[M.D. Holloway]

I was trying to explain failure the other day during a seminar I was giving. Basically all failure modes can be broken down (sorry for the pun) into a few basic conditions. Here is what I came up with. Mind you, it is part original and part known stuff floating around in very materials engineering textbook. I don't think I am missing anything let me know what you think and if you can back-up your arguement then I will include it in my next seminar!

I figuer there are four sources of failure – man, method, machine and material.

From these four sources spring forth the manifestations of failure. There are hundreds of reference books dedicated to failure analysis. Many of these texts are rich with equations, explanations and examples of hundreds of failure modes. After reading through a few dozen of these it became very obvious that failure can be broken down into basic elements regardless of the item.

Every failure is a combination of a change and an influence as well as a cadence, articulation and affect. Thousands of combinations can be the culprit which makes failure analysis an almost impossible effort unless you were to break it down to basic elements.

Various items fail for different reasons. When something fails or breaks, it is doing so because of the following physical Change:
• Deformation
• Fracture
• Rupture
• Molecular Transformation

Change occurs because of the following Environmental Influence:
• Force
• Temperature
• Time
• Chemical

These Influences have a Cadence:
• Steady
• Random
• Cyclic

The Cadence can have variations of Articulation:
• Amplitude (strong to weak)
• Frequency (fast to slow).

All of which Affect:
• Surface and work inward
• Inside and work outward
• Entire part, material, device or tool all at once.

Failure can have one or more primary Changes and Influences as well as one or more secondary Changes and Influences.

Failure can be a combination of several influences which alone would not facilitate change but in concert would bring about a manifestation of failure.

Describing the failure mode considers all of these. If a part fails on the surface due to a slow, steady, chemical / molecular transformation it may have experienced surface rust. That’s a rather long-winded description for something that is very common and understood with two words but the taximetrics of failure are actually very important in understanding, categorizing and potentially eliminating the opportunity for failure.

So whats missing?