Bolted Joint Reliability with Jorg Albrecht

It is my pleasure to welcome Jorg Albrecht to the podcast, the managing director of Heavy Technologies.

What do you consider a bolted joint?

Any piece of the mechanical equipment or any component that’s got a financial hole that needs to be held together by a friend component or components.

 

How do we normally determine if a bolt is ‘properly in place’?

You step back in, and you see you see whether the thing is leaking, or whether there are flames coming out of it, or whether it is shaking itself lose. Put the right twerk on it. If everything else is done properly and you got the right materials, and everything is okay. Look at the condition of the threads, plant, and washers.

 

How do we measure clamping force?

One cannot rely on indication of the tightness of the twerk at both the joints. You have to do some quality assurance. Verify what has been done. Measure the result of the input of the twerking process. Trying to apply a twerk figure to achieve a certain tightness is like controlling the speed of your car by measuring the deflection of your accelerator pedal right. More critical applications require more control, so stream gauging is way at the tip where we have some critical applications. Measure the actual stressed. There are certain devices that measure stress e.g., direct tension indicators. Load cells and stream gauges as well. Measuring elongation is an effective way of verifying what you’ve achieved when you’ve twerked the bolt or when you compete with the big hammer.

 

Where do we get these elongation values?

There are standard calculations that can be done, but it all depends on how much force is required by that bolt. What elongation corresponds to a certain amount of clamp force? The engineer design should calculate how much elongation we should need for those particular bolts to fit the clamp force.

 

Can organizations get the equipment and know how to verify this?

It all depends on the on the criticality of the application. Critical applications involve safety, or reliability and productivity of a plant. Bring in the experts. We work around the world to support mechanical contractors in the field of support and insurance companies to do the verifications to set up the other systems, to ensure that the bolted joints are reliable. We do training in the field as well in this regard.

 

What do you want our listeners to take away from the conversation today?

Twerk is nonsense in terms of a metric of the bull’s tightness. Twerk does not define tightness. It is only an input in an effort to achieve tightness, the clamp force. It is the clamp force that keeps your joints together, and not the input force.

 

Eruditio Links:

• Eruditio
• HP Reliability
• James Kovacevic’s LinkedIn
• Reliability Report

Jorg Albrecht Links:

• Jorg Albrecht LinkedIn
• Hevii Technology LinkedIn
• Hevii Technologie
• Book: An Introduction to the Design and Behavior of Bolted Joints by John Bickford
• Book: Introduction to the Design and Behavior of Bolted Joints, Fourth Edition: Non-Gasketed Joints by John Bickford

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