Symmetric Torsion Research Articles

Fatigue of iron and of Fe-Si 5% down to liquid helium temperature and the relationship between fatigue and brittleness

Abstract Fatigue of Armco iron and of Fe-Si 5% is studied at liquid nitrogen and liquid helium temperatures in symmetric torsion, and by estimating the plastic strain amplitudes from internal friction measurements and from comparison with the static stress-strain curves. It is shown that, contrary to previous experiments of MacCammon and Rosenberg, iron in pure shear still shows a definite fatigue curve also at 4°K. The corresponding plastic strain amplitude at the fatigue limit is of the order of 10−4. For Fe-Si 5%, on the other hand, fatigue at 4°K almost disappears, and this disappearance seems associated with a critical value of the strain to fracture of the order of 10−5. In the representation of Manson and Coffin of the plastic strain amplitude as a function of the number of cycles it is shown that the slope of the curves decreases with increasing brittleness and for the silicon alloy becomes almost zero at liquid helium temperature. The results obtained on the relationship between fatigue and britt...

Load Transfer Problem for an Embedded Shaft in Torsion

This paper deals with the axially symmetric torsion of a semi-infinite cylinder embedded into an elastic half space, where the cylinder is allowed to protrude by a finite amount. The problem is formulated to include the case of the protruding portion of the cylinder when it is a different material and partially bonded to the embedded portion. With the use of integral transforms and Dini series, the problem is reduced to the determination of the solution of an integral equation. Stress singularities of a fractional order are noted and computed at the juncture, when all members are perfectly bonded. A numerical solution of the integral equation is obtained for the case of a homogeneous cylinder. The bond stress on the cylinder—half space interface and the torque-twist (and consequently, strain energy) for the entire system are computed for different values of the elastic constants.

Rotationally Symmetric Stress and Strain in Shells of Revolution

In generalization of existing results of the linear theory of symmetrical bending and torsion of thin elastic shells of revolution and of the theory of pure bending and twisting of ring sector shells, this paper considers the differential equations of the theory of shells of revolution under the supposition of rotationally symmetric stress and strain, allowing for transverse shear deformation and for moments turning about the normals to the middle surface. In this way, making use of the simplified static‐geometric analogy which is associated with the introduction of the two mentioned effects, known results are rederived in a new way and some new results are obtained, in particular for the dislocation‐theory‐type problems of pure bending and twisting.

Torsion of a finite elastic cylindrical rod partially bonded to an elastic half space

A solution is given for the problem of axially symmetric torsion of a finite elastic cylindrical rod partially bonded to an elastic half space. The problem is formulated in a manner that involves coupling between dual Dini series and dual integral equations. Auxiliary functions are introduced and the problem is reduced to the solution of a Fredholm integral equation of the second kind. Approximate closed-form results are obtained when the radius of the bonded region is less than one-half the radius of the cylinder. Fractional order singularities in the stress are noted and calculated for the case when the crack vanishes.

On Axially Symmetric Punch, Crack and Torsion Problems

Related DatabasesWeb of Science You must be logged in with an active subscription to view this.Article DataHistorySubmitted: 01 January 1953Published online: 10 July 2006Publication DataISSN (print): 0368-4245ISSN (online): 2168-3484Publisher: Society for Industrial and Applied MathematicsCODEN: smjmap.1