Projectile perforation of concrete slabs will produce numerous concrete fragments on the rear face of the concrete slabs. These concrete fragments will cause serious secondary damage to the indoor personnel and equipm...Projectile perforation of concrete slabs will produce numerous concrete fragments on the rear face of the concrete slabs. These concrete fragments will cause serious secondary damage to the indoor personnel and equipment of protective structures.Accurately evaluating the damage area of concrete slabs is an important problem. Therefore, a theoretical model of a rigid projectile perforation of concrete slabs is constructed using the energy method in this paper. In this model, a new shear failure method is proposed to calculate the energy consumption of the shear formation by combining with the von-Mises failure criterion and failure strain. Based on the energy conservation and principle of minimum potential energy, explicit equations for the perforation performance are formulated. The theoretical predictions agree well with the experimental results. Furthermore,experiments on a high-speed projectile normal perforation of concrete are carried out to verify the accuracy of the corresponding theoretical prediction.展开更多
o satisfy the water demand for Tarim Basin's economic development in the year 2000, about 33 4×10 8 m 3 water needs to be further tapped. According to the analysis of the current status of water utilizati...o satisfy the water demand for Tarim Basin's economic development in the year 2000, about 33 4×10 8 m 3 water needs to be further tapped. According to the analysis of the current status of water utilization, it is pointed out that, to achieve such economic objectives, the policy of emphasizing both water exploitation and water conservation with the preference given to conservation measures must be followed. For this end, the potentials of exploring new additional sources and strengthening water conservation have been well analyzed, along with the calculation and tech economic assessment of some related parameters like the canal transmission efficiency in water delivery systems and the water irrigation efficiency in the field. The results indicate the potentials of water resource expansion and conservation are 34×10 8 m 3 and 57×10 8 m 3, respectively. Based on such research outputs, a water conservation program has been developed for the Tarim Basin, to provide important references and policy recommendations for the decision makers in Xinjiang agricultural department to implement water utilization measures.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11390362&11521062)
文摘Projectile perforation of concrete slabs will produce numerous concrete fragments on the rear face of the concrete slabs. These concrete fragments will cause serious secondary damage to the indoor personnel and equipment of protective structures.Accurately evaluating the damage area of concrete slabs is an important problem. Therefore, a theoretical model of a rigid projectile perforation of concrete slabs is constructed using the energy method in this paper. In this model, a new shear failure method is proposed to calculate the energy consumption of the shear formation by combining with the von-Mises failure criterion and failure strain. Based on the energy conservation and principle of minimum potential energy, explicit equations for the perforation performance are formulated. The theoretical predictions agree well with the experimental results. Furthermore,experiments on a high-speed projectile normal perforation of concrete are carried out to verify the accuracy of the corresponding theoretical prediction.
文摘o satisfy the water demand for Tarim Basin's economic development in the year 2000, about 33 4×10 8 m 3 water needs to be further tapped. According to the analysis of the current status of water utilization, it is pointed out that, to achieve such economic objectives, the policy of emphasizing both water exploitation and water conservation with the preference given to conservation measures must be followed. For this end, the potentials of exploring new additional sources and strengthening water conservation have been well analyzed, along with the calculation and tech economic assessment of some related parameters like the canal transmission efficiency in water delivery systems and the water irrigation efficiency in the field. The results indicate the potentials of water resource expansion and conservation are 34×10 8 m 3 and 57×10 8 m 3, respectively. Based on such research outputs, a water conservation program has been developed for the Tarim Basin, to provide important references and policy recommendations for the decision makers in Xinjiang agricultural department to implement water utilization measures.
