Micro-Fatigue Testing in Metallic Material
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Transcript of Micro-Fatigue Testing in Metallic Material
Important to use Accelerated Fatigue Test (AFT)
method to be able to save time and cost.
Modal Shaker DMA
Initial
Design
Existing 3-point
(Clamped) Design
Existing 3-point
Design
Improved 3-point
(Clamped) Design
Run Fatigue
Test using
DMA
13023NName: Uvarajan M Velayutham
UoG Matriculation No: 2059265S
1st Supervisor (in Singapore): Dr Christian Della
2nd Supervisor (in Glasgow): Prof William Sloan
Industry Supervisor: Dr Ronnie Teo
Micro-Fatigue Testing
in Metallic MaterialIntroduction
Aims and Objectives
a Development of AFT method using Modal Shaker
Conclusion
Conventional fatigue testing is very time consuming
and expensive.
Conventional fatigue testing machines have several
limitations.
This research aims to investigate the use of Modal Shakers
and Dynamic Mechanical Analyzers (DMA) for AFT, and the
objectives are :
a. Develop a novel AFT method using Modal Shaker.
b. Design a fixture assembly for AFT using both DMA &
Modal Shaker.
c. Improve existing DMA 3-point fixture, through analysis
and fatigue tests.
Complete system assembly for AFT using both
Modal Shaker and DMA systems :
Conventional
Fatigue Tester
Modal Shaker
(M1600W)
DMA
(Q800)
Testing
FrequencyLow High High
Loading
AmplitudeHigh High Low
Thermal
Control
1) Specimen
Preparation
Grinding
Polishing
Etching
2) Fixture
Mounting
Clamp
Calibration
3) Test
segments
Equilibrate
at 30˚C
Frequency
sweep at
100Hz for
100000
cycles
4) Microscopic
Analysis
Observe
for Micro-
cracks
formation
5) Nano-
indentation
Record
material
property
changes
during
fatigue
process
The novel fixture assembly can be used for AFT using both
Modal Shaker and DMA.
Project Workflow
Modal
Shaker
Dynamic
Mechanical
Analyzer
(DMA)
Fixture assembly (A) and rig (B) have been designed for
Modal Shaker based on first/fundamental design principles.
Rounded contact surfaces has reduced the stress concentration at
the support regions in the Improved 3-point (Clamped) design.
Improved 3-point (Clamped) Design:
Existing 3-point (Clamped) Design:
Initial Design:
Existing 3-point Design:
Running Fatigue Test using DMA:
Cyclic 3-point test in
DMA using existing
3-point design
Initial
Design
Existing 3-Pt
Design
Existing 3-Pt
(Clamped)
design
Improved 3-Pt
(Clamped)
design
Contact type Rounded Rounded Flat Rounded
Syst
em
Co
mp
ati
bil
ity Modal
Shaker
DMA
This developed AFT method can significantly reduce fatigue
testing time and cost.
References[1] Escobar, L.A, Meeker, W.Q, 2006. A review of accelerated test modals. Statistical Science, No.4,
pp. 552-577.
[2] Farrar, C.R, Duffey, T.A, Cornwell, P.J, & Bement, M.T, 1999. A review of methods for
developing accelerated testing criteria. In Proc. of the 17th International Modal Analysis
Conference, Kissimmee, FL, pp. 608-614.
[3] Sujan E. Wadud, 2012. Improvements in DMA Measurements Using Low-Friction 3-Point
Bending Clamps. TA Instruments.
[2, 3]
[1]
Critical points at corners
Flat contact
surface of clamp
Rounded contact
surface of clamp
T E S T S P E C I M E N
Fixture A
Rig B
c Improvement through test: A preliminary study
b Improvement through analysis
STRESS MAX
7.9 MPa
STRESS MAX
6.1 MPa
T E S T S P E C I M E N
SUPPORT SUPPORTACTUATOR
SUPPORT SUPPORTACTUATOR