Verification of the performance of rotatable jig for a single cantilever beam method using the finite element analysis

The performance of new jig for single cantilever beam test method was verified by finite element analysis. Two types of jig were designed for a small specimen that had relatively short length compared to the width of cantilever; one was simple fixed jig and the other was specially designed rotatable jig. The rotatable jig has a rotatable seesaw which adjusts the experimental misalignments between the specimen and test machine. Among the three translational and three rotational misalignments, following three important factors were considered; rotation about x-axis, rotation about z-axis, and translation in y-axis. Adhesive layer was modeled by cohesive zone element, and crack propagation behavior and the deviation of energy release rate were investigated. The fixed jig showed undesired asymmetric crack propagation and large deviation of energy release rate when it had rotational misalignment about x-axis. However, the proposed new rotatable jig showed almost symmetrical crack propagation and small deviation of energy release rate regardless of misalignments. Rotational motion of the seesaw automatically compensated the rotational misalignment of the specimen. The rotatable jig also showed relatively small deviation of energy release rate compared with the fixed jig by the rotational misalignment about the z-axis. In contrast, the rotatable jig showed deviation of energy release rate by translational misalignments in the y-axis. However, the magnitude of the deviation was very small within the controllable range of experimental misalignment. In conclusion, it was found out that the proposed jig was appropriate for the measurement of adhesion of a small specimen by single cantilever beam method.