There are numerous benefits of using image decomposition to analyse 3D DIC measured data, including (1) representation of the raw measurement data with efficiency and succinctness; (2) determination of the FRF of any point on the specimen by the use of the full-field shape features; and (3) elimination of DIC measurement noise.
The yield point of the specimen was determined according to the load displacement curve.1000kN, ± 250 mm.
The geometry of the specimen and the current stress state at any given point of the specimen affect the velocity of a 'pointer' running along these two curves.
In order to measure the deformation of specimens, deflection was measured at the center of the bottom and at the 1/4 point of the specimen length.
The middle point of the specimen is chosen as the exciting point and two pins are used so that the interference between the two loading directions will be released.
After the maximum strength point of the specimen, the specimen exhibits serious damage along the primary shear crack in its eastside and severe concrete collapse occurs on the compressed side of the specimen (Fig. 11c); then, the strength decreases to 737.6 kN (79.35% of the maximum strength).
The acceleration of the base is recorded by means of a piezoelectric accelerometer, and the vertical displacement of a suitable point of the specimen is recorded by means of an accurate laser sensor.
The strain field was determined using a home-developed image correlation technique that has allowed us to determine all the strain components at each point of the specimen, even with a non-homogeneous strain field.
A mathematically accurate treatment of the experimental measurement of Young's modulus is also presented, yielding a final expression for E (I ω) as a function of the two measured entities, namely the acceleration of the base and the vertical displacement of an adequate point of the specimen.
The residual stresses were measured on the surface and at selected interior points of the specimens.
