Hybrid energy harvesting based on cymbal and wagon wheel inspiration

The demand for self-sufficient electronic devices is increasing as well as the overall energy use, and such demands are pushing technology forward, especially in effective energy harvesting. A novel hybrid Energy Harvesting System (EHS) has been proposed and analysed in this paper. It has been demonstrated that the EHS is capable of converting enough energy to power a typical MEMS device. This has been achieved through unification of the nine Cymbal Energy Harvester (CEH) array, as an energy harvesting core, and Shape Memory Alloy (SMA) active elements, acting as a source of force stimulated by the environmental changes. A Finite Element Model (FEM) was developed for the CEH, which was verified and used for the analysis of CEH’s response to the change of the end-cap material. This was followed by the FEM for the EHS used for analysis of the location of SMA wires and force generated by each wire individually and then all together. As a further optimisation of the EHS a novel Wagon Wheel design was explored in terms of its energy harvesting capabilities. As expected, due to the increased displacement, an increase in the power output was achieved

Application of A Hybrid WKB-Galerkin Method in Control of Dynamic Instability of Piezolaminated Imperfect Column

This paper deals with the problem of dynamic instability of piezolaminated column subjected to arbitrary axial load. The aim of the analysis is to obtain the closed form solution for the equilibrium equation of the loaded column considering variable in time damping coefficient, presented as function of time. Solution of the problem is obtained using A Hybrid WKB-Galerkin method

Crush can behaviour as an energy absorber in a frontal impact

The work presented is devoted to the investigation of a state-of-the-art technological solution for the design of a crush-can characterized by optimal energy absorbing properties. The work is focused on the theoretical background of the square tubes, circular tubes and inverbucktube performance under impact with the purpose of design of a novel optimized structure. The main system under consideration is based on the patent US 2008/0185851 A1 and includes a base flange with elongated crush boxes and back straps for stabilization of the crush boxes with the purpose of improvement of the energy-absorbing functionality. The modelling of this system is carried out applying both a theoretical approach and finite element analysis concentrating on the energy absorbing abilities of the crumple zones. The optimization process is validated under dynamic and quasi-static loading conditions whilst considering various modes of deformation and stress distribution along the tubular components. Energy absorbing behaviour of the crush-cans is studied concentrating on their geometrical properties and their diamond or concertina modes of deformation. Moreover, structures made of different materials, steel, aluminium and polymer composites are considered for the material effect analysis and optimization through their combination. Optimization of the crush-can behaviour is done within the limits of the frontal impact scenario with the purpose of improvement of the structural performance in the Euro NCAP tests

Analytical model of the cymbal transducer dynamics, radial vibration of the piezoelectric disc

This article represents the first step in an attempt to obtain an analytical model of a cymbal transducer. The structure is considered as two mechanically coupled systems (i.e. a piezoelectric disc producing radial motion and end caps amplifying under the compression caused by this radial behaviour). Therefore, an analytical model of the piezoelectric disc, core driver of the cymbal, and its dynamics under an electrical signal are presented in this article. The function describing the radial motion of the disc, distribution of the electrical potential along the thickness, and displacement along the thickness are obtained analytically. The obtained radial motion function will be used for modelling the end cap amplification as a compressive loading