Anderson C.E.,Southwest Research Institute |
Riegel J.J.P.,Fountain Technology Inc.
International Journal of Impact Engineering | Year: 2015
The database for depth of penetration by projectiles into semi-infinite targets is quite extensive. The objective is to use the experimental semi-infinite penetration data to predict finite-thickness target effects. Similitude considerations are used to represent penetration response as a function of a normalized impact velocity, which is the ratio of the penetration pressure to the target strength. Then, a least-squares regression analysis methodology was applied to the normalized experimental data to provide an analytic expression for the normalized depth of penetration as a function of the normalized impact velocity over a very large velocity range, typically a few hundred meters per second to over 3500 m/s. We use the analytic expression, along with some simplifying assumptions, to estimate ballistic limit thickness T50 and/or the ballistic limit velocity V50. If a target is overmatched, i.e.; perforated by the projectile, an estimate is also made for the projectile residual velocity and residual length. The experimental data on which the regression fit is based consists of L/D 10 projectiles, so a procedure is also developed to account for different projectile aspect ratios. A series of examples are provided to demonstrate the utility and accuracy of the approach. © 2015 Elsevier Ltd.
Liu M.,Wuxi Jialine Electronics Materials Co. |
Zhuo H.,Wuxi Jialine Electronics Materials Co. |
Hou L.,Fountain Technology Inc. |
Zhang S.,University of Jinan
Hecheng Shuzhi Ji Suliao/China Synthetic Resin and Plastics | Year: 2014
The polymerization of 2, 2, 2-trifluoroethyl methacrylate (TFEMA) in supercritical carbon dioxide was performed, and the effects of the monomer concentration, initiator dosage and reaction temperature on the polymerization was explored. The copolymerization of TFEMA with dodecafluoroheptyl methacrylate (MBFA-12) as comonomer was carried out. The structure of the copolymer obtained and surface properties of the films made of the copolymer were studied. The results indicate that the monomer concentration, initiator dosage and reaction temperature are the factors influencing the homopolymerization of TFEMA. The solubility of the copolymer in supercritical carbon dioxide can be improved by copolymerizing TFEMA with MBFA-12. Consequently, the number average molecular mass of the copolymer increases from 22316 to 39985, and the relative molecular mass distribution decreases from 1.93 to 1.49. In addition, the glass transition temperature of the copolymer decreases to a certain extent. The surface properties of the copolymer films are improved with the increase in the monomer MBFA-12 content of the copolymer.
Liu M.,Wuxi Jialine Electronics Material Co. |
Hou L.,Fountain Technology Inc. |
Zhang S.,University of Jinan
Hecheng Shuzhi Ji Suliao/China Synthetic Resin and Plastics | Year: 2012
The copolymers of chlorotrifluoroethylene (CTFE) and vinyl acetate (VAc) were prepared in supercritical carbon dioxide. The effect of the monomer ratio on the polymerization and the structure and properties of the copolymers was explored, and the surface property and solution viscosity of the copolymers was studied. The copolymers with different structures and fluorine contents could be obtained by controlling the monomer ratio. The CTFE segments in the copolymers were kept constant at about 50% in molar content when the mass ratio of VAc to CTFE was less than 4:16. The fluorine content of the copolymers was the critical factor influencing the surface property of the copolymers. If the CTFE segments content in the copolymer rose, then the fluorine content in the product increased and the contact angle between the copolymer and the solvent became larger. The copolymers' film had the lowest surface energy of 0.028 J/m 2 when the mass content of fluorine of the product was 29.16%. The viscosity of the copolymer solution increased with the augmentation of the VAc segments content.
Riegel J.P.,Fountain Technology Inc.
Proceedings - 27th International Symposium on Ballistics, BALLISTICS 2013 | Year: 2013
The author has reviewed over 5000 published data points in an effort to identify high quality data that can be applied in the development of regressions and for comparison against analytical and numerical models It was noted that some of the data appears to have significant scatter. Outliers deserve more attention. According to Cliff Stoll one should "Collect raw data and throw away the expected. What remains challenges your theories." The goal is to either determine that the data are demonstrating an unusual behavior or that there was something unusual about the impact conditions. Unfortunately, in many cases the original reports failed to provide sufficient information to confirm the actual conditions at impact. The author identified a series of long rod penetrator DOP (depth of penetration) tests that he conducted with Charles Anderson at Southwest Research Institute that have not been previously published. They have been included in this paper and used for discussions of several analysis techniques that have been applied.
Jones T.L.,U.S. Army |
Riegel J.P.,Fountain Technology Inc. |
Meredith C.S.,U.S. Army |
Darling K.,U.S. Army |
And 2 more authors.
Magnesium Technology | Year: 2016
Experimental evidence to the extent of the plastic flow field in magnesium targets after ballistic impact has been lacking. The work described in this paper will include the ballistic characterization of the Magnesium alloy AZ31B-H24 in three orientations: normal direction; transverse direction; and rolling direction. Semi-infinite impacts from penetrators in each of the three directions will be shown. The targets were sectioned and machined using electrical discharge machining in preparation for polishing and etching to determine the extent of plastic flow that can be seen. The authors will investigate the applicability of Effective Flow Stress in the similitude-based empirical model and the Walker-Anderson Penetration Model for small arms penetration prediction. The results will be included in this paper. Copyright © 2016 by The Minerals, Metals & Materials Society. All rights reserved.