Introducing angularly periodic disturbances in dynamic models of rotating systems under non-stationary conditions

• This paper focuses on angular modeling to describe faulty bearing behavior.
• Instantaneous Angular Speed (IAS) is shown to be a key signal for fault detection.
• Defects are introduced as torque disturbance on rotating shaft in bearing dynamics.
• Simulations allow estimating this torque by comparing simulated IAS with experiments.
• A dedicated test bench is used for model validation in non stationary conditions.

A mechanical defect in a rotating system can be interpreted as the presence of a periodic angular perturbation. Understanding the interactions between the defect and its consequences on measurable quantities representative of dynamic behavior (acceleration, speed, etc.) necessarily involves the implementation of numerical models. The aim of this paper is to present a model suitable for introducing this kind of disturbance in the case of systems operating under non-stationary speed conditions. This model corresponds to a numerical extension of approaches increasingly used to analyze experimental signals.The resulting model can be used to investigate of the influence of disturbance parameters on the dynamic responses of the rotating system. It also allows comparisons of new assumptions on the origin of this perturbation. This new approach is illustrated by using the general framework of bearing faults.