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Conductive Heat Transfer Across a Bolted Automotive Joint and the Influence of Interface Conditioning

Shocks, Springs, Brakes, Frame, Body Work, etc

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BigBlockMopar
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Re: Conductive Heat Transfer Across a Bolted Automotive Joint and the Influence of Interface Conditioning

Post by BigBlockMopar » Thu Jan 16, 2020 3:00 pm

Interesting stuff.

How about this Bolt-pressure sensor?
https://www.sensorprod.com/tactilus/bol ... icator.php
(I could think with angle milled heads for instance)

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Re: Conductive Heat Transfer Across a Bolted Automotive Joint and the Influence of Interface Conditioning

Post by LoganD » Wed Jan 22, 2020 9:26 am

Bolted joints are an insane rabbit hole that can take over your life if you get into the hardcore engineering of it.

We've got a team of people who ONLY do bolted joint analysis, the information form we have to fill out and submit to have our setup analyzed makes you realize there's things you would never consider in the design. It's insane. It also makes you realize that many companies, even ones you might consider high quality, get it very wrong. Tough stuff.

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Re: Conductive Heat Transfer Across a Bolted Automotive Joint and the Influence of Interface Conditioning

Post by n2xlr8n » Fri Feb 28, 2020 10:36 am

LoganD wrote:
Wed Jan 22, 2020 9:26 am
Bolted joints are an insane rabbit hole that can take over your life if you get into the hardcore engineering of it.

We've got a team of people who ONLY do bolted joint analysis, the information form we have to fill out and submit to have our setup analyzed makes you realize there's things you would never consider in the design. It's insane. It also makes you realize that many companies, even ones you might consider high quality, get it very wrong. Tough stuff.
I totally agree- Though I'm not a ME, I've had experience with OEMs stating that the proper amount of torque applied to a fastened joint was measured by the flattening of the lock washer fitted on the nut side. I showed them it could take as little as 7 ft/lbs on a 3/4" fastener to flatten the lock washer...crickets ensued.
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Re: Conductive Heat Transfer Across a Bolted Automotive Joint and the Influence of Interface Conditioning

Post by Kevin Johnson » Fri Feb 28, 2020 9:02 pm

They might have been confusing Belleview washers with simple lock washers. Might not have taken good notes that day in class. :-k

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Re: Conductive Heat Transfer Across a Bolted Automotive Joint and the Influence of Interface Conditioning

Post by Rick! » Sat Feb 29, 2020 8:44 am

LoganD wrote:
Wed Jan 22, 2020 9:26 am
Bolted joints are an insane rabbit hole that can take over your life if you get into the hardcore engineering of it.

We've got a team of people who ONLY do bolted joint analysis, the information form we have to fill out and submit to have our setup analyzed makes you realize there's things you would never consider in the design. It's insane. It also makes you realize that many companies, even ones you might consider high quality, get it very wrong. Tough stuff.
Bolts in bending - bad.
Bolts in single shear - ok.
Bolts in double shear - better.
Bolted joints designed to use local stiffness to carry the load while the bolt just applies clamp - more better.
Sometimes applying more bolts or 12.9's doesn't necessarily make the joint better.
The best designed bolted joints can be easily defeated by manufacturing's selection of a torque tool.
One of the most accurate torque tools is a skilled person's sense of feel during the process.

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