Traditionally, power transfer through thick metallic barri- ers has required physical penetrations and wire feed-throughs, which reduces structural integrity and limits the environmental isolation provided by the barrier. The Faraday shielding pre- sented by these barriers, however, prevents efficient transfer of electromagnetic power, limiting many RF coupling techniques. More recently, the use of ultrasound has been shown as an ef- fective non-destructive technique for transmitting large amounts of power (100s of watts) through solid metallic mediums. By us- ing two coaxially aligned piezoelectric transducers loaded onto opposite sides of the barrier through an acoustic couplant, an ultrasonic channel is formed through which efficient power de-livery is possible. This work presents finite element modeling and simulations that help characterize the impacts of many me- chanical design factors on the power transfer efficiency of these ultrasonic channels, including: transducer-wall coupling effects, transducer and wall resonance modes, transducer dimensions, and barrier composition and dimensions. Physical channel mea- surements are also presented to show the strong correlation be- tween the finite element simulations and the systems modeled.