The friction of a sliding tactile contact was measured in an apparatus which simulated a keyboard. Results were taken for several materials. The friction coefficient was found to decrease with increasing load and with increasing speed. Experiments at varying humidity and surface roughness helped to define the friction mechanisms. It is concluded that tactile friction is predominantly adhesive, but modified by liquid bridging between the ridges of the skin and the counterface. Increased bridging due to higher humidity causes increased friction from viscous shearing effects, while increased roughness allows fewer bridges to form, decreasing the friction.

A study is presented of the symmetrical steady‐state motion of a rigid shaft supported by two ‘short’ (Ocvirk) journal bearings. The equations of motion for a balanced or unbalanced shaft were solved using numerical ‘initial value problem’ techniques. Frequency analysis, which was used to determine the components of the steady‐state motion, confirmed that, for most conditions, the motion was asymptotically periodic comprising a small number of components—principally at synchronous and half synchronous frequency. However, a region of the operating space was found, in which the motion was complex and did not settle to a limit cycle. An estimate of the extent of this region is given and the suspected cause investigated.

A numerical solution method is described for the determination of oil film shape and film pressure in the lubricated contact between an elastic sphere rolling on an elastic plane. Steady loading and an isothermal film are assumed. The Reynolds equation (governing film pressure) and the elasticity equation (governing deformation) are solved simultaneously for a lubricant with the pressure-viscosity characteristic η = η 0 e αp treatment of the elasticity equation is described such that the deformation matrix is sufficiently compact. To give generality to the solution a set of results was subjected to multiple regression, which indicated that the influence of load on film thickness was very small. The regression results compare well with published data. The effect of restricting the amount of lubricant to the contact was also studied. The computed film shapes under such ‘starved’ conditions were found to be very close to those found by optical interferometry.

A study of the mechanics of ice friction was performed in which various theoretical models were compared to experimental results. Analytical models indicate that ice friction is affected by load, speed, ambient temperature, and thermal properties of the counterface material. All four parameters were varied and the results compared to analytical models with additional study using regression analysis. Conclusions indicate that under some conditions the friction of ice is subject to a thermal control mechanism.

The use of PTFE-faced pads in large vertical axis hydro-generators was pioneered in Russia in the 1970s, prompted by a series of failures of conventional babbitt-faced bearings. Some advantages claimed include higher specific loading, lower power loss and the omission of oil-lift facilities. There is strong interest in the Industry concerning this material, but limited data are available on actual performance. Some results from extensive testing of PTFE-faced pads are given, for two sizes of pad. These are compared directly size-for-size with results for babbitt bearings of nominally the same area. The power losses for the two types of bearing were found to be almost identical. Some of the effects observed during testing are described and discussed, including the effect of creep. The test results are compared with predictions using the GENMAT analysis software. A method of allowing for creep in numerical modeling is discussed.

The benefits of three-dimensional modeling of thrust bearings are described and illustrated with examples. Data are given for the convection coefficients on the back face of pads and attention is drawn to improvements in bearing performance given by reducing the thermal resistance of pads. The importance of pad support in large bearings is illustrated by a case study in which the size of the support disk is varied. Improved performance can be obtained if the disk is sized correctly. Further improvement is obtained if part of the disk support is cut away.

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A large number of variables are associated with the design of pivoted pad bearings that makes a generalised approach using charts most difficult. All design offices now have readily available on-line computer terminals that have access to library programs. The development of a library program for this type of bearing is described and discussed. The analysis considers the entire bearing as opposed to the superposition of results of individual pads. This simplifies the solution of the temperature field for each pad and allows the inclusion of turbulence, hot oil carry over and thermal and elastic distortion of each pad. The analysis is verified against three sets of independent experimental results. It is shown that the effect of pad bending is to lower the bearing damping so that the unbalance response is increased.