Experiment and simulation on high-pressure equation of state for concrete
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摘要: 为研究高压下混凝土冲击压缩特性以及确定HJC本构模型状态方程参数,采用
$\varnothing $ 58 mm火炮加载技术和多普勒探针系统(Doppler probe system,DPS)测速技术,对抗压强度为26.5 MPa(C25)和42.1 MPa(C40)的混凝土进行反向平板撞击实验研究与数值模拟。DPS探针记录TU1无氧铜靶自由面粒子速度历史,根据一维应变弹塑性波理论,计算撞击压力,拟合得到2~11 GPa高压条件下混凝土波速与粒子速度(us-up)、压力与体积应变(p-μ)关系。实验结果表明:高压条件下,混凝土波速-粒子速度呈线性关系;两种初始密度、孔隙率相近,强度不同的混凝土波速-粒子速度、压力-体积应变关系存在明显差异,相同压力下,混凝土试件强度越高,体积应变越小。基于实验结果,确定了两种强度混凝土HJC本构模型状态方程参数,利用LS-DYNA动力有限元分析软件对平板撞击实验进行了数值模拟,靶板自由面粒子速度历史与实验曲线吻合较好,仿真结果表明混凝土中冲击波的追赶卸载现象仅存在于低速撞击条件下。Abstract: To study the dynamic compression characteristics of concrete under high hydrostatic pressure and to determine the equation of state parameters of the HJC constitutive model, inverse flyer-impact tests and numerical simulation analysis were conducted with two kinds of concrete flyers of which the compressive strengths were 26.5 MPa and 42.1 MPa, respectively. The concrete flyers were launched by$\varnothing $ 58 mm gun against TU1 copper targets. The particle velocity histories of the TU1 copper target free surface were measured by DPS (Doppler probe system). Based on the one-dimensional strain shock wave theory, the impact pressure was calculated. The relationships of shock velocity vs. particle velocity and pressure vs. volume strain in the pressure range of 2−11 GPa were fitted. The results show that the relationship between shock velocity and particle velocity of concrete is linear. The relationships of shock velocity vs. particle velocity and pressure vs. volume strain for concretes with similar initial density and porosity but different compressive strengths are obviously different. Under the same pressure, the higher the compressive strength of concrete, the smaller the volume strain is. According to the test results, the equation of state parameters of the HJC constitutive model were determined and the plate-impact tests were simulated by LS-DYNA. The simulated particle velocity histories of the TU1 target free surface were in good agreement with the experimental results. The simulation results show that the phenomenon of chasing and unloading of shock waves in concrete only exists under low velocity impact conditions.-
Key words:
- concrete /
- flyer-impact /
- equation of state /
- HJC /
- oxygen free copper
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图 15 HJC模型状态方程[2]
Figure 15. EOS of the HJC model
表 1 混凝土平板撞击实验数据
Table 1. Flyer-impact test data of concrete
编号 类别 v0/(m·s−1) up1/(m·s−1) up2/(m·s−1) us2/(m·s−1) σH/MPa C25v1017 C25 1017 343.9 845.0 3469.7 6450.4 C25v1259 C25 1259 441.0 1038.5 3682.8 8414.2 C25v1523 C25 1523 575.6 1235.2 4136.2 11240.0 C25v479 C25 479 112.6 422.7 2177.6 2025.1 C40v834 C40 834 276.3 695.8 3383.8 5121.2 C40v989 C40 989 355.5 811.3 3786.7 6681.6 C40v1279 C40 1279 476.1 1040.9 4037.4 9140.6 C40v1484 C40 1484 580.6 1193.7 4370.9 11348.0 表 2 混凝土HJC模型状态方程参数
Table 2. EOS parameters of the HJC model for concrete
混凝土 K1/GPa K2/GPa K3/GPa pL/MPa μL C25 56.34 −363.96 1689.50 0.9 0.171 C40 137.37 −971.90 3483.43 1.2 0.187 表 3 混凝土HJC模型主要参数
Table 3. Parameters of HJC model for concrete
混凝土 ρ/(g·cm−3) G/GPa fc/MPa T/MPa pC/MPa μC/10−3 C25 2.202 9.517 26.5 3.19 8.83 0.696 C40 2.177 11.79 42.1 4.02 14.03 0.893 注:G为剪切模量,fc为单轴抗压强度,T为最大静水拉伸强度,pC为压碎压力,μC为压碎体积应变。 -
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