Dr. Stefan Hurlebaus Profile

Dr. Stefan Hurlebaus

at Texas A&M Univ

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Publications (7)

Proceedings Article | 10 April 2010 Paper

Adaptive control of base-isolated buildings using piezoelectric friction dampers against near-field earthquakes

Maryam Bitaraf, Osman Ozbulut, Stefan Hurlebaus

Proceedings Volume 7643, 76432E (2010) https://doi.org/10.1117/12.847380

KEYWORDS: Buildings, Earthquakes, Adaptive control, Control systems, Fuzzy logic, Near field, Performance modeling, Matrices, Modulation, Picosecond phenomena

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This paper investigates the effectiveness of two adaptive control strategies for modulating control force of piezoelectric friction dampers (PFDs) that are employed as semi-active devices in combination with laminated rubber bearings for seismic protection of buildings. The first controller developed in this study is a direct adaptive fuzzy logic controller. It consists of an upper-level and a sub-level direct fuzzy controller. In the hierarchical control scheme, higher-level controller modifies universe of discourse of both premise and consequent variables of the sub-level controller using scaling factors in order to determine command voltage of the damper according to current level of ground motion. The sub-level fuzzy controller employs isolation displacement and velocity as its premise variables and command voltage as its consequent variable. The second controller is based on the simple adaptive control (SAC) method, which is a type of direct adaptive control approach. The objective of the SAC method is to make the plant, the controlled system, track the behavior of the structure with the optimum performance. By using SAC strategy, any change in the characteristics of the structure or uncertainties in the modeling of the structure and in the external excitation would be considered because it continuously monitors its own performance to modify its parameters. Here, SAC methodology is employed to obtain the required force which results in the optimum performance of the structure. Then, the command voltage of the PFD is determined to generate the desired force. For comparison purposes, an optimal controller is also developed and considered in the simulations together with maximum passive operation of the friction damper. Time-history analyses of a base-isolated five-story building are performed to evaluate the performance of the controllers. Results reveal that developed adaptive controllers can successfully improve seismic response of the base-isolated buildings against various types of earthquakes.

Proceedings Article | 9 April 2010 Paper

Optimum design of bridges with superelastic-friction base isolators against near-field earthquakes

Osman Ozbulut, Stefan Hurlebaus

Proceedings Volume 7643, 764306 (2010) https://doi.org/10.1117/12.847378

KEYWORDS: Shape memory alloys, Bridges, Earthquakes, Near field, Optical isolators, Terbium, Temperature metrology, Fuzzy logic, Motion models, Data modeling

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Proceedings Article | 1 April 2010 Paper

Performance evaluation of shape memory alloy/rubber-based isolation systems for seismic response mitigation of bridges

Osman Ozbulut, Stefan Hurlebaus

Proceedings Volume 7647, 76473X (2010) https://doi.org/10.1117/12.847601

KEYWORDS: Shape memory alloys, Bridges, Earthquakes, Temperature metrology, Optical isolators, Fuzzy logic, Motion models, Numerical simulations, Data modeling, Lead

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Proceedings Article | 30 March 2009 Paper

A temperature- and strain-rate-dependent model of NiTi shape memory alloys for seismic control of bridges

Osman Ozbulut, Stefan Hurlebaus

Proceedings Volume 7292, 729241 (2009) https://doi.org/10.1117/12.815637

KEYWORDS: Shape memory alloys, Bridges, Data modeling, Fuzzy logic, Temperature metrology, Earthquakes, Fuzzy systems, Numerical simulations, Complex systems, Systems modeling

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Proceedings Article | 19 May 2005 Paper

Fatigue and damage tolerance evaluation of an aircraft spoiler

Stefan Hurlebaus, Lothar Gaul

Proceedings Volume 5767, (2005) https://doi.org/10.1117/12.598126

KEYWORDS: Actuators, Tolerancing, Aerodynamics, Carbon, Fourier transforms, Inspection, Finite element methods, Composites, Chemical elements, Mechanics

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Proceedings Article | 16 May 2005 Paper

Modeling and parameter identification of an active anti-vibration system

Brad Beadle, Stefan Hurlebaus, Uwe Stoebener, Lothar Gaul

Proceedings Volume 5760, (2005) https://doi.org/10.1117/12.598123

KEYWORDS: Actuators, Vibration isolation, Motion models, Systems modeling, Solids, Feedback control, Control systems, Motion measurement, Sensors, Manufacturing

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Proceedings Article | 22 May 2000 Paper

Power flow estimation using pulsed ESPI

Paulo Alves, Jose Arruda, Lothar Gaul, Stefan Hurlebaus

Proceedings Volume 4072, (2000) https://doi.org/10.1117/12.386729

KEYWORDS: Finite element methods, Cameras, Digital filtering, Speckle pattern, Interferometry, Phase measurement, Wave propagation, Wave plates, Quality measurement, Statistical analysis

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Showing 5 of 7 publications

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