“…There are several approaches to the introduction of stiffeners. For example, in Kidane et al (2003) andJaunky et al (1996, a discrete approach is singled out, which can be found, for example, in Qu et al (2013), Amiro and Zarutskii (1983), Huang and Qiao (2020), Khalmuradov and Ismoilov (2020), Lee and Kim (1998), Mustafa and Ali (1989), Sadeghifar et al (2011), Talebitooti et al (2010, Wang et al (1997), Wang and Hsu (1985) and Zhao et al (2002), as well as an approach with stiffness smearing (Efimtsov and Lazarev (2009), Jaunky et al (1996), Bich et al (2013), Buragohain and Velmurugan (2009), Srinivasan and Krishnan (1989), Totaro (2016), Tu and Loi (2016), etc. ).…”