Tubular surfaces of center curves on spacelike surfaces in Lorentz-Minkowski 3-space

In this paper, we introduce three kinds of tubular surfaces associated to original center curves gamma lying in spacelike surfaces in Lorentz-Minkowski 3-space. It is demonstrated that these tubular surfaces can occur some singularities and the types of these singularities can be characterised by several invariants, respectively. Some interesting relations between the contacts of original curve gamma with osculating model surfaces, the contacts of gamma with slices, and the singularities of three kinds of surfaces are further revealed. Several examples are presented to explain the theoretical results.