Experimental study on strain distribution of ionic polymer–metal composite actuator using digital image correlation

Abstract

Ionic polymer–metal composite (IPMC) cantilever actuators demonstrate significant bending deformation upon application of excitation voltage across the electrodes. In this paper a cantilever beam shaped IPMC actuator with platinum (Pt) electrodes is fabricated to investigate the micro-scale lateral deformation behavior under DC voltages using a digital microscope to measure the deformation. The digital image correlation (DIC) method is utilized to analyze the displacement and strain fields of the sample. The experimental results indicate that the longitudinal normal strain is linearly distributed along the thickness direction and the strain gradient is approximately exponential with excitation voltage. The amplitude of the transverse strain is bigger than the longitudinal strain, and the strains are also found to decrease along the length direction of the IPMC cantilever actuator. The longitudinal and transverse normal strains of the IPMC actuator under DC voltages are compressive strains due to water loss effect in the air.

Deflection analysis of IPMC actuators under AC voltages using DIC method

“…In this work, Nafion-based IPMC actuator sample with Pt electrodes was manufactured by a typical four-step technique [7,13]. The IPMC material with a thickness of 0.7 mm was cut into dimensions of 40 mm × 10 mm.…”

“…Punning et al [12] developed a method called 'improved digital image correlation (DIC)' in MATLAB to measure the in situ factual strains of ionic electroactive polymer (IEAP) actuators under a scanning electron microscope (SEM). In our previous work, a digital optical microscope and the DIC method were used to develop an accurate micro-scale mechanical measuring technique for testing the displacement and strain fields of an IPMC actuator [13,14].…”