Stress analysis and calibration of tube drawing dies

Abstract

A theoretical and experimental method of calibrating tube drawing dies is outlined. The theoretical analysis was based on the solution of the finite difference forms of the simultaneous governing equations for a solid of revolution by means of a digital computer. The nature of the stress distributions was confirmed by means of the frozen stress technique of photoelasticity. The experimental technique for calibrating dies made use of Maxwell's Reciprocal Principle and the Principle of Superposition. The displacements of a die throat were measured at intervals around the throat when the die was loaded on the outer cylindrical surface by a pair of diametrically opposite compressive loads. A suitable interferometric proving ring for measuring these very small displacements was developed. The experimental and theoretical calibration results were found to be in close agreement.