failure analysis

Tacoma Narrows Bridge Collapsing in 7 November 1940

Tacoma Narrows Bridge Collapsing (video)

The concept of failure … is central to understanding engineering, for engineering design has as its first and foremost objective the obviation of failure. Thus the colossal disasters that do occur are ultimately failures of design, but the lessons learned from those disasters can do more to advance engineering knowledge than all the successful machines and structures in the world.” (To Engineer is Human – The Role of Failure in Successful Design, by Henry Petroski).

The Science Love Song
We can take it fast or really slow
But we can’t know with certainty where we’ll go
If at first we don’t succeed, we’ll try two more times
So our failure’s a statistically significant try

Some organizations specializing in failure analysis

  • National Transportation Safety Board (NTSB) – 10 most wanted list
  • Failure Analysis

What’s the problem?
Tacoma Narrows Bridge (video 4:12) – The Tacoma Narrows Bridge opened to traffic on July 1, 1940. Its main span collapsed into the Tacoma Narrows four months later on November 7, 1940, due to a physical phenomenon known as aeroelastic flutter caused by a 42 mph wind. This video is still shown to engineering, architecture, and physics students as a cautionary tale.

  • Ask – What were the factors that caused the bridge to fail? What did engineers learn from this?
  • Imagine – What were all the things that might have cause the bridge to fail? Many believed this was an example of elementary forced resonance with the wind providing an external periodic frequency that matched the natural structural frequency, but was not the actual cause.
  • Design, Build – The cause of the bridge’s failure was determined to be aeroelastic flutter. The towers and side spans—which survived the collapse of the main span were damaged beyond repair.
  • Improve – Its failure also boosted research in the field of bridge aerodynamics/aeroelastics which have themselves influenced the designs of all the world’s great long-span bridges built since 1940.

That’s engineering

  • Dependability, or reliability, describes the ability of a system or component to function under stated conditions for a specified period of time

Engineering ideas

  • system, component, failure, analysis, reliability, dependability, design, case studies