Research On Parameter Identification Method Of Cable Structure Based On LightGBM Algorithm

Cable bracing system is widely used in bridge structures,especially in long-span bridge structures,because of its advantages of large bearing capacity,clear force transmission and beautiful appearance.The parameter identification of cable support system is an important guarantee to ensure the safety and durability in construction and application stages.Based on the basic theory of frequency method and the inherent relation between physical parameters,this paper presents a practical calculation method to calculate one end of consolidation and one end of hinge.At the same time,a method of parameter identification of cable structure using Light GBM algorithm is proposed.Finally,the feasibility and accuracy of the method are verified by the data of design test and actual engineering.The research contents are as follows:(1)The free vibration equation of cable under four different conditions is summarized,and the string vibration theory and the calculation formula of cable force of two ends articulated cable considering bending stiffness are obtained,and the practical formula for calculating cable force of two ends consolidated cable is summarized.Finally,according to the inherent physical relations in the differential equation of cable free vibration,a simple and practical formula is derived for consolidation at one end and hinge at the other.(2)Machine learning algorithm is widely used in engineering projects due to its efficient computing power.A method using Light GBM algorithm to identify cable parameters is proposed.The Abaqus finite element software was used to generate several groups of samples to provide training,and the Light GBM algorithm model obtained by training was used to identify the cable parameters.The prediction accuracy of the algorithm met the requirements of practical engineering.(3)The cable scale test was designed,and the cable boundary condition was hinged at both ends.Light GBM algorithm was used to identify the cable force,which verified the accuracy of the method.According to the measured data of actual engineering,when the boundary condition is one end consolidated and the other hinged,the practical formula derived in this paper and Light GBM algorithm are used to identify the cable force,and the calculated results have good accuracy.