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The Hugoniot parameters of U71Mn steel under high pressure were studied by hypervelocity impact test of U71Mn steel with two-stage light gas gun. The plate impact test of U71Mn steel sample was carried out by means of symmetrical impact. The minimum impact speed was 1.843km/s and the maximum impact speed was 5.018km/s. The Hugoniot relation and Hugoniot parameter C and λ, then the accuracy of Hugoniot parameters of U71Mn steel under high pressure is verified according to Hugoniot equation of state (the relationship curve between impact pressure and density). The research results can provide reference for the application of U71Mn steel in the field of hypervelocity impact.

Shock compression and spallation damage of a dual-phase polycrystalline cobalt material is investigated via plate impact experiments along with free-surface velocity measurements. The as-received and postmortem samples are characterized with X-ray diffraction measurement and electron back-scatter diffraction. Free-surface velocity histories, the Hugoniot equation of state and spall strength at different peak shock stress are determined. Multiple deformation mechanisms are found. Except for the dislocation slip in both phase, { 10 1 ¯ 2 } and { 11 2 ¯ 1 } deformation twinning in the hexagonal close-packed (HCP) phase, and the face-center cubic (FCC) to HCP phase transition are also observed. The { 10 1 ¯ 2 } twin density at the impact surface increases with increasing shock stress, but is less than twin density at the spall plane for the same shot. Ductile fracture is the main damage mode, and voids are nucleated preferentially within the HCP phase because of the strain localization. The Johnson–Cook constitutive model can describe the dynamic responses of the dual-phase Co. With this model, finite element modeling is consistent with the shock compression part of experimental observations well.

Two sets of shock compression tests (i.e. conventional and reverse impact) were conducted to determine the shock response of two rock materials using a plate impact facility. Embedded manganin stress gauges were used for the measurements of longitudinal stress and shock velocity. Photon Doppler velocimetry was used to capture the free surface velocity of the target. Experimental data were obtained on a fine-grained marble and a coarse-grained gabbro over a shock pressure range of approximately 1.5-12 GPa. Gabbro exhibited a linear Hugoniot equation of state (EOS) in the pressure-particle velocity (P-up) plane, while for marble a nonlinear response was observed. The EOS relations between shock velocity (US) and particle velocity (up) are linearly fitted as US = 2.62 + 3.319up and US = 5.4 85 + 1.038up for marble and gabbro, respectively. This article is part of the themed issue ‘Experimental testing and modelling of brittle materials at high strain rates’.

In this paper, a new method is discussed for estimating the equation of state (EOS) of an unknown material in laser-induced shocks by measuring the particle velocities alone by using two frames optical shadowgraphy and impedance mismatch methods together. Identical shock waves are generated simultaneously in distinct regions of aluminum (reference) and aluminum with a gold step (unknown). The particle velocities in the two corresponding regions had been simultaneously measured under identical experimental conditions at laser intensities below ~ 5 × 10 13  W/cm 2 . The EOS coefficients of gold were obtained as ~ 0.33 (± 0.06) × 10 6  cm/s and 1.50 (± 0.22) using this technique. The advantages in the present technique for estimation of EOS over shock velocity measurements using a streak camera are discussed.

Three different orientations of a tape-wrapped carbon fibre composite with phenolic resin matrix (abbreviated to TWCP) have been investigated under one-dimensional shock loading. This has been achieved via a single-stage gas gun, with manganin gauges as the diagnostic tool. The orientations of TWCP studied in this paper were 25°, 45° and 90°, with respect to the impact face. The shock response of these orientations, for this material, has been obtained (the Hugoniot equation of state). These results have been contrasted with previously reported literature data for the same material at different orientations (0° and 20°). It was found that orientation had minimal effect on the behaviour of this composite under shock. The exception to this was the 90° orientation which exhibited an elastic precursor at particle velocities of less than 0.65 mm µs −1 ; where the shock velocity was equivalent to the elastic sound speed of the material.

Laboratory measurements of the shock Hugoniot at high pressure, exceeding several hundred Mbar, are of great importance in the understanding and accurate modeling of matter at extreme conditions. In this work we present a platform to measure the material properties, specifically the single shock Hugoniot and electron temperature, at extreme pressures of ∼Gbar at the National Ignition Facility (NIF). In these experiments we launch spherically convergent shocks into solid CH, using a Hohlraum radiation drive. X-ray radiography is applied to measure the shock speed and infer the mass density profile, enabling determining of the material pressure and Hugoniot equation of state. X-ray scattering is applied to measure the electron temperature through measurement of the electron velocity distribution.

The paper introduces a new method of calibration of the ruby pressure scale based on the Hugoniot equation of state and isotherm static method for a number of materials Al, Co, Ni, Cu, Zn, Mo, Ag, Ta, W, Pt, Au. New functional dependence P(λ) is determined herein. Analyzed are errors resulting from experimental and statistical values of shock pressure and the use of various functional dependences of equations of state. The proposed method of calibration is compared with most published calibration methods.

Davemaoite, as the third most abundant mineral in the lower mantle, constitutes significant amounts in pyrolite and mid-ocean ridge basalts. Due to its unquenchable nature, measurements by static compression techniques on physical properties of davemaoite at lower mantle conditions are rare and technically challenging, and those are essential to constrain compositions and properties of mineralogical models in the lower mantle. Here, we present Hugoniot equation of state and sound velocity of CaSiO3 glass under shock compression. The CaSiO3 glass transforms into the crystalline phase above 34 GPa and completely transforms into davemaoite above 120 GPa. Thermal equation of state and Hugoniot temperature of davemaoite have been derived from the shock wave data. The CaSiO3 glass under shcok compression has very high shock temperature. Shock wave experiments for sound velocity of CaSiO3 glass indicate that no melting is observed at Hugoniot pressure up to 117.6 GPa. We propose that the melting temperature of davemaoite should be higher than those reported theoretically by now.

A systematic study of the Hugoniot equation of state, phase transition, and the other thermodynamic properties including the Hugoniot temperature, the electronic and ionic heat capacities, and the Gr\"{u}neisen parameter for shock-compressed BeO, is presented by calculating the total free energy. The method of calculations combines first-principles treatment for 0-K and finite-T electronic contribution and the mean-field-potential approach for the vibrational contribution of the lattice ion to the total energy. Our calculated Hugoniot shows good agreement with the experimental data.

White dwarfs represent the final state of evolution for most stars 1 – 3 . Certain classes of white dwarfs pulsate 4 , 5 , leading to observable brightness variations, and analysis of these variations with theoretical stellar models probes their internal structure. Modelling of these pulsating stars provides stringent tests of white dwarf models and a detailed picture of the outcome of the late stages of stellar evolution 6 . However, the high-energy-density states that exist in white dwarfs are extremely difficult to reach and to measure in the laboratory, so theoretical predictions are largely untested at these conditions. Here we report measurements of the relationship between pressure and density along the principal shock Hugoniot (equations describing the state of the sample material before and after the passage of the shock derived from conservation laws) of hydrocarbon to within five per cent. The observed maximum compressibility is consistent with theoretical models that include detailed electronic structure. This is relevant for the equation of state of matter at pressures ranging from 100 million to 450 million atmospheres, where the understanding of white dwarf physics is sensitive to the equation of state and where models differ considerably. The measurements test these equation-of-state relations that are used in the modelling of white dwarfs and inertial confinement fusion experiments 7 , 8 , and we predict an increase in compressibility due to ionization of the inner-core orbitals of carbon. We also find that a detailed treatment of the electronic structure and the electron degeneracy pressure is required to capture the measured shape of the pressure–density evolution for hydrocarbon before peak compression. Our results illuminate the equation of state of the white dwarf envelope (the region surrounding the stellar core that contains partially ionized and partially degenerate non-ideal plasmas), which is a weak link in the constitutive physics informing the structure and evolution of white dwarf stars 9 . Researchers have measured the equation of state of hydrocarbon in a high-density regime, which is necessary for accurate modelling of the oscillations of white dwarf stars.