Blast loading experiments are among the most expensive because of their harsh environment and large number of experts involved in the tests. In some cases a very strict safety requirements and additional governmental permissions are needed, making the numerical approach the only reasonable and valuable tool for examination. Blast response of structures is of great importance in military applications. However civil and governmental structures are becoming more exposed to blast loads, as a result of increased possibility of terrorist attacks especially in the last two decades. Whatever the structure under investigation, blast loading model should be verified first. In that purpose we performed Arbitrary Lagrange Euler (ALE) simulation investigating the influence of most valuable material and numerical parameters. On the next two videos simulation results of 6 kg of TNT explosion in free air is presented. The influence of mesh density in blast wave development and its loading parameters is clearly visible;
$# LS-DYNA Keyword file created by LS-PrePost 4.0 - 14Apr2013(16:00)
$# Created on Nov-28-2013 (13:49:32)
*KEYWORD
*TITLE
$# title
LS-DYNA keyword deck by LS-PrePost
*CONTROL_ALE
$# dct nadv meth afac bfac cfac dfac efac
3 1 3 -1.000000 0.000 0.000 0.000 0.000
$# start end aafac vfact prit ebc pref nsidebc
0.0001.0000E+20 1.000000 1.0000E-6 0 2 1.0000E+5 0
$# ncpl nbkt imascl checkr
1 50 0 0.000
*CONTROL_ENERGY
$# hgen rwen slnten rylen
2 2 2 2
*CONTROL_TERMINATION
$# endtim endcyc dtmin endeng endmas
3.0000E-4 0 0.000 0.000 0.000
*CONTROL_TIMESTEP
$# dtinit tssfac isdo tslimt dt2ms lctm erode ms1st
0.000 0.600000 0 0.000 0.000 0 0 0
$# dt2msf dt2mslc imscl unused unused rmscl
0.000 0 0 0.000
*DATABASE_ELOUT
$# dt binary lcur ioopt option1 option2 option3 option4
2.0000E-6 0 0 1 0 0 0 0
*DATABASE_GLSTAT
$# dt binary lcur ioopt
2.0000E-6 0 0 1
*DATABASE_BINARY_D3PLOT
$# dt lcdt beam npltc psetid
0.000 0 0 60 0
$# ioopt
0
*DATABASE_TRACER
$# time track x y z ammg nid
0.000 1 0.000 0.400000 0.000 0 0
0.000 1 0.400000 0.000 0.000 0 0
0.000 1 0.000 0.300000 0.000 0 0
0.000 1 0.300000 0.000 0.000 0 0
*BOUNDARY_SPC_SET
$# nsid cid dofx dofy dofz dofrx dofry dofrz
2 0 0 1 0 0 0 0
*PART
$# title
shell_4p
$# pid secid mid eosid hgid grav adpopt tmid
1 5 1 1 1 0 0 0
*SECTION_ALE2D
$# secid aleform aet elform
5 11 0 14
*MAT_NULL_TITLE
AIR
$# mid ro pc mu terod cerod ym pr
1 1.290000 0.000 0.000 0.000 0.000 0.000 0.000
*EOS_LINEAR_POLYNOMIAL_TITLE
Air
$# eosid c0 c1 c2 c3 c4 c5 c6
1 -1.000E-6 0.000 0.000 0.000 0.400000 0.400000 0.000
$# e0 v0
2.5000E+5 1.000000
*HOURGLASS_TITLE
za ALE
$# hgid ihq qm ibq q1 q2 qb/vdc qw
1 1 1.0000E-6 0 1.500000 0.060000 0.100000 0.100000
*PART
$# title
$# pid secid mid eosid hgid grav adpopt tmid
2 2 2 2 1 0 0 0
*SECTION_ALE2D
$# secid aleform aet elform
2 11 0 14
*MAT_HIGH_EXPLOSIVE_BURN
$# mid ro d pcj beta k g sigy
2 1590.0000 6930.00002.1000E+10 0.000 0.000 0.000 0.000
*EOS_JWL
$# eosid a b r1 r2 omeg e0 vo
23.7120E+11 3.2310E+9 4.150000 0.950000 0.300000 7.0000E+9 1.000000
*INITIAL_DETONATION
$# pid x y z lt
2 0.000 0.000 0.000 0.000
*INITIAL_VOLUME_FRACTION_GEOMETRY
$# fmsid fmidtyp bammg ntrace
1 0 1 3
$# conttyp fillopt fammg vx xy xz radvel unused
6 0 2 0.000 0.000 0.000 0
$# xc yc zc radius unused unused unused unused
0.000 0.000 0.000 0.096580
*SET_PART_LIST
$# sid da1 da2 da3 da4 solver
1 0.000 0.000 0.000 0.000MECH
$# pid1 pid2 pid3 pid4 pid5 pid6 pid7 pid8
1 2 0 0 0 0 0 0
*ALE_REFERENCE_SYSTEM_GROUP
$# sid stype prtype prid bctran bcexp bcrot icoord
1 1 8 0 0 0 0 0
$# xc yc zc explim efac unused frcpad iexpnd
0.000 0.000 0.000 0.000 0.000 0.000 0
*ALE_MULTI-MATERIAL_GROUP
$# sid idtype gpname
1 1
2 1
*END
The next step was successful modeling of blast wave interaction with a rigid plate structure using fluid structure interaction (FSI) algorithm;
$# LS-DYNA Keyword file created by LS-PrePost 4.0 - 14Apr2013(16:00)
$# Created on Nov-28-2013 (11:37:21)
*KEYWORD
*TITLE
$# title
LS-DYNA keyword deck by LS-PrePost
*CONTROL_ALE
$# dct nadv meth afac bfac cfac dfac efac
3 1 3 -1.000000 0.000 0.000 0.000 0.000
$# start end aafac vfact prit ebc pref nsidebc
0.0001.0000E+20 1.000000 1.0000E-6 0 2 1.0000E+5 0
$# ncpl nbkt imascl checkr
1 50 0 0.000
*CONTROL_ENERGY
$# hgen rwen slnten rylen
2 2 2 2
*CONTROL_TERMINATION
$# endtim endcyc dtmin endeng endmas
3.0000E-4 0 0.000 0.000 0.000
*CONTROL_TIMESTEP
$# dtinit tssfac isdo tslimt dt2ms lctm erode ms1st
0.000 0.600000 0 0.000 0.000 0 0 0
$# dt2msf dt2mslc imscl unused unused rmscl
0.000 0 0 0.000
*DATABASE_ELOUT
$# dt binary lcur ioopt option1 option2 option3 option4
2.0000E-6 0 0 1 0 0 0 0
*DATABASE_GLSTAT
$# dt binary lcur ioopt
2.0000E-6 0 0 1
*DATABASE_TRHIST
$# dt binary lcur ioopt
2.0000E-6 0 0 1
*DATABASE_BINARY_D3PLOT
$# dt lcdt beam npltc psetid
0.000 0 0 60 0
$# ioopt
0
*DATABASE_BINARY_FSIFOR
$# dt lcdt beam npltc psetid
0.000 0 0 1200 2
*DATABASE_FSI
$# dt
2.0000E-6
$#dbsfi_id sid stype swid convid
1 2 0 0 0
*DATABASE_FSI
$# dt
2.0000E-6
$#dbsfi_id sid stype swid convid
2 3 0 0 0
*DATABASE_FSI
$# dt
2.0000E-6
$#dbsfi_id sid stype swid convid
3 4 0 0 0
*DATABASE_TRACER
$# time track x y z ammg nid
0.000 1 0.000 0.400000 0.000 0 0
0.000 1 0.400000 0.000 0.000 0 0
0.000 1 0.000 0.300000 0.000 0 0
0.000 1 0.300000 0.000 0.000 0 0
*BOUNDARY_SPC_SET
$# nsid cid dofx dofy dofz dofrx dofry dofrz
1 0 1 1 1 0 0 0
2 0 0 1 0 0 0 0
*PART
$# title
shell_4p
$# pid secid mid eosid hgid grav adpopt tmid
1 5 1 1 1 0 0 0
*SECTION_ALE2D
$# secid aleform aet elform
5 11 0 14
*MAT_NULL_TITLE
AIR
$# mid ro pc mu terod cerod ym pr
1 1.290000 0.000 0.000 0.000 0.000 0.000 0.000
*EOS_LINEAR_POLYNOMIAL_TITLE
Air
$# eosid c0 c1 c2 c3 c4 c5 c6
1 -1.000E-6 0.000 0.000 0.000 0.400000 0.400000 0.000
$# e0 v0
2.5000E+5 1.000000
*HOURGLASS_TITLE
za ALE
$# hgid ihq qm ibq q1 q2 qb/vdc qw
1 1 1.0000E-6 0 1.500000 0.060000 0.100000 0.100000
*PART
$# title
$# pid secid mid eosid hgid grav adpopt tmid
2 2 2 2 1 0 0 0
*SECTION_ALE2D
$# secid aleform aet elform
2 11 0 14
*MAT_HIGH_EXPLOSIVE_BURN
$# mid ro d pcj beta k g sigy
2 1590.0000 6930.00002.1000E+10 0.000 0.000 0.000 0.000
*EOS_JWL
$# eosid a b r1 r2 omeg e0 vo
23.7120E+11 3.2310E+9 4.150000 0.950000 0.300000 7.0000E+9 1.000000
*PART
$# title
$# pid secid mid eosid hgid grav adpopt tmid
3 6 3 0 0 0 0 0
*SECTION_BEAM
$# secid elform shrf qr/irid cst scoor nsm
6 8 1.000000 2 0 0.000 0.000
$# ts1 ts2 tt1 tt2
2.655936 2.655936 2.655936 2.655936
*MAT_ELASTIC
$# mid ro e pr da db not used
3 7850.00002.0400E+11 0.300000 0.000 0.000 0
*PART
$# title
$# pid secid mid eosid hgid grav adpopt tmid
4 6 3 0 0 0 0 0
*PART
$# title
$# pid secid mid eosid hgid grav adpopt tmid
5 6 3 0 0 0 0 0
*INITIAL_DETONATION
$# pid x y z lt
2 0.000 0.000 0.000 0.000
*INITIAL_VOLUME_FRACTION_GEOMETRY
$# fmsid fmidtyp bammg ntrace
1 0 1 3
$# conttyp fillopt fammg vx xy xz radvel unused
6 0 2 0.000 0.000 0.000 0
$# xc yc zc radius unused unused unused unused
0.000 0.000 0.000 0.096580
*SET_PART_LIST_TITLE
master
$# sid da1 da2 da3 da4 solver
1 0.000 0.000 0.000 0.000MECH
$# pid1 pid2 pid3 pid4 pid5 pid6 pid7 pid8
1 2 0 0 0 0 0 0
*SET_PART_LIST_TITLE
slave
$# sid da1 da2 da3 da4 solver
2 0.000 0.000 0.000 0.000MECH
$# pid1 pid2 pid3 pid4 pid5 pid6 pid7 pid8
3 0 0 0 0 0 0 0
*SET_PART_LIST_TITLE
slave 2
$# sid da1 da2 da3 da4 solver
3 0.000 0.000 0.000 0.000MECH
$# pid1 pid2 pid3 pid4 pid5 pid6 pid7 pid8
4 0 0 0 0 0 0 0
*SET_PART_LIST_TITLE
slave 3
$# sid da1 da2 da3 da4 solver
4 0.000 0.000 0.000 0.000MECH
$# pid1 pid2 pid3 pid4 pid5 pid6 pid7 pid8
5 0 0 0 0 0 0 0
*ALE_REFERENCE_SYSTEM_GROUP
$# sid stype prtype prid bctran bcexp bcrot icoord
1 1 8 0 0 0 0 0
$# xc yc zc explim efac unused frcpad iexpnd
0.000 0.000 0.000 0.000 0.000 0.000 0
*ALE_MULTI-MATERIAL_GROUP
$# sid idtype gpname
1 1
2 1
*CONSTRAINED_LAGRANGE_IN_SOLID
$# slave master sstyp mstyp nquad ctype direc mcoup
2 1 0 0 4 4 1 0
$# start end pfac fric frcmin norm normtyp damp
0.0001.0000E+10 0.100000 0.000 0.500000 0 0 0.000
$# cq hmin hmax ileak pleak lcidpor nvent blockage
0.000 0.000 0.000 0 0.010000 0 0 0
*CONSTRAINED_LAGRANGE_IN_SOLID
$# slave master sstyp mstyp nquad ctype direc mcoup
3 1 0 0 4 4 1 0
$# start end pfac fric frcmin norm normtyp damp
0.0001.0000E+10 0.100000 0.000 0.500000 0 0 0.000
$# cq hmin hmax ileak pleak lcidpor nvent blockage
0.000 0.000 0.000 0 0.010000 0 0 0
*CONSTRAINED_LAGRANGE_IN_SOLID
$# slave master sstyp mstyp nquad ctype direc mcoup
4 1 0 0 4 4 1 0
$# start end pfac fric frcmin norm normtyp damp
0.0001.0000E+10 0.100000 0.000 0.500000 0 0 0.000
$# cq hmin hmax ileak pleak lcidpor nvent blockage
0.000 0.000 0.000 0 0.010000 0 0 0
$
*END
The incident as well as reflected simulation results were compared with experimental results available in the US Army design manual Unified Facilities Criteria UFC 3-340-02 (previusly known as TM5-1300) and very good agreement was achieved. Additionally a real experiment available in literature was numerically simulated and the results were compared successfully;
After the number of successful validations we were finally able to analyze the response of mine blast loaded Light Amour Vehicle (LAV) chassis;
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