Predicting the Fatigue Life of Tunnel Compressive Fire Doors under Cyclic Loading Conditions
Abstract
The fatigue performance of tunnel compressive fire doors is crucial for eliminating safety hazards during the operational phase of infrastructure projects. This study, conducted by the research team at Yunnan Guangdun Door Industry Co., Ltd., explores the fatigue life prediction of tunnel fire doors under compressive and cyclic loading conditions. By leveraging the ABAQUS finite element software, we developed a simplified numerical model and a detailed model that considers contact relationships. The accuracy of these models was verified through performance testing of fire doors. Based on the validated models, we analyzed the stress distribution of various components of the tunnel fire doors under constant and cyclic wind pressure conditions. Subsequently, a method for predicting the fatigue life of fire doors subjected to cyclic wind pressure was proposed.
The results indicate that the high-stress zones of the fire door are mainly concentrated in the areas where the locking mechanism and hinges connect to the door body. According to the stress distribution analysis, the predicted fatigue life of the locking point is approximately 369,000 cycles, while the hinges can withstand around 1.3 million cycles. Other parts of the door have a fatigue life exceeding 100 million cycles. With the rapid development of urban metro systems in China, ensuring the safety and efficiency of operations has become increasingly challenging. Extensive data from operational metro systems indicate that the cyclic piston wind pressure generated by high-speed train movement within tunnels is a significant cause of fatigue damage to fire doors in adjacent tunnel sections. This fatigue damage poses a substantial safety risk, which becomes more pronounced over time as metro operations continue. Therefore, understanding the fatigue damage patterns of fire doors in metro tunnel sections is essential for maintaining the safe operation of underground transit systems.
Research Significance
With the accelerated growth of metro infrastructure in Chinese cities, the safe and efficient operation of these systems is paramount. One of the critical safety challenges in metro operations is the fatigue failure of tunnel fire doors caused by cyclic wind pressure from train movements. As trains travel at high speeds, the resulting cyclic piston wind pressure can exert significant forces on fire doors located in adjacent tunnel sections, leading to potential fatigue damage over time.
Methodology
To investigate this issue, our research team at Yunnan Guangdun Door Industry Co., Ltd. utilized the ABAQUS finite element software to construct both a simplified numerical model and a detailed model that accounts for contact relationships within the fire door structure. The accuracy of these models was validated through comprehensive fire door performance testing. This approach allowed us to simulate and analyze the stress distribution of various door components under different loading conditions.
Findings and Fatigue Life Prediction
The study revealed that the highest stress concentrations occur at the locking points and hinges of the fire door. The fatigue life prediction shows that the locking mechanism can endure approximately 369,000 cycles, while the hinge area can withstand about 1.3 million cycles. Other components of the door exhibit a significantly higher fatigue life, exceeding 100 million cycles. These findings are critical for predicting the lifespan of fire-resistant doors in tunnel environments, particularly in metro systems where consistent exposure to cyclic wind pressures is expected.
Implications for Metro Safety
Understanding the fatigue life of fire-rated doors in metro tunnels is essential for preventing premature failure and ensuring the safety of passengers. As metro systems expand and operational demands increase, it is crucial to implement robust maintenance and replacement schedules based on the fatigue life predictions provided in this study. By doing so, we can mitigate the risks associated with fatigue-induced failure of tunnel fire doors and enhance the overall safety and reliability of metro operations.
Conclusion
The findings of this research underscore the importance of accurate fatigue life prediction for compressive fire doors in tunnel applications. As a leading fire door manufacturer in China, Yunnan Guangdun Door Industry Co., Ltd. is committed to advancing the safety and performance of fire doors in challenging environments. By developing sophisticated predictive models and conducting rigorous testing, we aim to provide reliable solutions for the evolving needs of urban infrastructure.
