Visualization of strain distribution by piezoelectric thin film

The surface strain distribution can be obtained by measuring the electric potential at lattice points on the piezoelectric film mounted on the object. When a plate with a back surface defect is deformed, the resultant strain distribution reflects the size and the shape of the defect. Instead of scanning the probe of the electrostatic voltmeter, this paper attempts to visualize the strain distribution by means of absorption of charged polymer powder to the piezoelectric film. To analyze the phenomenon, we solved the Maxwell equations for the boundary with a typical potential distribution. The efficiency of the proposed method is verified by the dust figures for the plates with slit-like grooves and a circular-cylindrical one.