Digital image correlation

Home > Expertise > Digital image correlation

Material Testing with Full-Field Strain Distribution Visualization

Materials, components, or products are often subjected to various loads during their service life. Accurate strain measurements are crucial to understanding mechanical behavior. Traditional methods, like strain gauges and extensometers, provide only single data points over an averaged area.

Digital Image Correlation (DIC) is a contactless technique that delivers full-field strain distribution by tracking a speckle pattern on the material’s surface. It works on any size or type of material and achieves high accuracy, with resolutions of 1 µm for displacement and 10 µstrain for strain.

Unlike traditional sensors, DIC is ideal for materials like textiles, foams, or thin films, where attaching strain gauges is impractical. Combined with high-speed cameras, it is particularly effective for impact and high-strain rate tests, offering a robust solution for detailed strain analysis.

Application Example: Small Diameter Wire Compression Test

Quasi-static compression tests combined with in-situ full-field strain measurement using the Digital Image Correlation method.

application fields

Static, dynamic, and fatigue tests (standard or custom)
High strain rate tension and compression
Adhesive and cohesive properties
Composite delamination
Material or component failure and crack initiation points

The extracted data fields can be used to compare with finite element (FE) simulation and calibrate and validate material parameters and models.

Digital Image Correlation Features

Contactless and full-field distribution maps
Independent of material type, geometry, and size
Accurate displacement and strain datasets

Application Example: V-notch Shear Test

Digital Image Correlation strain measurement makes it possible to measure full-field strains at a specific field-of-view area.

3D Motion Analysis by Discrete Marker Tracking

To analyze the 3D motion of sub-components under load, displacements and rotations can be measured by tracking discrete markers applied at specific locations. This contactless method works for all material types and conditions, providing accurate motion data in a three-dimensional volume.

Markers are ideal for both static and dynamic loading, with high-speed cameras capturing up to 500,000 images per second. Image recordings can be synchronized with external signals, such as force or torque measurements, achieving sub-micrometer resolution through calibration and system optimization.

Additionally, markers enable precise coordinate alignment with reference systems, such as CAD or FE models.

Advanced motion analysis features

3D coordinates and relative points positions
3D displacements and rotations
3D velocities and accelerations
Video extensometry

Application Example: Marker Tracking on Textile Material

Two sets of markers were tracked during the tensile loading of a textile material. In this case, the relative displacements of the horizontal and vertical set of markers were used to calculate strains (virtual extensometer).