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 13023N Name: Uvarajan M Velayutham UoG Matriculation No: 2059265S 1 st Supervisor (in Singapore): Dr Christian Della 2 nd Supervisor (in Glasgow): Prof William Sloan Industry Supervisor: Dr Ronnie Teo Micro - Fatigue Testing in Metallic Material Introduction 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 Frequency Low High High Loading Amplitude High 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 System Compatibility 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 TEST SPECIMEN 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 TEST SPECIMEN SUPPORT SUPPORT ACTUATOR SUPPORT SUPPORT ACTUATOR