# I am having issues concatenating arrays

2 views (last 30 days)
A Poyser on 22 May 2023
Commented: A Poyser on 22 May 2023
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
A Poyser on 22 May 2023
Appologies I meant that I have also tried
stress_ratio = [stress_ratio; KIc0 / applied_stress];
which gives the vertcat error

VBBV on 22 May 2023
Edited: VBBV on 22 May 2023
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 on 22 May 2023
Edited: VBBV on 22 May 2023
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 on 22 May 2023
awesome, thanks

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