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Wen Y.,Nanjing University of Science and Technology | Xu C.,Nanjing University of Science and Technology | Wang H.,No 208 Research Institute of China Ordnance Industries | Chen A.,Nanjing University of Science and Technology | Batra R.C.,Virginia Polytechnic Institute and State University
International Journal of Impact Engineering | Year: 2013

We study experimentally and computationally the penetration of a steel sphere into a block of ballistic gelatin for developing an improved understanding of the damage caused to human soft tissues when impacted by a blunt object moving at a moderately high speed. The gelatin is modeled as an isotropic and homogeneous elastic-plastic material that exhibits linear strain-hardening and obeys a polynomial equation of state. Pictures taken by a high speed camera help construct the tunnel formed in the gelatin that is found to compare well with the computed one. Furthermore, computed time histories of the pressure at a point agree well with the corresponding experimentally measured ones for small times. The computed time histories of the temporary cavity size agree well with the corresponding experimental ones. These agreements between test findings and computed results imply that the computational model can reasonably well predict significant features of the impact event. Effects of impact velocity and sphere diameter on damage caused to the gelatin have also been studied. © 2013 Elsevier Ltd. All rights reserved. Source


Wang J.-S.,Changchun University of Science and Technology | Niu J.,No 208 Research Institute of China Ordnance Industries | Wang M.,NO. 63856 Peoples Liberation Army Troops | Hu M.,Changchun University of Science and Technology
Guangzi Xuebao/Acta Photonica Sinica | Year: 2014

In order to meet wide-field, high image quality and easy portability of infrared detection equipments, a large field transmissive infrared collimator system with working band of 8~14 μm, full field ≥24 °, aperture of 130mm was designed. A simple three-type telephoto lens structure and a non-spherical were used to solve the problem that how to balance the three transmission systems aberration. According to the theory of optical design optimization of multi-level system design, eventually a infrared transmissive collimator system was obtained, the MTF at 20 lp/mm was not less than 20%, distortion resolution rate infinity was less than 1% in the whole field of view and the position of each focal length corresponding to different wavelengths. The advantages are wide field of view, high resolution, good image quality and simple structure, which can provide high image quality, high-resolution infrared target source at infinity for a variety of infrared imaging, military infrared detection system performance parameters sights. A prototype application was developed and applied to verify alignment test. The results show that the prototype can get clear and accurate images to meet testing requirements. Source


Lu Y.,Nanjing University of Science and Technology | Zhou K.-D.,Nanjing University of Science and Technology | He L.,Nanjing University of Science and Technology | Li J.-S.,No 208 Research Institute of China Ordnance Industries | Huang X.-Y.,Unit 63856 of PLA
Binggong Xuebao/Acta Armamentarii | Year: 2015

The working condition of barrel forcing cone is worse during the firing process of small arms. To study the influence of the forcing cone angles on the stress of barrel forcing cone, the three-dimensional finite element models of barrel and projectile at different forcing cone angles are established, in which the structures of barrel and projectile, and nonlinear constitutive relations are considered. The effects of different forcing cone angles on the projectile engraving process are analyzed. The data of engraving resistance is obtained under the condition of different forcing cone angles. A response surface model of engraving resistance is established. The formula and the variation rules of projectile engraving resistance along with the forcing cone angle and engraving displacement are calculated based on the above data by using Hermite polynomial. A dynamic model of projectile engraving process is established in consideration of the engraving resistance. The engraving pressure during the projectile engraving process is solved by programming. The forcing cone angles among 0.11° and 1.13°, which satisfy the requirement of muzzle velocity of the projectile, are obtained, and then the best forcing cone angle of 0.56°, which could reduce the barrel stress to ensure the highest velocity and meet the design range of forcing cone angles in case of satisfying the interior ballistic behaviors, is got. © 2015, China Ordnance Society. All right reserved. Source


Wen Y.,Nanjing University of Science and Technology | Xu C.,Nanjing University of Science and Technology | Wang S.,No 208 Research Institute of China Ordnance Industries | Batra R.C.,Virginia Polytechnic Institute and State University
Journal of the Mechanical Behavior of Biomedical Materials | Year: 2015

The impact response of body armor composed of a ceramic plate with an ultrahigh molecular weight polyethylene (UHMWPE) fiber-reinforced composite and layers of UHMWPE fibers shielding a block of ballistic gelatin has been experimentally and numerically analyzed. It is a surrogate model for studying injuries to human torso caused by a bullet striking body protection armor placed on a person. Photographs taken with a high speed camera are used to determine deformations of the armor and the gelatin. The maximum depth of the temporary cavity formed in the ballistic gelatin and the peak pressure 40. mm behind the center of the gelatin front face contacting the armor are found to be, respectively, ~34. mm and ~15. MPa. The Johnson-Holmquist material model has been used to simulate deformations and failure of the ceramic. The UHMWPE fiber-reinforced composite and the UHMWPE fiber layers are modeled as linear elastic orthotropic materials. The gelatin is modeled as a strain-rate dependent hyperelastic material. Values of material parameters are taken from the open literature. The computed evolution of the temporary cavity formed in the gelatin is found to qualitatively agree with that seen in experiments. Furthermore, the computed time histories of the average pressure at four points in the gelatin agree with the corresponding experimentally measured ones. The maximum pressure at a point and the depth of the temporary cavity formed in the gelatin can be taken as measures of the severity of the bodily injury caused by the impact; e.g. see the United States National Institute of Justice standard 0101.06-Ballistic Resistance of Body Armor. © 2015 Elsevier Ltd. Source


Zou Y.,Nanjing University of Science and Technology | Xu C.,Nanjing University of Science and Technology | Zhang K.,No 208 Research Institute of China Ordnance Industries
Binggong Xuebao/Acta Armamentarii | Year: 2015

The matching of alterable caliber rifle is the key problem of the development of alterable caliber modularized rifle system. The numerical simulation models are established for 5.8 mm and 7.62 mm caliber rifles, and the numerical simulation models are verified by comparing the simulation results with the experimental results. The kinetic characteristic matching of bolt carrier, the ammunition feed matching and the ejection matching are analyzed based on the models. The matched-degree principle of the bolt carrier's kinetic characteristic matching is built, and according to this principle, a reasonable design project is selected. The result shows that the kinetic characteristic matching of the bolt carrier can be achieved well by changing the diameter of the gas chamber; the stability of ammunition feed and the ammunition feed matching can be improved by changing the angle of ammunition feed slope and the rounding edges; and the change in the position of the ejection port is an efficient measure of ejection matching. © 2015, China Ordnance Society. All right reserved. Source

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