A Procedure for Accurate One-Dimensional Strain Measurement Using the Grid Method
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This paper deals with the accurate calculation of strain using the grid method. The strain field is first directly deduced from the fringe pattern without calculating the displacement field. This procedure is validated with two numerical examples. Two types of experiment are then carried out: a translation and a tensile test. It is observed that some additional fictitious strains appear in both cases. They are due to two main reasons which interact with each other: the grid defects and the displacement of the grid lines during testing. A suitable procedure is proposed to cancel out these fictitious strains. This procedure is successfully applied in two cases of fringe patterns.
KeywordsFringe Full-field measurement Grid method Phase Strain
Ms. M. Georgescu is gratefully acknowledged for her help in the characterization of the grid with a microscope.
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