J. Ormondroyd

Bio: J. Ormondroyd is an academic researcher. The author has contributed to research in topics: Centrifugal pendulum absorber & Tuned mass damper. The author has an hindex of 1, co-authored 1 publications receiving 535 citations.

Seismic control of single-degree-of-freedom structure using tuned viscous mass damper

Abstract: SUMMARY In this study, we propose a new seismic control device, tuned viscous mass damper (TVMD), for building systems. We give a detailed description of an apparent mass amplifier using a ball-screw mechanism, which is one of the most important components for realizing the new device. We also derive a closed-form solution of an optimum seismic control design for a single-degree-of-freedom structure subjected to harmonic excitation. The performance of the new device is compared with those of the conventional viscous damper and viscous mass damper systems. The vibration control system using the TVMD is shown to be the most effective for linear structural systems with dampers having the same additional damping coefficient. The effectiveness of the TVMD for seismic excitation is verified by analyses and shake table tests with a small-scale TVMD. Copyright © 2011 John Wiley & Sons, Ltd.

Analytical Solutions to H∞ and H2 Optimization of Dynamic Vibration Absorbers Attached to Damped Linear Systems

Abstract: H∞ and H 2 optimization problems of the Voigt type dynamic vibration absorber (DVA) are classical optimization problems, which have been already solved for a special case when the primary system has no damping. However, for the general case including a damped primary system, no one has solved these problems by algebraic approaches. Only the numerical solutions have been proposed until now. This paper presents the analytical solutions for the H∞and H 2 optimization of the DVA attached to the damped primary systems. In the H∞ optimization the DVA is designed such that the maximum amplitude magnification factor of the primary system is minimized; whereas in the H 2 optimization the DVA is designed such that the squared area under the response curve of the primary system is minimized. We found a series solution for the H∞ optimization and a closed-form algebraic solution for the H 2 optimization. The series solution is then compared with the numerical solution in order to check the accuracy in connection with the truncation error of the series. The exact solution presented in this paper is too complicated to handle by a hand-held calculator, so we proposed an approximate solution for the practical object.