摘要:

AbstractIt was found that the breakup‐time of jets formed by shaped charges of cylindrical symmetry is given very accurately by the formula:\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm t}_{\rm B} {\rm = }\frac{1}{{{\rm V}_{{\rm PL}} }}\sqrt {8{\rm R } \cdot {\rm T}_{\rm L} } \cdot \sin {\rm \beta /2} $$\end{document}This formula is obtained from a general principal applied here for the first time which says that the breakup‐time of homogeneous ductile metals under very high strain rates is equal to the smallest initial dimension of the elongating metal divided by VPL. When applied to simple configurations such as a pipe which expands due to internal explosion this principal leads to a correct prediction of the average formed fragment dimensions. This principal provides for the first time an explanation to the experimental fact that metals' ductility can increase by an order of magnitude when the strain rate increases from 10−2to 105pro s

ISSN:0721-3115    

DOI:10.1002/prep.19790040502

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

AbstractOptical properties of small droplets of aqueous solutions of zinc chloride were studied in the 3 μm to 12 μm spectral range. The droplets are generated by combustion of a pyrotechnic screening smoke composition containing hexachloroethane and zinc. Mass extinction coefficients were determined and interpreted by the theory of Mie.The optical constants of aqueous solutions of zinc chloride are markedly different from those expected for a screening smoke of low IR transparenc

ISSN:0721-3115    

DOI:10.1002/prep.19790040503

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

AbstractIgnition behavior of solid propellant composed of 25 wt% polybutadiene and 75% ammonium perchlorate under subatmospheric conditions has been studied using a carbon dioxide laser whose radiant flux is uniformalized. Data of ignition time in Ar, N2and He atmospheres, and critical radiant flux and pressures over which ignition might be achieved, were obtained. Moreover, the data were compared with theoretical values, taking account of variable heat conductivity for the ambient gases with a surface ignition hypothesis.It is concluded that these ambient gases participate in the pre‐ and post‐ignition reactions and the ignition preventive behavior of He atmosphere is not predictable merely based on its high transport properties. The detailed observation of the ignition transient near the critical pressure revealed that the ignition in Ar atmosphere occurs in gas phase under less than 100 torr whereas in He atmosphere it occurs always at the condensed phase surf

ISSN:0721-3115    

DOI:10.1002/prep.19790040504

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

AbstractThe object of this paper is to obtain expressions for the burning rate pressure exponent and the temperature sensitivity of AP‐based and HMX‐based CMDB propellants in terms of the respective physical constants on the basis of a recently developed model of combustion for CMDB propellants and to examine the effects, if any, on these two parameters, of the changes in propellant composition, AP particle size and pressure. Computer programs were developed for this purpose and the results obtained for typical sets of input data presented in the paper. While the results of the calculation indicate a markedly strong dependence of the pressure exponent and the temperature sensitivity on pressure and composition for both AP‐based and HMX‐based CMDB propellants, the parameters are characterized by far lesser dependence on AP particle size for the AP‐based p

ISSN:0721-3115    

DOI:10.1002/prep.19790040505

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

ISSN:0721-3115    

DOI:10.1002/prep.19790040506

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

ISSN:0721-3115    

DOI:10.1002/prep.19790040501

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY