If I have Strong Energy attached to a Trapinch and it evolves into a Vibrava, what happens?
When you evolve from a Fighting type Pokemon to another type (Dragon, in this case), the Strong Energy is immediately discarded.
Source: Furious Fists FAQ (2014-08-28), TPCi Rules Team (2014-08-28)

Relevant cards

Note: All applicable cards may not be listed below.
XY3_104