Changing Values of a Large Array

So I am trying to change data in a 2716 by 1 array. I imported the data for this array from a text file. I need to change the last 665 lines of data in a new array and still have the original data as the first part of the array.

%%

%For true stress/strain we need to create the reduction of area as necking

%occurs

% point at which necking occurs: stress = 312.8 Mpa

true_Load = M.Load*1000; %kN

load_location = 312.8*area/1000; %location in text file

load_location;

%Necking begins: line 2043

%Fracture: line 2724

%2724-2043 = 681 lines of data need to be recreated for stress

%now that we have the location of the UTS we can take that and begin the

%reduction from original area to fracture area

reduc_Area = linspace(area, frac_Area, 665);

%redcu_Area should have comperable data for the

%necking that occurs till fracture. We now need to make

%true stress by inputting the extrapolated values into a new

%stress file

true_Stress = stress;

true_tress(2043:2716,:) = true_Load(2043:2716,:)/reduc_Area(2043:2716,:);

When I run this code I get:

Index in position 1 exceeds array bounds (must not exceed 1).

Error in AL6061_0hr (line 107)

true_tress(1:2716,:) = true_Load(2043:2716,:)/reduc_Area(2043:2716,:);

I have tried multiple things of what I thought would work but can not figure it out.

[Matthew Lancaster]

I figured it out, the fix was:

%%

%For true stress/strain we need to create the reduction of area as necking

%occurs

% point at which necking occurs: stress = 312.8 Mpa

true_Load = M.Load*1000; %kN

load_location = 312.8*area/1000; %location in text file

load_location;

%Necking begins: line 2043

%Fracture: line 2724

%2724-2043 = 681 lines of data need to be recreated for stress

%now that we have the location of the UTS we can take that and begin the

%reduction from original area to fracture area

reduc_Area = linspace(area, frac_Area, 674);

reduc_Area';

%redcu_Area should have comperable data for the

%necking that occurs till fracture. We now need to make

%true stress by inputting the extrapolated values into a new

%stress file

true_Stress = stress;

% true_Stress(2043:2716,:) = true_Load(2043:2716,:);

% true_Stress(2043:2716,:) = true_Stress(2043:2716,:)/reduc_Area(1:);

for i = 1:673

reduced_Area = reduc_Area(:,i);

true_Stress(2043+i,:) = true_Load(2043+i,:)/reduced_Area;

end%We now have true stress

By incorporating the for loop I was able to go in and change the value. linspace was creating a 674 by 1 array and when I tried to divide the true_Stress by reduc_Area it wasn't allowing it.

The for loop allowed me to create a single variable to divide by.

Answer 1

[Image Analyst]

Do not use two dimensions for a 1-D array. And you can do it vectorized (no for loop) if you use ./ like this:

true_Stress = stress; % Initialize.
true_Stress(2043:2716) = true_Load(2043:2716) ./ reduc_Area; % Element by element division.

[Matthew Lancaster]

Thank you