V. <i>On the strength of ductile materials under combined stress</i>

Abstract

1. Lack of knowledge of laws of strength.2. Separation of the isotropic materials into ductile and brittle.3. The, yield-, point, in Tension Tests. .4. ]he ),le]d-pomt~ rather than the ulnmate, stress the criterion of strength.5. Variations of the ultimate and yield-point stresses : annealing.6.The elastic limit.7. The elastic-limit effect probably due to the existence of local yieldpoints.8.The yield.point, in preference to the elastic limit, selected as the criterion of strength.9. Torsion a ease of combined stiess.10.I;ilst reason for use of thin tubes as specimens.11. Results of previous tcrsion exFeriments.12. Previous experiments upon the yield-point under combined stress.13.Experiments upon ultimate strength under combined stress.14.Theories of elastic strength under combined stress: the maximum stress theory.15.The maximum strain theory.16.Theorem upon the limiting values of (r. 17.The maximum strain theory not disproved by published experiments.18.The maximum shearing-stre~,s criterion of elastic strength.19.:Furtker reasons for adopting thin tubes as specimens.20.Range of stress covered by different types of experiment.21.Method &checking the isotropismof the materialasregards yield-point stresses. 22.Objections to tubes on account of w~nt of isotropy.23. Objections to tubes on account of large effect of defects.24.The system of Tests.25.The specimens and holders.26.The tension loads. 27.The application of torque.28.The friction of the torsion-rigging.-09.The application of the internal pressure.80. Measurement of the fluid pressure.31.A new type of pressure-gauge.32.Measurement of the distorsions.33.A new :Extensometer.34.Errors of extcnsometer.35.A new twist-measuring apparatus.36.Proof that the torsion-mirrors measure the twist.37. Effect of bending.38.As a transmission dynamometer.39.The diametral extensometer.40.Method of making the Tests.41.The determination of the sectional area and thickness of the tubes.4'2.Calculation of the stresses.43.Calculation of the strains.44.Maximum shear and slide are proportional