Comparison of Shock Response Spectrum for Different Gun Tests

J.A Cordes,P Vo,A.L Totten,D.W Geissler,J.R Lee,D.C Troast,J.D Metz

doi:10.1155/2013/980895

Abstract

The Soft Catch Gun at Picatinny Arsenal is regularly used for component testing. Most shots contain accelerometers which record accelerations as a function of time. Statistics of accelerometer data indicate that the muzzle exit accelerations are, on average, higher than tactical firings. For that reason, Soft Catch Gun tests with unusually high accelerations may not be scored for Lot Acceptance Tests (LAT) by some customers. The 95/50 Normal Tolerance Limit (NTL) is proposed as a means of determining which test results should be scored. This paper presents comparisons of Shock Response Spectra (SRS) used for the 95/50 scoring criteria. The paper also provides a Discussion Section outlining some concerns with scoring LAT results based on test results outside of the proposed 95/50 criteria.

Highlights

Precision munitions, such as the Army’s 155 mm Excalibur, include complex subsystems that undergo qualification and acceptance tests designed to emulate the high-g tactical environment
The purpose of this paper is to provide data and justification for a reasonable, cost-effective and technically sound strategy for conducting and scoring Excalibur Inertial Measurement Unit (IMU) lot acceptance testing
The Army understands that the Soft Catch Gun environment is not the same as the tactical environmental experienced by the Excalibur projectile

Summary

Introduction

Precision munitions, such as the Army’s 155 mm Excalibur, include complex subsystems that undergo qualification and acceptance tests designed to emulate the high-g tactical environment. The purpose of these tests is to demonstrate function and reliability of production lots. When failures occur, they are investigated, root cause is determined and improvements are made. They are investigated, root cause is determined and improvements are made Most of these tests are instrumented with pressure gages, accelerometers or both [1,2,3,4,5,6,7]. As of August 2010, over 500 Excalibur projectiles have been expended in support of Operation Iraqi Freedom and Operation Enduring Freedom with a reliability exceeding the 85% design threshold

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