Research On Influence Of Dynamic Response Of Equilateral Angle Steel Components Under Environmental Corrosion

The steel structure is widely used in industrial and civil buildings,especially in large public buildings,because of its advantages of high strength,uniform material and light weight.Corrosion of steel structure not only causes great economic losses,but also poses a hidden danger to structural safety.The damage of structure is incalculable while corroded steel structures is seriously damaged by terrorist attacks or accidental explosions.Therefore,it has been an important and urgent task to carry out the research on disaster protection of corroded steel structure under the action of explosion and explore how to reduce the function of explosion shock wave on the corroded steel structure and steel members and prevents the damage and even the overall collapse of the corroded steel structure.It is hard to solve explosion problems with theoretical calculation because of the superposition of the shock wave with the reflection and diffraction effect,and factors such as mechanical properties degradation after corrosion of structure,while the corroded steel structure under the explosion shock loading.The methods of field test and numerical simulation analysis was adopted to study the dynamic response and failure form of corroded steel structure under the action of explosion shock loading.This thesis mainly carries on the following research work:(1)Considering factors such as atmospheric environmental dry-wet alternate,accelerated corrosion efficiency,studied the influence of the changes in the corrosion ratio on the material parameters such as Q235 steel yield strength,ultimate tensile strength,elastic modulus,and elongation.The mechanical property degradation model of materials was obtained by experimental data fitting.(2)The explosion test of equilateral angle steel components was carried out to study the influence of explosion distance,explosion equivalent,equilateral angle steel type and corrosion ratio on the dynamic response and failure form ofequilateral Angle steel specimens.Based on the test results,the stress characteristics of corrosion equilateral angle steel members under explosive load were analyzed.(3)Based on the model parameters and the explosion test data of equal angle steel component,fluid-structure coupling numerical model was established through the dynamic explicit finite element analysis software ANSYS/ls-dyna.The interaction between blast wave and Angle steel of emulsion explosive is analyzed by numerical calculation of each condition of the explosion test.The results of numerical calculation and static explosion test were compared to verify the rationality of numerical calculation method.(4)Based on orthogonal experiment design method,the influence of corrosion ratio,flange width and slenderness ratio on the antiknock performance of equilateral angle steel members was studied through choosing appropriate parameters of the established fluid-structure coupling numerical model.