Failure Analysis

Roller Bearings, Railcar Owners and East Palestine

Posted on by jccarlton

Recently there was a derailment in East Palestine OH that has raised some controversy. This CNN video has most of the major issues.

Here is some NTSB Drone footage in another video

The ambulance chasers have come out and raised the controversy level to a high pitch already and are blaming Norfolk Southern for the derailment. But as usual, there is more to the story.

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What Will Happen If The Three Gorges Dam Fails

Posted on by jccarlton

Recently I have been seeing a lot of Facebook and Twitter post about the potential failure of the Three Gorges Dam in China. Most of the posts are speculating about total failure of the dam. This Twitter thread is a case in point:

I think that looking at a total dam failure potentially misses the more likely partial failure and I thought that I would look at some failures that don’t involve the total collapse of the dam, but are still very bad. Here is a simulation of what could happen if the dam fails.

To call it potential disaster is understating the case. A small dam failure in Jonestown PA is still talked about a century later as a major disaster. If Three Gorges fails, the scope of the disaster will be incalculable.

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So Why Did The Falcon 9 Go Boom?

Posted on by jccarlton

Thunder00t has a video here.

He has a rather snarky take on the anomaly and frankly I think he went a little overboard. He’s right that NASA hasn’t had a ground based failure since the old Atlas days.  So far until this happened SpaceX hadn’t had any fueling issues either.  So I don’t think that SpaceX is as incompetent as Thunderf00t seems to think that they are.

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So Why Did The Bulbs Fail?

Posted on by jccarlton

Dave Jones got some burned LED light bulbs in his mailbag.

https://www.youtube.com/watch?feature=player_embedded&v=V9tcC7Ks4_c#t=2402

He gives an interesting study of how they failed.  It turns out that it was a thermal issue rather than a component issue.  My question is why anybody would produce stuff that certain to fail.  Now if there were large assembly or component cost issue I could understand it, but the LEDs and resistors are going to cost within 1/10ths of a cent of each other and the bulbs are probably machine assembled.  So the issue has to come down to design.  I suspect that one problem is that it’s so easy to get Altium and make up a simple board like this.  And if you print out the board and light everything up it works just fine, for a while.  The design may have even been fine with the more expensive PCBs used for the prototypes.  Which was the same PCBs the first few batches had.

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