Calculates strain tensor along new direction in 3D problems with variables notation provided.

function E2=Transformation_Strain_3D(E1,T)

Input:
E1: Strain tensor with the following notation
E1=[epsilon_xx gamma_xy/2 gamma_xz/2;
gamma_xy/2 epsilon_yy gamma_yz/2;
gamma_xz/2 gamma_yz/2 epsilon_zz];

Total shear strain is divided by two to convert it to average shear strain

T: Transformation matrix with the following notation
T=[l1 l2 l3;
m1 m2 m3;
n1 n2 n3];
where l1,m1,n1 are the direction cosines for new coordinate X with old x,y and x directions
where l2,m2,n2 are the direction cosines for new coordinate Y with old x,y and x directions
where l3,m3,n3 are the direction cosines for new coordinate Z with old x,y and x directions

Output:
E2: Strain tensor in the new coordinate system