Advanced Fretting Fatigue Life Prediction Method for Naval Aerospace Applications

The U.S. Navy seeks the development of an advanced fretting fatigue life prediction tool to address critical gaps in understanding fretting fatigue mechanisms and to enable the evaluation of novel mitigation strategies for metallic aerospace structural components operating under diverse conditions. Despite numerous test-based studies and the development of empirical models aimed at improving the durability and performance of metallic components under fretting conditions, no consistent correlation has been established between operational parameters and the associated failure mechanisms or fatigue life variability. The inherently complex nature of fretting fatigue—governed by the coupled effects of fretting wear, multiaxial non-proportional loading with steep stress gradients, contact geometry, slip amplitude, coefficient of friction, and loading frequency—poses significant modeling challenges. As a result, a robust, physics-based life prediction approach capable of accurately capturing fretting fatigue behavior across different materials and loading conditions remains elusive. Compounding this challenge is the high uncertainty associated with current test methods, which limits the utility of experimental data for gaining deeper mechanistic insights. To address these challenges, Global Engineering and Materials, Inc. (GEM), in collaboration with its team member, proposes to develop a comprehensive, physics-informed modeling framework supported by a rigorous verification and validation (V&V) plan. The proposed modeling approach will integrate the following key elements: 1. Advanced interface contact modeling to capture stick, partial slip, and gross slip regimes. 2. Evolution of the contact interface including fretting wear as well as debris accumulation and depletion. 3. Degradation of interface properties and accumulation of plastic deformation under cyclic loading. 4. An enhanced multiaxial stress-driven fatigue damage indicator to account for steep stress gradients for accurate fretting fatigue life prediction. In Phase I, the proposed methodology will be demonstrated using representative case studies from the literature to validate the modeling framework. The validated multiphysics modeling tool will then be used to identify alternative operational regimes aimed at reducing the risk of fretting-induced failure. Additionally, a novel and targeted experimental plan will be developed to generate high-quality, low-uncertainty data that will support model validation and further mechanistic understanding, thereby enhancing model fidelity and practical utility.