Data-driven optical method for full-field stress measurements

Area of Science:

• * Optical measurement techniques
• * Materials science and engineering
• * Computational mechanics

Background:

• * Accurate full-field stress determination is crucial for material analysis and structural integrity.
• * Digital Image Correlation (DIC) provides full-field strain data but can be prone to errors.
• * Existing methods often rely on constitutive equations, limiting their applicability.

Purpose of the Study:

• * To develop and demonstrate an optical method for direct full-field stress measurement.
• * To combine a data-driven approach with DIC strain data for stress calculation.
• * To validate the method's accuracy and its ability to correct strain errors.

Main Methods:

• * Utilized a data-driven algorithm with a pre-existing material stress-strain dataset.
• * Employed iterative calculations based on a distance-functional algorithm without constitutive equations.
• * Integrated 2D-DIC strain measurements for stress component determination.

Main Results:

• * Successfully determined full-field stress distributions in uniaxial tensile and compact tensile tests.
• * Demonstrated accurate full-field stress calculation using established material datasets.
• * Validated that the method corrects erroneous DIC strain results by satisfying equilibrium and compatibility constraints.

Conclusions:

• * The proposed data-driven optical method accurately determines full-field stress.
• * The technique enhances the reliability of DIC strain measurements.
• * This approach offers a robust alternative for stress analysis without requiring explicit constitutive models.