The similarity law and its verification of cylindrical lattice shell model under internal explosion

It is very important to ensure that the results of a scale model experiment of the large-span space steel structure under internal explosion could accurately show the characteristics of its original model. For this purpose, a one-way inclined bar type of single layer cylindrical lattice shell was taken as an example in this paper, and the similarity law between the scale models and the original model under the internal explosion was deduced by the dimension analysis principle. Then, the original model and the scale models under internal explosions were simulated by ANSYS/LS-DYNA, and the correctness and the feasibility of the similarity law were compared and confirmed. The research results showed that: if the scale models conform to the similarity law, the propagation law and the overpressure distribution of shock waves to the scale models subjected to internal explosions were consistent with the original model; the phenomena of critical destruction of the scale models were similar to the experimental results. But the accuracy of the loading effects of blast (such as the overpressure peak of shock waves, the positive pressure time and the impulse etc.) and the structural dynamic responses obtained by the scale models was affected by the geometric incomplete similarity of the scale models and the strain rate effect of steel respectively, which would reduce with the decrease of the scaling coefficient. Especially, the research results also indicated that if the scaling coefficient was not less than 0.1, the maximum deviations of the overpressure peak of shock waves, the positive pressure time after conversion and the specific impulse after conversion would be 10%, 4.78% and 29.8%, respectively, and if the scaling coefficient was less than 0.25, the stress responses and displacement responses of the scale model under internal explosion would not be reliable. Based on the research results, the reasonable scaling coefficients to the scale model experiment of cylindrical lattice shell under internal explosion are proposed.