Strain-rate effects associated with the HJC concrete model

Johnson, Gordon R.; Holmquist, Timothy J.; Gerlach, C.A.

doi:10.1051/epjconf/201818301008

Cited by 7 publications

(4 citation statements)

References 6 publications

(17 reference statements)

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“…Johnson’s method for penetration and perforation problems. 16 According to, 17 the numerical method contains a new way to isolate discontinuity surfaces of materials that does not impose serious restrictions on the solution of the problems. For example, the crater depth obtained from the numerical study differs by less than 10% from experimentally obtained values, 18 a good agreement.…”

Section: A Mathematical Model and A Numerical Methodsmentioning

confidence: 99%

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Deep penetration of low velocity metal penetrators into ice

Orlov

Orlova

2021

Proceedings of the Institution of Mechanical Engineers, Part C:

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The paper summarizes the results of research of the destruction of an ice block with cylindrical and spherical penetrators at low velocity (≤325 m/s). The behaviour of ice at high strain rates is described by an elastic–plastic model of continuum mechanics. Numerical modelling of penetration is performed with IMPACT computer code. Algorithms of splitting nodes and destroying elements in a Lagrangian numerical method were modified to solve problems of penetration and perforation. The fracturing is described by a deterministic fracture model. Crack paths are examined; the damage is predicted and compared with existing experimental results. It was found that in the subsonic range of initial velocities the penetration time did not exceed 0.3 ms. Examination of the penetrators’ shapes showed that they were not plastic deformed.

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Section: A Mathematical Model and A Numerical Methodsmentioning

confidence: 99%

“…Several quantitative tests have been performed in. 3,12,16 In addition, several experiments 12,13 were repeated. The subject of comparison was the residual displacement of metal plate subjected impact of an ice cylinder.…”

Section: Test Calculationsmentioning

confidence: 99%

Deep penetration of low velocity metal penetrators into ice

Orlov

Orlova

2021

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…Regarding the strain-rate formulation in MHJC material model, Polanco-Loria et al [32] modified the original strainrate function to avoid negative rate enhancement predicted by the HJC model for low strain rates. In 2018, Johnson et al [60] argued that new experimental data showed that the strain-rate enhancement effects in concrete were greater than previously determined for the HJC model. When compared to material data available in the literature [61] for different concrete types, we see that the non-linear formulation with C = 0.04 as used by Polanco-Loria et al [32] provides reasonable results.…”

Section: Discussionmentioning

confidence: 97%

Projectile Impact on Plain and Reinforced Concrete Slabs

Jacobsen,

Kristoffersen,

Dey

et al. 2023

J. dynamic behavior mater.

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Reinforced concrete is a material frequently used in protective structures and infrastructure exposed to extreme loading. In this study, the ballistic perforation resistance of 100 mm thick plain and reinforced concrete slabs impacted by 20 mm ogive-nose steel projectiles was investigated both experimentally and numerically. Two different reinforcement configurations were used to investigate the effect of rebar diameter and spacing. Concrete with nominal unconfined compressive strength of 75 MPa was used to cast material test specimens and slabs. Ballistic impact tests were performed in a compressed gas gun facility. The mechanical properties of the concrete were found using standardised tests and two-dimensional digital image correlation, and the constitutive relation was described by a modified version of the Holmquist-Johnson-Cook model. Finite element models in LS-DYNA reproduced the projectile residual velocity in good agreement with the experimental results. The primary objective of the study was thus to validate a rather simple constitutive relation intended for large scale numerical simulations of concrete structures exposed to ballistic impact loading, while a secondary objective was to investigate the effect of reinforcement on the ballistic perforation resistance of concrete slabs both experimentally and numerically since the literature is somewhat inconsistent on this matter.

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“…All three models are readily available as standard models in the explicit finite element (FE) code LS-DYNA (LST, 2020). The Holmquist–Johnson–Cook (HJC) model (Holmquist et al, 1993; Johnson et al, 2018; Rajput et al, 2018) is another widely used model, and a modified version has been included due to its relative ease of calibration (Polanco-Loria et al, 2008). Numerous constitutive concrete models may be employed to simulate the ballistic impact resistance of concrete, for example, the Winfrith Concrete (WC) model (Broadhouse and Neilson, 1987), Concrete-Damage-Plasticity (CDP) (Lubliner et al, 1989) and a damage model based on effective rate-dependency proposed by Pereira et al (2018).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of automatic versus material test-based calibrations of concrete models for ballistic impact simulations

Antoniou

Kristoffersen

2023

International Journal of Protective Structures

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Concrete is used for protective structures all over the world. Accurate response estimates to a given threat is vital for designing such structures. Concrete models often require numerous input parameters for which sufficient experimental data can be challenging to obtain. Some models are accompanied by parameter generators which use the unconfined compression strength to extrapolate the remainder of the parameters based on experimental databases. This study investigates simulation of ballistic impact on high-strength concrete with 75 MPa nominal unconfined cylindrical compressive strength. The first objective is to investigate the accuracy parameter generators to produce input data for commonly used concrete material models. The second objective is to establish and evaluate a simplified parameter calibration procedure based on standard material experiments and data from the literature. The results employing parameter generators varied notably between the models while still giving decent ballpark estimates. The parameters obtained from inverse modelling of standardized material tests improved the results significantly. The findings of this study recommend caution when using automatic parameter generators. Although a detailed calibration of these concrete models is complicated, a simplified calibration gives reasonable predictions, making this the advisable approach for designing concrete protective structures.

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Strain-rate effects associated with the HJC concrete model

Cited by 7 publications

References 6 publications

Deep penetration of low velocity metal penetrators into ice

Deep penetration of low velocity metal penetrators into ice

Projectile Impact on Plain and Reinforced Concrete Slabs

Evaluation of automatic versus material test-based calibrations of concrete models for ballistic impact simulations

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