Accession Number : ADA319550

Title :   A Rapid Method for Determining Stress Concentrations for Autofrettaged Tubes Containing Multiple Axial Perforations Within the Wall.

Descriptive Note : Final rept.,

Corporate Author : ROYAL MILITARY COLL OF SCIENCE SWINDON (UNITED KINGDOM)

Personal Author(s) : Parker, A. P.

PDF Url : ADA319550

Report Date : AUG 1996

Pagination or Media Count : 32

Abstract : A simple method is developed for the determination of the stress concentration factor (SCP) arising from multiple, periodic, axial, elliptical holes within the wall of a gun tube. The model is based upon a simple superposition procedure with capping of any stresses that exceed yield magnitude, and is able to incorporate autofrettage residual stresses. There are two potential failure locations, namely the bore (radius R1) and the point on the hole boundary nearest the bore (radius Rn). By plotting the ratio of stress ranges due to firing at these two locations, taking account of pressure entering bore cracks, straightforward design plots of stress range ratio permit the selection of optimum radial hole location. This location is found to vary with the eccentricity of the hole's elliptical shape. The choice of ideal ellipse eccentricity depends upon Rn, percentage overstrain, and ratio of firing pressure/yield strength. A near optimum value for the case Rn/R1 = 1/4 is provided by the circular hole. A straightforward design procedure is proposed which requires only standard compendia in order to optimize hole shape.

Descriptors :   *AUTOFRETTAGE, *STRESS CONCENTRATION, STRESS STRAIN RELATIONS, OPTIMIZATION, FATIGUE LIFE, STRESS ANALYSIS, GUN BARRELS, FIRING TESTS(ORDNANCE), CRACK PROPAGATION, CYLINDRICAL BODIES, HOLES(OPENINGS), RESIDUAL STRESS, YIELD STRENGTH, BIAXIAL STRESSES, FAILURE(MECHANICS), AXIAL LOADS, PERFORATION, INTERNAL PRESSURE.

Subject Categories : Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE