Optical Powering Of Systems

Low Plasticity Burnishing (LPB) has been shown to provide twice the HCF strength ofshot peening, and four times the strength after FOD in Ti-6Al-4V and IN718 laboratoryspecimens exposed to turbine engine temperatures. The deep compressive layer producedby LPB is comparable to laser shock peening (LSP), and can fully arrest the growth of0.020 in. deep fatigue cracks. LPB offers higher speed, lower cost, and better surfacefinish than LSP, and is performed on conventional CNC machine tools in a manufacturingor engine overhaul shop environment.The feasibility of applying LPB to compressor blades critical to the NAVAIR IHPTETand VAATE programs to improve damage tolerance and HCF life will be established inPhase I. LPB processing parameters and control software will be developed for followingthe complex surface of a compressor blade using existing tooling and 4-axis LPBfacility. The HCF life and damage tolerance of LPB processed blades will be comparedto the current practice of shot peening. Thorough documentation of HCF performanceof LPB processed blades and development of an automated production LPB facility forblade rework will be undertaken in Phase II.The anticipated benefit of the proposed effort to NAVAIR is substantial reduction inthe total cost of aircraft ownership and improved fleet readiness. LPB bladeprocessing will improve engine HCF life and FOD tolerance, resulting in reducedcosts of both replacement parts and maintenance. Increased damage tolerance willreduce required inspection time for further man-hour savings and increased on-wingtime. The initial cost savings for the T56-A-427 compressor alone are estimated at$3.6M annually. Current military expenditures of $2B annually to address fatigue ofaging aircraft and legacy engines provide the immediate market for LPB and potentialsavings to the DoD.Commercialization will, therefore, begin with NAVAIR overhaul and then expand toother military aviation applications. LPB is well positioned for commercializationdue to low costs of operation and capitalization relative to laser shock peening(LSP),and improved depth and stability of the compressive layer produced by LPB relativeto shot peening. LPB can be applied easily during manufacturing operations withconventional CNC tools at engine overhaul centers for much less than new blade costs.Demand for improved HCF performance and cost reduction from military owner-operatorswill lead to LPB processing of new blades and other critical rotating parts duringmanufacturing. Military applications will be followed in the commercial aviationsector, driven by improved HCF performance and cost reduction. Potential secondarycommercial opportunities for LPB to improve HCF performance in the aerospace,automotive, and power generation turbine industries are vast, and will follow theinitial military applications over a period of several years.