Measuring bending stress on an ice/aluminium composite beam interface using an embedded piezoelectric PVDF (polyvinylidene-fluoride) film sensor

This paper deals with the measurement of the interfacial stress of a composite beam using an embedded piezoelectric PVDF (polyvinylidene-fluoride) strip. The composite beam consists of an aluminium beam on which an ice layer is deposited. The ice layer is formed from sprayed supercooled water droplets, simulating atmospheric icing of exposed structures. The beam is submitted to sinusoidal stress at the ice/aluminium interface by an electromagnetic shaker clamped to one end of the beam. The use of PVDF strips as a stress measurement apparatus was validated by numerical simulations. Experimental results demonstrated that a 25 µm thick PVDF strip used as an embedded interfacial stress sensor is sensitive only to bending stress and does not allow the measurement of interfacial shear stress. That way, the adhesion strength of an atmospheric ice layer cannot be measured. However, the use of embedded PVDF strips provides a new and original method for measuring the ice adhesion strength on different substrates, due to high repeatability and sensitivity of the measurement