Based on the three-stage perforation model, a semi-theoretical analysis is conducted for the ballistic per- formances of a rigid kinetic projectile impacting on concrete plates. By introducing the projectile resistanc...Based on the three-stage perforation model, a semi-theoretical analysis is conducted for the ballistic per- formances of a rigid kinetic projectile impacting on concrete plates. By introducing the projectile resistance coefficients, dimensionless formulae are proposed for depth of penetra- tion （DOP）, perforation limit thickness, ballistic limit veloc- ity, residual velocity and perforation ratio, with the projec- tile nosed geometries and projectile-target interfacial fric- tion taken into account. Based on the proposed formula for DOP and lots of penetration tests data of normal and high strength concrete targets, a new expression is obtained for target strength parameter. By comparisons between the re- sults of the proposed formulae and existing empirical formu- lae and large amount of projectile penetration or perforation tests data for monolithic and segmented concrete targets, the validations of the proposed formulae are verified. It is found that the projectile-target interfacial friction can be neglected in the predictions of characteristic ballistic parameters. The dimensionless DOP for low-to-mid speed impacts of non-flat nosed projectiles increases almost linearly with the impact factor by a coefficient of 2/（nS）. The anti-perforation ability of the multilayered concrete plates is dependent on both the target plate thickness and the projectile impact velocity. The variation range of the perforation ratio is 1-3.5 for concrete targets.展开更多
Recently,we reported our results on“realization of 2D metals at the angstrom thickness limit”in Nature[1],and we are glad to see that this work has sparked significant interests and lively discussions within both th...Recently,we reported our results on“realization of 2D metals at the angstrom thickness limit”in Nature[1],and we are glad to see that this work has sparked significant interests and lively discussions within both the scientific community and the general public.展开更多
Publisher Correction:Ferroelectricity at the extreme thickness limit in the archetypal antiferroelectric PbZrO_(3)Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4...Publisher Correction:Ferroelectricity at the extreme thickness limit in the archetypal antiferroelectric PbZrO_(3)Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License,which permits any non-commercial use,sharing,distribution and reproduction in any medium or format,as long as you give appropriate credit to the original author(s)and the source,provide a link to the CreativeCommonslicence,and indicate if you modified the licensed material.You do not have permission under this licence to share adapted material derived from this article or parts of it.The images or other third party material in this article are included in the article’s Creative Commons licence,unless indicated otherwise in a credit line to the material.If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use,you will need to obtain permission directly from the copyright holder.To view a copy of this licence,visit http://creativecommons.org/licenses/by-nc-nd/4.0/.展开更多
基金supported by the Funds for Creative Research Groups of China(51021001)the National Natural Science Foundations of China(51008304 and 51178461)China Postdoctoral Science Foundation Funded Project(2012M521714)
文摘Based on the three-stage perforation model, a semi-theoretical analysis is conducted for the ballistic per- formances of a rigid kinetic projectile impacting on concrete plates. By introducing the projectile resistance coefficients, dimensionless formulae are proposed for depth of penetra- tion （DOP）, perforation limit thickness, ballistic limit veloc- ity, residual velocity and perforation ratio, with the projec- tile nosed geometries and projectile-target interfacial fric- tion taken into account. Based on the proposed formula for DOP and lots of penetration tests data of normal and high strength concrete targets, a new expression is obtained for target strength parameter. By comparisons between the re- sults of the proposed formulae and existing empirical formu- lae and large amount of projectile penetration or perforation tests data for monolithic and segmented concrete targets, the validations of the proposed formulae are verified. It is found that the projectile-target interfacial friction can be neglected in the predictions of characteristic ballistic parameters. The dimensionless DOP for low-to-mid speed impacts of non-flat nosed projectiles increases almost linearly with the impact factor by a coefficient of 2/（nS）. The anti-perforation ability of the multilayered concrete plates is dependent on both the target plate thickness and the projectile impact velocity. The variation range of the perforation ratio is 1-3.5 for concrete targets.
文摘Recently,we reported our results on“realization of 2D metals at the angstrom thickness limit”in Nature[1],and we are glad to see that this work has sparked significant interests and lively discussions within both the scientific community and the general public.
文摘Publisher Correction:Ferroelectricity at the extreme thickness limit in the archetypal antiferroelectric PbZrO_(3)Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License,which permits any non-commercial use,sharing,distribution and reproduction in any medium or format,as long as you give appropriate credit to the original author(s)and the source,provide a link to the CreativeCommonslicence,and indicate if you modified the licensed material.You do not have permission under this licence to share adapted material derived from this article or parts of it.The images or other third party material in this article are included in the article’s Creative Commons licence,unless indicated otherwise in a credit line to the material.If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use,you will need to obtain permission directly from the copyright holder.To view a copy of this licence,visit http://creativecommons.org/licenses/by-nc-nd/4.0/.
