Concrete KC mat 72 model
bsak...@gmail.com
l...@schwer.net
By specifying the input Poisson’s Ratio (PR) and the bulk modulus on the associated equation of state (*EOS_TABULATED_COMPACTION), you can specify the elastic modulus calculated using the relationships among the elastic constants.
--len
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James Kennedy
Sent: Saturday, November 26, 2022 8:56 AM
To: 'bsak...@gmail.com' <bsak...@gmail.com>; 'LS-DYNA2' <ls-d...@googlegroups.com>
Subject: RE: [LS-DYNA2] Concrete KC mat 72 model
Bogdan Sakic
From: ls-d...@googlegroups.com <ls-d...@googlegroups.com> on behalf of l...@schwer.net <l...@schwer.net>
Sent: Saturday, November 26, 2022 8:56 AM
To: 'bsak...@gmail.com' <bsak...@gmail.com>; 'LS-DYNA2' <ls-d...@googlegroups.com>
Subject: RE: [LS-DYNA2] Concrete KC mat 72 model
By specifying the input Poisson’s Ratio (PR) and the bulk modulus on the associated equation of state (*EOS_TABULATED_COMPACTION), you can specify the elastic modulus calculated using the relationships among the elastic constants.
--len
From: ls-d...@googlegroups.com <ls-d...@googlegroups.com> On Behalf Of bsak...@gmail.com
Sent: Saturday, November 26, 2022 2:28 AM
To: LS-DYNA2 <ls-d...@googlegroups.com>
Subject: [LS-DYNA2] Concrete KC mat 72 model
Hi Everybody,
Is it possible to define modulus of elasticity for mat 72 or mat 72r3? I am modelling brick masonry and therefore i need a brittle material for implicit analysis, but the relationships regarding the compressive strength and modulus of elasticity for concrete will not fit my needs regarding the masonry. As i am also checking eigenvalues in my experimental campaign, this is quite important for me. Can you advice me on that?
Best regards,
Bogdan.
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Bogdan Šakić M.Sc.RWTH
Wissenschaftlicher Mitarbeiter / Research Assistant
Fakultät für Bauingenieurwesen
LBB - Lehrstuhl für Baustatik und Baudynamik
RWTH Aachen University
Mies-van-der-Rohe-Straße 1
52074 Aachen
James Kennedy
An LS-DYNA distributor in the UK, expert in civil engineering applications of LS-DYNA,,
kindly offered these comments several years ago...
"As far as I know, nobody here has attempted nonlinear analysis of
concrete with implicit LS-DYNA. My understanding is that other implicit
codes (e.g. ABAQUS, ADINA, etc) are OK for small amounts of nonlinearity
but once it comes to cracking and softening only explicit does the job
properly. We have done some work with LS-DYNA implicit on building
structures, but using elastic material for the concrete.
For explicit analysis of concrete using solids, we often use Mat84
(Winfrith). We wrote our own material model for concrete with shells (and beams)
(MAT_CONCRETE_EC2, mat_172)."
The comments still ring true in my opinion. Any implicit solver has a tendency
to become unstable (won't converge) when there is a high degree of material
nonlinearity that includes cracking, crushing, erosion. That does not mean
you can't attempt it. There is a far better chance at success if you employ
implicit dynamics rather than implicit static.
Sent: Saturday, November 26, 2022 5:21 PM
To: James Kennedy <j...@kbs2.com>
Cc: LS-DYNA2 <ls-d...@googlegroups.com>; L...@Schwer.net <L...@schwer.net>
Subject: Re: [LS-DYNA2] Concrete KC mat 72 model
XianBing AI
I am using mat72 R3 to study the impact performance of concrete, but after the model calculation, its hourglass energy is too large as shown in the figure. How can I solve this problem?
The figure below shows the details of the Hardening curve:
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l...@schwer.net
1\ It is difficult to say exactly why your hourglass energy is the same order of magnitude as your internal energy. Typically, hourglass energy is stimulated by point loads, i.e. concentrated loads on single nodes.
2\ I do not understand the message about the ”Hardening curve” as MAT072R3 does not refer to a hardening curve? Since your included image is only labeled as Ordinate versus Abscissa further comment is not possible.
--len
From: ls-d...@googlegroups.com <ls-d...@googlegroups.com> On Behalf Of XianBing AI
Sent: Sunday, December 4, 2022 10:31 PM
To: LS-DYNA2 <ls-d...@googlegroups.com>
Subject: Re: [LS-DYNA2] Concrete KC mat 72 model
Hello everyone
I am using mat72 R3 to study the impact performance of concrete, but after the model calculation, its hourglass energy is too large as shown in the figure. How can I solve this problem?
After I checked the k-file, the material card shows the following warning：
The figure below shows the details of the Hardening curve:
To view this discussion on the web visit https://groups.google.com/d/msgid/ls-dyna2/b8013291-e7fb-49d8-88cc-e40f5694cb61n%40googlegroups.com.
James Kennedy
To: 'XianBing AI' <a17671...@gmail.com>; 'LS-DYNA2' <ls-d...@googlegroups.com>
Omer Polat
However, at the beginning, the numerical analysis appears to be stiffer than the experimental response. I am trying to make this part closer to the experimental results. I suspect that this issue may be related to the EOS card.
Do you think my interpretation is correct? For concrete, the EV2 value in the d3hsp file is obtained as -0.0015. I have seen that some authors use this value as well. However, others have achieved solutions by modifying EV2, while some adjust parameters such as C2, K1, and K2. There are very few studies on this topic.
Could you please help me with this?
