Study On Impact Resistance Of Q420 Steel Tube Considering Corrosion Damage

Circular steel pipes are extensively used as structural members of trusses or tower,and are widely used in important building structures such as high-voltage transmission towers or large steel truss columns.Natural atmospheric corrosion and falling rock impact have threatened the safety and stability of steel structure buildings serving in mountainous regions,and even interfere with the development of local economy and daily life of residents.This dissertation studies the influence of atmospheric corrosion on the impact resistance of steel tubes,takes the Q420 steel tube that as the object and takes Jiangjin,an area of Chongqing in China,as an example.It puts forward the material damage model considering corrosion time,obtains model parameters by accelerated corrosion test,carries out drop hammer test of pre-corrosion Q420 steel pipe members,and conducts a simulation analysis of impact resistance in the ABAQUS software,compares the calculated results with the test results,and obtains the dynamic response variation law of corroded steel pipes under different impact conditions.This article mainly carries out the following research work:(1)Study on atmospheric corrosion damage of Q420 low-alloy high strength steel Based on the results of existing atmospheric exposure tests of low-alloy steels in the Jiangjin,an area of Chongqing,contrasted with the local adaptation of four classic corrosion prediction models,selected an more accurate model as the basis,the Q420 steel performance prediction model considering corrosion time was established according to the one-dimensional damage theory,so as to obtain the theoretical relationship between the weight loss rate and the corrosion time.The constitutive model parameters were obtained by carrying out accelerated corrosion and static tensile tests on Q420 steel pipe components by the dry-wet alternating weight loss method.The differences between the physical properties of the material surface,such as pitting conditions,yield strength,and elongation,were compared,and the effect of corrosion damage on the properties of the steel was analyzed.(2)Impact test of low-speed drop hammer of Q420 steel pipe after atmospheric corrosion damage The self-designed drop hammer test device was used to perform a drop weight impact test of Q420 steel pipes with five degrees of corrosion under constant axial force.The transient data such as impact force,acceleration,strain and impact process were obtained by using the high-speed acquisition instrument.The parameters of test results were statistically sorted out,and the influence of different impact parameters on the impact dynamic response results was analyzed,which provided practical basis for finite element calculation.(3)Study on the difference of impact response of Q420 steel tubes under different action The finite element model of cylindrical shell of Q420 steel pipes considering corrosiondamage weakening was established in the ABAQUS/Explicit module based on the established constitutive model of corrosion damage of Q420 steel.The numerical calculation was carried out on the Q420 steel pipe model under seven degrees of corrosion,six kinds of drop weight velocities and six kinds of drop weight masses.The difference of dynamic response of the different Q420 steel pipes under local area impulse load was analyzed by obtaining the impact time history curve,displacement time history curve,component deformation,deflection,etc..The test results were compared with the numerical calculation results.