MTS Fatigue Template - Manual (Page 111)

• 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.
11.2.11.0 Measure Thermal Strain
The Measure Thermal Strain button allows you to verify the strain at high temperature. Enter a value as
necessary and click OK to continue.
11.2.12.0 Measure Thermal Modulus
To measure the thermal modulus:
1. Click Measure Thermal Modulus.
The MTS TestSuite Input Parameters window prompts you to enter a load value to ramp to for a modulus
check.
2. Enter a load value and click OK.
A message appears: Click the Run button on the control panel to start measuring the modulus.
3. Click the Run button.
The Run button changes color.
4. A window appears with the Thermal Modulus Check Result.
• Click Accept to accept the result.
• Click Reject to discard the result.
• Click Measure Thermal Modulus to perform the modulus check again.
• Click View Data Report to see the results in report form.
MTS TestSuite 111
11.0 ASTM Trapezoidal Strain Elevated Temperature Template