Rapid Fatigue Limit Estimation of Metallic Materials Using Thermography-Based Approach

This work attempts to develop a theoretical model in combination with the representative volume element (RVE) theory for realizing rapid fatigue limit prediction. Within the thermodynamic framework, it is believed that two components, namely anelastic and microplastic behaviors, which correspond to recoverable and non-recoverable microstructural motions, contribute to temperature variation during high-cycle fatigue. Based on this, the constitutive equation of the response relationship between the temperature rise evolution and the stress amplitude of metallic materials can be deduced in combination with the heat balance equation. Meanwhile, a determination approach for the thermographic experimental data for accurate fatigue limit estimation is developed by combining it with a statistical method. Finally, the experimental data of metallic specimens and welded joints were utilized to validate the proposed model, and the results demonstrated great agreement between experimental and predicted data.