Degrees of freedom of leg

[konan90]

I am doing an FEA analysis on the human leg from femoral head up to lower tibia (excluding the pelvis and the ankle). I know where to place the forces but i don't know how to constrain the assembly.

 

[JohnRBaker]

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[BlasMolero]

Dear Konan90,
If you are an industrial user of NX, then consider the following suggestion:
You are studying a problem of full equilibrium between loads of action & reaction, then the INERTIA RELIEF feature is what you need.

Inertia relief is an advanced option that allows you to simulate unconstrained structures in the linear static solution with NX NASTRAN SOL 101, and in the linear static solution portions of SOLs 105 and 200. Typical applications of inertia relief include modeling an aircraft in flight, an automobile on a test track, or a satellite in space. The inertia relief method is a tool that you may not be familiar with.

Although the internal processing is somewhat complex, the interface to the inertia relief option is quite straightforward with NX NASTRAN. There are two ways to invoke the inertia relief:

• The first method is to specify the SUPORT entry explicitly by including PARAM,INREL,-1” in the Bulk Data Section.
• The second method (recommended) is to let NX Nastran select the SUPORT degrees of freedom automatically by including “PARAM,INREL,-2” in the Bulk Data Section.

Good luck and best regards,
Blas.

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

IBERISA
48011 BILBAO (SPAIN)
WEB:

http://www.iberisa.com

Blog de FEMAP & NX Nastran:

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[konan90]

Dear Blas Molero
Since it is the first time in my career that i come across with this problem i don't know what inertia relief is. What u say makes sense.

Thank you for your reply