Study on rubbing characteristics of blade-casing model considering transverse cracks

The study focuses on the nonlinear vibration response of a blade system with cracks subjected to coupled rub-impact failure. Initially, the cracked blade system is mathematically modeled based on the Lagrangian theorem, and its motion is derived using Hamilton's principle. Secondly, a revised rubbing model is proposed with consideration of varying depths and locations of the cracks. Subsequently, the influences of parameters related to crack failure and rub-impact are comprehensively investigated. Finally, a novel crack influence index is also proposed to study the impact of resonance effect on crack failure. Different dynamic characteristics, along with the resonance coupling effect, were compared to demonstrate the working mechanism. The results indicate that severe rubbing occurred as the crack depth increased and the crack position decreased. The impact of crack depth on rubbing deformation than that of crack location. In addition, larger cracking depths and smaller cracking locations result in larger cracking influence coefficients, while the resonance effect disrupts this influence law in some cases.