Analysis of a Multi-Degree-Freedom PDMS Composite Cantilever Beam for Energy Harvesting

Harvesting energy from moving bodies, especially automobiles and its local use to save external energy is the order of the day. Many attempts are made to harvest energy for car vibrations during travel and use it locally to energize devices like tire pressure monitors, dashboard lighting, etc. Vertical oscillations in a car during travel are with different displacement and frequencies. A harvester has to deform maximum for each of these so that more energy can be obtained. In the present work, a multi-degree-freedom cantilever made of polydimethylsiloxane and zinc oxide composite material is proposed and evaluated through Finite Element Analysis for base excitation at a natural frequency. Strain in the beam, which manifests as voltage due to piezo-electric property of the material, is found to be near maximum for most of the amplitudes and frequencies. The two-slot geometry of four beam structure is analyzed independently. It is concluded that the Eigen frequency reduces, and the device can be subjected to near resonance vibration during the service. Lowest Eigen frequency, highest displacement, and electric potential were observed for three-beam configurations.