The woven basalt fiber composites(WBFC) and the unidirectional [0°/90°/45°/-45°]s basalt fiber composites(UBFC) were prepared by hot-pressing.Three-point bending test,low velocity impact test,and b...The woven basalt fiber composites(WBFC) and the unidirectional [0°/90°/45°/-45°]s basalt fiber composites(UBFC) were prepared by hot-pressing.Three-point bending test,low velocity impact test,and ballistic test were performed to the prepared composites.After the tests,the specimens were recovered and analyzed for micromorphology.Three-point bending tests show that both the bending strength and stiffness of the WBFC surpass those of the UBFC.Low velocity impact test results show that the low velocity impact resistance to hemispherical impactor of the UBFC is higher than that of the WBFC,but the low velocity impact resistance to sharp impactor of the UBFC is lower than that of the WBFC.For the ballistic test,it can be found that the ballistic property of the UBFC is higher than that of the WBFC. After the tests,microscopic analysis of the specimens was applied,and their failure mechanism was discussed.The main failure modes of the UBFC are delamination and fibers breakage under the above loading conditions while the main failure mode of the WBFC is fibers breakage.Although delamination damage can be found in the WBFC under the above loading conditions,the degree of delamination is far less than that of the UBFC.展开更多
Flashover on polluted insulators is the most common accident occuring in power system.A great amount of work has been done to study the flashover characteristics on various kinds of insulators with several theoretical...Flashover on polluted insulators is the most common accident occuring in power system.A great amount of work has been done to study the flashover characteristics on various kinds of insulators with several theoretical models proposed.In these models,the amount and the distribution of the pollution on the insulator is critical to the flashover performance.However,very few simulation works has been carried out to study the pollution accumulation characteristics on the insulators.In this paper,both experimental and numerical efforts were given to study the pollution accumulation characteristics in order to evaluate the flashover probability.Experiments were performed first to have a bird view on the overall pollution distributions considering several crucial influential factors such as the wind speed and wind direction.AC porcelain insulators(XWP_2-160 type) were selected as the experimental samples and the equivalent salt deposit density(ESDD) was measured after the total predetermined amount of pollution was reached.Then, aerodynamic simulation was carried out to study the airflow and velocity distributions on each part of the insulator in clean air with regard to different wind speed and direction.It was found that the amount of the pollution on each section of the insulator has clear connections to the wind speed or air pressure distribution on the insulator surface.These distributions coincide to the pollution distribution obtained from experiments.Besides,the wind speed and air pressure distribution along the insulator chain was also studied.This work has shown that the numerical simulation may predict the pollution distribution on the insulators with practical accuracy.It is also possible to design new insulator shapes to reduce the pollution accumulation on critical areas according to the analysis in this work.展开更多
基金supported by the National Science Foundation of China(No.51571033)supported in part by the National Natural Science Foundation of China under Grant No.11521062。
文摘The woven basalt fiber composites(WBFC) and the unidirectional [0°/90°/45°/-45°]s basalt fiber composites(UBFC) were prepared by hot-pressing.Three-point bending test,low velocity impact test,and ballistic test were performed to the prepared composites.After the tests,the specimens were recovered and analyzed for micromorphology.Three-point bending tests show that both the bending strength and stiffness of the WBFC surpass those of the UBFC.Low velocity impact test results show that the low velocity impact resistance to hemispherical impactor of the UBFC is higher than that of the WBFC,but the low velocity impact resistance to sharp impactor of the UBFC is lower than that of the WBFC.For the ballistic test,it can be found that the ballistic property of the UBFC is higher than that of the WBFC. After the tests,microscopic analysis of the specimens was applied,and their failure mechanism was discussed.The main failure modes of the UBFC are delamination and fibers breakage under the above loading conditions while the main failure mode of the WBFC is fibers breakage.Although delamination damage can be found in the WBFC under the above loading conditions,the degree of delamination is far less than that of the UBFC.
基金Supported by East China Grid Company Ltd(200933- 04316C156)
文摘Flashover on polluted insulators is the most common accident occuring in power system.A great amount of work has been done to study the flashover characteristics on various kinds of insulators with several theoretical models proposed.In these models,the amount and the distribution of the pollution on the insulator is critical to the flashover performance.However,very few simulation works has been carried out to study the pollution accumulation characteristics on the insulators.In this paper,both experimental and numerical efforts were given to study the pollution accumulation characteristics in order to evaluate the flashover probability.Experiments were performed first to have a bird view on the overall pollution distributions considering several crucial influential factors such as the wind speed and wind direction.AC porcelain insulators(XWP_2-160 type) were selected as the experimental samples and the equivalent salt deposit density(ESDD) was measured after the total predetermined amount of pollution was reached.Then, aerodynamic simulation was carried out to study the airflow and velocity distributions on each part of the insulator in clean air with regard to different wind speed and direction.It was found that the amount of the pollution on each section of the insulator has clear connections to the wind speed or air pressure distribution on the insulator surface.These distributions coincide to the pollution distribution obtained from experiments.Besides,the wind speed and air pressure distribution along the insulator chain was also studied.This work has shown that the numerical simulation may predict the pollution distribution on the insulators with practical accuracy.It is also possible to design new insulator shapes to reduce the pollution accumulation on critical areas according to the analysis in this work.
