Factors Influencing the Fatigue Strength of Materials

A number of factors are considered which influence the static and fatigue strength of materials under practical operating conditions as contrasted with the relations obtaining under conditions of the usual testing procedure. Such factors are interruptions in operation, periodically fluctuating stress limits and mean stresses with periodic succession of several groups and stress states, statistical changes and succession of stress limits and mean stresses, frictional corrosion at junctures, and notch effects

Wrinkling Phenomena of Thin Flat Plates Subjected to Shear Stresses

This report covers a series of tests on thin flat elastic strips restrained at two parallel edges and subjected to shear by conversely directed stresses. Theoretical treatments, particularly those of Lilly, Southwell and Skan, and Timoshenko are briefly outlined. The problem to be solved by these tests was to find out whether, and to what extent the conditions and assumptions upon which the calculations are based are complied with in the tests. Three materials were used: celluloid, duralumin, brass. Owing to the high elastic deformability of celluloid, it was not only possible to observe the beginning but also to ascertain the type of deflection. The test data on celluloid was affirmed by the experiments with duralumin and brass

NACA Technical Memorandums

This report covers a series of tests on thin flat elastic strips restrained at two parallel edges and subjected to shear by conversely directed stresses. Theoretical treatments, particularly those of Lilly, Southwell and Skan, and Timoshenko are briefly outlined. The problem to be solved by these tests was to find out whether, and to what extent the conditions and assumptions upon which the calculations are based are complied with in the tests

NACA Technical Memorandums

"A number of factors are considered which influence the static and fatigue strength of materials under practical operating conditions as contrasted with the relations obtaining under conditions of the usual testing procedure. Such factors are interruptions in operation, periodically fluctuating stress limits and mean stresses with periodic succession of several groups and stress states, statistical changes and succession of stress limits and mean stresses, frictional corrosion at junctures, and notch effects" (p. 1)

La deformation plastique du zirconium au cours de l' oxydation

La déformation des tôles et des tubes produite lors de la corrosion du zirconium ou de ses alliages a été décrite dans de nombreuses publications. Bien des auteurs affirment que la déformation n'apparait de toute façcon qu'après la transformation noir-blanc. Par contre, nos essais montrent clairement que pendant l'essai de corrosion la déformation apparaît dès le début de ce phenomene. Ceci s'applique tant aux tubes qu'aux tôles fines d'utilisation courante (de l'ordre de 1 mm). Dès le début de la corrosion, ils subissent des tensions multiaxiales pouvant dépasser la limite élastique, ce qui conduit à la déformation plastique du métal. Ceci explique que la résistance à la corrosion du zirconium et de ses alliages est fonction de la résistance à la déformation, c'est-à-dire des propriétés mécaniques à la température de service. Dans le cas des assemblages, il est possible que cette déformation soit considérablement freinée par les conditions d'assemblage