University of Guilan Journal of Mathematical Modeling 2345-394X 9 3 2021 09 01 A linear theory of beams with deformable cross section 465 483 4610 10.22124/jmm.2021.17932.1548 EN Luca Sabatini Dip. S.B.A.I., University of Rome "La Sapienza", Via Antonio Scarpa 14, 00100 Roma, Italy Journal Article 2020 10 19 We present a direct model of beam  which takes into consideration the deformation of the section by effect of orthogonal actions. The variation of size and the distortion of the transversal sections are taken into account as well as the usual rigid rotation-torsion-warping. We deduce the equations of motion in terms of the kinematic descriptors. A simple numerical example is also presented  to show the consistence of the proposed model. https://jmm.guilan.ac.ir/article_4610_ccea1e91531138ea5fc7c8e36239c13d.pdf