Mechanical Components Example

A mechanical component was put into an accelerated test with temperature as the accelerated stress. The following times-to-failure were observed.

Determine the parameters of the Arrhenius-Weibull model.
What is your observation?

Solution to Example 3: Mechanical Components Example

The parameters of the Arrhenius Weibull model were estimated using ALTA with the following results:

β = 1.771456, B = 86.273322, C = 1170.142567.

A small value for B was estimated. The following observations can then be made:

Life is not accelerated with temperature, or
the stress increments were not sufficient, or
the test stresses were well within the “specification limits.”

A small value for B is not the only indication for this behavior. One can also observe from the data that at all three stress levels, the times-to-failure are within the same range. Another way to observe this is by looking at the Arrhenius plot. The scale parameter, η, and the mean life are plotted next.

It can be seen that life (η, and the mean life) is almost invariant with stress.