We will test the hypothesis that LIBS-measured oxygen concentration can characterize composite surface energies and be related to bond strength, determine what other variables may also affect the relationship, and determine the relationship between measured surface oxygen concentration, surface energy measured by contact angle, and bond strength measured by double cantilever beam (DCB). The goal will be to establish a LIBS method that allows fast, non-contact analysis of surface energy and surface preparation for bonding that contributes to ensuring good bonding between various substrates of interest, and to learn what other parameters need to be controlled to ensure valid results. In phase II, we will advance the TRL of the method, validate the method for other substrates of interest and demonstrate it in a simulated manufacturing environment. In Phase III, we will work with one or more Air Force prime contractors to qualify the method in their manufacturing processes and transition it to use in both multiple OEMs and in Air Force Material Command depots for repair of aircraft and components.
