LOW-COST MEASUREMENT TECHNIQUE OF POISSON'S RATIO OF THIN, SOLVENT- SENSITIVE POLYMER MEMBRANES

摘要

This paper investigates a low-cost testing procedure that measures Poisson 's ratio of thin membranes whose properties may be affected by traditional speckle patterns which are solvent-based. The shear modulus, a key indicator of how materials will fail - especially for thin membranes subjected to interfacial stresses - is a function of Young's modulus and Poisson 's ratio, which can be determined by tensile testing. The precision of using Digital Image Correlation (DIC) to measure Poisson's ratio coupled with a solvent-free speckle pattern of fused silica on polyimide film specimen is investigated. DIC processes for thin membranes are currently under development. As such, spraying a conventional speckle pattern may be unfeasible for thin polymer membranes whose properties are a function of solvent content. Experimental factors' effects, such as vibration and area to which DIC is applied, were also studied in a design of experiments. It was determined that using fused silica as a solvent-free speckle pattern, as opposed to a traditional solvent pattern, does not significantly affect the measurements of Poisson's Ratio of the polyimide film. Furthermore, it was found that the experimental factors noted above can play a significant role in fused silica-speckled Poisson 's ratio specimen.