Research on polyvinylidene fluoride (PVDF) piezoelectric film three-dimensional force sensor for metal material plastic cold heading forming processing

The research on real-time monitoring technology for impact force in forging machine tools has significant theoretical and practical implications for ensuring the normal functioning of the manufacturing process and improving the quality of the product formed during plastic metal forming. A novel polyvinylidene fluoride (PVDF) piezoelectric film three-dimensional heavy force sensor is proposed. The coupling field of piezoelectric materials in force sensors was analyzed based on the finite element method. The piezoelectric equation and PVDF constitutive equation are used to derive the PVDF electromechanical coupling equation and its differential form. The electromechanical constitutive equation of the material and the boundary conditions of the coupled field are derived. A finite element model of the electromechanical coupling of the PVDF piezoelectric film three-dimensional heavy force sensor is constructed based on the piezoelectric constitutive equation. The static and modal characteristics of the sensor are simulated by the ANSYS software. The quasi-static, dynamic, and impact simulation experimental results demonstrate that the sensor exhibits nonlinearity and repeatability errors of less than 1%. The first natural frequency of the sensor is 7.031 kHz. The mechanical model is capable of effectively predicting the static and dynamic performance of the PVDF film three-dimensional force sensor for dynamic measurement of heavy and strong impact loads. The method proposed in this paper can be extended to analyze the sensitivity and natural frequency prediction of various piezoelectric force sensors under any electromechanical load.