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- 2018
Propagation and Coalescence of Blast-Induced Cracks in PMMA Material Containing an Empty Circular Hole Under Delayed Ignition Blasting Load by Using the Dynamic Caustic Method
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Abstract:
In this paper, dynamic caustic method is applied to analyze the blast-induced crack propagation and distribution of the dynamic stress field around an empty circular hole in polymethyl methacrylate (PMMA) material under delayed ignition blasting loads. The following experimental results are obtained. ① In directional-fracture-controlled blasting, the dynamic stress intensity factors (DSIFs) and the propagation paths of the blast-induced cracks are obviously influenced by the delayed ignition. ② The circular hole situated between the two boreholes poses a strong guiding effect on the coelesence of the cracks, causing them to propagate towards each other when cracks are reaching the circular hole area. ③ Blast-induced cracks are not initiated preferentially because of the superimposed effect from the explosive stress waves on the cracking area. ④ By using the scanning electron microscopy (SEM) method, it is verified that the roughness of crack surfaces changes along the crack propagation paths.
In this paper, dynamic caustic method is applied to analyze the blast-induced crack propagation and distribution of the dynamic stress field around an empty circular hole in polymethyl methacrylate (PMMA) material under delayed ignition blasting loads. The following experimental results are obtained. ① In directional-fracture-controlled blasting, the dynamic stress intensity factors (DSIFs) and the propagation paths of the blast-induced cracks are obviously influenced by the delayed ignition. ② The circular hole situated between the two boreholes poses a strong guiding effect on the coelesence of the cracks, causing them to propagate towards each other when cracks are reaching the circular hole area. ③ Blast-induced cracks are not initiated preferentially because of the superimposed effect from the explosive stress waves on the cracking area. ④ By using the scanning electron microscopy (SEM) method, it is verified that the roughness of crack surfaces changes along the crack propagation paths.