anchor.diff:     EAL0 = E*A/L0
      EE   = EAL0* Eps0/(1+Eps0)
   
  -   K(1:12,1:12)=0
  -
  -   ! Note: only translatoinal DOF involved (1-3, 7-9)
  +   K(1:12,1:12)=0.0_ReKi
  +
  +   ! Note: only translational DOF involved (1-3, 7-9)
      K(1,1)= EE
      K(2,2)= EE
      K(3,3)= EAL0
  
positive.code: 
     t = rho*A*L;
  
     M(1:12,1:12) = 0
  
     M( 1,  1) = 13._ReKi/35._ReKi * t
     M( 2,  2) = 13._ReKi/35._ReKi * t
  
negative.code:    K(8,8)= EE
     K(9,9)= EAL0
  
  
     DC = 0.0_ReKi
     DC( 1: 3,  1: 3) = DirCos
     DC( 4: 6,  4: 6) = DirCos
     DC( 7: 9,  7: 9) = DirCos
  