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The shock wave equation of state for an alumina-filled epoxy, Castall 300, has been determined in the stress range from 0.4 to 3.7 GPa via gas gun experiments. Stress - particle velocity data was obtained by impacting Castall disks directly onto quartz gauges. Shock transit-time experiments were performed by impacting epoxy specimens surrounded by tilt pins and backed with quartz gauges. The results are compared with the shock response of an unfilled epoxy resin and an alumina-filled epoxy of different density.

Gas gun impact techniques have been used to investigate the electrical response of shock-depoled PZT 56/44 ferroelectric ceramic disks in the stress range from 0.7 to 8.8 GPa. External short-circuit current pulses were measured as the shock wave propagated axially through the disk in a direction either parallel or antiparallel to the remanent polarization vector. Complete charge release was not observed in any of the shots. About 82% of the available charge was released for both orientations in the stress range from 1.5 to 5.6 GPa. At stress levels of 6.8 and 8.8 GPa, the charge release for the antiparallel orientation shots was less than for the parallel orientation shots. A series of electrical polarization reversal measurements was performed under nonshock conditions on PZT disks to estimate the electrical properties in the region ahead of the shock front. Maximum electric fields for the regions ahead of and behind the shock front were estimated to be 1 to 6 kV/mm and 4 to 24 kV/ mm, respectively, as the shock stress was increased.

Gas gun impact techniques have been used to pulse charge nanofarad capacitors from the shock depoling of PZT 56/44 and PZT 95/5 ferroelectric ceramics. The PZT materials were depoled in the normal mode. Pulse powers of hundreds of kilowatts were produced in a few microseconds. The PZT 56/44 material was impacted in the stress range from 4.4 to 11.8 GPa. A maximum load voltage of 55 kV was produced at 7.9 GPa. Shock-induced electrical breakdown in the PZT material occurred at 11.8 GPa. The PZT 95/5 material was impacted at 1. 4 and 2.9 GPa stress levels. A maximum load voltage of 81 kV was produced at the higher stress.

An epoxy-encapsulated time-of-arrival pin and cable configuration (spikeducer) for use in shock wave experiments is described. The configuration provides a protective cover for a piezoelectric pin and facilitates accurate pin positioning in an experiment. A precision molding fixture has been designed for spikeducer fabrication. The details of fabrication and the application of spikeducers in a shock wave experiment are presented.

A simple, nondestructive, noncontaminating technique for the inspection of assembled projectiles for minimum ullage (internal free volume) is presented. The technique is based on the use of ideal gas formulas and the change in the pressure of a system that results from known change in the system volume. The laboratory demonstration apparatus based on the technique is described. Suggestions for application of the technique in a production facility are presented. Keywords: Nondestructive inspection; Thermal expansion; Ideal gas formulas; Plastic-bonded explosives; Ordnance safety.

A simple technique has been used to determine the sealing status of the O-ring in the body joint of assembled two-piece projectiles. The technique is based on the pumpdown rate when a vacuum pump is connected to the projectile internal volume. A laboratory demonstration system was assembled and was later successfully used in a production-line environment. Originator-supplied keywords: Nondestructive inspection, Vacuum, Projectiles, O-ring sea, and Ordnance safety.

Lead zirconate titanate (PZT) 56/44 ferroelectric ceramic materials have been shock depoled in the normal mode with capacitive loads. The shock waves were obtained via explosive plane wave techniques and shock stress attenuators. A series of explosive shock-stress attenuation experiments using manganin gauges was performed to determine the stress amplitudes obtainable with the various attenuators. The PZT material was shock loaded in the stress range from 4.6 to 13.1 GPa. Pulse powers of hundreds of kilowatts were produced in a few microseconds. The load capacitances ranged from 0.36 to 1.7 nF. Electrical breakdown or conduction in either the PZT unit or the external circuit occurred in all the experiments. A maximum load voltage of 95 kV was produced at 7.0 GPa. (Author)

This report describes the fabrication, calibration, and operation of a capacitor gauge that has been designed for use with the NSWC gas gun. The gauge was adapted from a Lawrence Livermore Laboratory capacitor gauge. A capacitor gauge measures the shock-induced motion of the free surface of a material specimen. The read time for the gauge is about 1 microsec when used with this gas gun. (Author)

Electrical equations have been derived for the ideal response of normal-mode shock-depoled PZT ferroelectric ceramics with resistive, capacitive, and inductive loads. It was assumed in the analysis that charge was released from the PZT material completely and instantaneously at the shock front. Both rectangular and hollow-cylinder shapes were considered for the PZT unit. Expressions for the charge, voltage, current, and energy in the circuit were obtained for times during and after the traversal of the unit by the shock front. These results and the electrical properties of shock-depoled PZT 56/44 ceramics were used to estimate the geometrical size of PZT units in single-shot pulsed power supplies for energy converters with resistive and capacitive input characteristics. (Author)

A new muzzle-flange configuration and flange alignment device are described for precision alignment of target assemblies in gas gun experiments. The muzzle configuration consists of a fixed barrel flange and a moveable target flange. The alignment device consists of a long precision rod which fits into the gun muzzle and three dial indicators for monitoring the target flange adjustment. (Author)

The positron lifetime technique for monitoring changes in material properties is described. Examples of positron lifetime measurements in metals and nonmetals are given. Experiments performed on fatigued and thermally degraded materials indicate that the positron lifetime spectrum is sensitive to these material changes. (Author)

The calibration of quartz stress gauge output current for impact experiments is described. Details of the current calibration circuit and its operation are presented. The circuit features include external triggering, selectable pulse width, and selectable pulse repetition frequency. Precision amplitude current calibration signals are recorded along with the quartz gauge signal for accurate shock stress measurements. (Author)

The Gas Gun Facility designed and installed at the Naval Surface Weapons Center is described. The gun is 10.4 m long and has a 40-mm bore. The projectile velocity can be varied from 0.03 to 1 km/s in a controlled manner. The gun is used for investigating the high stress state produced in target materials by planar impact. The following are discussed: (1) the design, construction, and performance details for the gun, (2) techniques for performing real-time shock wave measurements, (3) a system to soft recover impacted specimens, and (4) details of precision target fabrication for impact experiments. (Author)

Shock wave and ultrasonic measurements have been performed on HF-1 steel, heat treated to RC 40 hardness. The dynamic yield stress and elastic wave velocity were determined from precision gas gun experiments. Ultrasonic longitudinal and shear wave velocities were obtained with the pulse-echo technique; Poisson's ratio, Young's modulus, and the one-dimensional static yield stress were calculated. The elastic wave velocity from shock loading agrees favorably with the ultrasonic longitudinal wave velocity. (Author)

A system that permits the soft recovery of specimens shock-loaded with a gas gun has been designed and put in operation. The recovered specimens are used for metallurgical examination in studies of dynamic fracture processes. The function of the system is to separate the impacting projectile from the impacted specimen to prevent subsequent specimen damage. The system has been tested for projectile velocities up to 1050 ft/sec. This velocity range is adequate for studies of microscopic spall fracture.