Study of the Similarities in Scale Models of a Single-Layer Spherical Lattice Shell Structure under the Effect of Internal Explosion

Wenbao Wang,Lihui Le,Xuanneng Gao

doi:10.1155/2017/9181729

Abstract

The similarity of each scale model is verified based on the theory of similarity, deriving the similarity law of internal explosions in a single-layer spherical lattice shell structure via dimensional theory, calculated based on models with scaling coefficients of 1, 0.8, 0.6, 0.4, 0.2, and 0.1. The results show that the shock wave propagation characteristics, the distribution of the overpressure on the inner surface, the maximum dynamic response position, and the position at which the earliest explosion venting occurs are all similar to those of the original model. With the decrease of scaling coefficients, the overpressure peak value of the shock waves of each scale model, and the specific action time of the positive pressure zone, as well as specific impulse are increasingly deviated from the original model values; when the scaling coefficient is 0.1, the maximum relative error between the overpressure peak value at the measurement point and the specific action time of the positive pressure zone as well as the specific impulse and the original model value is 4.9%. Thus, it is feasible to forecast the internal explosion effect of the original structure size model by using the experiment results of the scale model with scaling coefficient λ≥0.1.

Highlights

In recent years, worldwide terrorist activities have become increasingly frequent, with an increasing number of bombing assaults
It can be seen that steel structures with large space, high visitor flowrate, and significant symbolic value are more likely to become a target of explosion attack, and once subject to a terrorist attack, heavy casualties, property damage, and adverse social impacts are likely [1,2,3]
The explosion effect of explosives in the structure is much more complex than that of an external explosion, primarily because of the multiple reflection and diffraction phenomena that occur during the transmission of shock waves when meeting the roof, walls, and a variety of structures and constructions within the structure; such phenomena cause continuous superposition or offset of the reflected waves and incident waves in the structure, with gas flow fields within the building exhibiting irregular movement, making it difficult to determine the shock wave pressure field acting on the roof [4,5,6]