The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing date sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Picatinny, NJ 07806-5000 Excalibur is the Army's new 155-mm, guided projectile. It is scheduled for fielding in 2008. The objectives of Excalibur's test program are: 1) shake-out the weak systems for redesign by testing at a margin load, 2) characterize the gun-launch loads for design improvements and failure reviews, and 3) demonstrate structural integrity and operability after gun launch. In this paper,"10 live-firings at the margin load, PMP +5%, are presented. Averages, standard deviations, and statistical correlations are given.
SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S)USA15.
The development of guided artillery projectiles has uncovered a need for the deployable fins that open upon muzzle exit. Knowledge of this base pressure drop is also important for the electronics designer because so-called "setforward" (the rapid "un-springing" of the projectile as it leaves the muzzle of the gun) has been identified as the cause of many component failures. An empirical relationship is developed for the base pressure drop in a 155 mm gun tube. This tube utilized a standard double-baffle muzzle brake. Several Instrumented Ballistic Test Projectiles (IBTP) were fired at various charge zones and the base pressure drops were compared and curve fits developed. A basic exponential decay curve with averaged coefficients was developed from the data. This empirical model can be utilized by researchers performing Computational Fluid Dynamics calculations as a check on results generated for the double baffle muzzle brake configuration.
This paper addresses the seismic analysis of a deeply embedded non-slender structure hosting the pumping unit of a reservoir. The dynamic response in this type of problems is usually studied under the assumption of a perfectly rigid structure using a sub-structuring procedure (three-step solution) proposed specifically for this hypothesis. Such an approach enables a relatively simple assessment of the importance of some key factors influencing the structural response. In this work, the problem is also solved in a single step using a direct approach in which the structure and surrounding soil are modelled as a coupled system with its actual geometry and flexibility. Results indicate that, quite surprisingly, there are significant differences among prediction using both methods. Furthermore, neglecting the flexibility of the structure leads to a significant underestimation of the spectral accelerations at certain points of the structure.
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