Analytical and experimental investigation of vibration response for the cracked fluid-filled thin cylindrical shell under transport condition

Abstract

Adverse conditions induce surface cracks in fluid-filled thin cylindrical shells, thereby diminishing their mechanical properties and load-bearing capacity. However, due to the discontinuity in vibration characteristics near the cracks and the strong coupling during the transport process, the free vibration response solution and state recognition oriented to the fluid-filled thin cylindrical shell containing a surface crack still face significant challenges. To address the above issues, a free vibration response solution method for fluid-filled thin cylindrical shell containing a surface crack based on Linear Spring Model and linear potential flow theory is proposed, which elucidates the interaction mechanism within the fluid-shell-crack coupling state and establishes a quantitative relationship between these coupling parameters and vibration response characteristics. Subsequently, a natural frequency isoline-based state recognition method is introduced to achieve unified identification of crack morphology and fluid state. Finally, a multi-channel LMS vibration test platform is built, and the error between analytical and experimental results is less than 4 %, thereby corroborating the accuracy and validity of the proposed vibration response solution method. The research findings indicate that both surface cracks and internal fluid contribute to the reduction in natural frequency, with the crack angle being the primary factor. Additionally, it is observed that apart from internal fluid velocity, all parameters exhibit extreme values near a length ratio of L/R = 10.