On mechanical damping of cantilever beam-based electromagnetic resonators

Muhammad Faruq Foong, Chung Ket Thein, Daniil Yurchenko

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)
679 Downloads (Pure)


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 damping dominates thermoelastic and air damping, hence becoming the major contributor
towards the mechanical damping. A novel method is proposed to define material damping in terms of the maximum critically damped stress at resonance. The new method is shown to be simpler and more accurate than previous methods. Using the developed governing equations, the conditions of optimum load resistance are derived for two particular cases. A comparison is made between the mechanical damping model and the constant mechanical damping assumption in terms of maximum power output. Different trends were noted between the two compared methods, suggesting that the constant mechanical damping assumption can lead to large errors in power prediction. Further analysis describes the existence of an optimum mass ratio for electromagnetic resonators operating under a low magnetisation parameter. Lastly, this paper shows that different frequency tuning methods are preferable under different operating conditions.
Original languageEnglish
Pages (from-to)120-137
Number of pages18
JournalMechanical Systems and Signal Processing
Early online date27 Sept 2018
Publication statusPublished - 15 Mar 2019


  • Cantilever beam
  • Electromagnetic resonator
  • Frequency tuning
  • Mechanical damping
  • Stress

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Signal Processing
  • Civil and Structural Engineering
  • Aerospace Engineering
  • Mechanical Engineering
  • Computer Science Applications


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