0 measure modulus, 0 strain-controlled test – MTS Fatigue Template User Manual

Page 97

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pin from your extensometer, the modulus is incorrect. If you type incorrect specimen dimensions, the modulus
is incorrect.

10.2.7.0 Measure Modulus

To check the modulus in the LCFS test:

1. Click Measure 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.

3. Click the Run button.

4. A window appears with the Modulus Check Result.

Click Accept to accept the result.

Click Reject to discard the result.

Click Measure Modulus to perform the modulus check again.

Click View Data Report to see the results in report form.

10.2.8.0 Strain-Controlled Test

A typical low-cycle fatigue (LCF) test sequence includes:

1. Ramp to mean level, if the mean level at the start of the test is not zero. All data recorded during the ramp

is stored in cycle number 0 (zero).

2. Identify a stable cycle for comparison with other test values.

3. Start the test cycle count, start test data collection, and run the test to completion.

4. Ramp the system to the mean load of the last cycle.

Cycle 0 (zero)

The application collects data for each complete cycle. A cycle starts at mean level and ends at mean level.
In most cases, mean level is zero. For cases where mean level is not zero, a ramp initially occurs to mean
level before the test actually starts. The application stores the data collected during this initial ramp in cycle
count 0.

Stable cycle determination

The application identifies the stable cycle based on user-entered parameters.

Application-determined stable cycle

For an application-determined stable cycle, a consecutive number of cycles must remain within the stable-cycle
deviation factor to determine the reference cycle. Typical cycle counts are from 5 to 100 cycles.

Enter the percentage deviation that consecutive cycles must be within, as compared to an initial cycle. If a
cycle deviates beyond this percentage before the stabilizing factor amount is reached, that cycle becomes

MTS TestSuite 97

10.0 ASTM Trapezoidal Strain Template

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