Loading Model And Dynamic Responses Of Single-layer Reticulated Domes Under Impact Loads

Long-span space structures, which are of great importance in both politics andeconomy, have been applied in significant occasions. Because of terroristic attacks andflight accidents in recent years, plane crashes into constructions sometimes happen. It isextremely necessary to study the dynamic responses of long-span space structures underaccidental loading which could cause much loss, such as impact loading. Reticulateddomes play vital roles in long-span structures, and this paper focuses on the failure ofreticulated dome under impact. In previous studies, the impactor, which is supposed to beof various sizes and material in reality, was regarded as a rigid body with a certain size forsimplification. Besides, no practical impacting case was considered. This paper resolvesthese problems.In the environment of a FEM software ANSYS/LS-DYNA, FE models of a60m-span Kiewitt-8reticulated shell and different impactors are founded. Main researchcontents are listed as following.1. Simplified impact model of force-time functions for reticulated domes underimpactThis paper illustrates the force-time curves of reticulated domes under impact loadto investigate the characteristics of the impact load. According to the momentum theoremand the law of conservation of energy and by means of FE method, a simplifiedforce-time function model is presented. Elasto-plastic time history analysis of the vertexloaded by the simplified model is carried out to estimate the impact resistance capacity ofthe structure.2. Influence on failure modes for reticulated domes impacted by impactors withdifferent sizesThe impact downward on the vertex of reticulated shell by impactors of differentsizes is investigated in this section. The difference of failure modes under differentconditions is analysed and explained according to the dynamic responses and energyabsorption of the structure.3. Influence on failure modes for reticulated domes impacted by elastoplasticimpactorsThis part is based on previous study of reticulated dome under impact of a2m-diameter impactor, but the impactor is an elastoplastic body which is of the same material as the structure. In accordance with the relationship between energy absorptionand failure modes in previous studies, the effect on failure modes subjected to thematerial of impactors is analysed.4. Analysis of an aircraft impact to reticulated domesBoth impact loading model (Riera Model) and numerical simulation are used toanalyse the deformation process of a reticulated dome crashed by an aircraft, and thelatter method is better. A small aircraft is modelled in ANSYS/LS-DYNA to describe thefailure process and failure modes of reticulated domes crashed by this aircraft. Differentaircraft attitudes impacting different target positions of the structure are stimulated.