%--------------------------
 % @Author: Jingqiao Hu
 % @Date: 2021-02-19 22:33:50
 % @LastEditTime: 2021-02-19 22:33:52
%--------------------------
function [u0, l0, D0] = material_paras(e0, nu0)
    u0 = 0.5*e0/(1+nu0);
    l0 = e0*nu0/((1+nu0)*(1-2*nu0));
    
    D0 = e0/(1+nu0)/(1-2*nu0)*...
    [ 1-nu0   nu0   nu0     0          0          0     ;
        nu0 1-nu0   nu0     0          0          0     ;
        nu0   nu0 1-nu0     0          0          0     ;
         0    0    0 (1-2*nu0)/2     0          0     ;
         0    0    0     0      (1-2*nu0)/2     0     ;
         0    0    0     0          0      (1-2*nu0)/2];
end