Experiment Of Fracture Behaviors And Control For Crack Propagation Under Blasting Load

Dynamic caustics experimental technique is used to study on dynamic mechanical characteristics and fracture control of the propagation of explosion crack. It is analysed of the experimental characterization of single and double holes under blasting load in PMMA. with explosion tests and fracture mechanics characterization of behavior are preceded. The relationships of mechanical behaviour between caustics'features of the crack tip have been revealed. The study explains both the explosion stress wave and gas products how to promote the propagation of blast crack, and also obtains the varieties with characteristic parameters of dynamic fracture mechanics of blast cracks; The experiments have been researched on the dynamic fracture behaviours of which are about of the empty holes, the bedding, the intermittent through cracks. Time course changes are gotten in the values and orientation of the main stress difference of the explosion stress field with the caustics characteristics of these small air holes. Propagating rules of the derived branch cracks from the ends of derivative through cracks are obtained under the explosive stress wave. The research results show that the direction of its propagation is different from the original one after a crack has crossed bedding, while the main crack usually can not go through the pre-fabricated crack to continue expansion. It has a good detail about the directional fracture mechanism of the cumulative energy cartridge, and also analyzes the dynamic characteristics of directional fracture control blasting both the double-seam thread jets and double-hole point jets and half-pipe point jets. Technical ideas are brought forward that the three cumulative energy cartridge constructions should be utilized in the directional fracture blasting.