I am using Galerkin's method to set up some pde solver for my problems(1D/2D) at hand.
Some abrupt material interfaces do exist, so far, what I did regarding this is simply:
1) no element across the interface, i.e. nodes exactly lie at the interfaces.
2) no special B.C. imposed on interfaces, just natural B.C.(as it is).
I am wondering:
1) is what I did sufficient to deal with the interfaces?
2) some people recommend to use zero thickness elements along the interfaces, so that every nodal point on the interface is associated with a duplicate node, is it necessary? and what is the justification?