MTS Multipurpose Elite - Manual (Page 242)

YieldIndexByZeroSlope
The YieldIndexByZeroSlope function determines the yield index by searching the curve in segments until
the angle of the curve decreases to the specified angle.
Returns
The function returns the index associated with the Yield point.
Syntax
YieldIndexByZeroSlope(y-axis, x-axis, angle, segmentLength[, threshold, startIndex, endIndex)
Parameters
y-axis - The Y axis data array used in the calculation of the yield index.
x-axis - The X axis data array used in the calculation of the yield index.
Angle - The angle of the slope used to determine the location of the yield point.
SegmentLength - The number of points to use in each slope calculation.
Threshold - An optional percentage of the peak value of the y-axis data that must be exceeded before
starting the search for the Yield Index. If this field is missing, 2% is used.
StartIndex - An optional starting index for the yield index search region. If this field is missing, the search
starts at the beginning of the data.
EndIndex - An optional ending index for the yield index search region. If this field is missing, the search
ends at the last point of the data.
Unit Class
Integer
Example
Y-Axis = Force array
X-Axis = Extension array
Angle = 0 rad
Segment Length = 10
Threshold = 2 N
Given these values, the algorithm starts looking for the first point in the Force array that exceeds 2 N.
The first Force point that exceeds 2 N becomes the start of the search region.
The slope of the Force and Extension data is calculated using 10 point segments.
The algorithm increments through the data until there is no more data to check or the slope decreases to
an angle of 0 radians.
YpeEndIndexByIncreasingLoad
The YpeEndIndexByIncreasingLoad function determines the end of the Yield Point Elongation.
242 | MTS TestSuite
Working with Variables