seismic loading are provided.

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Coupled aero-hydro-geotech real-time hybrid simulation of offshore wind turbine monopile structures

Al-Subaihawi,

Ricles,

Abu-Kassab

et al. 2024

Engineering Structures

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Characterization and real‐time hybrid simulation testing of rolling pendulum isolation bearings with different surface treatments

Cited by 4 publications

References 27 publications

Conditional adaptive time series compensation and control design for multi-axial real-time hybrid simulation

Conditional adaptive time series compensation and control design for multi-axial real-time hybrid simulation

Real‐time hybrid simulation of structural systems with soil‐foundation interaction effects using neural networks

Coupled aero-hydro-geotech real-time hybrid simulation of offshore wind turbine monopile structures

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