To enhance the high-speed impact resistance of reinforced concrete,a negative Poisson ratio design was implemented on the internal framework of the concrete.This design resulted in two variations of concrete specimens with different numbers of internal concave angles:one with six-ribbed and another with star-shaped steel reinforcement.Additionally,square reinforced concrete and plain concrete were used as control groups.Split Hopkinson pressure bar(SHPB)test was conducted to assess the high-speed impact resistance of these various types of reinforced concrete.Furthermore,a digital speckle correlation method(DSCM)was employed to analyze the field variations and microscale Poisson ratio.The results show that the negative Poisson ratio of reinforced concrete can be achieved by designing the structure of reinforced skeleton.The negative Poisson ratios of six-ribbed and star-shaped reinforced concrete under high-speed impact are-0.50 and-1.00,respectively.Under the high-speed impact,the trend of surface cracks of the three kinds of reinforced concrete is related to the shape of the steel skeleton.According to the strain field,the maximum strain values of both six-ribbed and star-shaped reinforced concrete occur in the vicinity of the internal concave angles,gradually decreasing outward from these internal concave angles.With the increase of the number of internal concave angles,the deformation ability and energy dissipation ability of reinforced concrete are significantly enhanced.The energy consumption of six-ribbed and star-shaped reinforced concrete is 1.76×105 and 1.86×105 J/m3,respectively,which is 1.17 times and 1.23 times that of square reinforced concrete.These results indicate that reinforced concrete with negative Poisson ratio is superior in energy dissipation,and these capabilities could be further strengthened with the increase in the number of internal concave angles.
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