Solid Element Erosion
Christy Hwang
$ OSU INN PIDOSU IACC
$# osu inn pidosu iacc exacc
1 4 1
*CONTROL_BULK_VISCOSITY
$ Q1 Q2 TYPE
$# q1 q2 type btype tstype
1.5 0.06 -2
*CONTROL_CONTACT
$ SLSFAC RWPNAL ISLCHK SHLTHK PENOPT THKCHG ORIEN ENMASS
$# slsfac rwpnal islchk shlthk penopt thkchg orien enmass
0.1 0.0 2 0 0 1 0
$ USRSTR USRFRC NSBCS INTERM XPENE SSTHK ECDT TIEDPRJ
$# usrstr usrfrc nsbcs interm xpene ssthk ecdt tiedprj
0 0 0 0 0.0 0 0 0
$ SFRIC DFRIC EDC VFC TH TH_SF PEN_SF
$# sfric dfric edc vfc th th_sf pen_sf
0.0 0.0 0.0 0.0 0.0 0.0 0.0
$ IGNORE FRCENG SKIPRWG OUTSEG SPOTSTP SPOTDEL SPOTHIN
$# ignore frceng skiprwg outseg spotstp spotdel spothin
2 1
$ ISYM NSEROD RWGAPS RWGDTH RWKSF ICOV SWRADF ITHOFF
$# isym nserod rwgaps rwgdth rwksf icov swradf ithoff
0 0 1 0.0 1.0 0 0.0 0
$ SHLEDG PSTIFF ITHCNT TDCNOF FTALL SHLTRW
$# shledg pstiff ithcnt tdcnof ftall unused shltrw igactc
1
*CONTROL_ENERGY
$ HGEN RWEN SLNTEN RYLEN
$# hgen rwen slnten rylen irgen maten drlen disen
2 2 2 2
*CONTROL_HOURGLASS
$ IHQ QH
$# ihq qh
6 0.1
*CONTROL_IMPLICIT_AUTO
$# iauto iteopt itewin dtmin dtmax dtexp kfail kcycle
1 100 205.00000E-5 0.005 0.0 0 0
*CONTROL_IMPLICIT_DYNAMICS
$ IMASS GAMMA BETA IRATE
$# imass gamma beta tdybir tdydth tdybur irate alpha
0 0.6 0.38 0.0 0.5 1.0 1
*CONTROL_IMPLICIT_GENERAL
$# imflag dt0 imform nsbs igs cnstn form zero_v
1 0.005 2 0 1 0 0 0
*CONTROL_IMPLICIT_SOLUTION
$# nsolvr ilimit maxref dctol ectol rctol lstol abstol
12 11 15 0.001 0.01 1.0000E-20
$# dnorm diverg istif nlprint nlnorm d3itctl cpchk
2 1 1 3 2 10
$# arcctl arcdir arclen arcmth arcdmp arcpsi arcalf arctim
$# lsmtd lsdir irad srad awgt sred
5
*CONTROL_OUTPUT
$ NPOPT NEECHO NREFUP IACCOP OPIFS IPNINT IKEDIT IFLUSH
$# npopt neecho nrefup iaccop opifs ipnint ikedit iflush
1 3 0 0 0.0 0 100 5000
$ IPRTF IERODE TET10 MSGMAX IPCURV
$# iprtf ierode tet10s8 msgmax ipcurv gmdt ip1dblt eocs
0 1
$ TOLEV NEWLEG FRFREQ MINFO SOLSIG MSGFLG
$# tolev newleg frfreq minfo solsig msgflg cdetol
1 1
*CONTROL_SHELL
$ WRPANG ESORT IRNXX ISTUPD THEORY BWC MITER PROJ
$# wrpang esort irnxx istupd theory bwc miter proj
20.0 1 -1 4 2 1 1 1
$ ROTSCL INTGRD LAMSHT CSTYP6 TSHELL
$# rotascl intgrd lamsht cstyp6 thshel
1.0 0 5 1 0
$ PSSTUPD SIDT4TU CNTCO ITSFLG IRQUAD
$# psstupd sidt4tu cntco itsflg irquad w-mode stretch icrq
0 0 3
$ NFAIL1 NFAIL4 PSNFAIL KEEPCS DELFR
$# nfail1 nfail4 psnfail keepcs delfr drcpsid drcprm intperr
0 0
*CONTROL_SOLID
$ ESORT FMATRIX NIPTETS SWLOCL
$# esort fmatrix niptets swlocl psfail t10jtol icoh tet13k
1 0 0
*CONTROL_SOLUTION
$# soln nlq isnan lcint lcacc ncdcf nocop
0 0 0 1000 0 0 0
*CONTROL_TERMINATION
$# endtim endcyc dtmin endeng endmas nosol
5.4 0 0.0 0.01.000000E8 0
l...@schwer.net
It would be helpful if you included your concrete material input card images.
--len
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James Kennedy
Dear Christy,
A note I have seen:
There is no erosion criterion in the material model, *mat_072r3. You can use *mat_add_erosion.
Sincerely,
James M. Kennedy
KBS2 Inc.
Aprill 17, 2023
From: ls-d...@googlegroups.com [mailto:ls-d...@googlegroups.com]
On Behalf Of Christy Hwang
Sent: Monday, April 17, 2023 1:25 AM
To: LS-DYNA2 <ls-d...@googlegroups.com>
Subject: [LS-DYNA2] Solid Element Erosion
Hi everyone,
--
Hwang Christy
Sent: Monday, April 17, 2023 10:15:03 PM
To: 'Christy Hwang' <christy...@gmail.com>; 'LS-DYNA2' <ls-d...@googlegroups.com>
Subject: RE: [LS-DYNA2] Solid Element Erosion
Hwang Christy
Sent: Tuesday, April 18, 2023 4:48:03 AM
To: Christy Hwang <christy...@gmail.com>; LS-DYNA2 <ls-d...@googlegroups.com>
Subject: RE: [LS-DYNA2] Solid Element Erosion
Dear Christy,
l...@schwer.net
l...@schwer.net
Christy –
Your input indicates no failure (erosion), but you allow damage via TYPE=1 (EQ.1.0: Bi-linear damage formulation). [This is a bit odd, as when an element becomes fully damaged, its time step will go to zero – might work with implicit solver?]
Please run the simulation again with TYPE=3 (EQ.3.0: No damage) to see if erosion still occurs.
It would also help to have a few of the lines from the “messag” or d3hsp file that are output each time an element/integration point fails.
--len
From: Hwang Christy <christy...@gmail.com>
Sent: Tuesday, April 18, 2023 5:44 AM
To: l...@schwer.net
Subject: Re: [LS-DYNA2] Solid Element Erosion
Hi Len,
Sorry that I needed to ask my professor’s permission to share the data as the simulation was based on an unpublished study. Please see the images as followed for your reference.
Thank you for your help.
Best regards,
Christy
I am trying simulate the flexure behavior of a concrete specimen. The failure flag of the concrete material was set to be no erosion but somehow the solid elements still got deleted at some stages. I looked at the control keywords that i used but i don't think I had set other erosion critera. I am wondering if anyone knows how can I keep the concrete solid elements not deleted.
James Kennedy
Dear Christy.
simple examples of *MAT_273
Cylinder subjected to confined compression illustrating the influence of element length in compression using tetrahedral meshes.
http://petergrassl.com/tempFiles/summaryLSDYNACylinder.pdf
http://petergrassl.com/Research/DamagePlasticity/CDPMLSDYNA/index.html
Three point bending tests illustrating the influence of element length using tetra- and hexahedral meshes.
http://petergrassl.com/tempFiles/summaryLSDYNATPBT.pdf
http://petergrassl.com/Research/DamagePlasticity/CDPMLSDYNA/index.html
Single element tests illustrating the influence of element length on the response in tension and compression.
http://petergrassl.com/tempFiles/summaryLSDYNASingleElement.pdf
http://petergrassl.com/Research/DamagePlasticity/CDPMLSDYNA/index.html
Sincerely,
James M. Kennedy
KBS2 Inc.
April 18, 2023
To view this discussion on the web visit https://groups.google.com/d/msgid/ls-dyna2/LOYP123MB3519EE7FF7675A92441308EEF89C9%40LOYP123MB3519.GBRP123.PROD.OUTLOOK.COM.
James Kennedy
p.s. Added paper:
In this project, a fiber reinforced polymer (FRP) confined concrete model was developed using *MAT_CDPM (*MAT_273) in LS-DYNA. Several finite element analyses are performed to predict the response of stress-strain relationship and to study the mechanics of confined concrete. The concrete was modelled as 4-node tetrahedron solid elements and the FRP was modelled as truss elements in the analysis. The results of the proposed model were compared with the experimental results and the analytical results:
Nwe, T.H., "Modelling of FRP Confined Concrete under Uniaxial Compression Using CDPM2 in LS-DYNA”, Master’s Thesis, School of Engineering, University of Glasgow, United Kingdom, August, 2017.