EOS_TABULATED_COMPACTION

Michał Kucewicz

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Jan 9, 2021, 10:23:08 AM1/9/21

to LS-DYNA2

Dear friends,

I am writing about EOS_TABULATED_COMPACTION and its usage with KCC concrete model (MAT_72_REL_3). I wanted to define pressure and unloading bulk modulus with DEFINE_CURVE to use more than 10 points. It is possible since LS Dyna R10.0 (I am using R11 and R12)I followed the instructions from user manual, and, unfortunatelly this method does not work.

Here are my input parameters:

*EOS_TABULATED_COMPACTION

$# eosid gama e0 vo lcc lct lck lcid

154 0.0 0.0 1.0 102 101 103 110

rest values are ZERO

*DEFINE_CURVE_TITLE

P

$# lcid sidr sfa sfo offa offo dattyp lcint

102 0 1.0 1.0 0.0 0.0 0 0

$# a1 o1

-0.051 302.4132

-0.048 272.8781

-0.045 244.8114

-0.042 218.2128

-0.039 193.0826

-0.036 169.4205

-0.033 147.2268

-0.03 126.5013

-0.027 107.244

-0.024 89.45499

-0.021 73.13423

-0.018 58.28173

-0.015 44.89747

-0.012 32.98148

-0.009 22.53373

-0.006 13.55423

-0.003 6.04299

0.0 0.0

*DEFINE_CURVE_TITLE

K

$# lcid sidr sfa sfo offa offo dattyp lcint

103 0 1.0 1.0 0.0 0.0 0 0

$# a1 o1

-0.051 9845.01

-0.048 9355.593

-0.045 8866.175

-0.042 8376.758

-0.039 7887.34

-0.036 7397.922

-0.033 6908.505

-0.03 6419.087

-0.027 5929.67

-0.024 5440.252

-0.021 4950.835

-0.018 4461.417

-0.015 3972.0

-0.012 3482.583

-0.009 2993.165

-0.006 2503.747

-0.003 2014.33

0.0 2014.33

Data from d3hsp:

It seems that parameters are zero, however the solver know, that curves are defined.

Equation-of-State Form 8 (Tabulated Compaction)

curve ID for C ................... = 102

curve ID for T ................... = 101

curve ID for B ................... = 103

volumetric strain ................ = 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

pressure with e=0 ................ = 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

multiplier of gamma*e ............ = 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

unloading bulk modulus ........... = 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

gamma ............................ = 0.00000E+00

e0 ............................... = 0.00000E+00

initial relative volume .......... = 1.00000E+00

load curve for energy generation . = 110

Do you have any idea how to properly use such EOS with curve definition?

Best regards

l...@schwer.net

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Jan 9, 2021, 12:04:42 PM1/9/21

to Michał Kucewicz, LS-DYNA2

I was not aware of this EOS8 change. I searched all the R10 release notes and could not find a mention of the parameters: LCC LCT LCK LCID. That said, these parameters appear in the current User Manual Volume II description of *EOS_TABULATED_COMPACTION.

I see no indication in the current User Manual Volume II of how to tell LS-DYNA you want to use DEFINE_CURVES rather than the direct input of ten values of volume strain, pressure, temperature and bulk unloading modulus, i.e. Parameter Card Pairs.

In your input, did you include blank lines for the Parameter Card Pairs? If so, try omitting these blanks lines and see if the DEFINE_CURVES are used as you intended.

--len

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James M. Kennedy

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Jan 9, 2021, 12:28:44 PM1/9/21

to Michał Kucewicz, LS-DYNA2

Dear Michal,

You stated-

Data from d3hsp:

It seems that parameters are zero, however the solver know, that curves are defined.

Please check further in d3hsp file for load curves 101, 102, 102, and 110.

Usually in d3hsp, load curves are echoed as shown in the following example:

l o a d c u r v e s

number of load curves = 1

load function id number= 2

number of time points = 7

discretization inc. = 100

initialization flag = 0

eq. 0 analysis only

eq. 1 initialization only

eq. 2 both

input format = 2e20.0

abscissa scale factor = 0.1000E+01

ordinate scale factor = 0.1000E+01

abscissa offset value = 0.0000E+00

ordinate offset value = 0.0000E+00

table definition = 0

eq.-2 4d table

eq.-1 3d table

eq. 0 curve

eq. 1 table

eq. 2 general X-Y data

eq. 3 function

eq. 4 3858 interpolation

eq. 5 4534a interpolation

eq. 6 general R-S data

abscissa ordinate

0.0000 0.0000000E+00

5.00000E-02 1.9100000E+00

0.20000 1.9100000E+00

0.40000 1.9100000E+00

0.65000 2.5000000E+00

0.80000 6.0000000E+00

0.85000 3.5000000E+01

Sincerely,

James M. Kennedy

KBS2 Inc.

January 9, 2021

From: ls-d...@googlegroups.com [mailto:ls-d...@googlegroups.com] On Behalf Of Michal Kucewicz
Sent: Saturday, January 09, 2021 9:23 AM
To: LS-DYNA2 <ls-d...@googlegroups.com>
Subject: [LS-DYNA2] EOS_TABULATED_COMPACTION

Dear friends,

--

Michał Kucewicz

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Jan 9, 2021, 1:47:46 PM1/9/21

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First answer:

Dear Len, thanks for your response,

I tried different methods to define those curves:

- setting all LCC, LCT and LCK by intiger number as a positive and negative values.

- same as above comment, but with and without blank lines in "Pairs Tab" - without those lines solver did not start the simulation and error termination occured. With all pair tabs set to "0" simulation started, but all eos constants were "zero" and the elements were deleted due to zero stiffness at the beggining of simulation and time step dt was about 4000 s. (I am absolutely sure that parameters defined in KCC are proper because I used them in many simulations)

- I also checked all above comments with the pairs of Ni, P, T and K defined as 0 and defined by 10 values which were the same as in curves I want to apply (just to verify if it read a values applied in a classic way) - in both cases in d3hsp the output for KCC rel 3 EOS definition was the same as this described above, where all values were equal to zero. It seems, that when typing boxes for curves are filled, the values below the first line are not considered by the solver, however, whet those lines are deleted from input file, simulation starts with error message.

- Another try was related to the different typing of abicassa for all defined curves. User manual II says that it must be "negative of the volumetric strain in monotonically increasing

order", which is opposite to the regime for typing the pairs of parameters in lines 2-9 in EOS_TABULATED_COMPACTION. Therefore I tried to use the curves which were in decreasing order, as in clasic input for this EOS, but with no improvement.

- I also tried setting the LCID to "0" and the effect was the same. Then I used the curve with ID 110 shown below:

My LCID is defined as:

*DEFINE_CURVE

$# lcid sidr sfa sfo offa offo dattyp lcint

110 0 1.0 1.0 0.0 0.0 0 0

$# a1 o1

0.0 1.0

1.1111111000e+07 1.0

Is it right? I am not fully understand the physical meaning of this parameter called "energy deposition rate as a function of time". Can you recommend a value which i should use for this curve? May it be the reason of error?

Answer 2:

Dear James, thank you for your response.

Yes, the curve is properly loaded by the solver:

This is the information from d3hsp:

load function id number= 101

number of time points = 18

discretization inc. = 100

initialization flag = 0

eq. 0 analysis only

eq. 1 initialization only

eq. 2 both

input format = 2e20.0

abscissa scale factor = 0.1000E+01

ordinate scale factor = 0.1000E+01

abscissa offset value = 0.0000E+00

ordinate offset value = 0.0000E+00

table definition = 0

eq.-2 4d table

eq.-1 3d table

eq. 0 curve

eq. 1 table

eq. 2 general X-Y data

eq. 3 function

eq. 4 3858 interpolation

eq. 5 4534a interpolation

eq. 6 general R-S data

abscissa ordinate

-5.10000E-02 0.0000000E+00

-4.80000E-02 0.0000000E+00

-4.50000E-02 0.0000000E+00

-4.20000E-02 0.0000000E+00

-3.90000E-02 0.0000000E+00

-3.60000E-02 0.0000000E+00

-3.30000E-02 0.0000000E+00

-3.00000E-02 0.0000000E+00

-2.70000E-02 0.0000000E+00

-2.40000E-02 0.0000000E+00

-2.10000E-02 0.0000000E+00

-1.80000E-02 0.0000000E+00

-1.50000E-02 0.0000000E+00

-1.20000E-02 0.0000000E+00

-9.00000E-03 0.0000000E+00

-6.00000E-03 0.0000000E+00

-3.00000E-03 0.0000000E+00

0.0000 0.0000000E+00

load function id number= 102

number of time points = 18

discretization inc. = 100

initialization flag = 0

eq. 0 analysis only

eq. 1 initialization only

eq. 2 both

input format = 2e20.0

abscissa scale factor = 0.1000E+01

ordinate scale factor = 0.1000E+01

abscissa offset value = 0.0000E+00

ordinate offset value = 0.0000E+00

table definition = 0

eq.-2 4d table

eq.-1 3d table

eq. 0 curve

eq. 1 table

eq. 2 general X-Y data

eq. 3 function

eq. 4 3858 interpolation

eq. 5 4534a interpolation

eq. 6 general R-S data

abscissa ordinate

-5.10000E-02 3.0241320E+02

-4.80000E-02 2.7287810E+02

-4.50000E-02 2.4481140E+02

-4.20000E-02 2.1821280E+02

-3.90000E-02 1.9308260E+02

-3.60000E-02 1.6942050E+02

-3.30000E-02 1.4722680E+02

-3.00000E-02 1.2650130E+02

-2.70000E-02 1.0724400E+02

-2.40000E-02 8.9454990E+01

-2.10000E-02 7.3134230E+01

-1.80000E-02 5.8281730E+01

-1.50000E-02 4.4897470E+01

-1.20000E-02 3.2981480E+01

-9.00000E-03 2.2533730E+01

-6.00000E-03 1.3554230E+01

-3.00000E-03 6.0429900E+00

0.0000 0.0000000E+00

Best regards

Michał Kucewicz

l...@schwer.net

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Jan 9, 2021, 2:25:13 PM1/9/21

to Michał Kucewicz, LS-DYNA2

Hello Michal –

Thanks for all the background and effort you have put into trying to decode how this material input is intended to be structured.

This User Manual description needs some work to make it clear what is intended.

I have never used the DEFINE_CURVE options and would guess the “energy deposition rate” applies to a combined mechanical- thermal solution – not typical in MAT072R23 applications.

I always leave the “Parameter Card Pairs” for temperature values set to zero, and use a constant bulk unloading modulus. Thus I only define volume strain and pressure as variable.

Does your model work with only the “Parameter Card Pairs,” i.e. leaving: LCC LCT LCK LCID blank?

It also bothers me that there is no indicated default values for these DEFINE_CURVE parameters, but hopefully they can be left blank and LS-DYNA will ignore the curves.

NOTE: LCT is to provide bulk modulus while “Parameter Card Pairs” provides bulk UNLOADING modulus.

I think you are going to need to seek help from support.

--len

To view this discussion on the web visit https://groups.google.com/d/msgid/ls-dyna2/a0d59bb9-e9dc-4bc6-973a-bd1e846af469n%40googlegroups.com.

LS-DYNA2

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Jan 11, 2021, 11:41:36 AM1/11/21

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Hello all,

I had this same problem recently and had to resolve it with LST support. The manual is very unclear about this, but I believe you need to reverse the sign convention on volumetric strain. It should be positive in compression (opposite the convention when using the ten points in the material data card). The points still need to be ordered to be monotonically increasing: for your curve 102, start from (0.0, 0.0) and ascend to (0.051, 302.4).

Please let me know if this resolves the issue. If not I can dig a little deeper into how I got this load curve option to work.

Ben Giddens

Protection Engineering Consultants

bgid...@protection-consultants.com

Michał Kucewicz

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Jan 12, 2021, 6:40:45 AM1/12/21

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Dear Len,

I agree, user manual should provide more clear information about application of EOS using basic piecewise curves characterising the material.

Now in simulations I do not define "Energy Deposition Rate" curve to prevent possible instabilities. I also thank you for your advice related to constant unloading bulk modulus. I made some cyclic tests and measured an unloading bulk modulus for several pressures and found that they increase with the pressure, thus, i applied measured into EOS. However, I tried it with constant value to check if it works (unfortunatelly not). I confirm, that my model works correctly with pressures, volumetric strains and unloading bulk modulus defined with 10 pair cards.

Dear Ben,

Thank you for your respoinse,

After your advice i tried four combinations:

- Curves with volumetric strain in increasing order defined by positive values (from 0.0 to 0.051)

- Curves with volumetric strain in decreasing order defined by positive values (from 0.051 to 0.0)

- Curves with volumetric strain in increasing order defined by negative values (from 0.0 to -0.051)

- Curves with volumetric strain in decreasing order defined by negative values (from -0.051 to 0.0)

Unfortunatelly, any of those definition did not worked for me. I will be very grateful for your help and for your efforts to find out what solution worked for you.

Best regards,

Michał Kucewicz

l...@schwer.net

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Jan 12, 2021, 11:33:57 AM1/12/21

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Thanks Ben for the additional insight.

This reinforces my opinion that the User Manual description of this keyword needs a lot of work.

--len

To view this discussion on the web visit https://groups.google.com/d/msgid/ls-dyna2/796b3574-d94d-4a14-81a5-0c8d1c125871n%40googlegroups.com.

LS-DYNA2

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Jan 12, 2021, 1:13:17 PM1/12/21

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I used the model quoted below to debug my implementation of EOS_008, and it looks like I was able to get yours working as well using the sign convention I mentioned. This model has just two elements which are constrained to undergo a few cycles of compression and decompression. One element uses curves specified within the material card while the other uses separately defined load curves. The pressure profile in the two elements is identical.

I only implemented the first ten points of your curves so that I could have identical behavior in both models. You should be able to expand from here.

I hope this works for you.

Ben Giddens

Protection Engineering Consultants

bgid...@protection-consultants.com

P.S. I assumed your pressure units were MPa and converted them to SI to match my model.

*KEYWORD

*CONTROL_OUTPUT

$# npopt neecho nrefup iaccop opifs ipnint ikedit iflush

0 0 0 0 0.0 0 0 0

$# iprtf ierode tet10s8 msgmax ipcurv gmdt ip1dblt eocs

0 1 2 0 1 0.0 0 0

$# tolev newleg frfreq minfo solsig msgflg cdetol

2 0 1 0 0 0 10.0

$# phschng demden icrfile spc2bnd penout shlsig hisnout engout

0 0 0 0 0 0 0 0

$# insf isolsf ibsf issf mlkbag

0 0 0 0 0

*CONTROL_TERMINATION

$# endtim endcyc dtmin endeng endmas nosol

1.0 1000

*CONTROL_TIMESTEP

$# dtinit tssfac isdo tslimt dt2ms lctm erode ms1st

$# dt2msf dt2mslc imscl unused unused rmscl unused ihdo

*DATABASE_BINARY_D3PLOT

$# dt lcdt beam npltc psetid

1e-9

$# ioopt rate cutoff window type pset

0 0.0 0.0 0.0 0 0

*PART

$# title

$# pid secid mid eosid hgid grav adpopt tmid

1 1 1 1 0 0 0 0

*PART

$# title

$# pid secid mid eosid hgid grav adpopt tmid

2 1 1 2 0 0 0 0

*SECTION_SHELL

$# secid elform

1 13

0.005 0.005

$-------------------------------------------------------------------------------

$ [kg-m-s-Pa]

$ Note: model is developed for gauge pressures

$-------------------------------------------------------------------------------

*MAT_NULL

$# mid ro

1 1910.0

*EOS_TABULATED_COMPACTION

$# eosid gama e0 vo lcc lct lck lcid

1 0.0 0.0 1.0

$# ev1 ev2 ev3 ev4 ev5

0.000 -0.003 -0.006 -0.009 -0.012

$# ev6 ev7 ev8 ev9 ev10

-0.015 -0.018 -0.021 -0.024 -0.027

$# c1 c2 c3 c4 c5

0.000000e+06 6.042990e+06 1.355423e+07 2.253373e+07 3.298148e+07

$# c6 c7 c8 c9 c10

4.489747e+07 5.828173e+07 7.313423e+07 8.945499e+07 1.072440e+08

$# t1 t2 t3 t4 t5

0.0 0.0 0.0 0.0 0.0

$# t6 t7 t8 t9 t10

0.0 0.0 0.0 0.0 0.0

$# k1 k2 k3 k4 k5

2.014330e+09 2.014330e+09 2.503747e+09 2.993165e+09 3.482583e+09

$# k6 k7 k8 k9 k10

3.972000e+09 4.461417e+09 4.950835e+09 5.440252e+09 5.929670e+09

*EOS_TABULATED_COMPACTION

$# eosid gama e0 vo lcc lct lck lcid

2 0.0 0.0 1.0 200 201 202

$# ev1 ev2 ev3 ev4 ev5

$# ev6 ev7 ev8 ev9 ev10

$# c1 c2 c3 c4 c5

$# c6 c7 c8 c9 c10

$# t1 t2 t3 t4 t5

$# t6 t7 t8 t9 t10

$# k1 k2 k3 k4 k5

$# k6 k7 k8 k9 k10

*DEFINE_CURVE

$ C function, pressure vs log volumetric strain

$# lcid sidr sfa sfo offa offo dattyp lcint

200 1.0 1.0e+06 0.0 0.0

$# a o

0.000 0.000000e+00

0.003 6.042990e+00

0.006 1.355423e+01

0.009 2.253373e+01

0.012 3.298148e+01

0.015 4.489747e+01

0.018 5.828173e+01

0.021 7.313423e+01

0.024 8.945499e+01

0.027 1.072440e+02

*DEFINE_CURVE

$# lcid sidr sfa sfo offa offo dattyp lcint

201 1.0 1.0 0.0 0.0

$# a o

-1.0 0.0

1.0 0.0

*DEFINE_CURVE

$# lcid sidr sfa sfo offa offo dattyp lcint

202 1.0 1.0e+06 0.0 0.0

$# a o

0.000 2.014330e+03

0.003 2.014330e+03

0.006 2.503747e+03

0.009 2.993165e+03

0.012 3.482583e+03

0.015 3.972000e+03

0.018 4.461417e+03

0.021 4.950835e+03

0.024 5.440252e+03

0.027 5.929670e+03

*BOUNDARY_PRESCRIBED_MOTION_NODE

3 2 0 1

4 2 0 1

7 2 0 1

8 2 0 1

*DEFINE_CURVE

$# lcid sidr sfa sfo offa offo dattyp lcint

1 0 1.0 -1.0e-01 0.0 0.0 0 0

$# a1 o1

-1.0000000e+20,1.0

0.000200000000,1.0

0.000200000001,-1.0

0.000300000000,-1.0

0.000300000001,1.0

0.000500000000,1.0

0.000500000001,-1.0

0.000600000000,-1.0

0.000600000001,1.0

0.000800000000,1.0

0.000800000001,-1.0

0.000900000000,-1.0

0.000900000001,1.0

1.00000000e+20,1.0

*ELEMENT_SHELL

$# eid pid n1 n2 n3 n4 n5 n6 n7 n8

1 1 1 2 3 4

2 2 5 6 7 8

*NODE

$# nid x y z tc rc

1 0.0 0.0 0.0 7 0

2 0.005 0.0 0.0 7 0

3 0.005 0.005 0.0 6 0

4 0.0 0.005 0.0 6 0

5 0.01 0.0 0.0 7 0

6 0.015 0.0 0.0 7 0

7 0.015 0.005 0.0 6 0

8 0.01 0.005 0.0 6 0

*END

Michał Kucewicz

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Jan 14, 2021, 1:08:39 PM1/14/21

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Sorry for delay in replying.

Thank you very much for your keyword! I verified it and it is working well. I will try to use your *.k file with KCC material instead on Null Material model and will respond here some feedback about it. I will also add some extra points in pressure and bulk modulus curves.