3 results about "Beam finite elements" patented technology

The present disclosure relates to a bridge sensor optimization layout and response reconstruction method, system and medium, relating to the field of bridges. The method comprises: establishing a finite element model of the bridge; deleting measurement points in the initial sensor layout scheme; calculating load transverse influence lines using the bridge finite element model, reconstructing strain response data of the deleted transverse strain measurement points; reconstructing displacement data of the deleted displacement measurement points and / or acceleration data of the acceleration measurement points based on the relationship between displacement and acceleration; reconstructing strain response data of the deleted longitudinal strain measurement points based on the relationship between strain and displacement, using sensor data of the retained longitudinal strain measurement points and using data of the longitudinal displacement measurement points; constructing the architecture of the BiLSTM neural network model; all sensor data and all reconstructed data are input into the network model, and the network model is used to predict the data of the deleted measurement points. The present disclosure realizes the optimization of the sensor layout while improving the reconstruction accuracy.

This invention discloses a method and system for calculating the time-varying reliability of cable corrosion fatigue in cable-stayed bridges. The method includes establishing and validating a finite element model of the cable-stayed bridge; simulating the time history of fluctuating wind speeds in the main girder and main tower using the harmonic synthesis method; obtaining the cable stress time history through buffeting analysis; establishing a probability model of equivalent stress amplitude and cycle number using the rainflow counting method and Miner's theory; constructing a probability model of the depth of dangerous pits and corrosion depth of steel wires under different corrosion degrees based on measured data; establishing a multi-stage series formula coupling pit evolution, pit-crack transformation, and crack propagation; constructing a limit state equation with a 2% wire breakage rate as a threshold; calculating the time-varying reliability of the cable under different wind speeds and corrosion degrees using random sampling; and statistically analyzing the mean and standard deviation of corrosion fatigue life. This invention accurately reflects the wind-corrosion coupling and multi-stage failure mechanism, is computationally reliable, and has strong versatility, making it suitable for safety assessment and life prediction of cables in various types of cable-stayed bridges.

This invention discloses a physical-data fusion-based method for rapid stress spectrum modeling and fatigue life prediction of bridge cranes, belonging to the field of crane structure safety assessment technology. Addressing the problems of low efficiency in traditional finite element stress calculation, the lack of consideration for the influence of variable stress ratios in conventional crack propagation models, and unreasonable handling of multiple alternating loads in a single working cycle, this invention establishes a stress sample library by building a finite element model of the crane's main beam and uses a gradient boosting decision tree model to achieve rapid stress prediction at critical points. Based on measured load spectra, the maximum and minimum stress values ​​of a single cycle are extracted to generate a stress spectrum. The Walker formula is used to correct the crack propagation rate, and the life prediction is completed by combining a periodic sample cycle method. This invention improves the efficiency of stress spectrum acquisition, ensuring that the stress spectrum compilation closely reflects actual service conditions, while correcting the life prediction deviation caused by variable stress ratios. It can be used for fatigue safety assessment and life prediction of in-service bridge crane metal structures, demonstrating high engineering practicality.