K&C Model of Steel Fiber Reinforced Concrete Plate under Impact and Blast Load
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摘要: 钢纤维混凝土(Steel fiber reinforced concrete,SFRC)具有优异的延性、韧性及能量吸收能力,被广泛应用于各类防护结构。K&C模型已成为研究普通混凝土构件动力响应的常用材料模型,但仍无法准确表征SFRC的动力特性。为了提高K&C模型在冲击及爆炸荷载作用下预测SFRC板动力响应的能力,对K&C模型进行了改进:基于大量三轴压缩实验数据,建立了新的失效强度面参数模型;采用反复试验法,建立了新的损伤演化模型,并校准了拉、压损伤参数;基于大量高应变率下SFRC的单轴压缩实验数据,建立了新的受压动力增强因子模型。通过LS-DYNA显式有限元动力分析软件模拟了SFRC板的动力响应,模拟结果验证了上述改进的有效性与可靠性。Abstract: Steel fiber reinforced concrete (SFRC) is widely used in protective structures due to its excellent ductility, toughness and energy absorption capacity. K&C model is a common constitutive model for studying the response of normal concrete components under impact and blast loads, but it cannot accurately characterize the dynamic response of SFRC. In order to improve prediction of K&C model for the dynamic response of SFRC plate under impact and blast load, this work improves K&C model: a new failure strength surface parameter model was established based on a large number of triaxial compression experimental data, a new damage evolution model was established by trial-and-error method, and the damage parameters of tensile and compressive were calibrated. A new compression dynamic increase factor (CDIF) model was established based on a large number of uniaxial compression experimental data of SFRC under high strain rate. The dynamic response of SFRC plate is simulated by explicit dynamic analysis software LS-DYNA. The effectiveness and reliability of the above improvements have been verified by simulation results.
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Key words:
- steel fiber reinforced concrete /
- K&C model /
- impact load /
- blast load /
- dynamic response
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表 1 改进的钢纤维混凝土K&C模型参数
Table 1. Parameters of the modified K&C model of SFRC
Strength surface a0/MPa a1 a2/MPa−1 a0y/MPa a1y a2y/MPa−1 a1f a2f/MPa−1 64.0 0.481 5.82×10−4 45.93 0.726 1.77×10−3 0.476 8.56×10−4 Damage Others b1 b2 b3 α αc αd λm Lw/mm fc/MPa ft/MPa ρ/(kg·m−3) ν ω 0.75 −1.50 1.15 3.00 0.381 1.90 9.5×10−5 24 175.3 13.8 2 600 0.19 0.5 表 2 平头弹丸的材料参数
Table 2. Materials parameters of the flat ended projectile
ρ/(g·cm−3) G/GPa A/MPa B/MPa N C M Tm/K TR/K 7.83 210 792 510 0.26 0.014 1.03 1 793 294 ε/(μs−1) cp/(J·kg−1·K−1) SPALL IT D1 D2 D3 D4 D5 1.0 × 10−4 4.77 × 10−5 3.0 0.0 4.00 0.00 0.00 0.00 0.00 表 3 实验数据与数值模拟结痂弹坑直径比较
Table 3. Comparisons of experimental data and numerical simulation of the scabbed crater diameter
Projectile velocity/(m·s−1) Scabbed crater diameter/mm Model error/% Experiment Original K&C Modified K&C Original K&C Modified K&C 58.2 120.5 132 106 9.5 12.0 76.0 119.2 148 124 24.2 4.0 104.0 120.3 28 128 76.7 6.4 -
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