The analysis of the finite element method requires continuous
connections of the nodes between different elements. However,
the specialized mesh size caused disconnections of the nodes on
divided small elements between different materials, which would
cause errors to occur in the estimation. With respect to this problem,
‘slide interfaces’ were assigned to these contact surfaces
between different mesh-sized materials during geometric building,
and they were specially treated by the program in the simulation
in order to carry out the estimation correctly (Wakao et al.,
2008; Liu et al., 2013).