collision.md

Collision

Slabs collide at moment $t^n$, we merge $B$ and $C$ and set following: $\Sigma_B = \Sigma_C$, where $\Sigma$ is tension.

Boundary conditions for the side bars we find at moment $t^n$ as follows. Let's add a mock node $i - 1/2$ with bars $i - 1$ and $i$ which we will use only for computations. This mock node we place to the left corner of the right stab.

And we suposse following for the mock node:

$\begin{align} \Sigma^n_{i-1/2} = 0 ; \phi^n_{i-1/2} = 0 \end{align}$