为满足科学试验的使用需求,设计一台2 kg TNT当量的圆柱形爆炸容器,并对其进行理论抗爆强度计算、数值模拟验证和动态试验监测。研究结果表明:2 kg TNT当量圆柱形爆破容器的结构设计合理,抗爆强度满足试验要求,最大允许工作压力具有较...为满足科学试验的使用需求,设计一台2 kg TNT当量的圆柱形爆炸容器,并对其进行理论抗爆强度计算、数值模拟验证和动态试验监测。研究结果表明:2 kg TNT当量圆柱形爆破容器的结构设计合理,抗爆强度满足试验要求,最大允许工作压力具有较大裕度;数值模拟中爆炸容器单元峰值压应力分别位于圆柱壳体和椭圆封头中心位置,均远小于屈服强度;减振沟以外监测点的峰值振动在安全允许振速范围内;噪声强度满足设计规范要求。爆炸容器结构设计合理,可为类似爆炸容器的设计和验证提供参考。展开更多
The mechanical performances such as tensile strength and blast property of metal lined SiC/SiC composite cladding tubes were investigated. Nb or Ta was selected as liner material, and the SiC/SiC composite layer was f...The mechanical performances such as tensile strength and blast property of metal lined SiC/SiC composite cladding tubes were investigated. Nb or Ta was selected as liner material, and the SiC/SiC composite layer was fabricated by winding and different precursor impregnation and pyrolysis(PIP) processes. The tensile strengths of different tube samples were measured at room temperature(RT) and 1200 °C, respectively. The blast property was investigated through the maximum water pressure of tubes. And the fracture microstructures were observed by SEM.The highest tensile strength at RT was 150.7 MPa. The blast strength was enhanced with the PIP process increasing from 1 to 4 cycles and the tube of 4 PIP cycles had the highest water pressure of 34.7 MPa. Compared with the metal tubes, the multi-layer structure improved tensile and blast properties significantly. The different processes such as PIP cycles and pyrolytic carbon(PyC) coating were important factors to enhance the mechanical performances of SiC/SiC-based tubes. However, the retention rate of tensile strength was only 18.5% at 1200 °C.展开更多
A Fisher discriminant analysis （FDA） model for the prediction of classification of rockburst in deep-buried long tunnel was established based on the Fisher discriminant theory and the actual characteristics of the p...A Fisher discriminant analysis （FDA） model for the prediction of classification of rockburst in deep-buried long tunnel was established based on the Fisher discriminant theory and the actual characteristics of the project. First, the major factors of rockburst, such as the maximum tangential stress of the cavern wall σθ, uniaxial compressive strength σc, uniaxial tensile strength or, and the elastic energy index of rock Wet, were taken into account in the analysis. Three factors, Stress coefficient σθ/σc, rock brittleness coefficient σc/σt, and elastic energy index Wet, were defined as the criterion indices for rockburst prediction in the proposed model. After training and testing of 12 sets of measured data, the discriminant functions of FDA were solved, and the ratio of misdiscrimina- tion is zero. Moreover, the proposed model was used to predict rockbursts of Qinling tunnel along Xi＇an-Ankang railway. The results show that three forecast results are identical with the actual situation. Therefore, the prediction accuracy of the FDA model is acceptable.展开更多
文摘为满足科学试验的使用需求,设计一台2 kg TNT当量的圆柱形爆炸容器,并对其进行理论抗爆强度计算、数值模拟验证和动态试验监测。研究结果表明:2 kg TNT当量圆柱形爆破容器的结构设计合理,抗爆强度满足试验要求,最大允许工作压力具有较大裕度;数值模拟中爆炸容器单元峰值压应力分别位于圆柱壳体和椭圆封头中心位置,均远小于屈服强度;减振沟以外监测点的峰值振动在安全允许振速范围内;噪声强度满足设计规范要求。爆炸容器结构设计合理,可为类似爆炸容器的设计和验证提供参考。
基金supported by the National Key R&D Program of China (No. 2018YFB1900603)the Natural Science Foundation of Hunan Province, China (No. 2020JJ4667)。
文摘The mechanical performances such as tensile strength and blast property of metal lined SiC/SiC composite cladding tubes were investigated. Nb or Ta was selected as liner material, and the SiC/SiC composite layer was fabricated by winding and different precursor impregnation and pyrolysis(PIP) processes. The tensile strengths of different tube samples were measured at room temperature(RT) and 1200 °C, respectively. The blast property was investigated through the maximum water pressure of tubes. And the fracture microstructures were observed by SEM.The highest tensile strength at RT was 150.7 MPa. The blast strength was enhanced with the PIP process increasing from 1 to 4 cycles and the tube of 4 PIP cycles had the highest water pressure of 34.7 MPa. Compared with the metal tubes, the multi-layer structure improved tensile and blast properties significantly. The different processes such as PIP cycles and pyrolytic carbon(PyC) coating were important factors to enhance the mechanical performances of SiC/SiC-based tubes. However, the retention rate of tensile strength was only 18.5% at 1200 °C.
基金Supported by the National 11th Five-Year Science and Technology Supporting Plan of China(2006BAB02A02)Central South University Innovation funded projects (2009ssxt230, 2009ssxt234)
文摘A Fisher discriminant analysis （FDA） model for the prediction of classification of rockburst in deep-buried long tunnel was established based on the Fisher discriminant theory and the actual characteristics of the project. First, the major factors of rockburst, such as the maximum tangential stress of the cavern wall σθ, uniaxial compressive strength σc, uniaxial tensile strength or, and the elastic energy index of rock Wet, were taken into account in the analysis. Three factors, Stress coefficient σθ/σc, rock brittleness coefficient σc/σt, and elastic energy index Wet, were defined as the criterion indices for rockburst prediction in the proposed model. After training and testing of 12 sets of measured data, the discriminant functions of FDA were solved, and the ratio of misdiscrimina- tion is zero. Moreover, the proposed model was used to predict rockbursts of Qinling tunnel along Xi＇an-Ankang railway. The results show that three forecast results are identical with the actual situation. Therefore, the prediction accuracy of the FDA model is acceptable.
