In order to solve the problem of experimental research on the penetration process of projectile into anchored rock mass, we derived the essential similarity conditions for the physical simulation experi- ment accordin...In order to solve the problem of experimental research on the penetration process of projectile into anchored rock mass, we derived the essential similarity conditions for the physical simulation experi- ment according to the similarity theory, carried out the experiment on the penetration process of a kind of penetrating bomb into the anchored rock mass of type III, and compared the experimental results with the values computed by the professional Young's empirical formula. The test results show that the phys- ical simulation experiment can represent the actual penetration process of projectile into anchored rock mass. The research method proposed in this paper provides technical support for the experimental research on the design and reconstruction of underground protection works.展开更多
The corrosion resistance characteristics of RE-rich RE_(50)Ta_(x)Zr_(50-x)O_(175+0.5x)oxides in RE_(2)Zr_(2)O_(7)-RETaO_(4)systems to calcium-magnesium-alumino-silicate(CMAS)at 1300°C,and the influence of RE^(3+)...The corrosion resistance characteristics of RE-rich RE_(50)Ta_(x)Zr_(50-x)O_(175+0.5x)oxides in RE_(2)Zr_(2)O_(7)-RETaO_(4)systems to calcium-magnesium-alumino-silicate(CMAS)at 1300°C,and the influence of RE^(3+)and Ta^(5+)on chemical reactions and reactive crystallization of CMAS melts were investigated.The results show that following the thermochemical reactions,apatite,pyrochlore,reprecipitated fluorite and residual Yb(Y)TaO4phases were the predominant reaction products.Formation abilities of apatite and pyrochlore were found to be proportional to the ionic radius of RE^(3+).The increase of Ta^(5+)amount can decrease the number of available RE^(3+)to form apatite.Moreover,the resistance characteristic to CMAS corrosion in RE_(50)Ta_(x)Zr_(50-x)O_(175+0.5x)systems was decided by the combined action of apatite and pyrochlore phases.The cohesive mixture of apatite and pyrochlore phases can generate a dense layer near the reaction front,which had a positive effect on suppressing CMAS infiltration.The ability of the fluorite+RETaO4two-phase field was determined to be sufficient to mitigate CMAS corrosion.展开更多
The development of an innovative drilling system makes it necessary to model the material of extra-terrestrial soil , i.e.regolith or lunar soil.And then the drilling process is numerically simulated.Since real regoli...The development of an innovative drilling system makes it necessary to model the material of extra-terrestrial soil , i.e.regolith or lunar soil.And then the drilling process is numerically simulated.Since real regolith is very scarce and costly , sand properties are investigated by means of experiments and sand model is constructed with the capability of partly reflecting these properties.With the use of smooth particle hydrodynamics ( SPH ) method in LS-DYNA , data analysis and modeling process are presented to reach the following achievements :( 1 ) Develop ageneral model approach of sand using SPH method ;( 2 ) Compare SPH results with experimental data to validate it ;( 3 ) Adapt the sand model to lunar soil while fitting the simulation of dual-reciprocating drilling ( DRD ) process.展开更多
文摘In order to solve the problem of experimental research on the penetration process of projectile into anchored rock mass, we derived the essential similarity conditions for the physical simulation experi- ment according to the similarity theory, carried out the experiment on the penetration process of a kind of penetrating bomb into the anchored rock mass of type III, and compared the experimental results with the values computed by the professional Young's empirical formula. The test results show that the phys- ical simulation experiment can represent the actual penetration process of projectile into anchored rock mass. The research method proposed in this paper provides technical support for the experimental research on the design and reconstruction of underground protection works.
基金supported by the National Natural Science Foundation of China(No.51801170)the National Postdoctoral Program for Innovative Talents,China(No.BX20180265)+2 种基金the Natural Science Foundation of Hunan Province,China(No.2019JJ50570)the China Postdoctoral Science Foundation(No.2019M652786)the Research Initiation Project of Xiangtan University,China(No.18QDZ24)。
文摘The corrosion resistance characteristics of RE-rich RE_(50)Ta_(x)Zr_(50-x)O_(175+0.5x)oxides in RE_(2)Zr_(2)O_(7)-RETaO_(4)systems to calcium-magnesium-alumino-silicate(CMAS)at 1300°C,and the influence of RE^(3+)and Ta^(5+)on chemical reactions and reactive crystallization of CMAS melts were investigated.The results show that following the thermochemical reactions,apatite,pyrochlore,reprecipitated fluorite and residual Yb(Y)TaO4phases were the predominant reaction products.Formation abilities of apatite and pyrochlore were found to be proportional to the ionic radius of RE^(3+).The increase of Ta^(5+)amount can decrease the number of available RE^(3+)to form apatite.Moreover,the resistance characteristic to CMAS corrosion in RE_(50)Ta_(x)Zr_(50-x)O_(175+0.5x)systems was decided by the combined action of apatite and pyrochlore phases.The cohesive mixture of apatite and pyrochlore phases can generate a dense layer near the reaction front,which had a positive effect on suppressing CMAS infiltration.The ability of the fluorite+RETaO4two-phase field was determined to be sufficient to mitigate CMAS corrosion.
文摘The development of an innovative drilling system makes it necessary to model the material of extra-terrestrial soil , i.e.regolith or lunar soil.And then the drilling process is numerically simulated.Since real regolith is very scarce and costly , sand properties are investigated by means of experiments and sand model is constructed with the capability of partly reflecting these properties.With the use of smooth particle hydrodynamics ( SPH ) method in LS-DYNA , data analysis and modeling process are presented to reach the following achievements :( 1 ) Develop ageneral model approach of sand using SPH method ;( 2 ) Compare SPH results with experimental data to validate it ;( 3 ) Adapt the sand model to lunar soil while fitting the simulation of dual-reciprocating drilling ( DRD ) process.
