| 1. | The stress intensity factor ( sif ) and the strain energy release rate were simulated with different pre - crack length for the cases with no - flow underfill and with capillary - flow underfill 本文第六章用断裂力学方涪和有限元模拟分析了填充不流动胶芯片断裂问题,计算了芯片的应力强度因于k和能量释放率g 。 |
| 2. | A global crack - line displacement fitting procedure ( gcdfp ) for computing stress intensity factors ( sif ) has been developed . the precision of sif is compatible with the corresponding cod data 使用paris公式求出裂纹前缘各点的裂纹扩展增量,并用三次b -样条函数对这些增量进行拟合,得到新的光滑裂纹前缘。 |
| 3. | The main contents are as following : ( 1 ) finite element method ( fem ) is used to study the effects of broken inclusion and debonded interface on the stress intensity factors ( sif ) 本文围绕含夹杂粉末高温合金涡轮盘的裂纹扩展寿命问题,开展了以下工作: ( 1 )用有限元法研究了夹杂裂开以及夹杂与基体界面脱开对应力强度因子的影响。 |
| 4. | With the aid of the " pseudo - traction " method , the superposition technique and the arrived fundamental solution , a method for getting the stress intensity factor ( sif ) for material such as rock with center inclined crack under compressive loading are given 采用“伪力法”和叠加原理,结合所求的基本解,给出了含中心斜裂纹的岩石类材料在压缩荷载作用下的应力强度因子( sif )的解法。 |
| 5. | The traction - free condition on the crack line is mended to get more accurate results . it can be expressed by a series of integral equations which can be discretized to a set of linear equations and then it can be solved easily . stress intensity factors ( sif ) are gotten through the root of the linear equations ( 2 )推导了远场应力、热应力耦合作用下含夹杂裂纹体的应力强度因子求解公式,改进了体积力法中的裂纹面合力平衡条件,将应力强度因子的求解归结为解一组积分方程,再将积分方程转化为线性方程组进行数值求解。 |
| 6. | Powder metallurgy turbine disks are worldwide adopted in most advanced aeroengine nowadays . the research of engineering application of them is actively being carried out in our country , and the key problem urgently needed to solve is their low cycle fatigue life prediction . the low cycle fatigue failure of powder metallurgy turbine disks is mainly caused by inclusions , so it ' s important to study the effect of inclusion on the stress intensity factors ( sif ) initiation and development of crack in powder metallurgy turbine disks 当前世界上大多数先进航空发动机均采用了粉末冶金涡轮盘,我国目前正在积极开展粉末冶金涡轮盘的工程应用研究,其低周疲劳寿命预测成了亟待解决的关键问题,夹杂物是引起其低周疲劳失效的主要原因,因此开展夹杂物对粉末冶金涡轮盘应力强度因子及裂纹萌生与扩展的影响具有重要意义。 |
| 7. | At the same time , bem formulae for interface crack analysis of thermal barrier coated structures are given in this paper . the method to evaluate nearly - singular integrals over crack tip elements and the formulae for calculating stress intensity factors ( sif ) using open and slip displacements on crack faces are presented too 基于边界元法、断裂力学等基本理论,本文导出了带热障涂层构件界面裂纹的断裂特性分析边界元法公式;结合先进的近奇异积分技术处理裂尖元的近奇异积分,利用位移法计算层间界面裂纹的应力强度因子。 |