Damage Tolerance Improvement of Ti-6-4 Fan Blades With Low Plasticity Burnishing

2002 ◽  
Author(s):  
P. S. Prevey ◽  
D. J. Hornbach ◽  
J. T. Cammett ◽  
R. Ravindranath
Keyword(s):  
Damage Tolerance ◽  
Low Plasticity Burnishing ◽  
Tolerance Improvement

Improved Damage Tolerance in Titanium Alloy Fan Blades With Low Plasticity Burnishing

2002 ◽  
Author(s):  
P. S. Prevey ◽  
D. J. Hornbach ◽  
T. L. Jacobs ◽  
R. Ravindranath
Keyword(s):  
Titanium Alloy ◽  
Damage Tolerance ◽  
Low Plasticity Burnishing

scholarly journals Case Studies of Fatigue Life Improvement Using Low Plasticity Burnishing in Gas Turbine Engine Applications

2003 ◽  
Author(s):  
Paul S. Preve´y ◽  
Ravi A. Ravindranath ◽  
Michael Shepard ◽  
Timothy Gabb
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Case Studies ◽  
Shot Peening ◽  
Damage Tolerance ◽  
Cold Work ◽  
Fatigue Performance ◽  
Surface Enhancement ◽  
Low Plasticity Burnishing ◽  
Life Improvement

Surface enhancement technologies such as shot peening, laser shock peening (LSP), and low plasticity burnishing (LPB) can provide substantial fatigue life improvement. However, to be effective, the compressive residual stresses that increase fatigue strength must be retained in service. For successful integration into turbine design, the process must be affordable and compatible with the manufacturing environment. LPB provides thermally stable compression of comparable magnitude and even greater depth than other methods, and can be performed in conventional machine shop environments on CNC machine tools. LPB provides a means to extend the fatigue lives of both new and legacy aircraft engines and ground-based turbines. Improving fatigue performance by introducing deep stable layers of compressive residual stress avoids the generally cost prohibitive alternative of modifying either material or design. The x-ray diffraction based background studies of thermal and mechanical stability of surface enhancement techniques are briefly reviewed, demonstrating the importance of minimizing cold work. The LPB process, tooling, and control systems are described. An overview of current research programs conducted for engine OEMs and the military to apply LPB to a variety of engine and aging aircraft components are presented. Fatigue performance and residual stress data developed to date for several case studies are presented including: • The effect of LPB on the fatigue performance of the nickel based super alloy IN718, showing the fatigue benefit of thermal stability at engine temperatures. • An order of magnitude improvement in damage tolerance of LPB processed Ti-6-4 fan blade leading edges. • Elimination of the fretting fatigue debit for Ti-6-4 with prior LPB. • Corrosion fatigue mitigation with LPB in Carpenter 450 steel. • Damage tolerance improvement in 17-4PH steel. Where appropriate, the performance of LPB is compared to conventional shot peening after exposure to engine operating temperatures.

scholarly journals Case Studies of Fatigue Life Improvement Using Low Plasticity Burnishing in Gas Turbine Engine Applications

2006 ◽  
Vol 128 (4) ◽  
pp. 865-872 ◽  
Author(s):  
Paul S. Preve´y ◽  
Ravi A. Ravindranath ◽  
Michael Shepard ◽  
Timothy Gabb
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Case Studies ◽  
Shot Peening ◽  
Damage Tolerance ◽  
Cold Work ◽  
Fatigue Performance ◽  
Surface Enhancement ◽  
Low Plasticity Burnishing ◽  
Life Improvement

Surface enhancement technologies such as shot peening, laser shock peening, and low plasticity burnishing (LPB) can provide substantial fatigue life improvement. However, to be effective, the compressive residual stresses that increase fatigue strength must be retained in service. For successful integration into turbine design, the process must be affordable and compatible with the manufacturing environment. LPB provides thermally stable compression of comparable magnitude and even greater depth than other methods, and can be performed in conventional machine shop environments on CNC machine tools. LPB provides a means to extend the fatigue lives of both new and legacy aircraft engines and ground-based turbines. Improving fatigue performance by introducing deep stable layers of compressive residual stress avoids the generally cost prohibitive alternative of modifying either material or design. The x-ray diffraction based background studies of thermal and mechanical stability of surface enhancement techniques are briefly reviewed, demonstrating the importance of minimizing cold work. The LPB process, tooling, and control systems are described. An overview of current research programs conducted for engine OEMs and the military to apply LPB to a variety of engine and aging aircraft components are presented. Fatigue performance and residual stress data developed to date for several case studies are presented including the following. (1) The effect of LPB on the fatigue performance of the nickel based super alloy IN718, showing the fatigue benefit of thermal stability at engine temperatures. (2) An order of magnitude improvement in damage tolerance of LPB processed Ti-6-4 fan blade leading edges. (3) Elimination of the fretting fatigue debit for Ti-6-4 with prior LPB. (4) Corrosion fatigue mitigation with LPB in Carpenter 450 steel. (5) Damage tolerance improvement in 17-4 PH steel. Where appropriate, the performance of LPB is compared to conventional shot peening after exposure to engine operating temperatures.

Improved High Cycle Fatigue Damage Tolerance of Turbine Engine Compressor Components by Low Plasticity Burnishing (LPB)

2006 ◽  
Author(s):  
Paul S. Preve´y ◽  
N. Jayaraman ◽  
Ravi A. Ravindranath ◽  
Michael Shepard
Keyword(s):  
Damage Tolerance ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Turbine Engine ◽  
Solution Approach ◽  
Industry Standards ◽  
Low Plasticity Burnishing ◽  
Recent Developments ◽  
Engine Components ◽  
And Control

Significant progress has been made in the application of low plasticity burnishing (LPB) technology to military engine components, leading to orders of magnitude improvement in damage tolerance. Improved damage tolerance can facilitate inspection, reduce inspection frequency, and improve engine operating margins, all leading to improved military readiness at significantly reduced total costs. Basic understanding of the effects of the different LPB process parameters has evolved, and finite element based compressive residual stress distribution design methodologies have been developed. By incorporating accurate measurement of residual stresses to verify and validate processing, this combined technology leads to a total solutions approach to solve damage problems in engine components. An example of the total solution approach to develop LPB processing of a 1st stage Ti-6Al-4V compressor vane to improve the foreign object damage (FOD) tolerance from 0.002 in. to 0.025 in. is presented. The LPB process, tooling, and control systems are described, including recent developments in real-time process monitoring for quality control. Performed on CNC machine tools, LPB processing is easily adapted to overhaul and manufacturing shop operations with quality assurance procedures meeting military and industry standards, facilitating transition to military depots and manufacturing facilities.

Damage tolerance of bismaleimide composites

1988 ◽  
Author(s):  
S. TYAHLA ◽  
H. STORR
Keyword(s):  
Damage Tolerance

Stacking Sequence Dispersion for Improved Damage Tolerance

2008 ◽  
Author(s):  
Claudio Lopes ◽  
Pedro Camanho ◽  
Zafer Gurdal ◽  
Omprakash Seresta ◽  
Pere Maimi
Keyword(s):  
Damage Tolerance ◽  
Stacking Sequence
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