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Investigation to the influence of additional magnets positions on four-magnet bi-stable piezoelectric energy harvester

Li Xinxin, Huang Kexue, Li Zhilin, Xiang Jiangshu, Huang Zhenfeng, Mao Hanling, Cao Yadong

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2022

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Vol. 70, nr 1

art. no. e140151

EN

To enhance the harvesting performance of a bi-stable piezoelectric energy harvester (BEH), this work proposes a four-magnet BEH (FBEH). FBEH consists of a piezoelectric cantilever beam with a tip magnet, a fixed magnet and two movable magnets. The two movable magnets relative to the fixed magnet can move in both horizontal and vertical directions. A nonlinear distributed parameter model of FBEH is derived through the Hamilton principle. The effects of the excitation frequency and amplitude as well as the horizontal and vertical gap on the harvesting performance are mainly investigated by using the bifurcation diagram, phase diagram, Poincaré map and output power. Numerical simulations demonstrate that the proposed FBEH decreases the potential barrier and creates a higher than typical bi-stable one when subjected to lower excitation amplitudes and frequencies.

2

Locking the movement of persons on the bridge crane

Kuľka Jozef, Mantič Martin, Kopas Melichar, Faltinová Eva

Advances in Science and Technology. Research Journal

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2018

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Vol. 12, no 2

260--265

EN

This article describes the design of a horizontal rope system for increasing the safety of work and movement on a specific device operating in height. This system is designed to be installed on a conventional existing crane footbridge or crane track structure and this system enables a free pass along the rope, without unclamp of spring hook on prolongation rope. The calculation was made by non-linear dynamic FEM analysis.

3

Nonlinear dynamic analysis of a rectangular plate subjected to accelerated/decelerated moving load

Mamandi A., Mohsenzadeh R., Kargarnovin M. H.

Journal of Theoretical and Applied Mechanics

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2015

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Vol. 53 nr 1

151--166

EN

In this paper, nonlinear dynamical behavior of a rectangular plate traveled by a moving mass as well as an equivalent concentrated force with non-constant velocity is studied. The nonlinear governing coupled partial differential equations (PDEs) of motion are derived by energy method using Hamilton’s principle based on the large deflection theory in conjuncture with the von-Karman strain-displacement relations. Then Galerkin’s method is used to transform the equations of motion into a set of three coupled nonlinear ordinary differential equations (ODEs) which then is solved in a semi-analytical way to get the dynamical response of the plate. Also, by using the Finite Element Method (FEM) with ANSYS software, the obtained results in nonlinear form are verified by FEM results. Then, a parametric study is conducted by changing the size of moving mass/force and the velocity of the traveling mass/force with a constant acceleration/deceleration, and the outcome nonlinear results are compared to the results from linear solution.

4

The investigation of the influence of a local elastic nonlinearity on vibrations of plane truss members

Pielorz A.

Engineering Transactions

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2003

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Vol. 51, iss.1

3-24

EN

The paper concerns theoretical investigations of plane trusses subject to longitudinal deformations, using nonlinear discrete-continuous models. An external excitation is applied to a rigid body located in a truss joint. In this joint a visco-elastic discrete element with a spring having a nonlinear symmetric stiffness is also located. It is assumed that the spring characteristic is of a soft type. Four nonlinear functions describing this characteristic are proposed. In the considerations the wave method is applied similarly to the case of a hard characteristic in [1]. The numerical analysis focus on the investigation of the effect of the local nonlinearity with a soft characteristic for two examples of plane trusses.

5

Discrete-continuous models in nonlinear dynamic investigations of selected physical systems

Pielorz A.

Engineering Transactions

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1999

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Vol. 47, iss. 2

155-171

EN

The paper deals with dynamic investigations of nonlinear discrete- continuous models in which elastic elements are deformed torsionally, longitudinally or transversally, and the classical wave equation can be used for the description of their motion. The investigations focus on nonlinear vibrations of the discrete-continuous models with a local nonlinearity described by the polynomial of a third degree. The detailed analysis for a simple nonlinear discrete-continuous system is done. It is shown that amplitude jumps in the case of a hard characteristic and the escape phenomenon in the case of a soft characteristic can occur.