Ductile tearing of polymer films

As polymers are made from long macromolecular chains, their deformation mechanisms are related with the sliding between these chains as threads in a cloth, this can be a little explanation of tearing. Now then, if during the load application the component is in yielding and it has a stress concentrator, as a crack may be, this sliding occurs in a stable manner and the stable crack growth is shown. In this work, complete-fracture crack tests where carried out for an Ethylene-Propylene Block Copolymer film prepared on DDENT specimens with two sharpening methods; by razor blade and by femtolaser beam. The Load-Displacement plots and the ligament length evolution for all specimens were recorded using a Digital Image Correlation System to approach the complete crack behavior, describing the EWF conventional method in the crack extension process. The main results of this work aim to say that the initiation of crack propagation occurs when the area under the load-displacement curve reaches the we value. This start of propagation shall be given by the material as a function of the initial crack conditions