Effect of fracture tunneling in DWT Tests

The work deals with the effective shape of the fracture during a Drop Weight Tear Test (DWT). An inexpensive technique, able to determine the geometrical shape of the fracture, is discussed and presented. The technique is capable to perform reliable measurements and offers a mathematical description of the fracture profile. In few words, the fracture tunneling measurement and its correlated effects are the objectives of this work. The technique is based on a copy of the fracture by a silicone mold, followed by a digital analysis of the tomographic images. The attention is finally focused on two different steels used in inshore gas piping. The tunneling measurement is exploited in a finite element simulation of the fracture propagation, thus opening the opportunity to update the kinematic models applied for Crack Tip Opening Angle assessment.