Ageing Module – Master Curve
The extended life module is recommended when the material operates below the endurance limit. Although cracks may not grow due to mechanical fatigue, the material properties may still evolve with exposure to heat history. A series of oven ageing experiments is used to develop master curves showing the evolution of stiffness, intrinsic strength, and fracture strength with time. The protocol also produces an estimate of the activation energy of the Arrhenius rate law describing the time-temperature dependence of ageing in the material.
Recommended for cases with fatigue life longer than 106 cycles, and when ageing must be taken into account.
Note: It is required to run FPM-IS in order to run this Module.
Experiment Overview
- ageing in oven at 3 temperatures for 3 time periods: 3 days, 10 days, 30 days
- static tearing raw data, 3 ageing periods x 3 ageing temperatures
- cutting force raw data, 3 strain levels x 3 ageing periods x 3 ageing temperatures
- number of slabs needed for test: 30
Analysis and Reporting / Deliverables
- cutting vs. tearing curve at each aged condition
- intrinsic strength T0 vs. ageing master curve
- tearing energy Tc vs. ageing master curve
- Arrhenius activation energy, Ea
- fatigue threshold strain, stress, energy vs. ageing curves (when ordered with FPM-C)
- parameters specifying ageing time and temperature dependence of T0 and Tc • extrapolation of ageing effects to longer timescales for an application-specific temperature
Use with:
- Arrhenius ageing law
