Plan

Before the experiment began a plan was created. It was decided that the data would be recorded directly in to an excel spreadsheet. This reduces the risk of the data being imputed incorrectly and effecting the results. The spreadsheet was then linked with the R markdown sheet. This was done so that any data in the spreadsheet could be created in to a graph and be checked. Once this was all completed the experiment was then begun.

The sample

The sample is mild steel with a round cross section

L = 13.424 # lenght
D = 3.55 # diameter
A = 3.14*D^2/4

Experiment

Before the mild steel could be tested in the tensometer a weigh bar needed to be selected. There were three to choose from that each went to a different level of force, 0-0.1 KN, 0-1 KN and 0-10 KN.The area was used to calculate that amount of force required for the sample to fail. This in turn was used to determine which weigh bar needed to be used. So based on the calculations the largest weigh bar was used, 0-10 KN.

Read in the data

This section is retrieving the data from the excel spreadsheet.

dt<-read.csv("TST_MS1.csv")

In the csv file, extention is in mm and force is in KN

Calculate stress and strain

dt$stress<-1000*dt$Force/A
dt$strain<-dt$Extention/L

Plot stress strain curve

plot(stress~strain,data=dt, xlab = "strain", ylab = "stress (MN/m^2)")

lm(stress ~ strain, data = dt)

## 
## Call:
## lm(formula = stress ~ strain, data = dt)
## 
## Coefficients:
## (Intercept)       strain  
##      -20.48      4812.40

coeff=coefficients