This paper deals with a theoretical and experimental study about the nonlinear behavior of metals subjected to intense ultrasonic, flexural vibrations. In the theoretical analysis a one-dimensional, second-order wave equation is established and solved by means of the successive approximation method. The solution for standing, flexural waves is obtained by applying the superposition principle. Spatial distributions of force, momentum, and particle velocity are derived as well as the waveforms. The experimental study is carried out with resonant, prismatic bars driven at their central sections at frequencies in the range of 20–30 kHz. The samples are driven by means of a piezoelectric transducer. The vibration amplitudes and waveforms are monitored by using a laser vibrometer. Good agreement is found comparing the experimental and theoretical results.