Fig. 4

Schematic diagram of the slab interface geometry designed as a B-spline in physical space, (x, z), evolving over parameterized time, \(\vartheta\). The putative initial and observed final coordinates of points on the assumed slab surface are interpolated to splines with an equal number of control points and equal number of knot vectors yielding \(\Gamma _\text {slab}(\vartheta =0)\) and \(\Gamma _\text {slab}(\vartheta =1)\). The slab interface surface at intermediate time is generated according to Eq. 22. The displacement vector of the slab surface, \(\varvec{d}_\text {slab}\), is shown from the initial to the final configuration