Abstract:
This thesis investigates the concept of thrust rating as a means
towards
reducing the life cycle costs of engine ownership. Towards this end,
this
thesis has discussed the concept of thrust rating, developed computer
programs for mechanical load type failures, which include creep, LCF, and
combinations thereof, and conducted simulations of improving life usage and
reducing life cycle costs.
A
study was performed on a military engine, under an original design
mission mix, that showed significant gains in creep-LCF life of the HPT blade
could be achieved, especially With the recently proposed and presumably more
accurate criterion- ductility exhaustion, by thrust rating. The savings were
expressed in terms of an approximate reduced life accumulation rates and life
cycle costs. The net result was a 50% increase in creep-LCF life with a
savings of $ 50.4 million. These calculations were based on a Feet of 300
engines having the designed lifetime of 8,000 operating hours per engine.
Throughout the thesis, mention is also made of employing the thrust
rating concept on other engines. To this end, the thesis will also give a
blueprint for conducting a feasibility study to employ thrust rating as a
maintenance tool. In addition to the technical aspects, the role of maintenance
and aircraft
operations policy will also be studied to determine the
interrelationships that exist between thrust rating technology and its
practical application.
