“…The solution in the classical case is constructed by various methods: operational calculus (Williams, 1952, Cook & Erdogan, 1972, Sinclair, 2004, functions of a complex variable (Parton & Perlin, 1981), Erie functions and integral equations (Cook & Erdogan, 1972;Andreev, 2014), separation of variables and expansion in series into various functions (Shannon et al, 2014(Shannon et al, , 2015Galadzhiev et al, 2011;He & Kotousov 2016), etc. The authors who are using numerical methods: finite element method (Koguchi & Muramoto, 2000;Barut et al, 2001;Xu & Sengupta, 2004;Lee et al, 2006;Xu et al, 2016;Dimitrov et al, 2001), finite element method in combination with by searching for eigenvalues by the Arnold method (Apel et al, 2002), the method of boundary elements and the method of boundary states (Mittelstedt & Becker, 2006;Koguchi & Da Costa, 2010 ), implementing the asymptotic idea by unlimited refinement of the FE-grid at the region near the special points or by constructing special finite elements. Many authors of asymptotic solutions in the study of the stress state near singular points (Williams, 1952;Koguchi & Muramoto, 2000;Wu, 2006, Koguchi & Da Costa, 2010He & Kotousov, 2016) are looking for singularity indices -parameters for solving the characteristic equations of the corresponding homogeneous problems.…”