Using for loop to build and plot data from a matrix

1 view (last 30 days)
Hello ! how are you?
I wrote a code that calculates strains by using matrices, and the answer that I receive from matlab is an array of (6x1) like this:
Now, I would like to perform the exactly same calculations but for different temperatures (T) from -30 to 280 degrees celcius in steps of 10 and store these results in a variable called Epsilon. In the end of calculations I should obtain a matrix of (6x32). The approach that I used MATLAB returns me a message saying that right and left hand side have different numbers of arrays.
Please find the code below:
% Material Mechanical Properties
Ex = 41*10^3; % [MPa]
Ey = 10.4*10^3; % [MPa]
Ez = 10.4*10^3; % [MPa]
Gxy = 4.3*10^3; % [MPa]
Gyz = 3.5*10^3; % [MPa]
Gxz = 4.3*10^3; % [MPa]
Vxy = 0.28;
Vyz = 0.50;
Vxz = 0.28;
% Material Thermal Properties
alphax = 7.0*10^-6; % [1/°C]
alphay = 26*10^-6; % [1/°C]
alphaz = 26*10^-6; % [1/°C]
% Holding true Matrix symmetry
Vyx = (Vxy * Ex)/Ey; % [MPa]
Vzx = (Vxz * Ex)/Ez; % [MPa]
Vzy = (Vyz * Ey)/Ez; % [MPa]
% Creation of the compliance matrix
E = [1/Ex,-Vxy/Ey,-Vxz/Ez,0,0,0 ; -Vyx/Ex,1/Ey,-Vyz/Ez,0,0,0 ; -Vzx/Ex,-Vzy/Ey,1/Ez,0,0,0 ; 0,0,0,1/(2*Gxy),0,0 ; 0,0,0,0,1/(2*Gyz),0 ; 0,0,0,0,0,1/(2*Gxz)];
% Creation of thermal matrix
alpha = [alphax ; alphay ; alphaz ; 0 ; 0 ; 0];
% Calculation of the stiffness matrix
K = inv(E);
% Calculation of Thermal Moduli (β)
Beta = -K * alpha;
% Point material stress
Sigma_xx = 12; % [MPa]
Sigma_yy = 10; % [MPa]
Sigma_zz = 14; % [MPa]
Tau_xy = 6; % [MPa]
Tau_yz = 3; % [MPa]
Tau_zx = 9; % [Mpa]
% Point material ΔT
T = [-30:10:280]; % [°C]
% Formation of stress vector
Sigma = [Sigma_xx ; Sigma_yy ; Sigma_zz ; Tau_xy ; Tau_yz ; Tau_zx];
Epsilon = zeros(6,length(T));
for i = 1:length(T)
% Calculation of strains
Epsilon(i) = E * Sigma + T(i) * alpha;
end
Unable to perform assignment because the left and right sides have a different number of elements.
Thank you in advance !

Accepted Answer

Cris LaPierre
Cris LaPierre on 15 Nov 2021
The calculation in your for loop returns more than 1 value, so your assignment must be to a number of rows and/or columns of the same size. Here, that means specifying rows and column.
Try this.
% Material Mechanical Properties
Ex = 41*10^3; % [MPa]
Ey = 10.4*10^3; % [MPa]
Ez = 10.4*10^3; % [MPa]
Gxy = 4.3*10^3; % [MPa]
Gyz = 3.5*10^3; % [MPa]
Gxz = 4.3*10^3; % [MPa]
Vxy = 0.28;
Vyz = 0.50;
Vxz = 0.28;
% Material Thermal Properties
alphax = 7.0*10^-6; % [1/°C]
alphay = 26*10^-6; % [1/°C]
alphaz = 26*10^-6; % [1/°C]
% Holding true Matrix symmetry
Vyx = (Vxy * Ex)/Ey; % [MPa]
Vzx = (Vxz * Ex)/Ez; % [MPa]
Vzy = (Vyz * Ey)/Ez; % [MPa]
% Creation of the compliance matrix
E = [1/Ex,-Vxy/Ey,-Vxz/Ez,0,0,0 ; -Vyx/Ex,1/Ey,-Vyz/Ez,0,0,0 ; -Vzx/Ex,-Vzy/Ey,1/Ez,0,0,0 ; 0,0,0,1/(2*Gxy),0,0 ; 0,0,0,0,1/(2*Gyz),0 ; 0,0,0,0,0,1/(2*Gxz)];
% Creation of thermal matrix
alpha = [alphax ; alphay ; alphaz ; 0 ; 0 ; 0];
% Calculation of the stiffness matrix
K = inv(E);
% Calculation of Thermal Moduli (β)
Beta = -K * alpha;
% Point material stress
Sigma_xx = 12; % [MPa]
Sigma_yy = 10; % [MPa]
Sigma_zz = 14; % [MPa]
Tau_xy = 6; % [MPa]
Tau_yz = 3; % [MPa]
Tau_zx = 9; % [Mpa]
% Point material ΔT
T = [-30:10:280]; % [°C]
% Formation of stress vector
Sigma = [Sigma_xx ; Sigma_yy ; Sigma_zz ; Tau_xy ; Tau_yz ; Tau_zx];
Epsilon = zeros(6,length(T));
for i = 1:length(T)
% Calculation of strains
Epsilon(:,i) = E * Sigma + T(i) * alpha;
% ^ Specify 'all rows'
end
plot(Epsilon)

More Answers (0)

Products


Release

R2020b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by