Stress-strain graph

I want to make Stress-Strain with linear regression and 0.2% off set graph.

But My code does not show me normal Stress-Strain graph.

I import excel data to matlab. I want to delete First column (start 76) but i cannot deleted.

I want to linear regression from 0 to 593 row data.

can you help me?

AluminumW = readtable("/Users/abc/Downloads/Steel Thursday.TXT");
AluminumW(1:75,:) = [];
AluminumW(593:end,:) = [];

disp = AluminumW(:,2);
force = AluminumW(:,3);

disp1 = table2array(disp);
force1 = table2array(force);

shift1 = disp1 - 0.081994;
shift2 = force1 - 0.11194;

d = 2.54;
r = d/2;
A = pi*r^2;

strain = shift1 / 12.7;
stress = shift2 / A;


figure(1)
plot(strain,stress)
xlabel('Engineering Strain')
ylabel('Engineering Stress (GPa)')
grid on
hold on

x = strain(60) - strain(1);
y = stress(60) - stress(1);

b1 = y / x;

slope = b1*strain;
plot(strain,slope,'g')
hold on

yield = strain + 0.002;

plot(yield,slope,'r')
hold off

Answer 1

[randerss simil]

To delete 1st column

AluminumW(1:75,1) = [];  % to delete 1st column

[randerss simil]

can you attach data file ?

[Junway]

here is

[randerss simil]

graph = readtable('data.xlsx')
plot(table2array(graph(:,1)),table2array(graph(:,2)))

This is what shows from your data file.

But your problem is related to another file ... if i am correct,

If possible can you share the Steel Thursday.txt file which is where the problem is

[randerss simil]

See this new data file which i added a first column.

Then i deleted it using the following command

graph = readtable('datastsr.xlsx')
graph(:,1) =[]
plot(table2array(graph(:,1)),table2array(graph(:,2)))

[randerss simil]

 x = table2array(graph(:,1));
 y = table2array(graph(:,2));
 p = polyfit(x,y,3); % cubic polynomial fit
  yfit = polyval(p,x); % poly evaluation
  yres = y-yfit; % residuals
  plot(x,y,x(1:50:end),yfit(1:50:end),'o','MarkerSize',2,'MarkerFaceColor','y')
  grid

If you want you can plot residuals and determine the regression coefficient R

[Junway]

How can I output like green line? I used excel file.

Two vertical lines are linear regression (Modules) 0.02 offset.

Steel = readtable(~~)
Steel(1480:end,:) = [];
Steel(1:64,:) = [];
Steel(114,:) = [];

disp = Steel(:,2);
force = Steel(:,3);

disp1 = table2array(disp);
force1 = table2array(force);

shift1 = disp1 + 0.088812;
shift2 = force1 - 0.004290;

d = 2.5;
r = d/2;
A = pi*r^2;

strain = shift1 / 14.8;
stress = shift2 / A;


figure(1)
plot(strain,stress)
xlim([-0.01,0.2])
ylim([0,.5])
xlabel('Engineering Strain')
ylabel('Engineering Stress (GPa)')
title('S v e')
grid on
hold on

x = strain(85) - strain(1);
y = stress(85) - stress(1);

b1 = y / x;

slope = b1*strain;
plot(strain,slope,'g')
hold on

yield = strain + 0.002;

plot(yield,slope,'r')
hold off

Answer 2

[Alfred Muchangi]

Could someone please help me with matlab script for plotting stress-strain curve give the following data:Test time, Standard force, Standard travel, Strain, Nominal strain