Dynamic Response Research On K8 Single-Layer Reticulated Dome Under Impact

The numerical modeling of failure mechanism and behavior control of building structures is the important problem of science and technology in the modern social development under the artificial calamity and natural calamity such as unexpected blast, earthquake, wind and sea wave in the civil engineering. Dynamic response (especially dynamic stability) is one of the key problems of the dynamic analysis of spatial cellular structures under impact. Dynamic response of K8 single-layer reticulated dome is studied by the finite element program ANSYS/LS-DYNA in the paper.First of all, the numerical modeling of the experiment course of the model tested before is analyzed under impact. The test resultsratio 1/7, 1/5 and 1/3 of the dome with span 40m is 1 : 1.32 : 1.60; The ratio of different member sections φ 108×3, φ 114× 3, φ 121 ×3 of the dome with span 40m and rise-to-span ratio 1/7 is 1 '. 1.15 : 1.34; The ratio of different spans 40m, 50m and 60m of the dome with rise-to-span ratio 1/5 and member section φ 114×3 is 1 : 0.85 : 0.81; When the buckling of the dome, nodal displacement time history and . final displacement, nodal acceleration time history, impact time history and duration time suddenly take place remarkable change at one time. These show the all characteristics parameters occur sudden change when the buckling of the dome.Last, the effects of action range and time of triangular impulse load and load shape on the structure dynamic stability are analyzed for the single-layer reticulated dome with span 40m, rise-to-span ratio 1/7 and member section φ 114×3. The results show that the dynamic stability critical load is 872.3kN/m2 when load fully distributes; When load distributes within third ring, it is 721.0kN/m2; When load distributes within second ring, it is 686.1kN/m2; Whenand the calculation results including the forms and durations of impulse forces, axial force responses and buckling modes are compared correspondingly. The judgment criterion of dynamic buckling of single-layer reticulated dome is discussed under impact. According to the criterion, the elastic and elastic-plastic critical momentums of the dynamic stability are achieved. The results show that the ratio of the critical momentums of the experiment on the test model, its elastic-plastic calculation and elastic calculation is 1 : 2.75 : 5.5.Then, dynamic responses including impact loads, nodal displacements and accelerations are calculated and analyzed for K8 single-layer reticulated dome with span 40m under impact of freely falling with certain initial velocity. According to the dynamic response, dynamic stability of plasticity is judged. The effects of span, rise-to-span ratio and member section on structure dynamic stability are analyzed. The results show that the critical momentums of the dome with span 40m, rise-to-span ratio 1/7 and member section φ 114×3 is 1872.2kgm/s; The ratio of different rise-to-spanload range gradually extends outward from dome top, the buckling mode changes from local hollow to overall hollow; When the duration time of the triangular impulse load is 50ms, the critical load is 10.3% of the 5ms; the critical load of the rectangle pulse load is 48.9% of the triangular impulse load; but buckling modes are basically identical.