Force Evaluation
For each nugget, a set of force and moment variables are created. The underlying assumption is that there is a stress distribution in the thin elastic layer which is proportional to the difference in displacements between the two boundaries. The traction vector in global coordinates is
The force vector in global coordinates is obtained by integration over the nugget area,
Finally, the force is decomposed in a normal force and a shear force:
The moments are evaluated around the center of the nugget (
X
n
), that is the location of the spot weld after projection on the destination boundary. In global directions, the moment vector
M
is
In the same way as the force, the moment is decomposed in a twisting moment around the normal of the boundary and a bending moment.
