Z-pins增强陶瓷基复合材料层间性能有限元分析
发布时间：2019-04-27 22:01
【摘要】：Z-pins增强二维编织陶瓷基复合材料,是在二维编织陶瓷基复合材料厚度方向插入Z-pins,达到提高层间断裂韧性、抗分层和抗冲击性能的目的。作为一种一体化设计的新型材料,Z-pins增强二维编织陶瓷基复合材料有重要的应用前景。因此,研究Z-pins增强陶瓷基复合材料的层间力学行为,对于材料设计和材料应用方面具有重要的意义和价值。本文通过结合Z-pins增强平纹编织陶瓷基复合材料层间剪切试验,采用有限元分析方法,分别建立了不同切口深度、有无固定夹具以及不同Z-pins的个数情形下的有限元模型,对比分析了切口深度、固定夹具、Z-pins的植入以及Z-pins的个数对层间应力分布的影响。研究表明:切口深度越大,切口附近的层间应力集中现象越明显,层间剪切强度随切口深度增加而减小。固定夹具可以使得试件受剪切面上的应力更均匀。植入一定数量的Z-pins减小了切口附近的集中应力区域,可以有效地提高平纹编织CMC的层间剪切强度。通过结合双悬臂梁试件试验,建立DCB试验有限元分析模型,用内聚力模型(CZM)模拟基体开裂,采用实体单元模拟Z-pins,分析Z-pins与层合板之间,在裂纹扩展过程中,Z-pins的脱胶和拔出过程,从而研究Z-pins增强陶瓷基复合材料Ⅰ型层间应变能释放率的影响。研究表明:Z-pins增强平纹编织碳/碳化硅陶瓷基复合材料,在增加Z-pins直径、减小Z-pins的间距、增加单位宽度上Z-pins的个数的情形下,都可以提高材料的Ⅰ型层间断裂韧性。
[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.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB332
[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.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB332
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