What is Hugoniot pressure?

What is Hugoniot pressure?

2.1 Initial impact pressure. As prior stated, the maximum point of the pressure profile of a bird-strike impact occurs in the very initial stages of the impact, this is called the Hugoniot pressure.

What is the Hugoniot elastic limit?

The Hugoniot elastic limit (HEL) is a measure of a particular material’s yield strength under the stress state generated by the LST. It may be observed and evaluated in the back-face velocity trace produced by the test. Thus the HEL may be an independent indication of surface velocity.

What is the Hugoniot curve?

The di erence between a detonation and the shock in an inert gas is in the form of h∞ . Chemical equilibrium is attained after the gas passes through the wave. • A plot of p∞ versus 1/ρ∞ for a given value of. (p0,1/ρ0) and the heat release −(h∞ − h1) is called the Hugoniot curve.

How do you calculate shock velocity?

The velocity of the gas is denoted by u, pressure by p, and the local speed of sound by a. The speed of the shock wave relative to the gas is W, making the total velocity equal to u1 + W.

Why does pressure increase across a shock?

Across a compression wave, the flow decelerates and the pressure increases. Because, any new disturbance created here will travel at a faster speed than wave speed c, since the pressure and temperature might have now risen here.

What is shock velocity?

In fluid dynamics, a moving shock is a shock wave that is travelling through a fluid (often gaseous) medium with a velocity relative to the velocity of the fluid already making up the medium. As such, the normal shock relations require modification to calculate the properties before and after the moving shock.

Does stagnation pressure increase across a normal shock?

Across a shock wave, the static pressure, temperature, and gas density increases almost instantaneously. The ratio of stagnation temperatures remains constant across a normal shock since the process is adiabatic, irreversible process; and entropy rises. The entropy values of the two points are not the same.

How is the Hugoniot equation of state determined?

The Hugoniot data for highly dense polycrystalline tungsten were obtained for pressures above 200 GPa, and the equation of state (EOS) was determined taking into account shear strength effects. For this study, we have made some improvements in measurement system and analyses of the shock wave data.

Which is the compressive strain of the Hugoniot equation?

Also reported is compressive strain which, by mass conservation, is simply the ratio of Hugoniot particle velocity to shock velocity. The U s -u p Hugoniot data from the present study over the stress range 2.2-24.1 GPa are plotted in Figure 2.

How is the pressure of a Hugoniot measured?

As can be seen in Fig. 6.24, the final method of pressure measurement has resulted in a good agreement of the Hugoniot pressures obtained from a hemispherical-ended cylinder to the theoretical values (if the pressure is read from sensors).

How is the Hugoniot curve determined from an ideal shock?

It can also be used to determine the Hugoniot curve analytically from a given equation of state. By an ideal shock, one means that a planar pusher is driven at constant velocity into the sample. The resulting shock wave is characterized by a planar shock front that travels at constant velocity during the measurement.