Proceedings of the

The 33rd European Safety and Reliability Conference (ESREL 2023)
3 – 8 September 2023, Southampton, UK

Reliability Analysis of Flexural Subassemblies Under Ultra-High and Low Cycle Fatigue based on Monte-Carlo Method

Yongtao Baia, Cheng Xieb and Julio Flórez-Lópezc

School of Civil Engineering, Chongqing University, China.


Flexural subassemblies are widely used in building structures (beams and columns) and bridges. Structures in earthquake prone areas are not only subjected to ultra-low cycle ( < 100 cycles) fatigue (ULCF) load caused by earthquake action, but also experience ultra-high cycle ( > 10 million cycles) fatigue (UHCF) load during their service life, such as vehicle load and wind load. This paper first introduced a method, that is ultra-high cycle fatigue pre-damage and ultra-low cycle fatigue damage (UHCF_PreD-ULCF_D) criteria based on lumped damage mechanics, to model the damage state of flexural subassemblies under combined fatigue loading. The fatigue loading test data of three flexural subassemblies were referred to verify the accuracy of the model; Then, the reliability analysis and computing process of flexural subassemblies under fatigue damage state based on Monte Carlo method were established; Finally, the reliability of flexural subassemblies was analyzed under the uncertainty of material constant, loading cycle and lateral force. The results showed that UHCF_PreD-ULCF_D models of the flexural subassemblies not only achieved high accuracy, but also greatly improved the computing speed and convergence when calculating the UHCF and ULCF loading responses. The efficient method of calculating structural damage state was well applicable to the Monte Carlo method for reliability analysis. The reliability analysis program proposed for flexural subassemblies could consider the uncertainty of external loads and material defects well, compute the failure probability of the components efficiently, and calibrate the critical value of the damage variable of the theoretical model corresponding to structural failure.

Keywords: Structural reliability, Flexural subassemblies, Ultra-high cycle fatigue, Ultra-low cycle fatigue, Lumped damage mechanics, Monte Carlo method, Mathematical methods, Uncertainty analysis.

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