1. Turbo Power Life Prediction- Overview
Company, Department, Name
day month year

2. VAC specialisation components
Compressor structures
VAC develops and manufactures parts to aero engines
The manufacturing idea ↔ “Make it Light” :
Fabricated structures i.e. total structure manufactured from sub-components (cast, sheet, forged material quality)
Typical fabricated components
Frames for:
”Cold” parts, Material:Titanium Temperatures < 450 °C
Hot parts, super alloys (nickel base materials) temperatures < 550 °C
New manufacturing processes
Metal Deposition (MD)
Fabricated structures  welds  defects (cracks)
Turbo Power focus on hot parts
Turbine structures
”Hot”
”Cold”
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Turbo Power

3. Fabricated structures
Welding issues from a manufacturing point of view:
Effects of deformation
Residual stress distribution
Temperature distribution
Fixturing
Weld sequence
Welding issues from a design point of view:
Initial defect sizes
Material properties in welds
Weld geometry
Calculation models
Residual stress distribution
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Turbo Power

4. Titanium & Ni-based structures
Metal Deposition, MD
Titanium & Ni-based structures
What is MD?
Building 3-D geometries directly in metal using a welding source and filler material
Why MD?
For aero engine components enable
Shorter lead time for product development
Cost effective fabrications - replace one-piece castings
New repair procedures
Mechanical properties  cast + HIP
Cost effective MD process by automation
Process
Knowledge
CAD model
Generate weld paths
Simulation
On-line controlled process
MD’ed geometry
Control
Weld prep / flange
Boss
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5. How does Fatigue life methods relate to NDT inspection ?
Cast material and welded structures are more likely to have inherent defects in the structure (2c~0.1 to 1.5 mm) than forged or sheet material.
NDT-inspection on finished part  risk of missing defects  one must allow defects in the structure
Conclusion:
Crack initiation analysis: Neglecting risk of cracks in structure  un-conservative LCF life prediction
Crack propagation analysis: Defining initial defect size from NDT (2c~1.5 mm)  risk of very conservative life prediction
Δ ε
Cycles to ”initiate”
a crack in a structure
structure Ni
Stress
Stress
Temperature
Cycles to propagate a crack until failure
weld
Time
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6. Summary Fatigue is a very complex phenomenon!
A successfull fatigue analysis procedure involves:
Material science/testing
Mathematical modelling
Manufacturing methods
Quality control
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7. Overview of projects
Fatigue life of thermal barrier coatings (TBCs) physically based modelling
Project aims at evaluate existing life methods for Thermal Barrier Coatings on Heynes 230, Hast-X and turbine material (no single crystal material).
Experiments and model evaluation at LiTH
VAC supplies test specimens, experiments and expertise
SIT supplies support on numerical simulation of experiments and expertise and perform limited amount of experiments
Funding: 3300 kkr
Quantification of the reliability of flaw detection for non-destructive techniques using probability of detection (POD) based on synthetic data
The main objective of this project is to enable simulated data to be used within the development of POD curves. These POD curves can then be used to find the optimal NDT technique in aspect of a specific object, material, defect size and other defect characteristics
Chalmers: Modeling and evaluation
VAC: Supplies expertise within NDT area
Funding: 2450 kkr
High temperature fatigue life prediction
Project aims at developing life models for the combination of cyclic loads and time dependent damage (Crack Initiation and Crack Propagation). Material, IN718.
Experiments and model development at LiTH
VAC supplies test specimens and expertise
SIT supplies experiment and expertise
Funding: 3770 kkr
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Turbo Power