Mechanical Parameters Determination of a Polymeric Membrane by Digital Image Correlation

Digital image correlation (DIC) is a powerful method for full-field strain test of polymeric materials and speckle pattern on the material's surface is a critical factor for the measurement accuracy. In this paper, a new speckle pattern technique is presented and used on mechanical parameter determination of a thin and soft polymeric membrane. The presented speckle pattern is generated by combination of image noise technology and film printing technique, and it is much easier to get fine speckle pattern compared with traditional spray speckle pattern technique which is a hard and time-cost work. To verify the validity of the presented speckle pattern technique, Young's modulus and Poisson's ratio are measured by presented speckle pattern and spray speckle pattern on a tensile testing machine. It is found that the measurement results by presented speckle pattern agree well with that by fine spray speckle pattern. With the presented speckle pattern technique, DIC becomes a more convenient and fast non-contact measurement technology for polymeric materials test.