find_elastic_limit: find_elastic_limit

In tbgitoo/textureAnalyzerGels: Reading and analyzing texture analyzer data

find_elastic_limit

Description

Estimates the end of the linear elastic segment where the compression force starts to plateau. In prototypical foams, this marks the transition from largely undeformed linear compression to wall buckling (Gibson&Ashby, 1997).

Usage

find_elastic_limit(theData,touch_point,gel_thickness=NULL)

Arguments

theData	Smoothened texture analyzer data, as produced by the smooth_texture_analyzer_data function; should contain only a one-way movement (down or up) for the chuck
touch_point	Point where the chuck touches the gel. This can be found from the Force - Distance diagram. where the force curve in a Force - Distance diagram raises abruptly
gel_thickness	Optionally, thickness of the gel to help make an educated guess of the extent of the elastic segment (20% of the gel height).

Details

The function uses both the slope and the actual force to find the initial touch point, hence the theData argument must have at least the columns Distance, pressure and pressureSlope

Value

Numerical value, indicating the position of the surface of the gel

Author(s)

Thomas Braschler

References

Gibson, L. J. & Ashby, M. F. Cellular Solids: Structure and properties. (Cambridge University Press, 1997).

See Also

smooth_texture_analyzer_data

Examples

data(sampleGelSmooth)
touch_point=find_initial_touch_point(sampleGelSmooth[sampleGelSmooth$direction=="down",])
elastic_limit = find_elastic_limit(sampleGelSmooth,touch_point)
plot(Force ~ Distance, sampleGelSmooth[sampleGelSmooth$direction=="down",]) 
lines(rep(touch_point,2),c(0,11),col="black")
lines(rep(elastic_limit,2),c(0,11),col="red")
text(touch_point,11.5,labels="Touch point",adj=0.5)
text(elastic_limit,11.5,labels="Elastic limit",adj=0.5,col="red")

tbgitoo/textureAnalyzerGels documentation built on March 30, 2022, 4:53 a.m.