MTS Multipurpose Elite - Manual (Page 235)

LowerYieldIndex
This LowerYieldIndex function is used to calculate the first occurrence of a zero slope after the upper yield
point.
1. The search for the Lower Yield Point begins after the upper yield index point.
2. The force must drop from the upper yield point by the listed tolerance before the lower yield index can
be identified.
3. From this point, the algorithm keeps track of the minimum load point, and stops searching when the
load value increases by the same amount as the drop from the upper yield index.
4. The Lower Yield index is reported as the minimum load point found during the search.
Returns
This function returns the index point in the array of the lower yield point.
Syntax
LowerYieldIndex(y-axis, tolerance, upperYieldIndex)
Parameters
y-axis - The force array data being analyzed for the zero slope.
Tolerance - The percentage drop in force from the upper yield index that must occur before a lower yield
index can be identified.
UpperYieldIndex - The index representing the location of the upper yield index.
Unit Class
Integer
MaxSlopeStartIndex
The MaxSlopeStartIndex and MaxSlopeEndIndex functions are used to determine a region of data where
the slope of the line is minimized based on the function arguments. The slope of the line is determined
using a Least Squares Fit on the Y and X channel data.
Returns
The MaxSlopeStartIndex function returns the last point of the region. If a valid region cannot be located
given the function arguments, a –1 will be returned as the index.
Syntax
MaxSlopeStartIndex (y-channel, x-channel, % segment length, % tolerance, min load, max load,
%strain point)
MTS TestSuite | 235
Working with Variables