Contact and tied interfaces
mfid, $T_{fail}$, $S_{fail}$, $n_T$, $n_S$
Parameter definition
mfid Merge failure command ID
$T_{fail}$ Tensile failure force
$S_{fail}$ Shear failure force
$n_T$ Tensile failure exponent
default: $n_T=2$
$n_S$ Shear failure exponent
default: $n_S=2$

This command specifies failure of a blind hole bolt MERGE interface. Failure is initiated when:

$\left( \frac{T}{T_{fail}} \right)^{n_T} + \left( \frac{S}{S_{fail}} \right)^{n_S} \geq 1$

where $T$ and $S$ are the total tensile and shear forces in the bolt-hole interface.

The command can also be used to predict failure of nut-bolt MERGE interfaces, but then only the tensile failure criterion will be active.