UHMWPE纖維混凝土靜三軸、動(dòng)劈裂以及抗侵徹性能試驗(yàn)研究
發(fā)布時(shí)間：2018-08-04 20:48
【摘要】：超高分子量聚乙烯(UHMWPE)纖維作為當(dāng)今世界三大高科技纖維之一,具有眾多優(yōu)良性能。以其作為增強(qiáng)體的纖維混凝土復(fù)合材料具有強(qiáng)度高,韌性好等特點(diǎn),因此可期望用于防護(hù)工程領(lǐng)域以改善混凝土抗拉強(qiáng)度低、脆性大等不利因素,提高結(jié)構(gòu)的抗侵徹防護(hù)性能。實(shí)際應(yīng)用中,防護(hù)結(jié)構(gòu)往往處于多向受力、高速變形等復(fù)雜應(yīng)力狀態(tài),常規(guī)試驗(yàn)結(jié)論往往難以滿足工程設(shè)計(jì)需求,這就要求對(duì)材料進(jìn)行有針對(duì)性的試驗(yàn)研究。本文基于上述研究背景,對(duì)UHMWPE纖維混凝土分別進(jìn)行了三軸壓縮試驗(yàn)、動(dòng)態(tài)劈裂試驗(yàn)以及侵徹試驗(yàn),研究了其三軸壓縮性能、動(dòng)態(tài)劈裂性能以及抗侵徹性能。論文主要工作及研究成果如下:(1)歸納分析了現(xiàn)有混凝土三軸壓縮試驗(yàn)、動(dòng)態(tài)劈裂試驗(yàn)以及侵徹試驗(yàn)技術(shù)和理論,據(jù)此,提出了本文試驗(yàn)研究設(shè)計(jì)方案及試件的制備工藝。(2)首次進(jìn)行了UHMWPE纖維混凝土的三軸壓縮性能試驗(yàn)研究。研究發(fā)現(xiàn),試件的破壞模式由不加圍壓的壓裂模式變?yōu)樾奔裟Ｊ?纖維不改變混凝土的破壞模式,但可以顯著減小裂縫寬度。壓縮強(qiáng)度隨圍壓的增加而增大,纖維的摻入使壓縮強(qiáng)度有所降低,與摻量有關(guān);基于現(xiàn)有強(qiáng)度準(zhǔn)則分析了壓子午線特征,得到纖維摻量對(duì)材料參數(shù)影響的公式。峰值應(yīng)變與壓縮韌性隨纖維摻量的增加而增大,纖維能顯著提高混凝土韌性,但隨著圍壓的增加,纖維的作用減弱。(3)首次進(jìn)行了UHMWPE纖維混凝土的動(dòng)態(tài)劈裂性能試驗(yàn)研究。研究發(fā)現(xiàn),纖維可以顯著減小混凝土裂縫寬度,延長(zhǎng)破壞時(shí)間,減弱劈裂破壞作用。在1~20s-1應(yīng)變率范圍內(nèi),纖維混凝土抗拉強(qiáng)度有明顯提高;基于對(duì)現(xiàn)有動(dòng)態(tài)抗拉強(qiáng)度提高因子(DIF)公式的分析,得到了與試驗(yàn)結(jié)果相符的UHMWPE纖維混凝土DIF公式。最后,利用微裂縫機(jī)理解釋了纖維混凝土DIF效應(yīng)弱于素混凝土的原因。(4)開展了UHMWPE纖維混凝土的抗侵徹性能試驗(yàn)研究。研究發(fā)現(xiàn),彈速越大,靶體破壞程度越大,纖維可以減輕靶體的破壞,迎彈面彈坑各項(xiàng)指標(biāo)隨纖維摻量的增加而顯著減小。在對(duì)比分析現(xiàn)有侵深經(jīng)驗(yàn)公式的適用性基礎(chǔ)上,基于Hughes公式提出了考慮纖維摻量的侵深預(yù)測(cè)模型,與試驗(yàn)結(jié)果吻合較好。
[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.
【學(xué)位授予單位】：國(guó)防科學(xué)技術(shù)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：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.
【學(xué)位授予單位】：國(guó)防科學(xué)技術(shù)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU528
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