Experimental and Numerical Studies of a Soft Impact Piezoelectric Energy Harvesting Using an MR Fluid

Numerical and an experimental study of a soft impact-based piezoelectric energy harvesting system employing a thin layer of magnetorheological (MR) fluid as the impact object is presented in this paper. MR fluid devices are mostly used as vibration suppressors in automobiles and other machinery. MR fluids exhibit variable rheological properties in the presence of a magnetic field, which makes them excellent vibration attenuation devices with easily adaptable damping forces. This behavior can be exploited in vibration energy harvesting to aid frequency up-conversion. The study is carried by solving the theoretical equations numerically and then validating the results experimentally. The Heaviside function is used to model the piecewise nonlinear dynamics of the proposed system. In this way, the sticky and inelastic behavior of the fluid, which causes a time-delay in the oscillations of the beam is best described. The results obtained indicated that increasing the magnetic field increases the voltage generated through frequency amplification. The voltage obtained with a load resistance of 200 k $\Omega $ increased from 9.29 V to 9.42 V when the magnetic field increases from 0.04T to 0.08T for the numerical study and 7.71 V to 8.46 V when the field increased from 0.044T to 0.085T in the experimental study. The frequency is amplified from 59.58 Hz at 0.04T to 82.76 Hz at 0.08T for the numerical results and from 61.02 Hz at 0.044T to 83.04 at 0.085T for the experimental results. The MR fluid acts as a soft impact object in this work.