In the engineering field, many structures and mechanical components will experience periodic loads during use, such as aircraft wings, bridges, automotive suspension systems, and various rotating machinery. Although these periodic loads are usually much lower than the static strength limit of materials, they can lead to a phenomenon called 'fatigue failure'. Fatigue failure is characterized by suddenness and concealedness, and once it occurs, it often causes serious consequences. Therefore, predicting the service life of structures or components through fatigue analysis has become a key link in engineering design and maintenance.



The core of fatigue analysis lies in studying the micro-damage accumulation process of materials under repeated loading. Fatigue life prediction is usually divided into three main methods: stress-life method (S-N curve method), strain-life method, and fracture mechanics method. Among them, the S-N curve method is the most common, which establishes the relationship between stress and life by determining the number of cycles that materials can withstand under different stress amplitudes through experiments.



In practical applications, fatigue analysis is often combined with finite element simulation technology to simulate the stress conditions of complex structures under different working conditions. By obtaining the stress history of key parts and combining it with the S-N curve of materials and cumulative damage theory (such as Miner's linear cumulative damage criterion), the fatigue life of the structure can be estimated.



Fatigue analysis is not only used for life prediction in the design stage, but also plays an important role in equipment maintenance and life management. By monitoring and analyzing equipment in operation, engineers can assess their remaining life, formulate reasonable maintenance and replacement plans, thereby avoiding sudden failures and improving the reliability and safety of the system.



In summary, fatigue analysis is an indispensable tool in modern engineering design and maintenance. It not only helps designers optimize structures and save material costs, but also effectively prevents safety hazards caused by fatigue failure, extending the service life of equipment and having important theoretical and engineering application significance.