Impact force measurement by in-plane piezoelectricity of polyvinylidene fluoride films

This manuscript provides a new idea to solve the problems related to measurement of impact force wave especially in the situation with a strong environment noise by utilizing the polyvinylidene fluoride (PVDF) film instead of strain gauge. According to our experimental results, an extremely high ratio between output signal and noise in environment (SN ratio) is realized even the infrequently employed in-plane piezoelectricity of film is utilized. Instead of piezoelectricity in thickness direction, attachment of film on Hopkinson pressure bar based on in-plane piezoelectricity could help us to avoid the influence from separation of Hopkinson pressure bar on measurement result. We could conclude that a more precise measurement could be realized by a short film rather than long one even though the short film shows a relative lower output signal. However, the output signal could be amplified by increasing its width. Besides, comparing with the use of strain gauge, broader bandwidth of film measurement is discovered. In the situation where the duration of impact force wave is extremely short, high accuracy measurement should be realized by PVDF film rather than strain gauge.