【摘要】：Z-pins增強(qiáng)二維編織陶瓷基復(fù)合材料,是在二維編織陶瓷基復(fù)合材料厚度方向插入Z-pins,達(dá)到提高層間斷裂韌性、抗分層和抗沖擊性能的目的。作為一種一體化設(shè)計(jì)的新型材料,Z-pins增強(qiáng)二維編織陶瓷基復(fù)合材料有重要的應(yīng)用前景。因此,研究Z-pins增強(qiáng)陶瓷基復(fù)合材料的層間力學(xué)行為,對于材料設(shè)計(jì)和材料應(yīng)用方面具有重要的意義和價(jià)值。本文通過結(jié)合Z-pins增強(qiáng)平紋編織陶瓷基復(fù)合材料層間剪切試驗(yàn),采用有限元分析方法,分別建立了不同切口深度、有無固定夾具以及不同Z-pins的個(gè)數(shù)情形下的有限元模型,對比分析了切口深度、固定夾具、Z-pins的植入以及Z-pins的個(gè)數(shù)對層間應(yīng)力分布的影響。研究表明:切口深度越大,切口附近的層間應(yīng)力集中現(xiàn)象越明顯,層間剪切強(qiáng)度隨切口深度增加而減小。固定夾具可以使得試件受剪切面上的應(yīng)力更均勻。植入一定數(shù)量的Z-pins減小了切口附近的集中應(yīng)力區(qū)域,可以有效地提高平紋編織CMC的層間剪切強(qiáng)度。通過結(jié)合雙懸臂梁試件試驗(yàn),建立DCB試驗(yàn)有限元分析模型,用內(nèi)聚力模型(CZM)模擬基體開裂,采用實(shí)體單元模擬Z-pins,分析Z-pins與層合板之間,在裂紋擴(kuò)展過程中,Z-pins的脫膠和拔出過程,從而研究Z-pins增強(qiáng)陶瓷基復(fù)合材料Ⅰ型層間應(yīng)變能釋放率的影響。研究表明:Z-pins增強(qiáng)平紋編織碳/碳化硅陶瓷基復(fù)合材料,在增加Z-pins直徑、減小Z-pins的間距、增加單位寬度上Z-pins的個(gè)數(shù)的情形下,都可以提高材料的Ⅰ型層間斷裂韌性。
[Abstract]:The two-dimensional braided ceramic matrix composites reinforced by Z-pins are inserted into the thickness direction of the two-dimensional braided ceramic matrix composites to improve the fracture toughness, delamination resistance and impact resistance of the two-dimensional braided ceramic matrix composites. As a new kind of integrated design material, Z-pins reinforced two-dimensional braided ceramic matrix composites have important application prospects. Therefore, it is of great significance and value to study the interlaminar mechanical behavior of Z-pins reinforced ceramic matrix composites in the aspects of material design and material application. In this paper, the finite element models with different notch depth, fixed fixture and different number of Z-pins are established by means of the Z-pins reinforced plain braided ceramic matrix composites interlaminar shear test, and the finite element analysis method is used to establish the finite element model of the ceramic matrix composites with different notch depth, fixed fixture and different number of Z-pins. The effects of notch depth, fixed clamp, Z-pins implantation and the number of Z-pins on the interlaminar stress distribution were compared and analyzed. The results show that the greater the notch depth is, the more obvious the interlaminar stress concentration phenomenon is, while the interlaminar shear strength decreases with the increase of notch depth. The fixed clamp can make the stress on the shear surface more uniform. The implantation of a certain amount of Z-pins reduces the concentrated stress area near the notch and can effectively improve the interlaminar shear strength of plain braided CMC. Based on the test of double cantilever beam, the finite element analysis model of DCB test is established. The crack of matrix is simulated by cohesion force model (CZM), and the crack is simulated by solid element. The relationship between Z-pins and laminate is analyzed in the process of crack propagation. The process of degumming and pullout of Z-pins was used to study the effect of strain energy release rate of Z-pins reinforced ceramic matrix composites on I-type interlaminar strain. The results show that Z-pins reinforced braided carbon / silicon carbide ceramic matrix composites can increase the diameter of Z-pins, decrease the spacing of Z-pins and increase the number of Z-pins per unit width. All of them can improve the type I interlaminar fracture toughness of the material.
【學(xué)位授予單位】：西安建筑科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TB332

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本文編號：2467342