Study On Dynamic Performance Of Aluminum Alloy Honeycombed Plate Beam Single Layer Latticed Shells

It is true that the aluminum-alloy latticed shell has been adopted by many architects because of its superiority of lightness, corrosion-resistance and easiness of processing when compared to the steel one. However, the degree of its strengthness, stiffness stability is to be improved owing to its low elasticity modulus. Therefore, the thesis intends to study the static and dynamic performances of a newly-structured latticed shell, which is innovatively formed by high-performance aluminum honeycombed plate and aluminum-alloy latticed shell.As for the study, the author introduces the equivalence theory and proves its feasibility at first. Secondly, a comparative study on the static performance between plate-beam latticed shell and latticed shell of the same parameter is carried out. Thirdly, the characteristics concerning self-vibration of this combined latticed shell as well as the influence of rise-span ratio, thickness of plate and core on this latticed shell are also touched on. Moreover, the response spectrum method and the time history method are employed in the analysis of how combined latticed shell reacts in earthquakes. Meanwhile, different parameters are also taken in account to see the respective reactions. Finally, the wind-vibration coefficient of this structure is measured in the wake of an analysis of the wind-vibration's time history, which is based on a simulated fluctuating wind load, and a comparison to the response to the static wind of this structure.Based on the study above, major findings are as follows.First of all, it is feasible and reliable to employ Hoff's equivalence plate theory to simulate the static and dynamic performances of honeycombed sandwich plate. To be specific, the error of the natural vibration frequency is around 10% and that of the displacement is 6%, thus the calculating precision meets the project's demand. In addition, in order to more effectively carry out the finite element's analysis and design on large-scale aluminum-alloy latticed shells, a new type of 8-node rectangular sandwich shell, which can be used to simulate honeycombed sandwich plate, is proposed. Thereafter, the simulated shell's displacement model, equilibrium equation as well as implement program are constructed.Secondly, under vertical evenly-distributed load, the largest displacement of this this new type mono-layered aluminum-alloy honeycombed latticed shell is only 11.9% of that of its plate-free counterparts and the maximum internal force of the beam is 39%. These embody the superiority of this new structure to its plate-free counterparts of the same span in terms of stiffness, strengthness and bearing capacity.Thirdly, owing to the relatively low stiffness at the top of this latticed shell in the vertical direction, such weakness will be appropriately strengthened when designing. The basic frequency of this structure reaches to the maximum when the rise-span ratio ranges from one forth to one third. Furthermore, the natural vibration frequency increases with the honeycombed plate and sandwich getting thicker.Fourthly, according to the parametric analysis under seismic circumstance, while the rise-span ratio increases, the force of the circumferential beam experiences a decrease before an increase, dropping to its minimum when the rise-span ratio is around one forth and one third. Besides, the force of the out-most beam in the radial direction also undergoes a decrease, followed with an increase. The forces of the rest of the radial beams and beams in the slanting direction, however, increasingly grow. As for the displacement, that in the horizontal direction atop this structure keeps decreasing while that in the vertical direction increases after a decrease. Along with the growing in thickness of honeycombed plate and sandwich, most beams'forces go down, so do the displacements in both horizontal and vertical directions at the top of this structure, except for some utmost radial beams.Finally, the wind-vibration coefficients of this plate-beam latticed shell,90% of which range form 2 to 3, are evenly distributed in terms of internal force. Moreover, those of nodes' replacement are also stable, with some singularity remaining exceptional, ranging from 2 to 5. In short, through a comprehensive calculation, it is suggested that the wind-vibration coefficient of this new type combined latticed shell be 3.2 or so.