An overview of gas turbine rotor bending: Causes, diagnosis, strengthening and prevention

This paper presents a comprehensive and structured review of gas turbine rotor bending, integrating its physical mechanisms, diagnostic methods, mitigation strategies, and predictive modelling approaches. The review systematically classifies the root causes and dominant thermo-mechanical bending modes, including those arising from non-uniform thermal fields, creep deformation, fatigue damage, and transient operating conditions. Established and emerging diagnostic techniques, such as vibration analysis, thermal monitoring, and visual inspection, are critically assessed in terms of their effectiveness for early detection and condition monitoring. The paper further evaluates strengthening and mitigation measures, encompassing material selection, rotor geometric design, thermal-mechanical load management, operational control strategies, and in-service rotor straightening methods. Recent advances in coupled thermal-mechanical-vibration simulation tools for predicting rotor bending and assessing straightening performance are also reviewed. On this basis, a system-level prevention framework is proposed that links design, operation, monitoring, and maintenance. By consolidating dispersed knowledge and identifying gaps in current practice, this review provides a unified reference and actionable guidance for the prevention and management of gas turbine rotor bending.