Michael I. Friswell

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The tortuosity of the track taken by an animal searching for food profoundly affects search efficiency, which should be optimised to maximise net energy gain. Models examining this generally describe movement as a series of straight steps interspaced by turns, and implicitly assume no turn costs. We used both empirical- and modelling-based approaches to(More)
SUMMARY When the dynamics of any general second order system are cast in a state-space format, the initial choice of the state-vector usually comprises one partition representing system displacements and another representing system velocities. Coordinate transformations can be defined which result in more general definitions of the state-vector. This paper(More)
This paper gives an overview of the use of inverse methods in damage detection and location, using measured vibration data. Inverse problems require the use of a model and the identification of uncertain parameters of this model. Damage is often local in nature and although the effect of the loss of stiffness may require only a small number of parameters,(More)
This paper investigates a quaternion-based finite time attitude synchronization and stabilization problem for satellite formation flying. Sufficient conditions are presented for finite time boundness and stability of this distributed consensus problem. More specifically, a nonlinear control law based on a finite time control technique is developed such that(More)
An experimental and theoretical electromechanical characterization of beam-like, uniform cross-section, unimorph structures employing single crystal piezoelectrics is presented. The purpose of the research is to understand and compare the actuation capabilities of several piezoelectric materials and substrate configurations so that optimal design choices(More)
This paper presents a novel approach to detect structural damage based on combining independent component analysis (ICA) extraction of time domain data and artificial neural networks (ANN). The advantage of using time history measurements is that the original vibration information is used directly. However, the volume of data, measurement noise and the lack(More)
This paper proposes a novel energy harvesting system model based on combined electromechanical and electromagnetic transduction technique. A cantilever substrate (beam) with piezoelectric (PZT) patch and a mass at the tip is considered for electromechanical transductions. A magnet is hanged through a spring at the tip of the composite beam over a printed(More)
Genetic algorithms have been the subject of considerable interest in recent years, since they appear to provide a robust search procedure for solving dicult problems. Due to the way the genetic algorithm explores the region of interest it avoids getting stuck at a particular local minimum and locates the global optimum. The genetic algorithm is slow in(More)
This research presents an experimental and theoretical energy harvesting characterization of beam-like, uniform cross-section, unimorph structures employing single-crystal piezoelectrics. Different piezoelectric materials, substrates, and configurations are examined to identify the best design configuration for lightweight energy harvesting devices for(More)