function ke = elasticStiffMtxUL(Elem,U)
    % Element properties
    E = Elem.E;
    A = Elem.A;
    I = Elem.I;
    L = elemLength(Elem,U);

    % Simplifications
    L2  = L*L;
    L3  = L2*L;
    EA  = E*A;
    EI  = E*I;

    % Elastic matrix
    ke = [ EA/L  0         0       -EA/L  0         0;
           0     12*EI/L3  6*EI/L2  0    -12*EI/L3  6*EI/L2;
           0     6*EI/L2   4*EI/L   0    -6*EI/L2   2*EI/L;
          -EA/L  0         0        EA/L  0         0;
           0    -12*EI/L3 -6*EI/L2  0     12*EI/L3 -6*EI/L2;
           0     6*EI/L2   2*EI/L   0    -6*EI/L2   4*EI/L ];
end