OMAE2008-58014 NONLINEAR DYNAMIC ANALYSIS OF FLEXIBLE RISER STRUCTURES

ABSTRACT An updated Lagrangian finite element formulation of a three-dimensional pipe elbow element is presented for large displacement and large rotation dynamic analysis. In this formulation a particular linearization method is used to avoid inaccuracies normally associated with the linearization schemes. The formulation has been implemented in a nonlinear finite element code and the results are verified. It is shown that the proposed formulation generates improved results over those previously reported in the literature

An Exact Analytical Solution to Exponentially Tapered Piezoelectric Energy Harvester

It has been proven that tapering the piezoelectric beam through its length optimizes the power extracted from vibration based energy harvesting. This phenomenon has been investigated by some researchers using semianalytical, finite element and experimental methods. In this paper, an exact analytical solution is presented to calculate the power generated from vibration of exponentially tapered unimorph and bimorph with series and parallel connections. The mass normalized mode shapes of the exponentially tapered piezoelectric beam with tip mass are implemented to transfer the proposed electromechanical coupled equations into modal coordinates. The steady states harmonic solution results are verified both numerically and experimentally. Results show that there exist values for tapering parameter and electric resistance in a way that the output power per mass of the energy harvester will be maximized. Moreover it is concluded that the electric resistance must be higher than a specified value for gaining more power by tapering the beam