三维应力强度因子分析及干涉预应力影响研究

【作者】 王锋；

【导师】 黄其青；

【作者基本信息】 西北工业大学 ， 固体力学， 2007， 硕士

【摘要】 应力强度因子K是裂纹尖端应力应变场奇异性强度的表征，控制着裂纹尖端附近的整个弹性场。对于裂纹扩展和剩余强度分析来说，获得应力强度因子是分析工作的基本条件之一。 本文采用ANSYS大型有限元分析软件，以孔边角裂纹为例，建立三维实体应力强度因子计算模型，通过独特的局部网格划分，创建了用ANSYS进行三维裂纹应力强度因子计算分析的简捷方法，并将计算结果和现有理论结果进行对比分析，其计算精确程度完全满足工程要求。 文中还以干涉孔边三维裂纹为讨论对象，在线弹性条件下，模拟在干涉状态下，由于干涉产生的预应力释放的真实过程，研究预应力释放对二、三维裂纹尖端应力强度因子的影响规律。文中将干涉预应力考虑为内部载荷，分别对不同裂纹长度下的含裂纹体进行干涉，在不同的干涉状态下直接求解应力强度因子，以此等效地模拟裂纹扩展过程中干涉预应力释放的应力强度因子求解。通过计算分析，给出了考虑干涉预应力释放的真实情况下裂纹尖端的应力强度因子随裂纹长度及模型厚度的改变趋势和规律，并与不考虑干涉预应力释放的情况下裂纹尖端的应力强度因子进行对比分析。 本文还通过计算分析，给出了工程典型结构——含裂纹连接耳片在干涉状态下的二、三维应力强度因子的有限元分析模型及结果。 文中所采用的方法是可靠、有效的，其分析结果及结论可作为该类结构裂纹扩展及剩余强度分析的参考依据。更多还原

【Abstract】 The stress intensity factors is a sign of the strength of the stress and strain threshing nearby the crack. It controls all elastic threshing nearby the crack. It is one of the basis factors to get the stress intensity factors for the growth of the crack and the analysis of the residue strength.This paper uses substantiality to create model in an engineering software ANSYS, and uses special method to plot gridding to the local model. It makes an example of the corner cracks on the hole’s edge to expatiate the simple method of the calculation of the stress intensity factors for the three-dimensional. It is found that the precision is enough for the need of the engineering after the compare between the results of the paper and the existing results.At the same time, the two-dimensional and the three-dimensional crack around interference hole is discussed in this paper. The engineer software ANSYS is used here to simulate the interference prestressing release, which is caused by forced fitting, in order to research how the interference prestressing release affects the stress intensity factors (SIFs) at the crack tips. The interference prestressing is regarded as the inner load, loaded to crack body with different crack lengths respectively, and the SIFs under different extrusion states were calculated, in such a way to simulate SIFs of the interference prestressing release in course of crack growth. By computational analysis, some results about SIFs at the crack tips considering the interference prestressing release change with crack lengths and models thickness were obtained, and compared with crack tip SIFs where the interference prestressing release is ignored.In the paper, it gives the calculations of the stress intensity factors at the conditions of the interference of the real structure-lug and draws an useful conclusions in engineeringThe computing method in the paper is reliable and effective, so the results and conclusions can be regard as the reference for the crack growth of this kind of更多还原