Bolt analysis, applying preload
Bolt analysis, applying preload
(OP)
I am trying to figure out if there is a way to apply a preload to a part in solidworks that is a bolt. We already modeled all of our fasteners to replicate minor diameter to see what the max stress is, but now I want to apply a preload to the bolts. I see that there are bolted connections you can use, and also you can use toolbox items, but what about a part model that is a bolt. I am not seeing an option for that anywhere, maybe we are doing the analysis incorrect? Any input would be appreciated.






RE: Bolt analysis, applying preload
Pre-loading of bolts can be achieved using connectors. But, that would be for simulating the joint, its effects, per se.
In your case, you are looking at the bolt itself. Then the approach is to model using gap/contact with pressure loading on the bolt / plate/washer interface appropriately to establish force equilibrium and run the analysis.
Normally, you can ascertain whether the loading was achieved by comparing the results of FEA to axial stress calculations to check convergence and efficacy of the contact boundary conditions, you have provided.
In such situations, when bolt stresses are involved, it is typically the fluctuating stress components, arising out of bending that tends to create havoc.
Hope this help,
Best regards
Nat
Natarajan Ramamoorthy
Design Engineering Consultant
www.egsindia.com
RE: Bolt analysis, applying preload
RE: Bolt analysis, applying preload
http://blog.gxsc.com/graphics_systems_solidnot/2013/09/bolted-joints-in-fea.html
RE: Bolt analysis, applying preload
Shigley's Mechanical Engineering Design Chapter 8 "Screws, Fasteners, and the Design of Nonpermanent Joints" and Bruhn's Analysis and Design of Flight Vehicle Structures Chapter D1 "Fittings and Connections. Bolted and Riveted." are my go-to references for bolted joint analysis.
RE: Bolt analysis, applying preload
The other approach is to use a temperature delta applied to the part to create a preload... (taking advantage of the shrinking what occurs when something is lowered in temperature). I haven't used this yet because my first trick has provided what I needed, but it is a good option I'm keeping in my pocket if I end up needing it...
RE: Bolt analysis, applying preload
Build a model i na new file and apply a temperature load that will shrink your bolt. In interative way you will know how temperature you have to apply to get desired pretennsion and then apply it to your work-model.
It's quite easy and works for sure in NX Nastran.
Naval Architect/ Structural Engineer