Spotweld (Bolt or Adhesive Connect)
 Node connect
 Spring (/PROP/TYPE13) connect
 Solid connect
Spring (/PROP/TYPE13) connect and solid connect could also model bolt or adhesive connect (glue).
Node Connect
Spring (/PROP/TYPE13) Connect
 Use failure criteria which available for a Spring TYPE13. For more details, see the comments on failure criteria in /PROP/TYPE13 (SPR_BEAM).
 Use Spot_{flag}= 20, 21, or 22 in Tied Contact (Tied Contact (/INTER/TYPE2)).Note: The modeling technique for the spotweld can also be used for other kinds of connections as welding lines, hemming, glue and bolts. For bolt modeling the use of tied interface is not necessary, as the shell nodes can be put directly in the rigid bodies.
 ${l}_{s}=4\text{\Delta}m\cdot {L}^{2}$
 $\text{\Delta}m$ : added mass
 ${l}_{s}={m}_{s}\cdot {L}_{s}{}^{2}$

 ${m}_{s}$
 Secondary node mass
 ${L}_{s}$
 Distance between the secondary node and the center
 ${l}_{s}$
 Inertia of the secondary node
If Spot_{flag}=0, there is no added mass, since the secondary node inertia is transferred as inertia to the main node. An added inertia that is too large will seriously decrease the accuracy.
Solid Connect
 The brick element use /PROP/TYPE43 and it has 4 integration point on the shear plane, which is between plane (1, 2, 3, 4) and plane (5, 6, 7, 8). One integration point in normal direction t. This element does not have time step itself and its stability is done by the nodal connection. So the thickness of a spotweld could be very small. This character is very useful for modeling glue.
 /INTER/TYPE2 used to connect solid spotweld with two upper and lower main surfaces.
 For this modeling
/MAT/LAW59+/FAIL/CONNECT (or
/MAT/LAW83+/FAIL/SNCONNECT) could
be used for solid spotweld.
 /MAT/LAW59 defines normal stress and shear stress curve (strain rate dependent) to describe the material character.
 With /FAIL/CONNECT elongation criteria and/or energy criteria could be used to describe the failure of spotweld.
 The failure occurs when the normal relative displacement or shear
relative displacement is reached according 2 behavior type:
Uncoupled failure (I_{fail}=0: unidirectional failure)
(2) with i=33 for normal direction and 13 or 23 for tangent directions$${\epsilon}_{i}\cdot f(\dot{\epsilon})>{\epsilon}_{maxi}$$  Coupled failure (I_{fail}=1:
multidirectional failure)
(3) The element deletion occurs when one integration point reaches the failure criteria, if I_{solid}=1, or all integration points reach the failure criteria, if I_{solid}=2.$${\left\frac{{\epsilon}_{N}}{{\epsilon}_{\mathrm{max}N}}*{\alpha}_{N}*{f}_{N}\left({\dot{\epsilon}}_{N}\right)\right}^{{\mathrm{exp}}_{N}}\text{+}{\left\frac{{\epsilon}_{T}}{{\epsilon}_{{\mathrm{max}}_{T}}}*{\alpha}_{T}*{f}_{T}\left({\dot{\epsilon}}_{T}\right)\right}^{{\mathrm{exp}}_{T}}>1$$  Use α and $\beta $ in /MAT/LAW83 to fit peel load and mixedmode load cases (ex: 30° and 60° load)
 In /FAIL/SNCONNECT defined is plastic elongation vs plastic elongation rate for damage initiation, failure for normal and shear direction.