On the Use of PVDF Sensors for Experimental Modal Analysis

Abstract

Polyvinylidene fluoride (PVDF) piezoelectric thin film sensors are already well-known as low-cost vibrational sensors. One of the primary reasons, in addition to the overall cost, is also the PVDFs high chemical resistance, thermal stability and flexibility, which makes them a compelling alternative to piezoelectric ceramic. The PVDF sensors can also be used to measure strain response, similarly to the piezoelectric strain gauges. In this paper a performance evaluation of a PVDF sensor and a commercially available piezoelectric strain gauge is made for the mode shape identification on a simple-beam structure. The estimated mode shapes using the PVDF sensor are compared to the mode shapes estimated from a piezoelectric strain gauge. Mode shapes for both sensors are estimated using a roving hammer excitation. The two sensors are compared using a coherence criterion for the FRFs and the identified mode shapes are compared using a MAC criterion. Promising results can be observed with the PVDF sensor, which can be regarded as a replacement for the standard piezoelectric strain gauge for specific applications.