MIL-HDBK-776

Abstract

FOREWOROD <br>Design charts and tables have been developed for the elastic torsional stress analyses of free prismatic shafts, splines and spring bars with virtually all common industrially encountered thick cross sections. Circular shafts with rectangular and circular }. iways, external. splines, and milled flats along with rectangular and X-shaped torsion bars are presented. <br>A computer program ("SIIAFT") was developed which provides a finite difference solution to the governing&#160;(POISSON's) partial differential&#160;equation which defines the stress functions for solid and hollow shafts with generalized contours. Using the stress function solution for the various shapes, and Pirandello's membrane analogy, dimensionless design charts (and tables) have been generated for transmitted torque and maximum shearing stress. The design data have been normalized for a unit dimension of the cross section (radius or length) and are provided for solid shapes. <br>The eleven solid shapes presented, along with the classical circular cross section solution, provides the means for analyzing 144 combinations of hollow shafts with various Outer and inner contours. Hollow shafts may be analyzed by using the computer program directly Or b.y using the solid shape. charts in this paper and the principles .of superposition based on the concept of parallel shafts. Stress/torque ratio curves are presented asking more intuitively recognizable and useful than those of stress alone.