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lotf tc"hA UI(is ~ of information is et~jmmaed to ""erAqtI hour per re4Oon~e. includin~g the time tor reviewingj instruction%. searchorl erotilnq data sourmes, Jod hei~rq t.ofltnin the. data ne%'Jed, and (0otpielIin] aid rrerwniimi Ise ýotfemton o1 information Send Comment% reqareing tis, burden estimate or any other A~pett of tn.$ ,4I(\tCie ot iii utraion rinlii(1n. su J,pi tioni for reducing this burden to Waiihingion Hleadquarters Services, OrreClorale for lot ormAlion Operations and fe~ports. Approved for public release, distribution is unlimited. ABSTRACT (Maximum 200 words)The U.S. Army Armament Research, Develiopmenti and Engineering Center (ARDEC) recently expressed a need for a tank-cannon-launched training projectile with reduced penetration capability. T'he expressed primary design goals for this projectile were to minimize the probability of personnel injury anid materiel loss in the event of an accidental impact during a training exercise. In order to meet these design goals the solid-steel flight body of a current kinetic energy (KB) training projectile, the M865EP, was replaiced with a hollow aluminum configuration. Because of the incorporationi of aluminum, theI structural integrity of the entire projectile during launch was questioned. T7hus, a thorough stress analysis of the new design was conducted to alleviate concerns about its structural integrity.j Two-dimensiona, axisymmetnic, quasi-static stress analyses were performed on two new KE training. projectile designs. T7he rirs analysis indicated tha structur failure was possible in the aft portion of the projectile due to compressive loading by the gun gases. Structural failure in this case would be circumferential yielding of the hollow flight body. The aft portionI of the round was redesigned, and subsequent stres analysis showed that the possibility of structural failure needed to be resolved. The finite-clement modeling approach, the applied boundary conditions, and the results of the stres analyses conducted, based on use of the von Mises failure criterion, will be disussed in detail.

As a means of verifying the design and operation of the Mortar Dragster, a commercially available, three-dimensional rigid body dynamics simulation program was exercised. The Mortar Dragster is a conceptual design for a range correction device for the 81-mm mortar. The design includes a series of drag surfaces, or tabs, which are actuated at some point in the trajectory of the projectile. The actuation places the entire series of drag surfaces into the airstream, thus slowing the projectile. Of specific interest are the collision forces and resulting tab hinge loads imparted by the opening tabs impacting the adjacent connected body because of integral torsion springs and air drag-induced torque loads. Collision forces predicted by the simulation program were of the same order of magnitude as hand calculations. The results of this investigation provided confidence in the final design of the tab mechanism before its flight testing and also provided further verification of the simulation program's performance.

No abstract

With the advances in microelectronics, sensor technology, and packaging design, the reality of an artillery projectile, range correction device is conceivable. A previous report entitled “Preliminary Design of a Range Correction Module for an Artillery Shell” (Hollis 1996) demonstrated a possible concept called the D-ring range correction device. One of the main objectives of the range correction device concept was to contain all the mechanical and electrical components within a fuze-like envelope, while maintaining certain constraints that would allow the fuze to fit into a variety of artillery shells used by North Atlantic Treaty Organization (NATO) countries. Another objective of the range correction device concept was to avoid any changes within the ogive of any of the projectiles in the existing stockpile. Range correction is achieved by a mechanism that symmetrically deploys four D-shaped blades, or drag blades, with the sole purpose of increasing drag. Estimates have been made of the percent change in drag as related to increases in frontal area. The deployed D-rings, with a spread of 80 mm, will increase the frontal area by 1.63 times. If the D-rings are extended a centimeter farther to a deployment diameter of 100 mm, the increase in frontal area is 2.39 times. An initial study by Brandon and Jara has indicated that reasonable maneuver authorities can be achieved for frontal areas of 7.3 in2 (47.1 cm2) and 10.7 in2 (69.0 cm2), which corresponds, respectively, to the 80-mm and 100-mm deployment diameters. This report is a culmination of many design iterations, numerical analyses, shock tests, and actual cannon launchings. Most of the design iterations and numerical analyses are not mentioned in this report simply because they were stepping stones that led to the final design. Structural analyses indicate that the overall prototype design is durable enough to withstand the most severe artillery cannon launching available today. The design should be capable of withstanding 15,000 g’s of inertial set-back loads with 150,000 rad/s2 of angular acceleration. In addition, the design is also capable of deploying at a velocity of 650 m/s, while spinning at 250 cycles per second. The next step would be to fabricate the design in order to truly verify the integrity of the structure and to determine the overall effect of the deployed drag blades on the range of flight.