AN ADVANCED EQUIPMENT FOR SINGLE-FIBER PULL-OUT TEST DESIGNED TO MONITOR THE FRACTURE PROCESS

A newly designed single-fibre pull-out machine with optimized stiffness in all components was developed, in order to obtain stable crack propagation during the fibre pull-out. On the basis of a mathematical model, which simulates the debonding process during a single-fibre pull-out experiment, calculations of the stress distribution, the force-displacement traces and the fracture propagation were made. Some of these results are compared with pull-out measurements using glass fibres embedded in thermoplastic matrices. The agreement between simulation and test results is good, and shows that stable crack propagation is achievable. Because friction has an important influence on pull-out forces, the interpretation of single-fibre test results has to be revised.