A method for ultrasonic welding of materials, comprising generating ultrasonic waves in a welding assembly; transmitting the generated waves along the welding assembly in a first direction; receiving the generated waves in a sonotrode, the waves entering the sonotrode while propagating along the first direction; causing the received waves within the sonotrode to propagate along a second direction, perpendicular to the first direction; and oscillating a welding surface of the sonotrode using peaks and valleys of the waves propagating in the second direction.