Research On Acoustic Emission Characteristics Of Damage Process Of Stud Connector

The stud connector is a key component of the steel-concrete composite girder bridge.It mainly subjected to shear force at the joint surface.Combined steel beams with concrete bridge decks to work together.Stud connector shear resistance and shear stiffness are important to evaluate its mechanical properties.When the stud connector damaged,will change its own mechanical properties.In turn,it will affect the durability and service life of the overall structure.In recent years,domestic and foreign scholars have conducted extensive research on the technical status and damage assessment of stud connectors.This paper relies on Hebei Provincial Youth Science Fund Project-“Study on Damage Mechanism of Composite Beam Stud Connector Based on Acoustic Emission(AE)Technology”.Combine AE nondestructive testing technology,starting from the microscopic damage mechanism.Exploring the characteristics of AE signals during the damage of the stud connector.Reveal the damage evolution mechanism of the stud connector.It provides a theoretical basis for the safety evaluation of steel-concrete composite girder bridges in service.The main research work of this article includes the following three aspects:(1)Using the key technologies of AE to finish source positioning.Noise reduction of AE signals.Selecting effective analysis method to analyze the characteristics of AE signals.Research were Using four sensors constituted rhombic array in jet-lag positioning method.Plane positioning of AE sources,accurately calculate the coordinates of its AE source.Set the threshold to 45 dB,can shield most of the noise.The parameter analysis method accurately describe the characteristics of AE signals.(2)Design launch test to research the mechanical damage properties of stud connector.Combined with finite element analysis verifying the launch test.At the same time as the launch test,using AE tester to acquire AE signals of stud connectors.Analyze it,and determine the effective AE signal characteristic parameters.Using tests combined with finite element analysis,the shear failure process of the stud connector can be divided into theree stages.As follow as flexible stage,elastoplastic stage and plastic stage.And use amplitude,energy,count,rise time,duration time,of AE signal parameters.Can specifically describe the damage characteristics of stud connectors during shear failure.(3)Using AE signal characteristic parameters of are created by stud connectors during damage.By analyzing its characteristic parameters,study its mechanical damage properties during the destruction process.Establish the joint parameter association diagram,to acquire the characteristics of AE signals during the shear failure process of a stud connector.The study found that the ringer parameters of AE signal parameters can reflect the development of cracks in stud connectors.Energy parameters can reflect the degree of damage of the stud connector.Amplitude parameters can analyze the deformation of the stud connector.Take the amplitude as the abscissa,associated graphs established by the remaining four feature parameters,respectively.The characteristics of the AE signal at the shear failure of the stud connector can be obtained.