MTS Fatigue Template - Manual (Page 98)

the new cycle against which following cycles are compared. Typical stable cycle deviation factors are around
1%.
Test completion
The LCF test runs until it meets one of the termination criteria. Examples of test termination criteria include:
• Non-controlling failure threshold (%)
• Peak-valley deviation
Non-controlling failure threshold (%)
For tests run in strain control, you define a percentage of stable load amplitude to use for failure detection.
When the test reaches the stable cycle, the test compares the peak loads with this cycle to determine if the
test should be terminated due to specimen failure. For tests run in load control, enter the percentage of stable
displacement for failure detection. When the stability reference cycle is reached, the test compares the peak
displacements to this cycle to determine if the test should be terminated due to specimen failure.
Crack initiation determination
After a stable cycle is identified, each subsequent cycle is compared to the stable cycle. If the non-controlling
range (force range for a strain controlled test) deviates by the user-entered percentage, the application stores
the cycle number as the crack initiation cycle. Typical range drops are near 5%.
Peak-valley control failure
If the control value end levels are not met, the test stops.
Ramp to mean load
When the test is complete, the system changes to force control and ramps to mean load at a rate set by the
user.
10.2.9.0 Strain Test
In the LCFS test:
1. Click Strain Test.
The MTS TestSuite Custom Message window appears with the message: Validate test parameter on
runtime display. Click Run Test to start testing. Click Change Parameters to go back and change any
parameters.
2. Click Run Test to start the test. A message appears: Click the Run button to start the Strain test.
3. Click the Run button. The Run button changes color.
4. Click Change Parameters to view the main menu, where you can change parameters and run the test.
10.2.10.0 Reattach Extensometer
If the test stops and you want to resume it, you must reattach the extensometer. On the main menu, click
Reattach Extensometer.
98 MTS TestSuite
10.0 ASTM Trapezoidal Strain Template