Timoshenko–Ehrenfest beam theory
The Timoshenko–Ehrenfest beam theory was developed by Stephen Timoshenko and Paul Ehrenfest early in the 20th century. The model takes into account shear deformation and rotational bending effects, making it suitable for describing the behaviour of thick beams, sandwich composite beams, or beams subject to high-frequency excitation when the wavelength approaches the thickness of the beam.
Source: Wikipedia — Timoshenko–Ehrenfest beam theory (CC BY-SA 4.0)