# i am getting this error "Brace indexing is not supported for variables of this type" at line which contains (S_bar{i}=​R{i}*T_1{i​}*R_1{i}*S​{i}*T{i});​.

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Mahmoud Chawki on 5 Apr 2022
Commented: KSSV on 5 Apr 2022
sigma1=0.002;
sigma2=-0.003;
tau_12=0.004;
E1=181;
E2=10.3;
mu_12=0.28;
G12=7.17;
tetha=0:90;
c=cosd(tetha);
s=sind(tetha);
Stress_12=[sigma1; sigma2; tau_12];
%S matrix calculation
S=[1/E1 -mu_12/E1 0;-mu_12/E1 1/E2 0;0 0 1/G12];
%Q matrix calculation
Q=inv(S);
%Strain Vector calculation
Strain_12=S*Stress_12;
for i=1:numel(tetha)
%Transformation matrix calculation
T{i}=[c(i).^2 s(i).^2 2.*s(i).*c(i); s(i).^2 c(i).^2 -2.*s(i).*c(i); -s(i).*c(i) s(i).*c(i) (c(i).^2)-(s(i).^2)];
%Inverse of the transformation matrix
T_1{i}=inv(T{i});
%R matrix
R{i}=[1 0 0; 0 1 0; 0 0 2];
R_1{i}=inv(R{i});
%S bar matrix calculation
S_bar{i}=R{i}*T_1{i}*R_1{i}*S{i}*T{i};
end

KSSV on 5 Apr 2022
Edited: KSSV on 5 Apr 2022
IN this line:
S_bar{i}=R{i}*T_1{i}*R_1{i}*S{i}*T{i};
S is a matrix not a cell. So replace it by:
S_bar{i}=R{i}*T_1{i}*R_1{i}*S*T{i};
Also try initializing R, T_1, R_1 etc. Note that you can also intialize them as 3D matrix.
R = zeros(3,3,numel(tetha)) ;
##### 2 CommentsShowHide 1 older comment
KSSV on 5 Apr 2022
?You have orange colored undeline in the code right? Those are warning, place the cursor there and see what MATLAB suggesting you.

### More Answers (1)

John D'Errico on 5 Apr 2022
Edited: John D'Errico on 5 Apr 2022
Is S a regular matrix?
S=[1/E1 -mu_12/E1 0;-mu_12/E1 1/E2 0;0 0 1/G12];
Yes. You then you assume it is a cell array for some reason.
S_bar{i}=R{i}*T_1{i}*R_1{i}*S{i}*T{i};
____
Did MATLAB tell you there was a problem on that line?