Gurudutt Chandrashekar's blog
https://imechanica.org/blog/20998
enA question on Residual Load Vector in Abaqus User Element Subroutine implementation
https://imechanica.org/node/8970
<div class="field field-name-taxonomy-vocabulary-6 field-type-taxonomy-term-reference field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/taxonomy/term/76">research</a></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>
Hello all,
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I am implementing a Finite Shell element in Abaqus as a User Element. I have a question regarding the Residual Lod vector that has to be defined in the User Element Subroutine.
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We know that K(du)=R-f where R is the external force vector at time t+dt
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f is the internal force vector at time t which depends on the present stress state
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K is the stiffness matrix in the present configuration and du is the displacement incremen from time (t) to (t+dt)
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The above equation is for a non linear analysis.
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Now, if I am doing a non linear analysis ,how exactly do I specify the external force vector in the UEL subroutine?. The external forces are sent as an input from the input file. If I need to write the code for the residual load vector then I must be aware of the external forces as well. The two examples in the Abaqus documentation on UEL subroutine just multiply the stiffness matrix with the displacements and equate it to RHS (residual force vector). I do not totally understand this point.
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<ul><li>If I am doing a displacement based analysis,where I constrain some nodes and apply displacements at other nodes and apply no external forces at all,then how exactly do I define the residual force. I know that the solver solves for the Reaction forces but I would not be aware of those values to implement them in my Fortran code.
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</ul><ul><li>If I am doing a linear analysis where there is no residual,how exactly do I define the RHS term in my UEL subroutine. Is it again RHS(i,1)=RHS(i,1)-AMATRX(i,j)*U(i) ? (where RHS(i,1) is assigned zero values initially) </li>
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</div></div></div>Fri, 24 Sep 2010 11:33:06 +0000Gurudutt Chandrashekar8970 at https://imechanica.orghttps://imechanica.org/node/8970#commentshttps://imechanica.org/crss/node/8970Writing ABAQUS UEL subroutines in Fortran 90 or higher versions .
https://imechanica.org/node/8633
<div class="field field-name-taxonomy-vocabulary-6 field-type-taxonomy-term-reference field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/taxonomy/term/76">research</a></div></div></div><div class="field field-name-taxonomy-vocabulary-8 field-type-taxonomy-term-reference field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/taxonomy/term/5424">UEL ABAQUS</a></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>
Hello everyone,
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I am a student of Msc in Computational Engineering at Ruhr University Bochum in Germany. I am implementing a new piezoelectric element as a part of my Master Thesis. I am supposed to write a UEL subroutine and implement it in abaqus.I would like to know whether anyone has written subroutines in Fortran 90 or further versions and implemented them in abaqus. All the Help documents in Abaqus have subroutines written in F77. If it possible in F90, then it will be very helpful if someone could point out the necessary modifications that one has to make to the F90 file to run it in Abaqus. I think many ppl have this question .I myself have been trying to figure out an answer from past 1 month but could not find a convincing solution anywhere.
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</div></div></div>Fri, 30 Jul 2010 20:20:24 +0000Gurudutt Chandrashekar8633 at https://imechanica.orghttps://imechanica.org/node/8633#commentshttps://imechanica.org/crss/node/8633Error | iMechanica