I am having issues concatenating arrays

I have a piece of code that I am trying to concatinate some arrays. I am being told that they are not consistent, and that vertcat has an error

% ...

N_Vv = 100;
Vv = linspace(0, 0.7, N_Vv);
cdp_initial = 0; % Initial vanishing crack density parameter
cdp_increment = 0.01; % Increment value for cdp
applied_stress = 100; % Applied stress (modify as per your requirement)
N_cycles_max = 1000; % Maximum number of cycles (modify as per your requirement)

stress_ratio = zeros(N_Vv, 1); % Preallocate stress_ratio as a vector of zeros

for k = 1:N_Vv
    % Homogenised stiffness and compliance with voids and cracks
    % ...

    % Calculate stress intensity factor (KIc) based on Griffith's equation
    KIc0 = sqrt(1E-3 * (1 - Vv(k)) / 2 * eps' * Am * C2m * Fc * Am' * eps);

    % Estimate fatigue life based on crack growth rate
    % ...

    % Increment cdp based on applied stress and number of cycles
    % ...

    % Store maximum/applied stress ratio at the corresponding index
    stress_ratio(k) = KIc0 / applied_stress;

    % ...
end

the line that says

stress_ratio(k) = KIc0 / applied_stress;

gives the error

I have also tried

 stress_ratio(k) = KIc0 / applied_stress;

which tells me that the left and right sides have a different number of elements

How can I figure out how to correct this scaling issue

Thanks in advance

[A Poyser]

Appologies I meant that I have also tried

stress_ratio = [stress_ratio; KIc0 / applied_stress];

which gives the vertcat error

Answer 1

[VBBV]

In the below line you have several variables, C2m, Fc, Am which may be multidimensional matrices

 KIc0 = sqrt(1e-3 * (1 - Vv(k)) / 2 * eps' * Am * C2m * Fc * Am' * eps);

[VBBV]

The resulting matrix will produce a matrix with different dimensions, and you try to assign to single element in matrix in the below line

stress_ratio(k) = KIc0 / applied_stress;

replace it with

stress_ratio(k,:) = KIc0 / applied_stress;

or

stress_ratio{k} = KIc0 / applied_stress;

[A Poyser]

Thanks for the support, I am finding that neither of these two alternatives seem to work

stress_ratio(k,:) = KIc0 / applied_stress;

tells me that left side is 1x1 and the right side is 6x6

stress_ratio{k} = KIc0 / applied_stress;

tells me that indexing is not supported for this type of variable

Thanks

Alex

[VBBV]

Ok, It seems you have preallocated stress_ratio as

stress_ratio = zeros(N_Vv, 1); 

Then you need to change it as

stress_ratio = zeros(N_Vv, length(C2m),length(Am)); 

whichever that fits dimension. Then assign it to the variable stress_ratio as

stress_ratio(k,:,:) = KIc0 / applied_stress;

Its better not to preallocate any zeros to variable since it size of matrices change every iteration, Its better to use cell arrays instead to store multdimensional matrices as they dynamically adjust the dimensions of the matrices

% comment the below line
%stress_ratio = zeros(N_Vv, 1); 

% use the below
stress_ratio{k} = KIc0 / applied_stress;

[A Poyser]

awesome, thanks