Integrally Bladed Rotor (IBR) Maintenance and Life Management

BDC is developing a process called SMART BLEND(TM) for inspecting blended IBRs/Blisks. IBRs are susceptible to foreign object damage and blending is a relatively low cost method using machining to repair that damage.  The difficulty is that blending changes the geometries of the blades so that they no longer meet specifications.  More specifically, blending changes the frequencies of the blades as well as their aerodynamic characteristics.  The proposed program integrates advanced methods for extracting information from engine tests, bench tests of damage components, new techniques for modeling aerodynamic and structural coupling, and advanced aerodynamic computer analyses to assess how blending affects the HCF life of a representative advanced fan stage from the F119 engine.  Initial results indicate that the proposed work would allow the safe repair of IBRs in order to quickly return them to service resulting in improved safety, enhanced fleet readiness, and lower costs. BENEFITS: In this AF SBIR Phase II proposal, it is planned that the BDC/Duke mistuning technology will be adapted so that it will work not only for relatively small HP compressor Blisks but also for larger stages such as the 1st stage fan on the F119 engine.  Developing economical and safe methods for repairing 1st stage fans is particularly critical because of the fans direct exposure to FOD and its high replacement cost. Pratt & Whitney has agreed to partner with BDC in the proposed SBIR Phase II at no cost to the contract.  With Pratt &Whitney as an active participant in the program, there is every expectation that the capability developed in this SBIR will be transitioned to operational service to meet what are already important Air Force needs.  In addition, the latest models of commercial aircraft engines also use IBRs/Blisks.  As a result, the proposed technology has dual use potential in that it can also be applied to commercial as well as military engines.