钢筋混凝土的负泊松比设计与抗弯性能研究

Negative Poisson Ratio Design and Flexural Performance of Reinforced Concrete

将钢筋混凝土的方形结构箍筋改变为六肋结构、星形结构,设计制备出拥有负泊松比效应的钢筋混凝土梁。通过三点弯曲试验和落锤冲击试验数值模拟分析混凝土的抗弯性能,同时通过数字散斑相关方法分析其变形行为以及泊松比。结果表明:六肋结构和星形结构的箍筋能够提高混凝土的抗弯承载力,延缓其裂缝开展,提高其能量吸收率与弯曲韧性,星形箍筋的钢筋混凝土抗弯承载力和弯曲韧性系数分别可达22.6 kN及3.86 MPa;随箍筋结构中内凹角数量的增加,混凝土的抗弯性能增强,泊松比反而减小,且星形箍筋的钢筋混凝土甚至出现了负泊松比的现象,泊松比最小可达-0.03。

The reinforced concrete beam with negative Poisson ratio effect was designed and fabricated by changing the square stirrup of reinforced concrete into six-ribbed structure and star-shaped structure.The flexural performance of concrete was simulated by three-point bending test and drop hammer impact test,and its deformation behavior and Poisson ratio were analyzed by digital speckle correlation method.The results show that the stirrups of six-ribbed structure and star-shaped structure can improve the flexural capacity of concrete,delay the development of cracks,and improve energy absorption rate and flexural toughness.The flexural capacity and coefficient of flexural toughness of star-shaped reinforced concrete are up to 22.6 kN and 3.86 MPa,respectively.With the change of stirrup structure,the flexural performance of concrete is enhanced,but the Poisson ratio decreases,and the phenomenon of negative Poisson ratio even appears in reinforced concrete with star-shaped stirrup.The minimum Poisson ratio can reach-0.03.