Controlling Dynamic Fracture and Structural Disintegration

Abstract

In recent years, dynamic techniques to partially or fully disintegrate structures utilizing electrical energy have been proposed, which may be more controllable than other conventional dynamic demolition methods, for instance, blasting by explosives. So far, by applying electric discharge impulses in the field, we have performed fracture experiments of relatively small brittle concrete specimens, and together with our finite difference numerical investigations, we have pointed out that the development of fracture network depends very sensitively on the geometrical settings in the specimens (e.g. positions of blast holes (energy sources), empty dummy holes, free surfaces and interfaces to reflect and/or diffract waves and control crack propagation directions). Here, we continue our study and observe that even for dynamic disintegration in more realistic, large concrete slabs, the geometrical settings do play a crucial role and in this case, pre-set slits have strong effect on wave propagation and eventual dynamic fracture pattern. Our three-dimensional numerical code for a PC may well explain the experimental results, suggesting that further research to find the optimal geometrical settings for more predictable and controlled dynamic structural disintegration should be conducted from the wave dynamics point of view.