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Subject: Re: Gaussian points?
Author: Kim Ravn-Jensen
Date: 2001-05-14 03:56:00

I am sure that the answers are available to you in some textbooks
near you. Take the following brief clues for what they are:

--- In xansys@y..., "fea diff" wrote:
> I am relatively new to FEM field. Can anybody help me I have some
basic queries. answers to which I could not find.

> 1. FEM softwares solve for nodal displacements.

Yes, this is the basic part of it all.

The shape functions interpolate the stresses within the element.

Forget about stresses for now, they are a derived quantity.
Concentrate on understanding how the displacements are calculated.

> then what are Gaussian points?

They are inside the elements. They are used when, in your numerical
model, the system energy is expressed by means of the nodal
displacements. The system energy has a volume integral in it, and
Gaussian points are well-suited for discretizing that integral
(turning the integral into an algebraic sum).

> 2. In a spring element matrix K12 means the force at node 1
corresponding to unit disp at node 2.
> similarly for a 2D triangular element. what is the
interpretation?

The discretization of the above integral turns it into a matrix which
is multiplied with the vector of nodal displacements on both sides to
give the scalar quantitity of energy. The "K"'s are the elements of
that matrix - no more, no less. I like to state for myself that you
can watch displacements and you can experience energy(/work) - but
you can neither see forces nor stresses. These quantities come into
existence as something with which you multiply displacements in order
to obtain work.

Best regards
Kim Ravn-Jensen

Alfa Laval Copenhagen A/S - Maskinvej 5 - DK-2860 Søborg - Denmark
Phone: +45 39536000 - Direct Phone: +45 39536511 - Fax: +45 39536560
E-mail: kim.ravn-jensen@a...

> Sumit A.
> Graduate student.
> Pune.

Posts possibly associated with message #23727AuthorDateScore
23724Gaussian points?fea diff fea_diff@2001/05/14 
23727Re: Gaussian points?Kim Ravn-Jensen2001/05/140
23732Re: Gaussian points?David Gross2001/05/14 
30798DESOL and stresses on gaussian pointsJoseph Jeong2001/11/02 
30811Re: DESOL and stresses on gaussian pointss.ramprasad s.ramprasad@2001/11/04 
30847Re: DESOL and stresses on gaussian pointsJoseph Jeong2001/11/05