T-H Acceleration Factor

The acceleration factor for the T-H relationship is given by:

$images\9_4_1.gif$

where,

ˇ $images\luse.gif$ is the life at use stress level,

ˇ $images\laccel.gif$ is the life at the accelerated stress level,

ˇ $images\vu.gif$ is the use temperature level,

ˇ $images\va2.gif$ is the accelerated temperature level,

and,

ˇ $images\ua.gif$ is the accelerated humidity level,

ˇ $images\uu2.gif$ is the use humidity level.

The acceleration factor is plotted versus stress in the same manner used to create the life vs. stress plots. That is, one stress type is kept constant and the other is varied (see Figures 3 and 4 below).

$images\accfactstress.gif$

Fig. 3: Acceleration factor vs. temperature for a fixed relative humidity.

$images\accfacrelhum.gif$

Fig. 4: Acceleration factor vs. relative humidity for a fixed temperature.