混合纤维增强水泥基复合材料的力学性能试验及数值模拟

发布时间：2019-03-11 09:14

【摘要】：混凝土是目前应用最广泛的工程材料，存在抗拉强度低、韧性差等固有弱点，改进的主要方法是掺加纤维，已有研究证明，混凝土的强度等级越高、纤维的掺量越大、纤维的长径比越大、在基体中的分布越均匀、钢纤维增强混凝土的强度也越高，其抗冲击、抗侵彻、抗爆炸和抗震塌能力越强。本文通过钢纤维和聚乙烯醇(PVA)纤维混合增强水泥基复合材料（HFRCC）的立方体、棱柱体、圆柱体轴心抗压试验、直接拉伸试验和梁的四点弯曲试验，得到了该材料的抗压强度、弹性模量、峰值应变、泊松比和抗拉强度等力学性能指标，结合相关文献资料对该材料的抗压和抗拉性能进行了研究。研究结果表明该材料的压缩性能与混凝土相差较大，与PVA单纤维增强水泥基复合材料（FRCC）相近，，而抗拉强度比FRCC高，运用规范公式能很好表达其压缩应力应变曲线上升段，其压缩应力应变曲线可以用一多项式来描述。基于实测的准静态力学数据，采用考虑损伤的HJC本构模型，使用ANSYS/LS-DYNA有限元软件对参考文献中金属弹丸对钢纤维三维编织增强混凝土靶板的侵彻过程抗冲击和抗侵彻进行了数值模拟，从数值角度验证所取模型参数的有效性。然后根据验证后的参数对混合纤维增强水泥基复合材料和普通混凝土进行侵彻模拟，考察混合纤维增强水泥基复合材料的动力性能，结果表明：混合纤维增强水泥基复合材料具有较好的整体性、韧性、耗能能力等。以上结论对工程防护、抗侵彻、抗震塌等有非常重要的指导意义。
[Abstract]:Concrete is the most widely used engineering material at present, there are inherent weaknesses such as low tensile strength, poor toughness and so on. The main improvement method is to add fiber. It has been proved that the higher the strength grade of concrete is, the greater the content of fiber is. The greater the length-diameter ratio of the fiber is, the more uniform the distribution in the matrix is, the higher the strength of the steel fiber reinforced concrete is, and the stronger the anti-impact, anti-penetration, anti-explosion and anti-seismic sloughing ability of the steel fiber reinforced concrete is. In this paper, the cube, prism, cylinder axial compression test, direct tensile test and four-point bending test of concrete-based composite (HFRCC) reinforced with steel fiber and polyvinyl alcohol (PVA) fiber were carried out. The compressive strength, elastic modulus, peak strain, Poisson's ratio and tensile strength of the material were obtained. The compressive and tensile properties of the material were studied. The results show that the compressive performance of the material is quite different from that of concrete, which is similar to that of PVA single fiber reinforced cement-based composites (FRCC), and the tensile strength is higher than that of FRCC. The upward section of the compressive stress-strain curve can be well expressed by using the criterion formula. The compressive stress-strain curve can be described by a polynomial. Based on the measured quasi-static mechanical data, the HJC constitutive model considering damage is adopted. ANSYS/LS-DYNA finite element software is used to simulate the penetration process of metal projectiles in reference to steel fiber reinforced concrete target in the process of anti-impact and anti-penetration. The validity of the model parameters is verified from the numerical point of view. Then according to the verified parameters, the penetration simulation of the hybrid fiber reinforced cement-based composites and ordinary concrete is carried out, and the dynamic properties of the hybrid fiber-reinforced cement-based composites are investigated. The results show that the hybrid fiber reinforced cement-based composites have good integrity, toughness, energy dissipation capacity and so on. These conclusions have very important guiding significance for engineering protection, anti-penetration, anti-earthquake collapse and so on.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU528.572

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