A multiaxial stress-strain analysis for proportional cyclic loading

A simplified treatment is presented for the analysis of tubular specimens subject to in-phase tension-torsion loads in the elasto-plastic regime. Use is made of a hardening function readily obtainable from the uniaxial cyclic stress-strain curve and hysteresis loops. Expressions are given for incremental as well as deformation theories of plasticity. The reversals of loading are modelled by referring the flow equations to the point of reversal and calculating distances from the point of reversal using a yield critertion. The method has been used to predict the deformation response of in-phase tests on an En15R steel, and comparisons with experimental data are provided. The material exhibited a non-Masing type behaviour. A power law rule is developed for predicting multiaxial cyclic response from uniaxial data by incorporating a hysteretic strain hardening exponent.

Download Full-text

Stress-Strain Analysis of Cyclic Plastic Bending and Torsion

Journal of Engineering Materials and Technology ◽

10.1115/1.3443465 ◽

1978 ◽

Vol 100 (2) ◽

pp. 157-163 ◽

Cited By ~ 11

Author(s):

N. E. Dowling

Keyword(s):

Cyclic Loading ◽

Alloy Steel ◽

Strain Analysis ◽

Strain Curve ◽

Cyclic Stress ◽

Curve Analysis ◽

Pure Bending ◽

Stress Strain Curve ◽

Stress Strain ◽

Plastic Bending

Analysis of stresses, strains, and damping energies is considered for cyclic loading of simple geometries. For beams under pure bending and for circular shafts under torsion, it is shown that cyclic loading may be handled by analysis that differs from that applicable to monotonic loading only by the substitution of a cyclic stress-strain curve. Analysis and experiment are successfully compared for rectangular beams of an alloy steel.

Download Full-text

Stress-Strain Curves for Oxygen-Free High Conductivity Copper at Shear Strain Rates of up to 103s-1

Proceedings of the Institution of Mechanical Engineers ◽

10.1243/pime_proc_1970_185_125_02 ◽

1970 ◽

Vol 185 (1) ◽

pp. 1149-1158 ◽

Cited By ~ 2

Author(s):

K. Bitans ◽

P. W. Whitton

Keyword(s):

Shear Strain ◽

Testing Machine ◽

Shear Bands ◽

Strain Curve ◽

Strain Rates ◽

Adiabatic Shear Bands ◽

Stress Strain Curve ◽

Stress Strain ◽

The Given ◽

Tubular Specimens

Shear stress-shear strain curves for o.f.h.c. copper at room temperature have been obtained at constant shear strain rates in the range 1 to 103s-1, using thin walled tubular specimens in a flywheel type torsion testing machine. Results show that, for a given value of strain, the stress decreases when the rate of strain is increased. Moreover, the elastic portion of the stress-strain curve tends to disappear as the rate of strain is increased. It is postulated that these effects are due to the formation of adiabatic shear bands in the material when the given rate of strain is impressed rapidly enough. A special feature of the design of the testing machine used is the rapid application of the chosen strain rate.

Download Full-text