Validation of Digital Image Correlation for Sheet Metal Strain Measurement 2010-01-0955
The automobile industry has an increasing demand for lightweight components, improve product performance, efficiency and increase safety. For optimization of design and manufacturing of these components the detail measurement of critical material properties such as strain limit, strength coefficients, anisotropy coefficients et al, are required. The most commonly used method for finding the material properties is tensile test with extensometer. But this system only provides an average strain over the specimen gauge length and is not applicable to post diffuse necking.
Digital Image Correlation (DIC) technique is the latest state of art technique. Because of its capability of fast data acquisition, this technique is suited well for characterization of material properties both in the elastic and plastic ranges. It also has advantages of full field, non-contact, and considerately high precision for displacement and strain measurements. The previous investigations clearly demonstrate that DIC has a great potential for providing whole field true strain measurement well into the diffuse necking region. But most of the investigations do not give any proof regarding the reliability and accuracy of DIC technique.
This paper will investigate the whole field true strain measurement and validation of the DIC technique using the stress strain curve of the specimen. The method use to prove this is called as “Gauge Effect”. This technique provides a practical approach for the validation of DIC.