A dual 3D DIC-system application for DSL strain and displacement measurements

Department of Mechanical Engineering, Technical University of Denmark, Nils Koppels Allé, 2800 Kgs Lyngby, Denmark

^a e-mail: cbe@mek.dtu.dk

Abstract

This paper describes a dual 3D Digital Image Correlation (DIC) system application for DLS strain and displacement measurements, where two 3D DIC-systems are used in parallel. The bonded specimens were tested to failure under monotonic loading in a uni-axial tensile testing machine at ambient temperature. Both surface inplane strain and full-field displacement values were recorded using two DIC systems: high speed (HS) and high resolution (HR). The HS system was used in a parallel setup with the HR system in order to detect the initial failure location and crack propagation rate during the brittle failure mechanism, where an interface crack is propagating between the straps and the inner adherent. Using two inherently different DIC systems involve a number of problems. This involves synchronization of the HS and HR systems, a common illumination level and speckle pattern. This paper therefore describes guidelines for a mutual system setup, applied in an experimental study of steel/epoxy DLS joints under pure tension.