TY JOUR TI APPLICATION OF THE BENDING WAVE METHOD FOR INSPECTION OF SLAB AND WALL STRUCTURES KW bending wave velocity KW stiffness characteristics KW plate thickness KW experimental studies KW different frequency ranges JO Bulletin of Belgorod State Technological University named after. V. G. Shukhov AU Fan, C.. PY 2023 IS 8 PB Belgorod State Technological University named after V.G. Shukhov