Unveiling Stress Mitigation and Lifespan Extention Strategies for Spherical Elastomeric Bearings in Aerospace Applications

Abstract

Spherical elastomeric bearings play a pivotal role in aerospace applications, specifically in the context of helicopters. While extensive research has focused on planar elastomeric bearings, the complexity introduced by multilayer geometries with different composite materials has restricted investigations into their spherical counterparts. These bearings must delicately balance stiffness against perpendicular loads and flexibility along the layers. The stress experienced by elastomers over time contributes to bearing aging, emphasizing the imperative of stress reduction to prolong their useful life. In this study, we employ nonlinear finite element analysis to model and examine the mechanical behavior of spherical elastomeric bearings. Stress distributions are determined using the hyper-elastic Mooney-Rivlin approach. Notably, our research explores uncharted territory by investigating the influence of various parameters, including hole shape and diameter, layer thickness, profile, and the number of layers. The findings reveal that the outermost layers bear the highest stress levels under pressure and displacement loads. A significant contribution of this research is the demonstration that altering the shape and thickness of these outer layers can effectively reduce the maximum stress experienced by all layers. Particularly, the study highlights that the most substantial stress reduction is achieved by modifying the hole diameter. This breakthrough holds the promise of an extended lifespan for elastomeric bearings, suggesting practical advancements in aerospace applications.