Page 202 - Tribology in Machine Design

Sliding-element bearings 187

neglected, i.e. the pad is assumed to be infinitely long. Let

ft = the mean thickness of the film,
h + e = ihe thickness at inlet,
h — e = the thickness at outlet,
A = the thickness at a section X-X, at a distance x from the
centre of the breadth, so that

Adopting the same procedure as that used in fluid mechanics

Suppose x' is the value of x at which maximum pressure occurs, i.e. where
dp/dx=0, then, for continuity of flow

so that

Similarly shear stress

so that

Integrating eqn (5.30), the pressure p at the section X-X is given by

where x' and k are regarded as constants. As dA/dx = — 2e/B, this becomes

The constants x' and k are determined from the condition that p=0 when
x = ± %B, i.e. when X = h — e and h 4- e respectively. Hence