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Computational Mechanics Forum

Linearization procedure in nonlinear FEM

Submitted by phunguyen on
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Computational Mechanics Forum

Hello,

As far as I know, there are two ways to derive the linearized equations (employed in the Newton-Raphson method) in nonlinear finite element methods. 

In the first approach, starting with the weak formulation, the FE approximations are substituted into the weak form, you then get the semi-discrete equations. After that, the linearization is applied on this discrete equation to get the tangent matrix. The book of Prof. Ted Belytschko followed this approach.

Change density in Abaqus subroutine

Submitted by perzo on
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Computational Mechanics Forum

Hi



I have a question about possibilities implement
user-material subroutine included changing material density. I have
thermal problem where I should assume diffrent density. I would like
implement changing density in every material element and watching
strain distribution as a result of diffrent density.

Is it possible in Abaqus? If yes which subroutine i should use.      



Thanks for help

How to define a displacement rate as a pressure uniform load?

Submitted by Gadoo on
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Abaqus 6.7-1



Dear All,

I would like to simulte a 2-d tension test which has been conducted using a displacement rate 1mm/min till failure. Can some one explain how to define this displacement rate using Abaqus 6.7? Also, I would ask another question, can this displacement rate be considered as a vilocity? and can be modeled as a velocity field?

Regards,

M. G. H

McGill University, Canada 

ABAQUS shell element stress output

Submitted by PJtree23 on
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ABAQUS shell S4 stress

Hello,

 

I am running ABAQUS EXPLICIT to simulate aortic valve function.  I created a model using hex shell elements.  When the simulation is complete the output contours are in U,Magnitude, in the list of primary variables to show; there are a few other options, put they are all of kinematic/dynamic nature, there are no options for material stresses or strains.

 

I want some informations about computational mechanics as i want to do my master's in this field

Submitted by Zahidul Mustakim on
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Computational Mechanics Forum

Hello Everyone,

I am Md. Zahidul Mustakim from Bangladesh. I have graduated in Mechanical Engineering and I want to pursue my Master's Study in the field of Computational Engineering/Mechanics. As i was not familiar with this field in my undergrad study I really dont know much about this subject. I would be really grateful if You please send me some informations about the points mentioned bellow:

1. Is computational Engineering same as Numerical Simulation?

Applying Non-Uniform Distributed Forces/Pressures in Abaqus

Submitted by andycph on
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ABAQUS

 I am working on a problem involving wind-tunnel testing of a component. Basically, the component has numerous pressure tappings on its surface to measure the pressure in the wind tunnel. I am required to apply these pressure measurements into the Abaqus model. I am looking for some suggestions as to how best to accomplish this. Basically, the output from the pressure tappings looks like this (I moitted some details...):

Stress Terms of a Visco Hypoelastic formulation for FEA.

Submitted by shrimad on
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Visco hypoelasticity

Hi all,




I am implementing visco-hypoelasticity in my FEA code for my research as


given in the 4.8.6 ANSYS manual.




I have relaxation only in the shear modulus and not in the pressure. The


manual doesn't give the explicit expression for the shear elastic stress


term and the pressure stress term. I extrapolated the expressions from what


is given, and the code is not working properly. Can you please tell me if


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