Metal Angle Correction in the Cylinder Test

Abstract

Abstract. Cylinder test data shows that the copper wall angle, , increases with time in a given shot and becomes much larger if the wall is at half-thickness. The true velocity is suggested to be that perpendicular to the wall, and this brings full and half-wall data in closer agreement. The equation for calculating the detonation energy density, E d , at each cone relative volume becomeswhere  is the angle of the measuring probe,  m the initial metal density,  o the initial explosive density, R o the initial explosive radius, R and x the later radius and wall thickness, and u  the wall velocity. This provides a unique solution to the energy density that does not require empirical coefficients or standards.(R+x)/cos is the wall length of the cone perpendicular to the cylinder surface and we use this as a description of the constant relative volume. This leads to a definition of the cone relative volume of gas products as beingAs a standard for full-wall cylinders, we take v c relative volumes of 2.43, 4.50 and 7.12 at the scaled wall displacements of 6, 12.5 and 19 mm. For a full-wall copper cylinder at the three points, the wall angles average 10.0, 11.0 and 11.6 degrees. Besides Cylinder test data on copper, previously unpublished framing camera pictures also measure angles for 8 different metals. The angles are a function of wall thickness and relative volume but of nothing else, including the type of metal. For modeling, our simulation code calculates the wall velocity as seen along a particular probe direction, as this is a more realistic comparison to measurements than a zone particle velocity.

Size effect and cylinder test on several commercial explosives

“…Table 2 lists the Cylinder test results. Today's Cylinder test analysis calculates the detonation energy density while accounting for the angle of the PDV probe [4], with the energy varying as the cosine of the probe angle. Table 2 lists results for Semtex H with six probes at the same distance down the cylinder but with probe angles from 5 to 10°.…”

“…The size (diameter) effect for detonation velocity [1] and the copper-wall Cylinder test for detonation energy density [2][3][4] are basic measures of detonation.…”

A Systematic Method to Determine and Test the Ignition and Growth Reactive Flow Model Parameters of a Newly Designed Polymer‐Bonded Explosive

“…The reaction product JWL equation of state is calculated by using the methods described by Lan [26] and Souers [27]. The time dependence of the radial displacement and velocity of the tube are expressed as (4) (5) in which r m0 and r m denote radius of central surfaces of the tube for the initial and a given moment, respectively.…”

Cylinder Test Correction for Copper Work Hardening and Spall

“…The multiplier increases linearly with increasing air gap width. The differences between explosives are not related to detonation velocity but to the angle of the wall tilt, V.W efind this fit to the calculations where X gap is the scaled air gap, which can range from 0t o 0.3 mm in Equation (5). This effect makes liquid and powdered explosives special because they have no air gap.…”

“…Scaling means to reduce all times and distances (but not velocities) to am ythical 12.7 mm inner wall radius, so that different sized shots may be easily compared.Equation (1) assumes the same wall thickness always, so correcting for copper wall-thinning came next [4]:where S and X are the inner radius and wall thickness at al ater time during expansion. We next corrected for the different directional angles used in the streak camera and with lasers [5,6].T his explained the difference between the streak camera and the laser experiments, but it left unanswered why half-wall tubes (wall 1/10th the radius) showed less wall loss than the standard full-wall (1/5th radius). Also unanswered was the question of how accurate the Cylinder test really is.…”