Grzegorz Litak

Lublin University of Technology · Department of Automation

The chromium nitride coating is a hard coating used to improve the sliding friction and wear behavior and is applied to engine components in various operating conditions even at an elevated temperature. In this study, chromium nitride was deposited by a physical vapor deposition process onto the cast iron substrate. All tribological tests were perf...

This paper examines the oscillations of a spherical pendulum with horizontal Lissajous excitation. The pendulum has two degrees of freedom: a rotational angle defined in the horizontal plane and an inclination angle defined by the pendulum with respect to the vertical z axis. The results of numerical simulations are illustrated with the mathematica...

As an effective means to overcome the shortcomings of linear systems only performing well near the resonance frequency, monostable piezoelectric energy harvesters (MPEHs) have been investigated widely in the area of energy harvesting. However, it is difficult to achieve a perfectly symmetric potential energy function due to the asymmetries in magne...

This paper presents the results of numerical simulations of a non-linear, tristable system for harvesting energy from vibrating mechanical devices. Detailed model tests were carried out in relation to the system consisting of a beam and three permanent magnets. Based on the derived mathematical model and assuming a range of control parameter variab...

Due to the broadband response characteristics at low levels of excitations, nonlinear multistable systems have garnered a great deal of attention in the area of energy harvesting. Moreover, various performance enhancement strategies of multistable harvesters have been proposed and discussed extensively for systems with perfectly symmetric potential...

We study the effect of an amplification mechanism in a nonlinear vibration energy harvesting system where a ferromagnetic beam resonator is attached to the vibration source through an additional linear spring with a damper. The beam moves in the nonlinear double-well potential caused by interaction with two magnets. The piezoelectric patches with e...

In this work, we explore the nonlinear dynamics for capturing energy from a device, which is considered support with cantilever beam ferromagnetic containing piezoceramic patches connected to an electrical circuit that collects energy for capture. The free end of the ferromagnetic cantilever beam is under the effect of two magnetic poles, and we co...

Traditional structures adopt a split design with vibration control, energy harvesting and monitoring, which is difficult to meet the needs of technological development. The development of new structure from a single function to a multifunctional integration structure requires that the structure not only has the characteristics of low-frequency vibr...

In this paper, we compare three energy harvesting systems in which we introduce additional bumpers whose mathematical model is mapped with a non-linear characteristic based on the hyperbolic sine Fibonacci function. For the analysis, we construct non-linear two-well, three-well and four-well systems with a cantilever beam and permanent magnets. In...

The phenomenon of amplitude jump usually means the presence of multi-solution ranges and unstable periodic solutions, which has not been fully explored in the field of vortex-induced vibration energy harvesting. In this study, semi-analytical periodic solutions of vortex-induced vibration energy harvesters (VIVEHs) are obtained using the incrementa...

This article classifies the dynamic response of rolling bearings in terms of radial internal clearance values. The value of the radial internal clearance in rolling-element bearings cannot be described in a deterministic manner, which shows the challenge of its detection through the analysis of the bearing's dynamics. In this article, we show the o...

The paper presents the application of a new impulse excitation diagram (IED) to help realize high-energy orbits in nonlinear energy harvesting systems. In the case of non-linearity, we can deal with the occurrence of coexisting solutions and the proposed diagram allows for the use of the impulse excitation method in order to change the solution. Fo...

Dynamical systems for kinetic energy harvesting have recently been designed that use nonlinear mechanical resonators and corresponding transducers to create electrical output. Nonlinearities are important for providing a broadband input frequency efficiency, which is necessary to ensure that the output voltage is at a satisfactory level in the case...

Dynamical systems for kinetic energy harvesting have recently been designed that use nonlinear mechanical resonators and corresponding transducers to create electrical output. Nonlinearities are important for providing a broadband input frequency efficiency, which is necessary to ensure that the output voltage is at a satisfactory level in the case...

The basic types of multi-stable energy harvesters are bistable energy harvesting systems (BEH) and tristable energy harvesting systems (TEH). The present investigations focus on the analysis of BEH and TEH systems, where the corresponding depth of the potential well and the width of their characteristics are the same. The efficiency of energy harve...

Paper presents computer simulations conducted to study the influence of the configuration of an energy harvesting system with tunnel mechanical characteristics in terms of its energy generation efficiency. In this context, numerical simulation experiments were carried out to assess the impact of physical properties and initial conditions on the occ...

This paper proposes a novel vortex-induced vibration piezoelectric energy harvester attached to two asymmetrical splitter plates (VIVPEH-S), which aims at converting the vibration mode from vortex-induced vibration (VIV) to galloping and improving the energy harvesting efficiency. The conceptual designing of VIVPEH-S with two asymmetrical splitter...

Energy harvesters based on non-linear systems are promising devices for extracting energy from mechanical vibrations. This paper presents a new design of energy harvester consisting of two coupled nonlinear systems; the Duffing oscillator and a system with quasizero stiffness. A numerical analysis of the dynamics of the harvester is carried out, pr...

In the paper, flow boiling in three parallel minichannels with a common inlet and outlet area was examined. The synchronization between flow distributions in minichannels was analyzed in local area (image analysis) and as the process of the synchronization between inlet and outlet pressure fluctuations. These processes were studied using cross recu...

This paper presents the results of numerical simulations of a non-linear, bistable system for harvesting energy from ambient vibrating mechanical sources. Detailed model tests were carried out in relation to the system consisting of a piezoelectric beam with additional springs attached. Based on the springs selection symmetry of potential wells was...

A nonlinear energy harvester with asymmetric potential wells is studied numerically. An energy transducing piezoelectric patch is attached to the cantilever elastic beam to harvest kinetic energy of the moving frame. To obtain an asymmetric effect in the double well potential induced by permanent magnets, an elastic ferromagnetic beam resonator mis...

This article demonstrates the possibility of energy harvesting by mistuned pendulums with torsional coupling. Two pendulums of different lengths with coils and magnets at the pivots are used as electromagnetic harvesters. The ambient energy source to the system is considered in the form of harmonic base excitations. Torsional coupling is achieved b...

In this work, we analyzed the nonlinear fractional dynamics in the equations of motion of a bar coupled to support under the effect of a potential described by two equally spaced magnetic poles. We also considered Bouc–Wen damping in the equations of motion. For external force vibrations, we considered an equation of a non-ideal motor based on the...

Interpretation of acceleration time-series from rolling-element bearings is sometimes challenging if no prior knowledge of the system is available. The evaluation must adapt operational conditions or the actual value of operational parameters. In our analysis, we apply the machine learning methods and statistical indicators in the diagnosis of dyna...

The subject of the research contained in this paper is a new design solution for an energy harvesting system resulting from the combination of a quasi-zero-stiffness energy harvester and a two-stage flexible cantilever beam. Numerical tests were divided into two main parts-analysis of the dynamics of the system due to periodic, quasiperiodic, and c...

The influence of heat, developed in process, on the performance of bearings applied in rotational systems is often studied. In the present work, the influence of thermal expansion on the reduction of the radial clearance after assembly and the dynamics of the self-aligning ball bearing are experimentally studied. The course of the temperature chang...

We use friction to simultaneously damp and excite a pendulum system. A Froude pendulum attached to a suspension shaft is subjected to a frictional load. We investigate two types of response of the system: regular and chaotic responses, depending on the excitation frequency. A transient chaotic solution was also obtained. We identify the motions usi...

We examine the nonlinear response of two planar pendula under external and kinematic excitations, which are very relevant as paradigmatic models in nonlinear dynamics. These pendula act under the action of an additional constant torque, and are subjected to one of the following excitations: a further external periodic torque, and a vertically perio...

In this paper, an electronic circuit based on Macek equations was developed in which the phenomenon of hyperchaos was observed. Synchronization of signals was applied using the technique optimal linear feedback control (OLFC) and embedded in digital signal processor (DSP), with the circuit with hyperchaotic behavior as a master system and a periodi...

PurposeThe present work examines the influence of additional moderate amplitude high-frequency (HF) excitation on energy harvesting (EH) in the inertially excited bistable Duffing-type harvester with nonlinear damping.Method By introducing the slow and fast time scale we split the dynamics of the electromechanical system and obtain the effective ha...

With the advent of technology miniaturization, portable electronic devices are evolving at a rapid pace, especially in the field of wireless sensor networks for IoT applications. On the contrary, battery technology has not seen a similar growth in miniaturization. Also, frequent replacement of batteries is challenging for devices located in remote...

In this work, we present a quantitative and qualitative analysis of the dynamic response of ball bearings dependent on radial internal clearance. We measured the vibrations of a rotating system based on self-aligning ball bearings for different clearances and rotating speeds. The analysis of vibration spectra was conducted considering a set of diff...

Hydroxyapatite possesses desirable properties as a scaffold in tissue engineering: it is biocompatible at a site of implantation, and it is degradable to non-toxic products. Moreover, its porosity enables infiltration of cells, nutrients and waste products. The outcome of hydroxyapatite implantation highly depends on the extent of the host immune r...

In this work, modeling and nonlinear analysis of an energy harvesting system from vibrating mechanical devices are presented. Detailed model analyses are carried out for the system consisting of two flexible beams interconnected mechanically through elastic and dissipative elements and electrically by circuits through piezoelectric patches. During...

Vibration mitigation is atracting lot of researcher to safegaurd machines and structurs. Energy harvesting along with vibration mitigation gives added advantage of generating enough electrical energy to powerup sensors. Vibration energy harvesting converts vibration into useful electrical energy using suitable trnsduction method. Nonlinear energy s...

Broadband frequency energy harvesting systems are based on nonlinear resonators. Ambient kinetic energy is transformed to electric energy by a piezoelectric patch installed on the elastic beam. In this paper we study a bistable energy harvester consisted of the resonator with some nonlinearities induced by magnets. The system is excited with the co...

In this paper, a study on modelling energy harvesting efficiency of a quasi-zero stiffness system is presented. Mechanical characteristics of the system are identified, and the effect of its stiffness and geometry on the function describing energy potential barrier is determined. It has been shown numerically that an increase in equivalent stiffnes...

We investigated the mathematical model of a ferromagnetic cantilever beam containing patches of piezoceramic materials for vibration energy harvesting. The beam is coupled to a hysterical Bouc-Wen damper. One of the beam end is clamped to the vibrating frame. It contains the piezoelectric patch coupled to an electric circuit for energy transduction...

Ambient vibration conditions greatly influence the response of nonlinear energy harvesters. Recently, simulations and experiments have verified that tristable energy harvesters have excellent energy harvesting performance and complex nonlinear characteristics, which are important in broadening their effective operating frequency range. The response...

The subject of the model research contained in this paper is a new design solution of the energy harvesting system with a star-shaped structure of elastic elements and variable configuration. Numerical experiments focused mainly on the assessment of the configuration of elastic elements in the context of energy harvesting efficiency. The results of...

In this paper, a study on modelling energy harvesting efficiency of a quasi-zero stiffness system is presented. Mechanical characteristics of the system are identified, and the effect of its stiffness and geometry on the function describing energy potential barrier is determined. It has been shown numerically that an increase in equivalent stiffnes...

We propose a system for collecting energy based on a structure with two bars, in which one of its ends is embedded in the moving system frame and the other end is under the action of magnetic fields. The recessed tips are connected to an electrical system in which a resistor generates a voltage due to the current produced by the PZT deformations. H...

Dual Energy X-ray Absorptiometry (DXA) is a tool that allows the assessment of bone density. It was first presented by Cameron and Sorenson in 1963 and was approved by the Food and Drug Administration. Misplacing the femoral neck box, placing a trochanteric line below the midland and improper placement of boundary lines are the most common errors m...

The piezoelectric energy-harvesting system with double-well characteristics and hysteresis in the restoring force is studied. The proposed system consists of a bistable oscillator based on a cantilever beam structure. The elastic force potential is modified by magnets. The hysteresis is an additional effect of the composite beam considered in this...

This chapter presents the results of computer simulations of the system of energy harvesting from vibrating mechanical devices. Detailed model tests were carried out for the system of cantilever beams coupled with elastic elements. The end of one vibrating element is loaded with a permanent magnet, which defines a non-linear potential characteristi...

In this work, the investigation of energy harvesting for a U-frame-type (portal frame) structure is presented. The structure is considered as a composite made out of a Shape Memory Alloy (SMA), accounting for a non-ideal DC motor of limited power supply attached to its rigid body. The energy harvesting is carried out using a piezoelectric material...

Tribological behaviour is characterized by the strong nonlinear effects in its response, which are hardly identified with standard signal processing methods. One of the challenges in the analysis of wear phenomena is identification of its propagation and potential quantification. In our study, we propose application of wavelet-based methods, i.e. c...

This paper presents the results of modelling a new nonlinear multi-stable QZEH (quasi-zero energy harvester) system for harvesting energy from vibrating mechanical devices. Detailed tests were carried out on the system model, which consisted of a beam and a system of springs, which were used to determine the potential of a quasi-flat well. Two-dime...

The special issue entitled "Mathematical modelling, nonlinear dynamics, bifurcation, synchronization and control of mechanisms driven by power supply," published by The European Physical Journal: Special Topics (EPJST), aims to bring into discussion works involving nonlinear and dynamic and chaotic behaviors, which are frequently found in mechanica...

This paper analyzes the energy efficiency of a Micro Fiber Composite (MFC) piezoelectric system. It is based on a smart Lead Zirconate Titanate material that consists of a monolithic PZT (piezoelectric ceramic) wafer, which is a ceramic-based piezoelectric material. An experimental test rig consisting of a wind tunnel and a developed measurement sy...

This paper investigates the nonlinear dynamics of a flexible tyre coupling via computer modelling and simulation. The research mainly focused on identifying basins of attraction of coexisting solutions of the formulated phenomenological coupling model. On the basis of the derived mathematical model, and by assuming ranges of variability of the cont...

In the present work, a method for the analysis of short time intervals in ball bearings is proposed. We study the effect of the internal clearance on the dynamics of ball bearings using recurrence plots and the recurrence quantification approach. In the proposed method, we focused on the analysis of dynamic states generated from the 2-DOF mathemati...

In this paper, the dynamical behavior of a four-dimensional magnetohydrodynamic model, consisting of a generalized Lorenz model, is investigated. A nonlinear dynamical analysis is performed using Lyapunov exponents and bifurcation diagrams, focusing on the chaotic and hyperchaotic behaviors associated with the bifurcation parameter \(\left( k_{1} \...

The paper proposes and investigates nonlinear vibrations mitigation strategies of an externally excited pendulum. This problem is highly relevant to the crane’s payload behavior, which dynamics is typically described by a nonlinear pendulum model. Currently, there are various active control strategies to mitigate swinging vibrations of the payload...

In the paper, a new 3D energy harvesting system is provided. This work discussed the Lagrange approach to derive the differential equations of motion in the case of energy harvesting systems. An electromechanical system consists of a mechanical resonator, a piezoelectric transducer and electrical circuit with the load resistor. A flexible slender r...

In this paper, the frequency broadband effect in vibration energy harvesting was studied numerically using a quasi-zero stiffness resonator with two potential wells and piezoelectric transducers. Corresponding solutions were investigated for system excitation harmonics at various frequencies. Solutions for the higher voltage output were collected i...

This work aimed to investigate the performance of the process of capturing electricity through piezoelectric ceramic materials, installed in one and two elastic beams due to the action of magnetic field forces, of non-linear behaviour and subject to different forms of excitement of the environment.

A four-degree-of-freedom mechanical system composed of two weakly coupled modules with external forcing is modelled and numerically investigated. Each module contains internal vibro-impact oscillator. The mathematical model is built based on the compliant impacts with realistic nonlinear stiffness and damping characteristics. The model of resistanc...

This paper analyzes the dynamics of a nonlinear piezoelectric energy harvesting device connected to a portal frame accounting for the influence of the fractional order derivative introduced due to damping. The identification of the behavior of the portal frame is obtained by the analysis of time histories, phase planes, FFT spectrum and 0-1 test. T...

The two-phase flow patterns (air–water) in horizontal square minichannel (3 x 3 mm) has been analysed. The multifractal analysis of pressure drop fluctuations was used for qualitative assessment of two-phase flow patterns. The results of the complexity analysis using the multifractal exponents spectra. The proposed method allows us to identify the...

A frequency transmission band of the nonlinear energy harvester is studied numerically. For the analysis, the nonlinear piezoelectric energy harvesting system based on cantilever elastic beam is applied to harvest kinetic energy of the moving frame. We used a double well potential induced by permanent magnets for a ferromagnetic beam resonator. A p...

The automotive industry faces huge challenge in environmental protection by reducing fossil fuels and energy consumption by developing various practical solutions in energy harvesting. The current analysis is related to the diesel engine power supply system in a passenger off-road vehicle for the application of the piezoelectric energy harvesting s...

The stochastic resonance (SR) in a bistable system driven by nonlinear frequency modulation (NLFM) signal and strong noise is studied. Combined with empirical mode decomposition (EMD) and piecewise idea, an adaptive piecewise re-scaled SR method based on the optimal intrinsic mode function (IMF), is proposed to enhance the weak NLFM signal. At firs...

Often the input values used in mathematical models for rolling bearings are in a wide range, i.e., very small values of deformation and damping are confronted with big values of stiffness in the governing equations, which leads to miscalculations. This paper presents a two degrees of freedom (2-DOF) dimensionless mathematical model for ball bearing...

Radial internal clearance (RIC) is one of the most important parameters influencing on rolling bearing exploitation in mechanical systems. Lifetime of rotary machines strongly depends on a condition of applied rolling elements, thus a study on applied clearance is very important in terms of maintenance and reliability. This paper proposes, a novel...

Vibration energy harvesting systems are using real ambient sources of vibration excitation. In our paper, we study the dynamical voltage response of the piezoelectric vibrational energy harvesting system (PVEHs) with a mechanical resonator possessing an amplitude limiter. The PVEHs consist of the cantilever beam with a piezoelectric patch. The prop...

Vibration energy harvesting systems are using real ambient sources of vibration excitation. In our paper, we study the dynamical voltage response of the piezoelectric vibrational energy harvesting system (PVEHs) with a mechanical resonator possessing an amplitude limiter. The PVEHs consist of the cantilever beam with a piezoelectric patch. The prop...

In this paper, a tristable viscoelastic isolation system with stochastic excitation under both displacement and velocity delayed feedback control is considered. Firstly, the theoretical expressions of the mean first-passage time (MFPT) to measure the activated escape between different potential wells are derived. Induced nonlinear transition dy