Engineering Failures and Excessive Vibrations

How about a plane crash due to fatigue?

Hey! that is a good case study on Engineering Failure caused by excesive vibrations. So Far no body did that... I think so..

Hello,

There is an excellent book that you should read called 'Why buildings fall down'.

It gives a whole host of studies of different accidents and their root causes. You should be able to find a topic in there and expand on it. Good Luck.

Graduates of Canadian Engineering Schools are given an iron ring. Originally the rings were made of steel recovered from a bridge failure as a result of engineering miscalculation in the province of Quebec. I guess the bridge wasn't that big, because now there are not made of the bridge.

The failure of that bridge would be interesting.

However you could look at failure mechanisms of honeycomb core sandwich panels by fatigue. You will find it an interesting subject and will demonstrate to you why these structures form such an important part of the aerospace industry. An area you may well want to pursue a career in.

Cheers,

Bloefeld

considering that you did not specify what specific engineering you are studying I would suggest that you look at vibration failures n bearings. Nearly all engineers, regardless of specialty have to deal with rotating stock. proper alignment of shafts in pumps, motors and thrust bracing is not given enough attention in the education process, as with much of engineering, there is not enough time in college to delve deep into every topic. Pumps fail, Motors burn up and even Helecopters crash due to failure of bearings. There is wonderful information in print and on the internet if you decide to look into vibration induced bearing failure of rotary equipment.

Good luck.

In (March ?) 1953, the 1st of a series of British Comet aircraft crashed due to, or were found to have excessive metal fatigue due to harmonic vibration, etc....

...the Comet fuselage (and crash) failure was due to fatigue from pressurization and depressurization cycles...

And to the form of the windows which increased stresses at the corners not rounded enough.

You can make a career studying vibration failures in rotating equipment, I always ran into compressor vibration experts. Those failures are always pretty interesting.

If you want to do it on aircraft, the NTSB just recommended to the FAA to prevent further flight of Zodiac CH-601XL, in part due to control flutter. More info can be found here:

http://www.ntsb.gov/Pressrel/2009/090414a.html

http://tech.flygsw.org/flutter.htm

Another case you might look at is compression, and high rpm reciprocating compressors, all kinds of vibrations and failures there, structural, mechanical, material. Just an idea.

How about rigid motor mounts?

It would be rather helpful to know what engineering discipline you are studying so the responder knows the context of your perspective. For instance a mechanical engineer will worry when things aren't moving, a civil engineer is worried when things are moving, and a metallurgical engineer worries when either the mechanical or civil engineer are assuming homogenity in the alloys they are using.

Seismic vibrations would seem to be a rich area. There is plenty of material available for study, but quite frankly, there is a lot more to be done. There are a lot of people whose lives are potentially affected by seismicly induced vibration failure.

Consider any of the bridges, buildings, etc that fell down in the last "big one", as well as those that stayed up.

Working out a good, low cost, reliable joinery method would be a huge contribution. There are methods now, but they look like a fresh set of eyes might do well.

Another famous aeronautical failure related to vibration is the case of the Lockheed Electra.

The aircraft was designed to have radial engines, but turbine power came along so they were used instead. The much lighter turbines had to be mounted much further forward than the radials in order to maintain the correct CG, so they are mounted in long nacelles.

So anyway they applied large amounts of torque to the wing structure in turbulent air and in hard landings. This resulted in work-hardening of the wing spars.

Several planes lost wings in turbulence before anyone figgered it out.

Vibration...excessive weight who knows...The 35W bridge collapse would be a great research study. Even the TSB came up with conflicting results. Under designed from the beginning, built on shacky ground and never inspected over the years. You've heard of the collapse ???

Twin Towers is another one .

Hello,

If this project is still alive, I have a suggestion. I read years ago about the V-22 Osprey Aircraft in a Popular Science Magazine. This tilt rotor aircraft was to replace Helicopters for the Navy and Marines.

There were a number of fatal crashed caused by Hydraulic and software failures. I think that vibration was a cause of at least one of the failures or a result of the afore mentioned reasons. There was a problem as the rotors were being tilted and the craft experienced an uncontrolable vibration. It might be worth investigating.

Go to http://www.dragonfly-windturbine.com/DragonflyWindTurbine.html and find Project 2 on the website, where it references a 1941 wind turbine. There are also photos from the more modern one that failed, though I don't know whether vibration per se, ordinary fatigue, or something else was the root cause on that one. Old Gravely [brand] mowers with sickle bars used to shake themselves apart, loosening nuts & bolts routinely (we used to check a series of the worst ones every time we refueled! We'd carry wrenches and a few fasteners in our pockets when we mowed). Converted horse-drawn sickle bar mowers used behind tractors were not much better, but usually had enough wooden parts to damp things more. Any product class with an inherent imbalance might be a starting point. Ornithopters, anyone? See http://www.earlyaviator.com/archive1.htm for a variety of designs.