00670naa#a2200205#i#450# EN\INFRA-M\bibl\5901 20240922212507.7 1998-071X 20150425b2015####ek#y0engy0150####ca RUS RU Change in the Natural Vibration Frequency Spectrum of the Steel Pipe Mathematic Model Depending on Sizes, Location, and Number of Local Defects Journal article Moscow INFRA-M Academic Publishing LLC. 2015 12 с. Journal article local Suslonov A. Samarin V. Sushchev Sergey Petrovich Novgorodova A. naukaru.ru