Maximum Load-carrying Capacity Research Articles

Failure of notched columns

A theoretical basis is given for recent experimental results[1, 2] for the maximum load-carrying capacity of sharply notched aluminum columns loaded eccentrically in compression. A failure criterion is developed. The failure criterion is successfully applied to 13·25-in. columns, of 1 2 - by 1 2 -in. cross section, which have notches of 0.170 in. depth or less.

The behavior of suddenly squeezed oil films

The behavioral characteristics of suddenly-squeezed castor oil films between convex steel surfaces were studied from the points of view of obtaining a continuous picture of the minimum oil film thickness, the maximum load-carrying capacity, the maximum pressure developed within the films, and the viscosity of the oil. The films exhibited great elastic properties. Light was the primary tool used in the investigation.

Paper 1: The Hydrodynamics of Flat Contacts: Friction Studies in the Pin and Disc Machine

The friction of run-in flat steel specimens lubricated with plain mineral oils has been measured in a pin and disc machine over a wide range of operating conditions. The hydrodynamic region was identified with the aid of electrical contact measurements and the corresponding friction data were considered in terms of the various theories which have been proposed to explain hydrodynamic action in nominally flat sliding contacts. It was concluded that the Lewicki inflow, the surface roughness, and the viscosity-density wedge mechanisms could not explain the observed friction; but that it could be explained if the surfaces formed a wedge whose angle was constant over the whole range of operating conditions. It is suggested that the wedge may be formed during the running-in process by mechanical effects such as flexural distortion. Particularly striking is the strength of the hydrodynamics which can occur in such ‘flat’ contacts: in terms of the wedge analysis the contact was operating close to the maximum theoretical load-carrying capacity. The implications with respect to the use of the pin and disc machine as a test rig are discussed and it is suggested that there might be a practical application in the design of ‘self-adjusting‘ slider bearings.