Engineering topics
Publications and source records attributed to Menichelli, V. J..
By terminating the discharge of energy into an insensitive electroexplosive device, firing-energy parameters can be determined. A simple capacitor-discharge system providing exponential pulses terminated at an adjustable width is described. Basic theory and application to testing are discussed.
Several nondestructive test techniques were developed for electroexplosive devices. The bridgewire responds, when pulsed with a safe level current, by generating a characteristic heating curve. The response is indicative of the electrothermal behavior of the bridgewire-explosive interface. Bridgewires which deviate from the characteristic heating curve were dissected and examined to determine the cause of the abnormality. Deliberate faults were fabricated into squibs. The relationship of the specific abnormality and the fault associated with it is demonstrated.
A self-balancing bridge for ascertaining the electrothermal and nonlinear behavior of an electroexplosive device is described. A sinusiodal current is passed through the device which provides a signal in the form of a unique Lissajous display. The display can be qualitatively evaluated and abnormal units can be readily detected.
Immediate longitudinal detonations have been observed in confined small-diameter columns of PETN, RDX, and tetryl by using a focused Q-switched ruby laser. The energy ranged from 0.8 to 4.0 J in a pulse width of 25 nsec. A 1000-A-thick aluminum film deposited on a glass window was used to generate a shock wave at the window-explosive interface when irradiated by the laser. In some cases, steady-state detonations were reached in less than .5 microsec with less than 10% variation in the detonation velocity.
Nondestructive pulse technique for quality control of electroexplosive devices, noting cost reduction
Half-sine wave pulse firing of electroexplosive devices
Terminated capacitor discharge firing of electroexplosive devices
The firing characteristics of insensitive electroexplosive devices to certain impulsive waveforms have been investigated. For these waveforms, energy is delivered in a time short compared to the thermal time constant and therefore cooling plays a negligible role. One waveform is a terminated capacitor discharge wherein the regular discharge of a capacitor is terminated at a preset point. Another is a half-sine wave pulse. The theory, design, and application of both impulsive waveform generators are presented together with certain limited experimental observations.
Several nondestructive test techniques have been developed for electroexplosive devices. The bridgewire will respond, when pulsed with a safe level current, by generating a characteristic heating curve. The response is indicative of the electrothermal behavior of the bridgewire-explosive interface. Bridgewires which deviate from the characteristic heating curve have been dissected and examined to determine the cause for the abnormality. Deliberate faults have been fabricated into squibs. The relationship of the specific abnormality and the fault associated with it is discussed.
Instantaneous longitudinal detonations have been observed in confined columns of PETN, RDX, and tetryl when pulsed with light energy from a focused Q-switched ruby laser. The laser energy ranged from 0.5 to 4.2 J with a pulse width of 25 nsec. Enhancement of the ignition mechanism is hypothesized when a 1000 A thick aluminum film is vacuum deposited on the explosive side of the window. Upon irradiation from the laser, a shock is generated at the aluminum-explosive interface. Steady-state detonations can be reached in less than 0.5 microsec with less than 10% variation in detonation velocity for PETN and RDX.
Nondestructive testing of insensitive electroexplosive devices by transient techniques
Initiating explosives with pulsed ruby lasers