14.5 Summary
501
matrix, the third platform stage due to the fiber bridging mechanism and the
final softening stage due to the pullout and/or broken of fibers. Then a corresponding dynamic tensile fracture model is presented based on the assumption
that the strain-rate only affects the tensile strength similar to the traditional
concrete. Finally, a new dynamic tensile damage model is established and
incorporated into the Kong-Fang material model.
(2) All the parameters needed in the modified Kong-Fang material model, i.e.,
parameters related to the failure surface, damage and EoS are carefully calibrated using the static and dynamic uniaxial compressive and tensile tests,
triaxial compression test, hydrostatic pressure test and flyer-plate-impact test,
etc. It should be pointed out that the calibrated parameters, especially the DIF
and EoS, can be directly used in other material models, e.g., the K&C material
model.
(3) Comparison of the numerical predictions by the modified Kong-Fang material
model with experimental data on UHPCC structures subjected to impact and
blast loadings demonstrates that the modified Kong-Fang material model can
well predict the dynamic response (impact force and deflection) and failure in
UHPCC structures subjected to intensively dynamic loadings.
(4) Corresponding numerical predictions by the original Kong-Fang material
model show that it cannot be used for UHPCC material. This indicates that
material models originally developed for traditional concrete, without carefully parameter calibration or model modification, cannot be directly used for
UHPCC material. The use of these original material models may result in
underestimation of structural stiffness even to a wrong prediction.
References
AUTODYN. Theory Manual (Revision 4.3)[M]. Century Dynamics, Inc, 2013.
BAYLOT J T, BRITT J R, CARRE G L, COLTHARP D R, DAVIS L K, DRAKE J L, HUFF W
L, KIGER S A, ROHANI B, ROOKE A D. Fundamentals of protective design for conventional
weapons[M]. U.S. Army Engineer Waterways Experiment Station: 1984.
CADONI E, FORNI D. Experimental analysis of the UHPFRCs behavior under tension at high
stress rate[J]. The European Physical Journal Special Topics, 2016, 225: 253–264.
CLARK J. Preliminary Investigation of ultra-high performance concrete behavior at high strain
rates using the split-Hopkinson pressure bar[D]. Michigan: Michigan Technological Univ., 2013.
CURBACH M, SPECK K. Zweiaxiale Druckfestigkeit von ultrahochfestem Beton[J]. Beton-und
Stahlbetonbau, 2010, 102(10): 664–673.
ERZAR B, PONTIROLI C, BUZAUD E. Shock characterization of an ultra-high strength
concrete[J]. The European Physical Journal Special Topics, 2016, 225: 355–361.
FANG Q, WU H. UHPCC targets under projectile impact. In: concrete structures under projectile
impact[M]. Singapore: Springer, 2017.
FUJIKAKE K, SENGA T, UEDA N, OHNO T, KATAGIRI M. Effects of strain rate on tensile
behavior of reactive powder concrete[J]. Journal of Advanced Concrete Technology, 2006, 4(1):
79–84.
501
matrix, the third platform stage due to the fiber bridging mechanism and the
final softening stage due to the pullout and/or broken of fibers. Then a corresponding dynamic tensile fracture model is presented based on the assumption
that the strain-rate only affects the tensile strength similar to the traditional
concrete. Finally, a new dynamic tensile damage model is established and
incorporated into the Kong-Fang material model.
(2) All the parameters needed in the modified Kong-Fang material model, i.e.,
parameters related to the failure surface, damage and EoS are carefully calibrated using the static and dynamic uniaxial compressive and tensile tests,
triaxial compression test, hydrostatic pressure test and flyer-plate-impact test,
etc. It should be pointed out that the calibrated parameters, especially the DIF
and EoS, can be directly used in other material models, e.g., the K&C material
model.
(3) Comparison of the numerical predictions by the modified Kong-Fang material
model with experimental data on UHPCC structures subjected to impact and
blast loadings demonstrates that the modified Kong-Fang material model can
well predict the dynamic response (impact force and deflection) and failure in
UHPCC structures subjected to intensively dynamic loadings.
(4) Corresponding numerical predictions by the original Kong-Fang material
model show that it cannot be used for UHPCC material. This indicates that
material models originally developed for traditional concrete, without carefully parameter calibration or model modification, cannot be directly used for
UHPCC material. The use of these original material models may result in
underestimation of structural stiffness even to a wrong prediction.
References
AUTODYN. Theory Manual (Revision 4.3)[M]. Century Dynamics, Inc, 2013.
BAYLOT J T, BRITT J R, CARRE G L, COLTHARP D R, DAVIS L K, DRAKE J L, HUFF W
L, KIGER S A, ROHANI B, ROOKE A D. Fundamentals of protective design for conventional
weapons[M]. U.S. Army Engineer Waterways Experiment Station: 1984.
CADONI E, FORNI D. Experimental analysis of the UHPFRCs behavior under tension at high
stress rate[J]. The European Physical Journal Special Topics, 2016, 225: 253–264.
CLARK J. Preliminary Investigation of ultra-high performance concrete behavior at high strain
rates using the split-Hopkinson pressure bar[D]. Michigan: Michigan Technological Univ., 2013.
CURBACH M, SPECK K. Zweiaxiale Druckfestigkeit von ultrahochfestem Beton[J]. Beton-und
Stahlbetonbau, 2010, 102(10): 664–673.
ERZAR B, PONTIROLI C, BUZAUD E. Shock characterization of an ultra-high strength
concrete[J]. The European Physical Journal Special Topics, 2016, 225: 355–361.
FANG Q, WU H. UHPCC targets under projectile impact. In: concrete structures under projectile
impact[M]. Singapore: Springer, 2017.
FUJIKAKE K, SENGA T, UEDA N, OHNO T, KATAGIRI M. Effects of strain rate on tensile
behavior of reactive powder concrete[J]. Journal of Advanced Concrete Technology, 2006, 4(1):
79–84.