How many disasters and faillures from bad material choice? 4

[enginesrus]

I can think of and have seen many failures, due to engineers choosing the wrong materials to make or build the devices from.
Lets start naming some.
I'll start out with the use of flammable magnesium castings in old aircraft engines.

 

[Enable]

Thanks comcoskid for that example. Super interesting

CWB (W47.1) Div 1 Fabricator
Temporary Works Design

https://www.enable-inc.com/

 

[CWB1]

That's kind of like a hot water heater….Hot water doesn't need heating

Hot water needs heating if you want it to stay hot. My hot water heater cycles to heat the hot water regularly, if it didn’t I would replace it.

Agreed tho, it is like saying wood stove, gas stove, electric stove, gasoline engine, diesel engine, nuke power plant, etc…..adjectives are good.

 

[waross]

Almost all of the wood burning stoves that I have seen had a heat exchanger installed in the side of the fire box for hot water. water from the hot water tank circulated through the heat exchanger by convection.
A couple of old stoves that did not have the exchanger installed had provision for adding a heat exchanger.
As the combustion process consumed oxygen, make-up air infiltrated into the house.
On cold winter days, the moisture content of the make-up air could be extremely dry.
Without mitigation, the RH could drop to uncomfortable low levels.
It was always my understanding that the right-hand tank, furthest from the heat source, was intended to add moisture to the air and bring the RH up to a more comfortable level.
Is this suggestion compatible with your observations, John?

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[thebard3]

Hot water doesn't need heating. -- George Carlin

I hoped everyone would realize that was supposed to be humorous.

Brad Waybright

The more you know, the more you know you don't know.

 

[JohnRBaker]

waross, yes that's true, it helped keep the humidity at a reasonable level, but I can remember my mother telling us how if we needed some extra hot water, it was there. Now that thinking may have been left over from where we lived when I was born. At that time, and up until I was five-years old, we had no lights or running water. The only hot water was what you heated on the stove, so in that case the water reservoir really was an additional source of hot water, especially if you didn't want to wait to heat a pan of water.

John R. Baker, P.E. (ret)
EX-'Product Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[ehbadger]

Comcokid (Electrical)21 Oct 21 00:59
This thread is titled "How many disasters and failures from bad material choice?"

But what is more interesting is Engineering Failures that resulted from too good a material.

Had an example of this at my plant a while back.
Used Tantalum-lined piping (big $$) in one unit, some was installed in a methanol service after a recovery column.. turns out super "dry" MeOH pits tantalum and you need some small fraction of water content to avoid it. Now SOP is to run the column slightly "dirty" and force some water carryover to protect the piping.

 

[oldrunner]

Welding on stress proof steel. One 200 ton stiff leg failure of mast base - hurt the operator. One curved concrete bridge elevated section for the old 280 highway in SF. C-bracket broke because fabricator substituted a stress proof rod which included some welding for another high strength steel without telling anyone. Two cranes were picking the section when the bracket broke and load turn sideways. They got it on the ground before the load was lost.

 

[Alistair_Heaton]

They have done away with the side hot water heaters here on the wood cooking ranges.

Result the RH drops to under 5% when its -20 deg C outside. And then they wonder why their wooden house basically eats its self and flooring needs to be replaced every 3 seasons.

With the fire on I need about 8 ltrs of water per hour to keep the RH at 30%

 

[waross]

How about disasters because the engineering is too good.
Up until the late 40s to early 50s, most US cars had solid front axles.
The ride was quite rough compared to independent front suspension.
In 1949, Ford came out with a new model passenger car.
It was lower and quieter than previous models and had a very smooth ride due to the introduction of independent front suspension.
My Grandfather told me of heading north from Winnipeg on a hunting trip on the first day of the season.
He said that at almost every curve or turn on the highway there was a new '49 Ford in the ditch.
The first time out on the highway in the new car.
Due to the smooth and quiet ride, the drivers were going much faster than they should have been until they missed a corner.
Forward 12 years and it was GM's turn.
They introduce torsion bar independent front suspension on heavy trucks.
The result? Drivers driving too fast on rough roads and doing damage to the rear axles and rear suspension.
I am not sure about 1962 but the 1963 models were back to the solid front axle design.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!