An apparatus that passes vibrational energy across a mechanical structure lacking a perforation. The disclosed apparatus and method provide the ability to transfer work (rotary or linear motion) across pressure or thermal barriers or in a sterile environment without generating contaminants; the presence of reflectors in the solid barrier to enhance the efficiency of the energy/power transmission, and the ability to produce a bi-directional driving mechanism using a plurality of different mode resonances, such as a fundamental frequency resonance and a higher frequency resonance. In some instances, a plane within the mechanical structure lacking a perforation is a nodal plane of the vibrational energy field.