Spherical nanoindentation stress-strain analysis
Please read Spherical Nanoindentation Stress-Strain Analysis in MATLAB.pdf for an introduction to the code.
(1) Kalidindi and Pathak. (2008) Acta Materialia. http://dx.doi.org/10.1016/j.actamat.2008.03.036
(2) Vachhani et al. (2013) Acta Materialia. http://dx.doi.org/10.1016/j.actamat.2013.03.005
(3) Pathak and Kalidindi. (2015) Materials Science and Engineering R. http://dx.doi.org/10.1016/j.mser.2015.02.001
(4) Weaver et al. (2016) Acta Materialia. (Supplemental Material) http://dx.doi.org/10.1016/j.actamat.2016.06.053
The main reason for writing this code was to make the determination of the zero-point correction and indentation stress-strain curves more robust by semi-automating the analysis, developing metrics for determining appropriate answers, and providing some estimate of the uncertainty
of the appropriate answer including measurements from the indentation stress-strain curve (e.g. indentation yield strength).
The intended use is that the user would select a representative answer for each test and include the statistics of multiple appropriate answers for one test when determining the final answer, values, or properties.
RunME.m - load, analyze, plot, save data with this script. Most of the parameters which require adjusting are set in this script.
LoadTest.m - imports nanoindentation in excel format. Important to set/check the indenter properties, the "End of Test" marker, and correct columns of raw data. CSM corrections are also calculated in here.
smoothstrain.m - applies a moving average to the hardening fit stress-strain data. Not always used.
filterResults.m - cuts down the results based on different criteria. A new criterion can be added by coping the 'case' logic used for other variables.
CalcStressStrainWithYield.m - here is where the indentation stress-strain curve is calculated
FindYield_v2.m - function for determining the yield point and hardening slopes.
FindYieldStart.m - function for determining if a pop-in occurs and some markers needed for determining the yield point
MyPlotSearch.m - plotting function for the 3-D scatter plot of the results. In order to change the axes of the 3-D plot, modify this code and in SearchExplorer.m
NIAnalyzeSearch.m - this function does the zero=point and modulus regression analyses. It gets called many times so try not to add more to it. A speed up in computation might come from better coding with this function and the sub functions it calls.
MyHistSearch.m - plotting function for histograms of relevant variables in the results. Viewing this data can be helpful for updating the filter to determine the results.
SearchExplorer.m - interactive plotting function for the 3D scatter plot for the results. Important - the scaling of the indentation stress-strain curve plot is done manually because it always causes problems. Find the variables: mstrain and mstress and adjust accordingly.
subslider.m - creates a subplot of historgrams for many vairables. A NewFilt variable can be created based on the slider values of all the variables in the plot.
MyHistResults.m - spits out the statistics for indentation properties for the saved analyses.
Shouldn't have to touch these...
Driver.m
SingleSearchAllSegments.m
mypolyfit.m
rsquare.m