Analysis Of Mechanical Behavior Of Steel Columns And Frame Structures Under Local Damage

As a prefabricated and industrialized structure,the steel structure has been widely used in industrial and civil buildings.However,due to the special material properties of steel,corrosion has seriously jeopardized the mechanical properties of steel structures.Understanding the damage of steel structures by corrosion is a hot issue in structural engineering.This paper mainly studies the influence of local pitting corrosion on the mechanical properties of axial compression members,and introduces the damage components into the overall structure to study the stress and deformation of the overall steel structure after damage.The specific research work and conclusions are as follows:(1)According to the H-shaped steel axial compression members used in the study,the available finite element model is established,and the rationality of the finite element model is verified by numerical analysis results and theoretical solutions;(2)According to the structural safety test data,study the mechanical properties of the axial compression members when the pitting corrosion is placed at the column foot.The study found that when the pitting corrosion is distributed on the web,DOP and a have less influence on the ultimate bearing capacity of the member,when the DOP reaches a limit value,a is the main influencing factor of the ultimate bearing capacity of the component.When the pitting corrosion is distributed at the flange,the R of the member has a segmental linear relationship with DOP,with the increase of DOP,the R decreases from slow to fast,and the larger a,the smaller the DOP when the R accelerates to decrease.When DOP is constant,as the a increases,the downtrend of ultimate bearing capacity of the component approximates the quadratic function relationship;(3)Analyze the deformation and force characteristics of the member,and further study the mechanical properties of the axial compression member when the pit is distributed in the column.The study found that when the pitting is distributed on the web,the ultimate bearing capacity of the member is less affected.The larger the a,the faster the R decreases as the DOP increases.When the pitting corrosion is distributed at the flange,the R is approximately linear with DOP.The larger α,the faster the R decreases when the DOP increases.When the pitting parameters are the same,the influence of pitting distribution on the bearing capacity in the middle of the column is greater than that in the peg;(4)Establish a framework model,introduce damage components,and perform linear elastic analysis under static conditions.The analysis results show that under the preset conditions,the damage structure has no significant change in maximum stress and position,displacement and deformation compared with the original structure,but the stress at the damage site increases;(5)Apply earthquake incentive to the overall frame model to study the dynamic response of the structure.The study found that the frequency of the damaged structure is lower than the original structure,which indicates that the overall stiffness of the structure is reduced after the damage.When different earthquakes occur,the maximum interlayer displacement angle in the damage structure is slightly increased,and the position is unchanged.The maximum stress increases,but the increase is different.In this experiment,the stress increases by 11.36%,and the position may change.At the same time,the maximum displacement has a small increase.Figure[58]table[12]reference[49].