“…Moreover, the interest in composite materials, exhibiting continuously varying effective material parameters at the macroscopic level, lead to numerous studies of the so-called functionally graded beams (FGBs). These works propose several ways to take into account a material heterogeneity in the transverse direction [10], in the axial direction [7,11], or in both directions [12]. Ultimately, beams that are both geometrically and materially heterogeneous are also considered [13,14,15].…”