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186concrete
- 1. SIMPLIFIED CONCRETE MODELING WITH *MAT _CONCRETE_DAMAGE_REL3 LS-DYNA USER WEEK 2006 JAPAN RESEARCH INSTITUTE, LIMITED 29 - 30 November 2005 Nagoya, Japan Len Schwer Schwer Engineering & Consulting Services Windsor CA USA Len@Schwer.net L. Javier Malvar Karagozian & Case Structural Engineers Burbank CA USA malvarl@adelphia.net
- 2. 2 PRESENTATION OUTLINE I. Simple Concrete Model Motivation II. Mat 72R3 User Inputs III. Laboratory Data & Mat 72R3 Comparisons
- 3. 3 APPLICATIONS with CONCRETE • Civilian – Roadside Barrier Impacts – Earthquake Response • Defense – Penetration & Perforation – Blast Protection STRUCTURES MODELING:
- 4. 4 CONCRETE is COMPLEX Concrete is porous with a nonlinear bulk modulus. Concrete is porous with a nonlinear bulk modulus. Concrete has a nonlinear pressure dependent yield strength. Concrete has a nonlinear pressure dependent yield strength. 0 50 100 150 200 250 300 350 400 450 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 Volume Strain Pressure[MPa] Mat 72R3 0 50 100 150 200 250 300 350 400 450 500 0 100 200 300 400 500 600 700 Mean Stress [MPa] StressDifference[MPa] Mat 72R3 Typical metal response. σ σ σ σ1 σ2 σ1 >σ2 σ2
- 5. 5 LS-DYNA CONCRETE MODELS Soil and Foam Model (Mat 5) Pseudo-TENSOR (Mat 16) Orientated Crack (Mat 17) Geological Cap (Mat 25) Concrete Damage (Mat 72) Concrete Damage Rel3 (Mat 72R3) Brittle Damage (Mat 96) Soil Concrete (Mat 78) Winfrith Concrete (Mat 84) Johnson Holmquist Concrete (Mat 111) Schwer Murray Cap (Mat 145) CSCM Concrete (Mat 159) THREE SIMPLIFIED CONCRETE MODELS ARE AVAILABLE Simplified Model = Minimum User Input 1 or 2 Parameters Mat 25 Requires 12 User Inputs
- 6. 6 MAT CONCRETE DAMAGE REL3 Mat 72R3 can be used either with complete user specified inputs or internal parameter generation. Internal parameter generation is based upon the concrete’s unconfined compressive strength. As an example, the concrete’s tensile strength is obtained from the relation: ( ) 1/3 2 0 1.58 c t f f a ⎛ ⎞ ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ ⎝ ⎠ ′ =′
- 7. 7 MAT 72R3 INPUTS Example for a 45.6 MPa concrete, the non-zero user inputs are: Example for a 45.6 MPa concrete, the non-zero user inputs are: Card 1 – RO – concrete density (2.17E-3 g/mm^3) Card 2 – A0 – negative of the unconfined compressive strength (-45.6 MPa) Card 3 – RSIZE & UCF – conversion factors for length 3.972E-2 for inches–to-millimeters and 145 for psi-to-MPa. All of the other input parameters are blank, or zero. σ
- 8. 8 MAT CONCRETE DAMAGE REL3 • Mat 72R3 generated parameters are written in keyword format to the LS- DYNA “messag” file. This includes the required Equation-of-State. • The user can modify these generated parameters, e.g. change the tensile strength, and use the modified inputs to update the model parameters. $ $--------------------------- MATERIAL CARDS ------------------------------------ $ LS-DYNA Keyword Generated Input for Release III $ [Default values = K&C generic f'c=6580 psi concrete] $ >>> Users need to change/check: MatID & RO & Rsize & LocWidth for units <<< *MAT_Concrete_Damage_Rel3 $ MATID RO PR 72 2.120E-04 1.900E-01 $ f't A0 A1 A2 B1 OMEGA A1F 3.518E+00 1.182E+01 4.463E-01 2.020E-03 1.600E+00 5.000E-01 4.417E-01 $ sLambda NOUT EDROP RSIZE UCF LCRate LocWidth NPTS 1.000E+02 2.000E+00 1.000E+00 3.937E-02 1.450E+02 0.000E+00 2.540E+01 1.300E+01 $ Lambda01 Lambda02 Lambda03 Lambda04 Lambda05 Lambda06 Lambda07 Lambda08 0.000E+00 8.000E-06 2.400E-05 4.000E-05 5.600E-05 7.200E-05 8.800E-05 3.200E-04 $ Lambda09 Lambda10 Lambda11 Lambda12 Lambda13 B3 A0Y A1Y 5.200E-04 5.700E-04 1.000E+00 1.000E+01 1.000E+10 1.150E+00 8.928E+00 6.250E-01 $ Eta01 Eta02 Eta03 Eta04 Eta05 Eta06 Eta07 Eta08 0.000E+00 8.500E-01 9.700E-01 9.900E-01 1.000E+00 9.900E-01 9.700E-01 5.000E-01 $ Eta09 Eta10 Eta11 Eta012 Eta13 B2 A2F A2Y 1.000E-01 0.000E+00 0.000E+00 0.000E+00 0.000E+00 1.350E+00 2.958E-03 6.438E-03 $
- 9. 9 45.6 MPa Concrete & MAT 72R3 0 100 200 300 400 500 600 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 Volume Strain Pressure[MPa] ICT Mat 72R3 Isotropic Compression Test - Laboratory Data (ICT) and MAT 72R3Isotropic Compression Test - Laboratory Data (ICT) and MAT 72R3 σ σ σ Also called a Hydrostatic Compression Test
- 10. 10 45.6 MPa Concrete & MAT 72R3 Triaxial Compression Test - Laboratory Data and MAT 72R3Triaxial Compression Test - Laboratory Data and MAT 72R3 0 100 200 300 400 500 600 0 100 200 300 400 500 600 700 Mean Stress [MPa] StressDifference[MPa] Triaxial Failure Surface Mat 72R3 σ1 σ2 σ1 >σ2 σ2 Typically, 3 or more Triaxial Compression Tests are needed to define the shear failure surface
- 11. 11 45.6 MPa Concrete & MAT 72R3 Uniaxial Strain Test - Laboratory Data (UXE) and MAT 72R3Uniaxial Strain Test - Laboratory Data (UXE) and MAT 72R3 -150 -50 50 150 250 350 450 0 100 200 300 400 500 600 Mean Stress [MPa] StressDifference[MPa] UXE Mat 72R3 σ ε=0 ε=0 A Uniaxial Strain Test exercises both the cap and shear failure surfaces.
- 12. 12 45.6 MPa Concrete & MAT 72R3 Direct Pull Test - Laboratory Data and MAT 72R3Direct Pull Test - Laboratory Data and MAT 72R3 -4.5 -4 -3.5 -3 -2.5 -2 -1.5 -1 -0.5 0 -200 -150 -100 -50 0 Axial Strain [% times 10,000] AxialStress[MPa] Mat 72R3 Ave f't Test 01 Test 02 Test 03 Test 04 Test 05 σ Also called a Uniaxial Tension Test
- 13. 13 SUMMARY • The latest release of the Concrete Damage Model, i.e. Release 3, provides a robust representation of complex concrete laboratory responses. • Mat 72R3 requires minimal user inputs, i.e. unconfined compression strength. •Mat 72R3 is intended as a replacement for Mat 72, although Mat 72 is retained for backward compatibility. • Users may want to evaluate the other two minimal input concrete models: Pseudo-TENSOR (Mat 16) and CSCM Concrete (Mat 159) • The latest release of the Concrete Damage Model, i.e. Release 3, provides a robust representation of complex concrete laboratory responses. • Mat 72R3 requires minimal user inputs, i.e. unconfined compression strength. •Mat 72R3 is intended as a replacement for Mat 72, although Mat 72 is retained for backward compatibility. • Users may want to evaluate the other two minimal input concrete models: Pseudo-TENSOR (Mat 16) and CSCM Concrete (Mat 159)
- 14. 14 REFERENCES Malvar, L.J., Simons, D., “Concrete Material Modeling in Explicit Computations,” Proceedings, Workshop on Recent Advances in Computational Structural Dynamics and High Performance Computing, USAE Waterways Experiment Station, Vicksburg, MS, April 1996, pages 165-194. (LSTC may provide this reference upon request.) Malvar, L.J., Crawford, J.E., Wesevich, J.W., Simons, D., “A Plasticity Concrete Material Model for DYNA3D,” International Journal of Impact Engineering, Volume 19, Numbers 9/10, December 1997, pages 847- 873. Malvar, L.J., Ross, C.A., “Review of Static and Dynamic Properties of Concrete in Tension,” ACI Materials Journal, Volume 95, Number 6, November-December 1998, pages 735-739. Malvar, L.J., Crawford, J.E., Morrill, K.B., “K&C Concrete Material Model Release III — Automated Generation of Material Model Input,” K&C Technical Report TR-99-24-B1, 18 August 2000 (Limited Distribution).