Study On Responses Of Single-layer Reticulated Domes Subjected To External Blast Loading Using GBS System

With the development of the society, large span space structures, represented by space dome structures, have been wildly used. However, terroristic activities, especially terror bombings, have become more and more rampant, and large space structures are more likely to become terrorists' targets due to their large density of population inside and weak blast resistance. Therefore, it is urgely needed and significant to do researches for the blast resistance performances of large span space structure.GBS system is a set of facilities for blast experiments using gas explosives combined with acetylene and air. It is convenient to operate and safe for its separate facility for blast. AUTODYN is a subprogram of ANSYS for explicit dynamic analysis with an adaquate material database, a complete algorithm analysis for fluid-structure interaction and the REMAP technique, which can be used for accurate blast load simulation. Due to the lack of blast experiments for large span space structures, based on GBS system, a K6 single-layer reticulated dome reduced scale model has been designed for the external blast loading experiment to analyse its dynamic response. Meanwhile, the same dome model and experimental environment have been built in the AUTODYN circumstance to simulate the blast loading process to help conduct the experiment, and the result of simulation will be compared with that of the experiment to discuss the applicability of the simulation method.During the preparation stage, a material characteristic test for the mechanic property parameters of the materials of the dome model has been conducted as well as a modal test for the precision of the model production. As the experiment is successfully conducted, five response modes, including non-damaged, slightlydamaged, damaged, severely-damaged and collapsed, have been summarized to describe the dynamic response of the dome model subjected to external blast loading. Since the response of the slightly-damaged dome is not so obvious, another external loading experiment has been conducted, proving the weakening of the dome structure caused by the slight damage.Based on the equivalence principle of blast energy, the gas explosion is converted into TNT for numerical simulation. By comparing the simulative result with the experimental result both in macroscopic response and parameter analysis, the TNT converting method proves to be available for describing the largest response of the dome and solving simplified problems. To improve the accuracy of the simulative result of the method, the reduction factor in the equivalence principle has been further revised according to the experiemental result, and the improved method has been successfully used for analyzing the response of the slightlydamaged dome subjected to external blast loading. Besides, a new modeling method to completely simulate the experimental environment has been come up with and discussed. For further experiments and numerical modeling, some suggestions based on this research have been put forward.