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Zeng X.,Nanjing University of Science and Technology | Zhou K.,Nanjing University of Science and Technology | He L.,Nanjing University of Science and Technology | Gong P.,Nanjing University of Science and Technology | And 2 more authors.
Advanced Materials Research | Year: 2012

To investigate the wounding effects in human on the basis of the similarity theory, by taking the temporary cavity as the research object, through the analysis on the forming of cavity and its physical process, main influencing factors effecting temporary cavity are obtained, which can provide a good theoretical basis for similarity research in wounding ballistics in the future, and the killing effect of the high speed steel ball is more deeply described. © (2012) Trans Tech Publications, Switzerland. Source


Li J.M.,Taiyuan University of Technology | Li J.M.,North University of China | Xiong S.B.,Taiyuan University of Technology | Xiao F.,No208 Research Institute Of China Ordnance Industries
Advanced Materials Research | Year: 2013

Though analysis of the blast wave changing law and the basic equation of blast wave overpressure functions in air, blast wave overpressure functions have been simplified. A simplified form of blast wave overpressure function is acquired, and experimental certificated. The results show that the simplified function curve correctly reflects the characteristics of the experimental curve. The blast wave created to simplify the function is reasonable. © (2013) Trans Tech Publications, Switzerland. Source


Yang Y.,Beijing University of Technology | Cai L.-G.,Beijing University of Technology | Zhuo X.,No208 Research Institute Of China Ordnance Industries | Wang Y.-D.,Beijing University of Technology | Liu Z.-F.,Beijing University of Technology
Beijing Gongye Daxue Xuebao/Journal of Beijing University of Technology | Year: 2015

To control and accurately calculate support stiffness and critical speed, numerical calculation models have been established, which considered the mixed preload mechanism of angular contact ball bearing. Taking a spindle system as finite element model, bearing group model and shaft model were coupled to structure the shaft-bearing model. The coupled model was iterated to obtain spindle system dynamic parameters, and then the whirl frequency of spindle was analyzed. The shaft-bearing model dynamics calculation process was set up, and the support stiffness and whirl frequency of spindle was researched in different preload mechanism. Theoretical calculation results show that compared with the traditional method, this model has higher precision to predict high speed spindle dynamic characteristics in operation. Adopting reasonable preload method and selecting proper preload force is conducive to improve the critical frequency of spindle system in operation. ©, 2015, Beijing University of Technology. All right reserved. Source


Wu Q.-J.,Nanjing University of Science and Technology | Zhou K.-D.,Nanjing University of Science and Technology | He L.,Nanjing University of Science and Technology | Zeng X.,Nanjing University of Science and Technology | Li J.-S.,No208 Research Institute Of China Ordnance Industries
Nanjing Li Gong Daxue Xuebao/Journal of Nanjing University of Science and Technology | Year: 2011

To research the damage mechanism of the composite thick-wall cylinder, based on the continuum damage mechanics theory, an energy-based stiffness degradation method is proposed to predict the progressive failure properties of a steel-carbon fiber/polyimide composite thick-wall cylinder. Three failure modes of carbon fiber/polyimide composites, including fiber breakage, matrix cracking and fiber/matrix interface shear failure are considered in the model. A three-dimensional finite element technique including the multiframe restart analysis and the arc-length algorithm is employed to conduct the progressive failure analysis. The result shows that: matrix cracks first, then the fiber breakage causes final failure of the whole structure before interface shear failure and liner damage; there is no shear failure or lining failure in this process; the strength of fiber decides the strength of composite thick-wall cylinder. Source


Wen Y.K.,Nanjing University of Science and Technology | Xu C.,Nanjing University of Science and Technology | Dong X.H.,Nanjing University of Science and Technology | Wang S.,No208 Research Institute Of China Ordnance Industries
Advanced Materials Research | Year: 2013

Ultra-high molecular weight polyethylene (UHMWPE) fiber reinforced plastic (UFRP) is an integral part of hard body armor. The intensive study on the material characterization of UFRP can help to understanding the bulletproof mechanism and behind-armor blunt trauma (BABT) well, and thus improve the performance of body armor. The research presented in this paper represents an effort to characterize the properties of UFRP under quasi-static and ballistic loading. The tensile behavior along the fiber direction and through thickness compressive behavior were obtained using an universal material testing machine. Experiments show that the tensile strength and compressive strength of UFRP are approximately 500MPa and 650MPa, respectively. The through thickness shear strength of UFRP was also obtained according to the punch-shear testing, and a set of special clamp was used to clamp the samples. The composite has been found to have a low shear strength. The UFRP was impacted by a 4.8mm diameter spherical fragment with velocity 694m/s~920m/s, to study the ballistic performance. And the height and radius of the deformed conical region on the back face of UFRP were captured using high-speed photography technique. Results show the maximum transient height of the cone is about 3 to 4 times greater than the final height of the cone, and the radius of the cone reaches to 59±7.4mm. The ballistic limit of the 11mm thick UFRP is approximately 800m/s. © (2013) Trans Tech Publications, Switzerland. Source

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