Our Research

Forming Strain Measurement

The deformation measuring system ARAMIS® is well suited for in-situ strain mapping: measuring three-dimensional deformation and strain distributions of real components under static or dynamic load. The deformation measuring system ARAMIS® records an object under load using CCD cameras.

 

Tensile Test - ARAMIS®

 

Dome Limit Height Test - ARAMIS®

The deformation measuring system ARGUS® is used for post-deformation strain mapping.The system records an object after load using CCD cameras. The measuring results allow for easy verification of the shaping process. Areas with huge deformations are highlighted as 'hot spots'.

 

Application

The strain mapping processes are applicated for non-contact and material independent determination of deformation and strain and used for:

  • Testing materials
  • Estimating stability
  • Dimensioning components
  • Examining non-linear behavior
  • Characterizing creep and aging process
  • Determination of FLC

The major and the minor strain distribution,displacement, shape transformation etc. can be presented in a three-dimensional graphic. For each stage of load, the 3D coordinates of the object surface are calculated on the basis of digital image processing delivering also the 3D displacement and the strain.

 

Image Correlation Analysis

  • A marking pattern is applied to an undeformed object surface
  • Successive images of this pattern are recorded by high resolution CCD camera/s either during or after the object deformation
  • The surface is divided into facets, and their coordinates are tracked and correlated from image to image with a sub-pixel accuracy
  • Based on the results of the correlation analysis, local displacements and strains are calculated and displayed in an interactive 3D model of the deformed object

 

Experimental Techniques

ARGUS:

  • Regular marking pattern
  • Post-deformation imaging at different angles

ARAMIS:

  • Random marking pattern
  • Imaging during deformation at arbitrarily chosen stages

 

Strain Distribution in Uniaxial Tension by Digital Speckle Correlation


Analysis via ARGUS


Analysis via ARAMIS

 

Strain Distribution in Notched Tube Sample

Click a picture to view a movie.

Horizontal Strain Distribution

Vertical Strain Distribution