This work reports a comparative study on piezoelectric energy harvesting from vortex-induced vibration (VIV) with multi-stability characteristics by introducing the nonlinear magnetic forces. A lumped-parameter model for the piezoelectric cantilever-cylinder structure is considered for the sake of qualitative investigation. Firstly, the buckling displacement of harvester in monostable and bistable configurations is evaluated by virtue of a static analysis. Then, the coupled frequency and damping of the harvester varying with the electrical load resistance are determined for different values of the spacing distance between magnets. Subsequently, the dynamic behaviors and generated voltage of the harvester in two configurations are elaborately investigated, showing that varying the spacing distance is followed by a shift of lock-in region which is significant for performance optimization according to ambient wind conditions. In addition, the results show the harvester in monostable configuration displays a hardening behavior while a softening behavior takes place in bistable configuration, both of the harvester in two configurations can widen the synchronization region.

The implementation of Industry 4.0 requires a digital transformation incorporating industrial internet of things (IIoTs) involving continuous data acquisition, storage, and utilization for an automated decision support system to provide optimum efficiency. For this digital transformation, autonomous wireless sensor networks (WSNs) are essential and can work for long periods, sometimes years or decades. Powering these WSNs remains a challenge while energy harvesting technologies are considered a potential long-term solution; hence the concept of Industry 4.0 is complete with the incorporation of energy harvesting systems. In this chapter, the latest research advances on energy harvesting in Industry 4.0 are summarized, providing a clear framework for selecting the right phenomenon, type, and excitation. For this purpose, types of energy harvesting with advantages and limitations, available sources of ambient energy and excitation phenomena, viable transduction mechanisms, and insight into possible applications are discussed in Industry 4.0 perspective. In the end, two case studies are included, followed by future trends and possibilities. <!----> <!----> <!----> <!---->