In the past I was asked several times about AC on boards and its consequences due to electro-magnetic induction. How does an alternating current change trace heating and how does it influence the traces around? Plenty of approximating formulae on skin and proximity effect for simplified geometries can be found in literature. For traces in boards it is better to solve Maxwell's equations directly.
Over Christmas and New Year there is some time to play with. A test code gives good results for classic test cases. What has to be done now is to define industrial use cases and to solve them.
Call for Action: If you work with AC in printed boards and want to contribute, please leave a message in the comment field below.