A method to transfer distributed Lorentz forces in 3D to a finite element mechanical model

The problem of transferring distributed Lorentz forces acting on a coil to a mechanical mesh in 3D is studied. The same analysis was presented a few months ago for the 2D case. Although the physics and the mathematical procedure is the same, the actual details are different enough to be worth being analyzed. With these routines it is possible to perform the magnetic analysis with one tool (for example, ROXIE in 2D, Vector Fields Opera in 3D) and then to project the Lorentz forces on an independent mechanical mesh (for example, in ANSYS). This has the potential to streamline the design of superconducting magnets; a similar analysis strategy is adopted at LBNL. An appendix lists an example of code that can be used to transfer such forces, in an attempt to provide a ready-to-use recipe to the interested engineer.