| 1. | Mechanical analysis of reinforced bar being vertical to matrix crack
基体裂纹的垂直强化筋力学分析 |
| 2. | 2 . the mechanical properties and fracture mode of 3d c / sic depend on the matrix cracks " propagation in interphase
( 2 ) 3dc sic复合材料的力学性能和断裂模式与基体裂纹在界面相区的扩展方式密切相关。 |
| 3. | 4 . the matrix cracks " deflection can occur along the m / i interface , within the interphase and along the i / f interface , which can be predicted by modeling the matrix cracks " defection
( 4 )基体裂纹会在界面相区内的m i界面、界面相内部和i f界面等多个位置发生偏转。 |
| 4. | Then it was necessary to study the matrix crack and delamination damages in detail , which occurred with the maximum probability and played the most important role on fwc failure . two models about damage analysis were established b y using energy method and shear lag method . the mechanism of damage and the effect to structure performance caused by damage are studied further
在此基础上，深入地研究了壳体损伤发生概率最大、而危害又相当明显的典型损伤类型? ?基体开裂和分层损伤，分别采用能量法和剪切滞后方法建立基体开裂和分层损伤的模型，对损伤的机理和损伤对壳体性能的影响进行了深入的研究。 |
| 5. | Against the background of the microstructural evolution of three dimensional braiding c / sic composites , used such analytical methods as lm , sem and tem , it is studied that the matrix cracks propagate in the composites with different interphase thickness under three - point - bend testing , as well as under the creep testing . the main conclusions are as follows : 1
本文以三维编织c sic复合材料微结构演化为背景，采用光学显微镜( lm ) 、扫描电镜( sem )和透射电镜( tem )等分析手段，研究了不同界面相厚度的复合材料在三点弯曲测试中基体裂纹的扩展规律，以及基体裂纹扩展对蠕变过程的影响。 |
| 6. | It was found that the cracks can penetrate the interphase and the fiber rapidly when the interphase is thin , which causes the low flexural strength and fracture toughness , as well as the composites " brittle fracture . while the interphase is thick , multiple toughening mechanisms such as the crack deflection and matrix cracking can be activated , which cause the composites " flexural strength and fracture toughness is high and the composites " non - brittle fracture
当界面相较薄时，基体裂纹能够迅速穿过界面相和纤维，复合材料具有较低的弯曲强度和断裂韧性，表现为脆性断裂模式；当界面相较厚时，复合材料能产生裂纹偏转、基体开裂等多种增韧方式，具有较高的弯曲强度和断裂韧性，呈韧性断裂模式。 |
| 7. | 3 . the two stages of primary creep and steady - state creep of 3d c / sic correspond to the gradual saturation of matrix crack and the opening of these cracks respectively . the transverse crack is the main contributor to the macroscopic creep strain of 3d c / sic , and its opening is controlled by the creep temperature
( 3 ) 3dc sic复合材料的减速蠕变阶段和稳态蠕变阶段分别对应着基体裂纹趋于饱和和逐渐张开这两个过程；横向基体裂纹是3dc sic复合材料宏观蠕变应变的主要贡献者，温度是影响横向裂纹张开速度的一个重要因素。 |
| 8. | There are three main kinds of matrix cracks within the as - received composites : cracks induced by mismatch of thermal expansion coefficients , cracks between bundles and cracks induced by matrix ' s delamination . they locate within the bundles , between the bundles and on the surface of the bundles respectively
主要结果如下： ( 1 )研究表明，在原始3dc sic复合材料内部主要存在三种裂纹：热失配裂纹，纤维束间裂纹和基体分层裂纹，它们分别存在于纤维束内部，纤维束之间和纤维束表层。 |
| 9. | By way of comparing the results obtained from netting theory , compound theory , nonlinear fem and experimental test , the conclusion could be drawn that matrix crack damage surely existed in the cylinder part of structure . when the structure was subject to internal pressure up to 6 . 8mpa , which was the maximum loading of hydrostatic test , the deformation of the global structure and stress and strain distributed in any parts of structure were obtained
通过对网格理论、复合理论和非线性有限元方法计算结果与试验值之间的相互比较，可以看出：非线性有限元计算结果介于网格理论和复合理论之间，且有限元计算结果与复合理论结果更加接近，表明在水检压力下壳体筒段确实存在着基体开裂等损伤。 |
