Due to the unique structural mode and material property of a composite sandwich plate, related research such as fragment impact resistance of a composite mast is short of publication and urgent in this field. In this ...Due to the unique structural mode and material property of a composite sandwich plate, related research such as fragment impact resistance of a composite mast is short of publication and urgent in this field. In this paper, the commonly accepted sandwich core board theory was modified. Damage caused by a fragment attack was simulated onto a sandwich plate model built with solid and shell elements. It was shown that shear failure and vast matrix cracking are the main reasons for outer coat damage, and tension failure and partial matrix cracking are the cause for inner coat damage. Additionally, according to complexities in actual sea battles, different work conditions of missile attacks were set. Ballistic limit values of different fragment sizes were also obtained, which provides references for enhancing the fragment impact resistance of a composite mast.展开更多
In this experiment, red sandstone specimens, having slenderness ratios of 0.5, 0.7, 0.9 and 1.1 respectively, were subjected to blow tests using a Split Hopkinson Pressure Bar(SHPB) system at a pressure of 0.4 atmosph...In this experiment, red sandstone specimens, having slenderness ratios of 0.5, 0.7, 0.9 and 1.1 respectively, were subjected to blow tests using a Split Hopkinson Pressure Bar(SHPB) system at a pressure of 0.4 atmospheres. In this paper, we have analyzed the effect of slenderness ratio on the mechanical properties and energy dissipation characteristics of red sandstone under high strain rates. The processes of compaction, elastic deformation and stress softening deformation of specimens contract with an increase in slenderness ratio, whilst the nonlinear deformation process extends correspondingly. In addition, degrees of damage of specimens reduced gradually and the type of destruction showed a transformation trend from stretching failure towards shear failure when the slenderness ratio increased. A model of dynamic damage evolution in red sandstone was established and the parameters of the constitutive model at different ratios of length to diameter were determined. By comparison with the experimental curve, the accuracy of the model, which could reflect the stress–strain dynamic characteristics of red sandstone, was verified. From the view of energy dissipation, an increase in slenderness ratio of a specimen decreased the proportion of energy dissipation and caused a gradual fall in the capability of energy dissipation during the specimen failure process. To some extent, the study indicated the effects of slenderness ratios on the mechanical properties and energy dissipation characteristics of red sandstone under the high strain rate, which provides valuable references to related engineering designs and academic researches.展开更多
基金Supported by the Research-in-advance Foundation of Naval Armory under Grant No.401030101the National Defense Science and Technology Cooperation Foundation(2007DFR80340)Research-in-advance Foundation of National Defense Science and Technology in Shipbuilding Industry(07J1.1.6)
文摘Due to the unique structural mode and material property of a composite sandwich plate, related research such as fragment impact resistance of a composite mast is short of publication and urgent in this field. In this paper, the commonly accepted sandwich core board theory was modified. Damage caused by a fragment attack was simulated onto a sandwich plate model built with solid and shell elements. It was shown that shear failure and vast matrix cracking are the main reasons for outer coat damage, and tension failure and partial matrix cracking are the cause for inner coat damage. Additionally, according to complexities in actual sea battles, different work conditions of missile attacks were set. Ballistic limit values of different fragment sizes were also obtained, which provides references for enhancing the fragment impact resistance of a composite mast.
基金Financial support for this work, provided by the National Basic Research Program of China (No. 2013CB227900)the National Natural Science Foundation of China (No. 51074166), the National Natural Science Foundation for Young (Nos. 51304200, 51304201 and 51104128)+3 种基金the Specialized Research Fund for the Doctoral Program of Higher Education of China (No. 20120095110013)the Open Fund of the State Key Laboratory of Coal Resource and Safe Mining (No. 10F08)the Colleges and Universities in Jiangsu Province Plans to Graduate Research and Innovation (No. CXLX13_935)the College Students’ Innovative Entrepreneurial Foundation of China University of Mining and Technology (No. 2013DXS03)
文摘In this experiment, red sandstone specimens, having slenderness ratios of 0.5, 0.7, 0.9 and 1.1 respectively, were subjected to blow tests using a Split Hopkinson Pressure Bar(SHPB) system at a pressure of 0.4 atmospheres. In this paper, we have analyzed the effect of slenderness ratio on the mechanical properties and energy dissipation characteristics of red sandstone under high strain rates. The processes of compaction, elastic deformation and stress softening deformation of specimens contract with an increase in slenderness ratio, whilst the nonlinear deformation process extends correspondingly. In addition, degrees of damage of specimens reduced gradually and the type of destruction showed a transformation trend from stretching failure towards shear failure when the slenderness ratio increased. A model of dynamic damage evolution in red sandstone was established and the parameters of the constitutive model at different ratios of length to diameter were determined. By comparison with the experimental curve, the accuracy of the model, which could reflect the stress–strain dynamic characteristics of red sandstone, was verified. From the view of energy dissipation, an increase in slenderness ratio of a specimen decreased the proportion of energy dissipation and caused a gradual fall in the capability of energy dissipation during the specimen failure process. To some extent, the study indicated the effects of slenderness ratios on the mechanical properties and energy dissipation characteristics of red sandstone under the high strain rate, which provides valuable references to related engineering designs and academic researches.
