摘要:

To a first approximation, the effect of isotope exchange on the Hugoniot of a material can be represented by a scaling of the density inPh(V).For deuterated polyethylene, this approximation is adequate to the accuracy of the data. Data for deuterated polyethylene and required scaling is presented. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1303442

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

A new photographic method was developed to measure the evolution of shock wave front velocity in polymers continuously with time. This kind of experiment is motivated by our previous studies which showed that the Hugoniot curves of two kinds of polyethylene specimens have very peculiar shape in the vicinity of the particle velocity around 150 m/s. We observed the shock velocity history in PMMA and two kinds of PE specimens especially in the vicinity of 150 m/s. Shock velocity in PMMA is found to be almost constant within the experimental conditions tested. While in PE specimens it becomes slower with the propagation distance. This tendency depends strongly on shock strength as well as on the difference in materials. It is noticeable that this unsteadiness of shock velocity was found to be different even in PE specimens with different molecular weight. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1303443

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

Proposed is semiempirical equation-of-state model for organic compounds over a broad region of thermodynamic parameters, which takes into account transformations of substances at high dynamic pressure. Equations of state for polystyrene, polyimide, and poly(m-phenilene isophthalamide) are developed; the critical analysis of calculated results in comparison with the set of available at high energy density experimental data is made. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1303444

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

An equation of state model has been developed for tributyl phosphate, an industrial solvent and plasticizer, using published thermodynamic properties for this and similar molecules. The model includes a condensed and a vapor phase. It was developed with the aid of PANDA, a code that provides tools for modeling the equation of state behavior of materials. Development of the model is described. Predictions with the new equation of state are compared to experimental results. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1303445

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

A model is presented to estimate the characteristic vibrational stiffness of an atomic lattice, given the pairwise interaction potential of the constituent atom. Unlike nearest-neighbor approaches (e.g., Slater or Dugdale and MacDonald), the vibrational stiffness is shown to be distinct from the bulk (i.e., volumetric) stiffness. This vibrational stiffness implies a characteristic vibrational frequency of the lattice that varies with the lattice spacing, which is used to infer the Grueneisen function of the lattice. Because non-nearest lattice neighbors are accounted for, the equations are expressed in terms of triple summations of the pairwise potential. However, an analytical fit to these triple summations has been developed. Furthermore, the analytical form calibrates to a range of cold- and shock-compression data, resulting in an analytical frequency-based equation of state (EOS) for crystalline solids. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1303446

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

This paper describes an ab initio method for estimating intermolecular potential parameters required for equations of state. The intermolecular potentials are thermodynamically averaged over the Euler angles of the system as proposed by Ree to give a spherical average at that intermolecular distance. An alternative treatment using the multipole moments of the angular dependent potentials is also described. The results obtained in a detonation state calculation for the explosive FEFO agree well with those measured in experiments. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1303447

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

Group Theoretical Methods as defined by Lie are applied to the problem of temperature independent, hydrodynamic shock in a Birch-Murnaghan continuum. Ratios of the group parameters are shown to be linked to physical parameters specified in the second, third, and fourth order BM-EOS approximations. We provide an illustrative example of how the expansion ratio(c1/c2)and the material resistance condition(c4/c2)are a function of the compression ratio &bgr;, for a spherical shock wave propagating through MgO and Na. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1303448

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

Shock temperature measurements of various ionic solids and metals have recently been only somewhat corroborated by static experiments using laser-heated diamond anvil cells. In each technique, optical pyrometry is employed; however, the shock temperature measurements of the several groups usually use from four to twelve wavelengths between 400 and 1050 nm, while the diamond cell experiments involve optical multichannel analyzer data over a smaller spectral range. We propose that the argon pressure medium often used in laser-heated diamond anvil cell measurements exhibits a spectral transmittance filtering effect that affects the apparent temperature measured. This is due to the large thermal gradients and the concomitant refractive index variations. We use an optical transfer matrix approach to calculate the effect on the measured spectral radiance and temperature, and find that measured temperature may be inaccurate due to this interference effect by as much as 10&percent;. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1303449

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

Strongly nonliniear waves in 1-D chains are considered in long wave approximation for arbitrary interaction law between particles. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1303450

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

The centered shock waves or simple waves generated by oblique plate impact of nonlinear elastic solids are studied. Attention is restricted to materials for which the fast wave is purely longitudinal. This includes isotropic materials and appropriately aligned orthotropic or transversely isotropic materials. The emphasis is on the derivation of exact or approximate relations between stress, strain, particle velocities, and wave speeds which areuniversalin the sense that they do not involve material constants or material functions. For isotropic materials, universal relations for the difference between the longitudinal and lateral stresses are derived. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1303451

出版商:AIP    

年代:1900

数据来源: AIP