Research On Degradation Rule And Probabilistic Distribution Model Of Probability Distribution Of The Bearing Capacity Of Welded Hollow Spherical Joints With Random Pit Corrosion

Welded hollow spherical joints(WHSJs)are one of the most commonly used joints in reticulated shell structures.Corrosion that occurs at the surface of WHSJs has different influences on the compression capacity of WHSJs.Pit corrosion is a typical corrosion type for steel structures.However,the influence of pit corrosion in different locations on the loading capacity of WHSJs has not been quantified.Randomness is the nature of corrosion,including the random location and random size.The random size was indicated by the random planar size and random thickness.The corrosion of steel structures is always the multiple-random problem.The WHSJs in actual project are always subjected both axial force and moment.The appearance of tensioning force may affect the probability distribution of moment capacity for WHSJs with random corrosion.It provides a basis for random analysis of complex stress state of WHSJs structure with random pitting.Including the following:(1)The present study aims to reveal the influence of corrosion located in different places on the compression capacity of WHSJs.The influence of corrosion location on compression capacity was systematically investigated and the accuracy of the finite element model was validated.Furthermore,the influence of corrosion and geometrical parameters on the random distribution of compression capacity was analyzed.Then,the analytical method to predict the compression capacity was put forward.(2)In this study,nonlinear numerical analyses were conducted to investigate the influence of several parameters on the bending capacity of a WHSJs.A numerical model of the WHSJs with random pit corrosion was proposed to investigate the mechanical behavior of the corroded WHSJs.Results indicated that the moment capacity of the WHSJs with random corrosion pits was normally distributed.A probabilistic distribution model of the corroded WHSJs was proposed.The failure probability could be deduced based on the formulae of the upper and lower bounds of the moment capacity.(3)The objectives of this work are to construct a probabilistic distribution model of the compression capacity of WHSJs with random pit corrosion and to establish the relationship between the probabilistic distribution model and the specified corrosion(including corroded thickness Tc,pit diameter Dc and pit number n)and geometrical parameters(including the thickness and diameter of spherical body T and D).The influences of the corrosion and geometric parameters on the random distribution of compression capacity were first analyzed.Then,the probabilistic distribution model of the compression capacity of WHSJs with random pit corrosion was established.The analytical method given in this paper owns high accuracy in predicting probabilistic distribution model of compression capacity with knowing Tc/T and n when Dc.(4)A series of nonlinear numerical analyses was conducted to investigate the influences of these parameters on the mass loss and compression capacity or bending capacity of WHS Js.This work aimed to construct a probabilistic distribution model of the compression capacity or bending capacity of WHSJs with multiple-random pitting corrosion and establish the relationship of the probabilistic distribution model with the specified corrosion and geometric parameters.This work provided a method for determining the probabilistic model of WHSJs under actual conditions and served as a basis for the stochastic analysis of integral structures connected by WHSJs with random pitting corrosion.The method to determine the probabilistic model of WHSJs in actual condition was also given.This work can serve as a basis for the stochastic analysis of integral structures connected by WHSJs with randomly located corrosion.(6)A large number of stochastic FE analysis was conducted in this work to investigate the influence of compression force or tensioning force on probabilistic distribution of bending capacity of WHSJs.The objectives of this work are to investigate the influence of compression force or tensioning force on bending capacity and construct a probabilistic distribution model of the bending capacity with considering the influence of compression force or tensioning force.The proposed method is validated and it has high accuracy in predicting the probabilistic distribution of bending capacity of WHSJs in complex force state.