Facing problem with plot function

I am trying to plot stress vs strain but the how can i remove the line between the first and last point when my data does connect those two points. Is it problem of plot function? how to i do it cause the scatter function does not look good as i want continuous plot

Answer 1

[Fangjun Jiang]

plot it with a marker, e.g. plot(Strain, Load,'+')

Answer 2

[Star Strider]

The first and last p[oints apparently have the same coordinates.

If your data ars sorted, for example by the x-coordinates, remove the last point in the data.

x = linspace(1, 11, 25).';
y = 30 - (x/10).^4;

xy = [0 0; x y; 0 0];
disp(xy)

         0         0
    1.0000   29.9999
    1.4167   29.9996
    1.8333   29.9989
    2.2500   29.9974
    2.6667   29.9949
    3.0833   29.9910
    3.5000   29.9850
    3.9167   29.9765
    4.3333   29.9647
    4.7500   29.9491
    5.1667   29.9287
    5.5833   29.9028
    6.0000   29.8704
    6.4167   29.8305
    6.8333   29.7820
    7.2500   29.7237
    7.6667   29.6545
    8.0833   29.5731
    8.5000   29.4780
    8.9167   29.3679
    9.3333   29.2412
    9.7500   29.0963
   10.1667   28.9316
   10.5833   28.7454
   11.0000   28.5359
         0         0

figure
plot(xy(:,1), xy(:,2))
grid
axis([-1 12  -1 35])
title('Original Data')

xy = xy(1:end-1,:);                 % Eliminate The Repeated Last Row
disp(xy)

         0         0
    1.0000   29.9999
    1.4167   29.9996
    1.8333   29.9989
    2.2500   29.9974
    2.6667   29.9949
    3.0833   29.9910
    3.5000   29.9850
    3.9167   29.9765
    4.3333   29.9647
    4.7500   29.9491
    5.1667   29.9287
    5.5833   29.9028
    6.0000   29.8704
    6.4167   29.8305
    6.8333   29.7820
    7.2500   29.7237
    7.6667   29.6545
    8.0833   29.5731
    8.5000   29.4780
    8.9167   29.3679
    9.3333   29.2412
    9.7500   29.0963
   10.1667   28.9316
   10.5833   28.7454
   11.0000   28.5359

figure
plot(xy(:,1), xy(:,2))
grid
axis([-1 12  -1 35])
title('Slightly Edited Data')

.

[Sam Chak]

Hi @Arindam

Technically, the plot completes the loop because it appears that when the force on the specimen is suddenly removed, the load immediately drops to zero, and the specimen somehow seemingly returns to its original shape (the pre-elongated state, ). However, if the last point is intended to be at the fracture point, then the stress would drop to zero while the strain remains at its maximum value.

[Star Strider]

@Sam Chak -- Thank you!