Chung Ket Thein

University of Nottingham Ningbo China | Ningbo · School of Aerospace

This study investigates wind energy harvesting from electromagnetic dual cantilever flutter (DCF) and multi cantilever flutter (MCF) arrays. Initially, the bare DCF was tested under several wind speeds at four different gap distances to analyse and verify its behaviour. Results suggest that the characteristics of the DCF is ideal for electromagneti...

As reactive components, capacitors and inductors play an important role in the tuning of energy harvesters, but only a few monotonic connection modes between reactive components and load resistors are usually considered. The impact of diverse connection modes between reactive components and load resistor on energy harvester is worth exploring. In t...

An investigation on how the degree of coupling determined by the coil size and the magnet spacing affects the bandwidth and or resonance of an electromagnetic vibration energy harvester was presented in this work. The vibration energy harvesting model was realized as a magnet mounted on a linear spring, the response of the magnet was however constr...

In high-speed electrical machines (HSEM), mechanical vibration associated with critical speeds of rotor systems can be detrimental to the machine operational stability, especially for vibration near resonances. The structural sizing of a rotor system is often constrained to its mechanical parameters, such as its overall weight, maximum torque, and...

This work investigated the dynamic responses and evaluated the performance of a two-degree-of-freedom (2DOF) coupled coil-magnet electromagnetic vibration harvester excited at low frequencies. Three different connection modes with individual, in-series, and in-parallel configurations of the transduction coils were considered. Such approach was take...

The current revolution in the field of electromagnetic vibration energy harvester requires that both wireless sensor nodes and relevant power sources be cost- and size-optimized while ensuring that, during design/fabrication of the sensor’s power sources, the power deliverable to the sensors be maximum. Flux density dependency on the nature of the...

This paper proposes composite laminates interleaved with recycled carbon fiber and short virgin aramid fiber non-woven mats to enhance the trade-off of mechanical damping and stiffness. Compared with their virgin counterparts, recovered carbon fibers (rCFs) have the potential for damping enhancement at the cost of only minimal degradation in streng...

Carbon fiber reinforced polymer composites (CFRPs) are one of the most widely used composite types and wastes associated with them (CFRPs) get generated through either their manufacturing or end-of-service-life. Predominately due to environmental concerns and governmental regulations, recycling these CFRPs is needed and to make use of the recycled...

This study investigates the structural optimisation of a multi-cantilevered electromagnetic anti-phase energy harvester by considering the optimum material choice. The mathematical model for the harvester was first developed, displaying an excellent correlation when compared with the experimental results. Afterwards, the anti-phase harvester was st...

Triangular cantilever beams are often desired in piezoelectric vibration energy harvesting applications, as they result in a better performance due to the higher and more uniform stress they exhibit. However, the application of this cantilever geometry has not yet been explored for other transduction methods. In this study, the application of a tri...

Due to the increased demand for a sustainable source of energy, the research on energy harvesting has increased in the last twenty years. Energy harvesting aims to gain energy from the ambient environment and convert this energy into electrical power. There are different kinds of renewable energy sources and vibration energy harvesting (VEH) is the...

Sensors are devices that measures a change in physical stimulus by converting it into an electronic signal which can be read by a designated instrument. To overcome the real-life challenges associated with powering a sensor using conventional batteries and chargers, this work focuses on formulating analytical framework for designing an ecofriendly,...

Abstract—This work considered an energy harvester system with tip coil and a permanent magnet modelled as an equivalent SDOF system. The aim here is to adequately redefine the electromagnetic damping ratio of electromagnetic energy harvester from the established principles of electromagnetic transduction of the Maxwell’s equations and the Faraday’s...

The paper proposes a novel electromagnetic vibration energy harvester based on the concept of anti-phase vibration. Anti-phase motion is desirable in electromagnetic vibration energy harvesting applications as it results in a higher power output due to the increase in the relative velocity between the coil and the magnet components. The proposed de...

This chapter reviews present usage of vibration-based energy harvesting (VEH) devices and their applications. The evolution of energy resources and advancement in electronic technologies has resulted in the need for a self-sustainable wireless/portable electronic device in current modern society. Batteries are non-beneficial in the miniaturization...

This paper demonstrates a two-stage optimisation for a single-degree-of-freedom (SDOF) electromagnetic vibration energy harvester under a harmonic base excitation vibration. In this paper, a designed cantilever beam was used to verify the optimisation methods. The dynamics of the beam was modelled using the Euler-Bernoulli beam theory. By deriving...

This study investigates several important considerations to be made when optimising the structural aspects of a single-degree-of-freedom (SDOF) electromagnetic vibration energy harvester. Using the critically damped stress method, the damping and power output of the harvester were modelled and verified, displaying an excellent agreement with the ex...

A cantilever beam-based vibration energy harvester is generally preferred due to its simplicity and effectiveness as compared to a spring mass system. This paper analyses the use of a spring to amplify the performance of a conventional single degree of freedom (SDOF) cantilever beam-based vibration energy harvester. A spring was introduced to modif...

Often when optimising a vibration energy harvester, the mechanical damping is given little significance and is usually assumed to be a constant. This paper analyses the importance of mechanical damping variation in modelling the behaviour of a cantilever beam-based electromagnetic resonator. It is shown that for beam volumes above 100 mm³, material...

This paper proposes a novel method to increase the power output of a cantilever beam-based electromagnetic vibration energy harvester through anti-phase resonance. A new cantilever beam design is presented to achieve this. By introducing an anti-phase motion between the coil and the magnets at resonance under the same base excitation input, the rel...

Research has shown that the damping of a vibrating structure is highly dependent on its stress function. In this study, the bending stress and damping of wide cantilever beams under free vibration were analyzed using the classical plate and beam theory. The damping stress equation for cantilever beams under free vibration was derived based on the e...

This paper presents a novel and simplified method to predict the damping ratio and power output of a cantilever-based electromagnetic vibration energy harvester through finite element analysis. A strong relationship was determined between the mechanical damping of a structure and the resonant stress at the clamped end of the structure under critica...

Vibration energy harvesting has emerged as a promising source of sustainable power for wireless sensor networks. This paper describes the effect of alike magnetic pole repulsion on the natural frequency and operational bandwidth of a cantilever-based vibration energy harvester. Experimental result shows that the magnetic repulsive force produced by...

The concept of Internet of Things has prompted the need for a sustainable energy source to power wireless sensor networks. Vibration energy harvesting emerges as an applicable option. This paper presents a finite element analysis of a new electromagnetic vibration energy harvester design aimed to increase the power output of an electromagnetic vibr...

Vibration energy harvesting has emerged as a promising source of sustainable energy to power small electronics. This study investigates the effect of total damping on the power output of an electromagnetic vibration energy harvester. Analytical results show that an increase in the effective mass of the harvester increases the mechanical damping but...

The optimisation process of a vibration energy harvester is usually restricted to experimental approaches due to the lack of an analytical equation to describe the damping of a system. This study derives an analytical equation, which describes the first mode damping ratio of a clamp-free cantilever beam under harmonic base excitation by combining t...

Piezoelectric materials are excellent transducers for converting mechanical energy from the environment for use as electrical energy. The conversion of mechanical energy to electrical energy is a key component in the development of self-powered devices, especially enabling technology for wireless sensor networks. This paper proposes an alternative...

This chapter reviews present usage of vibration-based energy harvesting (VEH) devices and applications. The evolution of energy resources and advance in electronic technologies has resulting the need of self-sustainable wireless/portable electronic devices in current modern society. Batteries are non-beneficial in the miniaturization process of ele...

This chapter reviews present usage of vibration-based energy harvesting (VEH) devices and applications. The evolution of energy resources and advance in electronic technologies has resulting the need of self-sustainable wireless/portable electronic devices in current modern society. Batteries are non-beneficial in the miniaturization process of ele...

Piezoelectric materials are excellent transducers in converting vibrational energy into electrical energy, and vibration>based piezoelectric generators are seen as an enabling technology for wireless sensor networks, especially in self>powered devices. This paper proposes an alternative method for predicting the power output of a bimorph cantilever...

This paper presents a parametric study on the development of a computational model for bias two-wheel tire through finite element analysis (FEA). An 80/90- 17 bias two-wheel tire was adopted which made up of four major layers of rubber compound with different material properties to strengthen the structure. Mooney-Rivlin hyperelastic model was appl...

This paper presents a novel switched damping method which is able to improve the operational bandwidth of a linear electromagnetic energy harvester. In this system, different damping coefficients, in which values are computed based on the adaptive percentage-varying factor, are electronically switched at different points within the predefined oscil...

This paper presents a structural application of a sizing and shape based on a reliability-related multi-factor optimisation. The application to a load cell design confirmed that this method is highly effective and efficient in terms of sizing and shape optimisation. A simple model of the S-type load cell is modelled in finite element analysis softw...

Purpose – The aim of this paper is to present a novel multifactor structural optimisation method incorporating reliability performance. Design/methodology/approach – This research addresses structural optimisation problems in which the design is required to satisfy multiple performance criteria, such as strength, stiffness, mass and reliability un...