Flange bolted connection Analysis

[Gokulkrishna]

Hi All,

I had a doubt about performing an FEA on an Flange bolted connection.

The flanges are designed as per ASME B16.5.

Line Size: 24in 900ANSI
MOC: A182 F316L
Stud and Nut: B7 & 2H
Torque on stud: Stud is tensioned to 50ksi and the torque applied is 8782 ft lbs (I converted this torque into force so as to apply bolt preload on the stud by using the fomula T=KPD
T = Applied Torque
K = coefficient of friction for Shank & threads = (0.152)
P = force = 277326 lbf (calculated force)
Applied this calculated force on the studs as Bolt Preload in the FEA.

The gasket we use is CPR-HF by flexitallic (

http://flexitallic.com/uploads/files/flyCprHf.pdf).

This is of composite material. PTFE, SS 316 and graphite.

The issue I'm currently facing is that I dont have the material properties of PTFE and graphite. Can someone help me on this?

Also I saw that there is an option to create an Gasket material in NX Nastran. Can someone guide me on how to perform Analysis when there is a gasket involved?

I'm using Solver NX NASTRAN SOL 101 Linear Statics – Global Constraints.


Thanks & Regards,
Gokulkrishna

 

[BlasMolero]

Hello,
Bolt preload is a load you can define in the SIM environment of NX ADVSIM. In the FEM you have to create CBAR elements to simulate the bolt, spider elements (rigid elements RBE2) between bolt head and part and bolt nut and part, and finally in the SIM you have to define contact surface-to-surface between the flanges of the bolted connection.

GASKET is a nonlinear model material only available in the ADVANCED NONLINEAR module (SOL601).

Best regards,
Blas.

~~~~~~~~~~~~~~~~~~~~~~
Blas Molero Hidalgo
Ingeniero Industrial
Director

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