Two-node unidirectional gap element (GAPUNI)

This is a standard gap element defined between two nodes. The clearance $ d$ of the gap and its direction $ \boldsymbol{n}$ are defined by using the *GAP card. Let the displacement vector of the first node of the GAPUNI element be $ \boldsymbol{u_1}$ and the displacement vector of the second node $ \boldsymbol{u_2}$. Then, the gap condition is defined by (Figure 77):

$\displaystyle d+\boldsymbol{n} \cdot (\boldsymbol{u_2} -\boldsymbol{u_1}) \ge 0.$ (13)

Figure 77: Definition of a GAPUNI element
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