Design and optimisation of 3D-printed energy harvesters for railway bridges

This paper investigates energy harvesting on railway bridges. The type of harvester studied is a cantilever bimorph beam with a mass at the tip and a load resistance. These parameters are adjusted to find the optimal design that tunes the harvester to the fundamental frequency of the bridge. An analytical model based on a variational formulation to represent the electromechanical behaviour of the device is presented. The optimisation problem is solved using a genetic algorithm with constraints of geometry and structural integrity. Additive manufacturing to 3D print energy harvesters is used to maximise design flexibility and energy performance. The proposed procedure is implemented in the design and manufacture of an energy harvesting device for a railway bridge on an in-service high-speed line. The structure under study corresponds to a six-arched concrete bridge with double ballasted track. The proposed design is experimentally validated and the performance under operating conditions is evaluated in a test field.