UHMWPE纤维混凝土静三轴、动劈裂以及抗侵彻性能试验研究
发布时间：2018-08-04 20:48
【摘要】：超高分子量聚乙烯(UHMWPE)纤维作为当今世界三大高科技纤维之一,具有众多优良性能。以其作为增强体的纤维混凝土复合材料具有强度高,韧性好等特点,因此可期望用于防护工程领域以改善混凝土抗拉强度低、脆性大等不利因素,提高结构的抗侵彻防护性能。实际应用中,防护结构往往处于多向受力、高速变形等复杂应力状态,常规试验结论往往难以满足工程设计需求,这就要求对材料进行有针对性的试验研究。本文基于上述研究背景,对UHMWPE纤维混凝土分别进行了三轴压缩试验、动态劈裂试验以及侵彻试验,研究了其三轴压缩性能、动态劈裂性能以及抗侵彻性能。论文主要工作及研究成果如下:(1)归纳分析了现有混凝土三轴压缩试验、动态劈裂试验以及侵彻试验技术和理论,据此,提出了本文试验研究设计方案及试件的制备工艺。(2)首次进行了UHMWPE纤维混凝土的三轴压缩性能试验研究。研究发现,试件的破坏模式由不加围压的压裂模式变为斜剪模式,纤维不改变混凝土的破坏模式,但可以显著减小裂缝宽度。压缩强度随围压的增加而增大,纤维的掺入使压缩强度有所降低,与掺量有关;基于现有强度准则分析了压子午线特征,得到纤维掺量对材料参数影响的公式。峰值应变与压缩韧性随纤维掺量的增加而增大,纤维能显著提高混凝土韧性,但随着围压的增加,纤维的作用减弱。(3)首次进行了UHMWPE纤维混凝土的动态劈裂性能试验研究。研究发现,纤维可以显著减小混凝土裂缝宽度,延长破坏时间,减弱劈裂破坏作用。在1~20s-1应变率范围内,纤维混凝土抗拉强度有明显提高;基于对现有动态抗拉强度提高因子(DIF)公式的分析,得到了与试验结果相符的UHMWPE纤维混凝土DIF公式。最后,利用微裂缝机理解释了纤维混凝土DIF效应弱于素混凝土的原因。(4)开展了UHMWPE纤维混凝土的抗侵彻性能试验研究。研究发现,弹速越大,靶体破坏程度越大,纤维可以减轻靶体的破坏,迎弹面弹坑各项指标随纤维掺量的增加而显著减小。在对比分析现有侵深经验公式的适用性基础上,基于Hughes公式提出了考虑纤维掺量的侵深预测模型,与试验结果吻合较好。
[Abstract]:Ultra high molecular weight polyethylene (UHMWPE) (UHMWPE) fiber, as one of the three high-tech fibers in the world, has many excellent properties. The fiber reinforced concrete composite has the characteristics of high strength and good toughness, so it can be expected to be used in the field of protective engineering to improve the low tensile strength of concrete, large brittleness and other adverse factors, and improve the penetration and protection performance of the structure. In practical application, the protective structure is often in complex stress state, such as multi-direction force, high-speed deformation and so on. The conventional test conclusion is often difficult to meet the engineering design requirements, which requires targeted experimental research on materials. Based on the above research background, the triaxial compression test, dynamic splitting test and penetration test of UHMWPE fiber reinforced concrete are carried out, and its triaxial compression, dynamic splitting and penetration resistance are studied. The main work and research results are as follows: (1) the existing concrete triaxial compression test, dynamic splitting test and penetration test technology and theory are summarized and analyzed. The experimental design scheme and the preparation process of the specimen are proposed. (2) the triaxial compression performance of UHMWPE fiber reinforced concrete is studied for the first time. It is found that the fracture mode of the specimen changes from the fracturing mode without confining pressure to the oblique shear mode, and the fiber does not change the failure mode of concrete, but it can significantly reduce the crack width. The compressive strength increases with the increase of confining pressure, and the compressive strength decreases with the addition of fiber, which is related to the content of the fiber. Based on the existing strength criterion, the characteristics of the compression meridian are analyzed, and the formula of the influence of fiber content on the material parameters is obtained. The peak strain and compressive toughness increase with the increase of fiber content, fiber can improve the toughness of concrete, but with the increase of confining pressure, the effect of fiber is weakened. (3) the dynamic splitting behavior of UHMWPE fiber concrete is studied for the first time. It is found that the fiber can significantly reduce the crack width, prolong the failure time and weaken the splitting failure. In the range of 1~20s-1 strain rate, the tensile strength of fiber reinforced concrete is obviously improved, and based on the analysis of the existing (DIF) formula of dynamic tensile strength improvement factor, the UHMWPE fiber reinforced concrete DIF formula, which is consistent with the test results, is obtained. Finally, the reason why the DIF effect of fiber reinforced concrete is weaker than that of plain concrete is explained by using micro-crack mechanism. (4) the penetration resistance of UHMWPE fiber reinforced concrete is studied experimentally. It is found that the larger the velocity of the projectile, the greater the damage degree of the target body. The fiber can reduce the damage of the target body, and the targets of crater on the projectile surface decrease obviously with the increase of fiber content. Based on the comparison and analysis of the applicability of the existing penetration empirical formulas, a penetration prediction model considering fiber content is proposed based on the Hughes formula, which is in good agreement with the experimental results.
【学位授予单位】：国防科学技术大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528
[Abstract]:Ultra high molecular weight polyethylene (UHMWPE) (UHMWPE) fiber, as one of the three high-tech fibers in the world, has many excellent properties. The fiber reinforced concrete composite has the characteristics of high strength and good toughness, so it can be expected to be used in the field of protective engineering to improve the low tensile strength of concrete, large brittleness and other adverse factors, and improve the penetration and protection performance of the structure. In practical application, the protective structure is often in complex stress state, such as multi-direction force, high-speed deformation and so on. The conventional test conclusion is often difficult to meet the engineering design requirements, which requires targeted experimental research on materials. Based on the above research background, the triaxial compression test, dynamic splitting test and penetration test of UHMWPE fiber reinforced concrete are carried out, and its triaxial compression, dynamic splitting and penetration resistance are studied. The main work and research results are as follows: (1) the existing concrete triaxial compression test, dynamic splitting test and penetration test technology and theory are summarized and analyzed. The experimental design scheme and the preparation process of the specimen are proposed. (2) the triaxial compression performance of UHMWPE fiber reinforced concrete is studied for the first time. It is found that the fracture mode of the specimen changes from the fracturing mode without confining pressure to the oblique shear mode, and the fiber does not change the failure mode of concrete, but it can significantly reduce the crack width. The compressive strength increases with the increase of confining pressure, and the compressive strength decreases with the addition of fiber, which is related to the content of the fiber. Based on the existing strength criterion, the characteristics of the compression meridian are analyzed, and the formula of the influence of fiber content on the material parameters is obtained. The peak strain and compressive toughness increase with the increase of fiber content, fiber can improve the toughness of concrete, but with the increase of confining pressure, the effect of fiber is weakened. (3) the dynamic splitting behavior of UHMWPE fiber concrete is studied for the first time. It is found that the fiber can significantly reduce the crack width, prolong the failure time and weaken the splitting failure. In the range of 1~20s-1 strain rate, the tensile strength of fiber reinforced concrete is obviously improved, and based on the analysis of the existing (DIF) formula of dynamic tensile strength improvement factor, the UHMWPE fiber reinforced concrete DIF formula, which is consistent with the test results, is obtained. Finally, the reason why the DIF effect of fiber reinforced concrete is weaker than that of plain concrete is explained by using micro-crack mechanism. (4) the penetration resistance of UHMWPE fiber reinforced concrete is studied experimentally. It is found that the larger the velocity of the projectile, the greater the damage degree of the target body. The fiber can reduce the damage of the target body, and the targets of crater on the projectile surface decrease obviously with the increase of fiber content. Based on the comparison and analysis of the applicability of the existing penetration empirical formulas, a penetration prediction model considering fiber content is proposed based on the Hughes formula, which is in good agreement with the experimental results.
【学位授予单位】：国防科学技术大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528
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