Study On Dynamic Responses And Damage Mechanism For Supporting Column Of Spherical Reticulated Shell Under Internal Explosion

The large-span spatial structure is widely applied in large public buildings because of its large internal space and beautiful appearance.Such buildings are usually urban landmarks and city business cards,which are easy to become targets of terrorist attacks.Therefore,explosion-proof researches for large-span space structures is very necessary.In this paper,the spherical reticulated shell structure is selected as the research object,aiming to research the overpressure of the explosion-proof key position,dynamic responses and damage mechanism of supporting columnss by the means of combining numerical simulation with experiment.The main contents as following:?1?The internal explosion experiments of the scale spherical reticulated shell model were carried out.The effects of the explosive quality on the structural damage effect and the overpressure at measuring point are analyzed,and the numerical simulation results were compared with the experimental results.The comparison result show that the numerical simulation results and the experimental results have similar structural damage effects under different explosive quantities and the relative errors of the overpressure at measuring points are within the acceptable error range,which proves the correctness of the simulation method and parameter setting.?2?Based on the correctness of numerical simulation,ANSYS/LS-DYNA is used to establish the internal explosion model of the spherical reticulated shell structure.The explosion-proof key positions of the spherical reticulated shell structure and the reflection amplification factor of the key position are proposed.On the basis of the empirical formula of the incident wave overpressure,the formula for calculating peak overpressure of reflected wave at key positions is fitted with considering the effects of the proportional distance,the vector span ratio and the high span ratio.Then,the calculation results are compared with the test results and the simulation results respectively.The comparison results show that the relative error between the simulation results and the calculated results is small,and the relative error between the experimental results and the calculated results is slightly larger,but they are all within the acceptable error range,which proves the feasibility of the fitting calculation formula.?3?Taking the supporting columns of the spherical reticulated shell as the research object,the effects of column height,column section size,explosive quality and explosive position on the dynamic response of the supporting column were studied.The results show that the stress response and displacement response both decrease with the increase of column height;the web height of the I-shaped steel column has little effect on the stress response and displacement response;with the increase of explosive quantity,both the stress response and the displacement response have significant improvement.In the eccentric explosion,the stress response of the anti-eccentric directional supporting column and the eccentric directional supporting column are equivalent,but the displacement response of the anti-eccentric directional supporting column is larger.?4?Based on the residual bearing capacity failure criterion,the evaluation method of the spherical reticulated supporting columns under internal explosion is proposed.According to the damage index D_COL,the damage degree of the supporting column is divided into mild damage,moderate damage,serious damage and failure.The damage process of the supporting columns is analyzed,and the influence law of the explosive quality,the vector span ratio and the column height on the damage index of the supporting column is obtained by parameter analysis.The mechanisms of the damage of the supporting column is explained,which provides effective basis for the engineering explosion-proof design.