Bolted joint diagram - Short explanation close to PERFECT!

[@blu3fish]

I can't even express how much value this video has, you did a great job! thank you and wish you luck

[@cooperjio]

I could never understand this diagram when my professor explained it in German as I´m a non-native German speaker, thankfully I found your video & finally could I understand! Brilliant explanation Nicos

[@nicosfinanzschule84]

I'm very happy because of your compliment! Thanks a lot, Cooper Jio!

[@lewis72]

It does take a while to get your head round a bolt diagram, even if explained in your own language !

[@hubertkaka7567]

Nicos this is great explanation. Is it possible for you to make also a video with the example? It would be great to see how clamping height influences the residual clamping force. It would perfectly explains why bolt extenders are in use.

[@shankhashubhragiri4541]

he is my professor at the uni and this translated video helps me so much more to understand it clearly.

[@mixedsurface]

Very helpful explanation. Thank you for posting!

[@abinashmohapatra4147]

Nicos, great explanation. Looking forward to more videos on bolted joint!

[@sandurful]

Awsome explanation.. Thanks for sharing this information..

[@rakshithpoojari9988]

Thank you for the video. please make video on how to calculate tightening torque and Pre load as per VDI 2230. It helps a lot

[@fabriziotroisi3818]

Very nice explanation, thanks.

[@Mahawisdomsaga]

what will be the impact, if we add gasket of thickness 0.5mm in b/w the plate

[@nicosfinanzschule84]

A gasket is often made of a soft material. When it is placed between the plates, the axial stiffness of the plates will be greatly reduced, i.e., the slope of the line describing the deformation behavior of the plate will decrease, it's curve will become flatter. The ratio of bolt stiffness to plate stiffness will decrease accordingly. The proportion of additional axial operating force F_BA acting on the bolt will increase, which can be critical. The unloading of the plates F_PAwill be less, which is probably more positive in terms of residual clamping force F_CR and sealing performance.

[@lewis72]

How can you know the joint stiffness of the plates ? The plates will not compress uniformly as they'll compress the most directly under the bolt heads but then less as you move away from the bolt underhead region. I generally just model it in CAE.

[@nicosfinanzschule84]

Your are right and this is not simple to calculate. It depends from the design of the plates, the distance of the screw from the plate borders and the load application point. You can find an analytical procedure in the actual german standard VDI 2230 "Systematic calculation of highly stressed bolted joints" Part 1: Joints with one cylindrical bolt.

[@josealvim4762]

I'd like to know what happen when we use a TTY torque pre-load. There is no more elasticity in the bolt, but they say it's good for fatigue!!!

[@nicosfinanzschule84]

Your comment is correct at first glance. However, it is also important to consider that the torsional stress in the screw decreases over time due to relaxation processes, allowing for dynamic loads. See one of my newer videos about relaxation. Essentially, yield-controlled tightening aims to minimize all tolerances resulting from friction and strength variations, which can result in significant over-dimensioning. Therefore, it is acceptable to tigthen to the limit during assembly.

[@bonusben3486]

good video overall, but some small mentions to everyone with extra questions: what is shown in the second half of the video only applies, when the external force is applied on the outside of the plates. if it applies to somewhere inside the plates, or the inside boundary, the outside part is considered as part of the bolt stiffness. head and nut stiffness arent mentioned in the video, but are also accounted toward the total bolt stiffness. to calculate the stiffnesses of plates and bolt, there are common formulas to estimate the effective area of the compression/elongation. for the plates, these depend on the total area (relative to the bolt diameter) surrounding the bolt. if instead of a nut, the plate is threaded, then the used part of the thread is considered as a nut, with the remaining inside part of the plate being considered normal plate. incase setting is considered, the minimum expected assembly force should be pretension force plus setting force. the setting force is calculated from stiffnesses and setting distance, which depends on survace roughness and is estimated with tables. setting can take place on any contact survace.

[@nicosfinanzschule84]

Your are right. Here, the most simple case i s shown. If you want to see, what happens, when the load is not applied directly under the bolt, you can watch the Video "Der Krafteinleitungsfaktorn bei Schraubenverbindungen" in this series. To calculate the stiffness of screw and plates, I reccomend you the actual german standard VDI 2230 "Systematic calculation of highly stressed bolted joints" Part 1: Joints with one cylindrical bolt, issued by the German Society of Engineering Verein Deutscher Ingenieure. There you can also find values and examples to calculate preload changes due to embedding.

[@philb912]

Very good video. I'd like to know though, is "e" in mm or in mm/mm ?

[@nicosfinanzschule84]

"e" is a physical length. It's unit is "mm" or "µm" (from the European perspective).

[@rakshithpoojari9988]

In case of bolted joint with external tensile load, why part of Fo is required to release the compression of the joint. As we apply tensile load on Bolt it will elongate hence compression on the joint is automatically released as its still within its elastic limit. Please clarify this

[@nicosfinanzschule84]

The fraction of Fo isn’t necessary to relieve the plates. That occurs automatically, indeed. However, as it’s a system of interlocked preloaded stiffnesses, the external load acting on the screw also results in the relief of the plates. Consequently, the fraction of force previously required for compressing the plates is no longer necessary. Therefore, the screw is relieved by this amount, and only a fraction of the external force acts additionally on the screw. These two components, relief and additional load, distribute in proportion to the two stiffnesses.

[@xaviergonzalez5828]

Best video ever Sir! Thank you!!!!

[@jagadeeshmadugula5651]

Good explanation, please upload remaining bolt joint videos in English, very helpful in understanding

[@APAPictures]

Very nice explanation. Can you make other bolted joint video in English? Thanks

[@dance5875]

Excellent video

[@johncrow5552]

4:55 "drops below the required clamping force" how do you know what the required clamping force is?

[@nicosfinanzschule84]

The required clamping force is not an inherent characteristic of the screw connection but a requirement imposed on the screw connection based on its application. This could, for example, be a minimum clamping force for a static seal or a minimum contact force to ensure frictional force transmission.

[@amatoallahouchen5894]

nice one ! thanks a million!

[@gurwinderachal]

Vielen Dank explained in simple words

[@pankajsadavarte3158]

nice Explanation

[@fatiherkoc4203]

Gibt es dieses Video auch in Deutsch

[@abraxas596]

Ja, im gleichen Kanal: Schraubendiagramm erklärt in 4:44 min!

[@prabhurao751]

how to calculate pretension in bolted joint??

[@abraxas596]

Rule of thumb: 90% of the bolts yield stress

[@homaebrahimian2525]

Perfetto!!!!!!!!!!!!! Grazie Mille!!!!!!!!

[@milanhin5024]

Thank you!

[@omarsh3150]

You are amazing 👏 ❤ 💖

[@Sibasish07]

ABSOLUTE GOD!!

[@beatspop9815]

Add subtitles

[@nicosfinanzschule84]

Done!

[@anirudhkatti699]

His accent is so difficult to understand

[@nicosfinanzschule84]

I'm sorry, but I try my very best!