External disturbance is an important cause of underground pressure pipeline damage,which leads to accidents,and it is crucial to study the risk of damage caused by external disturbance and come up with proper preventi...External disturbance is an important cause of underground pressure pipeline damage,which leads to accidents,and it is crucial to study the risk of damage caused by external disturbance and come up with proper prevention and control measures.We reviewed literature on risk identification of underground pressure pipelines damage due to external disturbance was conducted,and a list of risk factors was formed.Based on the list of risk factors,fault tree analysis was carried out on underground pressure pipelines damage caused by external disturbances,and risk prevention and control measures were proposed through the calculation of minimum cut sets,minimum path sets,and structural importance,in hopes of providing reference for the normal operation of underground pressure pipelines.展开更多
This work employed an inductively coupled plasma wind tunnel to study the dynamic oxidation mechanisms of carbon fiber reinforced SiC matrix composite(C_(f)/SiC)in high-enthalpy and high-speed plasmas.The results high...This work employed an inductively coupled plasma wind tunnel to study the dynamic oxidation mechanisms of carbon fiber reinforced SiC matrix composite(C_(f)/SiC)in high-enthalpy and high-speed plasmas.The results highlighted a transition of passive/active oxidations of SiC at 800–1600℃and 1–5 kPa.Specially,the active oxidation led to the corrosion of the SiC coating and interruption of the SiO_(2) growth.The transition borders of active/passive oxidations were thus defined with respect to oxidation temperature and partial pressure of atomic O in the high-enthalpy and high-speed plasmas.In the transition and passive domains,the SiC dissipation was negligible.By multiple dynamic oxidations of C_(f)/SiC in the domains,the SiO_(2) thickness was not monotonously increased due to the competing mechanisms of passive oxidation of SiC and dissipation of SiO_(2).In addition,the mechanical properties of the SiC coating/matrix and the C_(f)/SiC were maintained after long-term dynamic oxidations,which suggested an excellent thermal stability of C_(f)/SiC serving in thermal protection systems(TPSs)of reusable hypersonic vehicles.展开更多
基金This project was funded by Consulting Research Project of Chinese Academy of Engineering:Research on Innovative Development Strategy of Urban Safety Engineering(Project number:2020-02)。
文摘External disturbance is an important cause of underground pressure pipeline damage,which leads to accidents,and it is crucial to study the risk of damage caused by external disturbance and come up with proper prevention and control measures.We reviewed literature on risk identification of underground pressure pipelines damage due to external disturbance was conducted,and a list of risk factors was formed.Based on the list of risk factors,fault tree analysis was carried out on underground pressure pipelines damage caused by external disturbances,and risk prevention and control measures were proposed through the calculation of minimum cut sets,minimum path sets,and structural importance,in hopes of providing reference for the normal operation of underground pressure pipelines.
基金This work was supported by the National Natural Science Foundation of China(Nos.11902333 and 51972027)the CARDC Fundamental and Frontier Technology Research Fund.
文摘This work employed an inductively coupled plasma wind tunnel to study the dynamic oxidation mechanisms of carbon fiber reinforced SiC matrix composite(C_(f)/SiC)in high-enthalpy and high-speed plasmas.The results highlighted a transition of passive/active oxidations of SiC at 800–1600℃and 1–5 kPa.Specially,the active oxidation led to the corrosion of the SiC coating and interruption of the SiO_(2) growth.The transition borders of active/passive oxidations were thus defined with respect to oxidation temperature and partial pressure of atomic O in the high-enthalpy and high-speed plasmas.In the transition and passive domains,the SiC dissipation was negligible.By multiple dynamic oxidations of C_(f)/SiC in the domains,the SiO_(2) thickness was not monotonously increased due to the competing mechanisms of passive oxidation of SiC and dissipation of SiO_(2).In addition,the mechanical properties of the SiC coating/matrix and the C_(f)/SiC were maintained after long-term dynamic oxidations,which suggested an excellent thermal stability of C_(f)/SiC serving in thermal protection systems(TPSs)of reusable hypersonic vehicles.
