Effect of the Preexisting Fissure with Different Fillings in PMMA on Blast-Induced Crack Propagation
In order to study the dynamic crack propagation law in fissured rock under the different fillings, a borehole with 7 mm diameter was processed in the center of a polymethyl methacrylate (PMMA) specimen. The preexisting fissure with different angles (θ = 0°, 45°, and 90°) and different distances (L =...
Saved in:
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Wiley
2018-01-01
|
| Series: | Advances in Materials Science and Engineering |
| Online Access: | http://dx.doi.org/10.1155/2018/7378282 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1832552388483874816 |
|---|---|
| author | Xin Yang Xiangguo Zeng Chuanjin Pu Dingjun Xiao |
| author_facet | Xin Yang Xiangguo Zeng Chuanjin Pu Dingjun Xiao |
| author_sort | Xin Yang |
| collection | DOAJ |
| description | In order to study the dynamic crack propagation law in fissured rock under the different fillings, a borehole with 7 mm diameter was processed in the center of a polymethyl methacrylate (PMMA) specimen. The preexisting fissure with different angles (θ = 0°, 45°, and 90°) and different distances (L = 20, 30, 40, 50, and 60 mm) was prefabricated around the borehole. Air, soil, and water were employed as fillings in the fissure, respectively. The experiment of explosive loading was carried out by a single detonator, and the dynamic crack propagation process of the experimental specimens was simulated by nonlinear dynamics software AUTODYN. The results show that the blast-induced cracks are the most favorable and unfavorable to propagate when θ = 0° and θ = 45°, respectively. The length of the far-end wing crack decreases with the increase of the distance L, and the length of the far-end wing crack in the air-filled specimens is larger than those in soil-filled and water-filled specimens. The damage-pressure curve of the far-end wing crack initiation point shows “S”-type change, and the damage-pressure curve shows two obvious damage evolution processes of initial nonlinear and later linear stages. With the increase of the angle, the distance from the borehole to the crack initiation point decreases and the compressive stress wave peak value should increase, but the tensile force peak value decreases. Meanwhile, the relationships between pressure and average velocity of the initiation point and L, θ, and fillings are established, respectively. The numerical simulation agrees with the experimental results well. It can be seen that the fillings types, angle, and distance have a mutual restraint relationship with the reflected and absorbed stress wave energy. The phenomenon of crack propagation under different fillings can be explained well from the viewpoint of discontinuity degree and stress wave energy, which reveals the general law of blast-induced crack propagation. |
| format | Article |
| id | doaj-art-c51542b71ab9429481e2612696961600 |
| institution | Kabale University |
| issn | 1687-8434 1687-8442 |
| language | English |
| publishDate | 2018-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Advances in Materials Science and Engineering |
| spelling | doaj-art-c51542b71ab9429481e26126969616002025-02-03T05:58:52ZengWileyAdvances in Materials Science and Engineering1687-84341687-84422018-01-01201810.1155/2018/73782827378282Effect of the Preexisting Fissure with Different Fillings in PMMA on Blast-Induced Crack PropagationXin Yang0Xiangguo Zeng1Chuanjin Pu2Dingjun Xiao3College of Architecture and Environment, Sichuan University, Chengdu, Sichuan 610065, ChinaCollege of Architecture and Environment, Sichuan University, Chengdu, Sichuan 610065, ChinaSchool of Environment and Resource, Southwest University of Science and Technology, Mianyang, Sichuan 621010, ChinaSchool of Environment and Resource, Southwest University of Science and Technology, Mianyang, Sichuan 621010, ChinaIn order to study the dynamic crack propagation law in fissured rock under the different fillings, a borehole with 7 mm diameter was processed in the center of a polymethyl methacrylate (PMMA) specimen. The preexisting fissure with different angles (θ = 0°, 45°, and 90°) and different distances (L = 20, 30, 40, 50, and 60 mm) was prefabricated around the borehole. Air, soil, and water were employed as fillings in the fissure, respectively. The experiment of explosive loading was carried out by a single detonator, and the dynamic crack propagation process of the experimental specimens was simulated by nonlinear dynamics software AUTODYN. The results show that the blast-induced cracks are the most favorable and unfavorable to propagate when θ = 0° and θ = 45°, respectively. The length of the far-end wing crack decreases with the increase of the distance L, and the length of the far-end wing crack in the air-filled specimens is larger than those in soil-filled and water-filled specimens. The damage-pressure curve of the far-end wing crack initiation point shows “S”-type change, and the damage-pressure curve shows two obvious damage evolution processes of initial nonlinear and later linear stages. With the increase of the angle, the distance from the borehole to the crack initiation point decreases and the compressive stress wave peak value should increase, but the tensile force peak value decreases. Meanwhile, the relationships between pressure and average velocity of the initiation point and L, θ, and fillings are established, respectively. The numerical simulation agrees with the experimental results well. It can be seen that the fillings types, angle, and distance have a mutual restraint relationship with the reflected and absorbed stress wave energy. The phenomenon of crack propagation under different fillings can be explained well from the viewpoint of discontinuity degree and stress wave energy, which reveals the general law of blast-induced crack propagation.http://dx.doi.org/10.1155/2018/7378282 |
| spellingShingle | Xin Yang Xiangguo Zeng Chuanjin Pu Dingjun Xiao Effect of the Preexisting Fissure with Different Fillings in PMMA on Blast-Induced Crack Propagation Advances in Materials Science and Engineering |
| title | Effect of the Preexisting Fissure with Different Fillings in PMMA on Blast-Induced Crack Propagation |
| title_full | Effect of the Preexisting Fissure with Different Fillings in PMMA on Blast-Induced Crack Propagation |
| title_fullStr | Effect of the Preexisting Fissure with Different Fillings in PMMA on Blast-Induced Crack Propagation |
| title_full_unstemmed | Effect of the Preexisting Fissure with Different Fillings in PMMA on Blast-Induced Crack Propagation |
| title_short | Effect of the Preexisting Fissure with Different Fillings in PMMA on Blast-Induced Crack Propagation |
| title_sort | effect of the preexisting fissure with different fillings in pmma on blast induced crack propagation |
| url | http://dx.doi.org/10.1155/2018/7378282 |
| work_keys_str_mv | AT xinyang effectofthepreexistingfissurewithdifferentfillingsinpmmaonblastinducedcrackpropagation AT xiangguozeng effectofthepreexistingfissurewithdifferentfillingsinpmmaonblastinducedcrackpropagation AT chuanjinpu effectofthepreexistingfissurewithdifferentfillingsinpmmaonblastinducedcrackpropagation AT dingjunxiao effectofthepreexistingfissurewithdifferentfillingsinpmmaonblastinducedcrackpropagation |