Predictive Wear Assessment of Plain Bearings in Variable Stator Vanes: Accounting for Geometric Tolerances in Early-Stage Design
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The Variable Stator Vane (VSV) [1] system is a complex kinematic system associated with the first stages of the high-pressure compressor. It enables adjustment of the stator vane incidence angle according to the incoming primary airflow conditions. From a technological point of view, the rotational guidance of the stator blades is carried out by plain bearings. However, over multiple flight cycles, wear in these joints can compromise system integrity, posing a challenge for reliability during the preliminary design phase. The objective of this work is to propose a simulation tool for a preliminary design stage making it possible to predict the wear of these guiding elements over a large number of flight cycles, while integrating the geometric deviations specified by the geometric tolerancing of the assembly. The proposed methodology is based on a simplified local-global approach to the problem of conformal contact in mechanical joints [2]. The following assumptions are adopted: the solids are considered rigid, the small perturbation framework is used, the contacting surfaces are idealized as perfectly smooth (i.e., neglecting surface roughness), and wear is modeled using an Archard-type law [3, 4]. The displacement of the stator vane is evaluated using a small displacement torsor to take into account wear or initial geometric defects [5, 6], in this framework the displacements are linearized. The problem is solved using a Newton–Raphson scheme with a semi-analytical tangent operator, enabling a significant reduction in computational cost [7]. Finally, to assess the influence of geometric deviations on system integrity, the model is integrated into a Monte Carlo simulation framework. This approach enables predictive wear assessment over a large number of flight cycles, providing insights into the robustness of the VSV system from the earliest stages of design.
