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在航空航天领域内,轴对称复合结构得到了广泛的应用,而分层和孔隙是常规工艺缺陷中最常见的类别。众所周知,像分层那样的理想的片状二维缺陷不能用X射线检测出来,但是,分层事实上总是有一定厚度的。这时.如果超声C扫描不适用的话,可使用切向X射线照相来获取零件中缺陷的永久性记录。但是,在应用这方法时,恒稳的可检测性及缺陷间的比较关系需要仔细地统计才能得到。问题的难点在于单束X射线在零件中穿过的光程既随零件的几何形状不同而不同,也与射线源-零件-胶片的位置有关。本文所作的探讨旨在:(a)弄清不同尺寸和位置的缺陷在采用本工艺方法时可检测的范围及其局限性。(b)怎样选择最佳射线照相参数。文中的工作虽然是针对具体尺寸的轴对称碳纤维增强塑料管的,但所提出的工艺方法在其适用范围内可很好地应用于其它任何零件。1 射线束光程的计算在我们的研究中,射线源-零件-胶片的位置如图1。X射线束在零件实体中穿过的光束(BD)是连续变化的,假设其中一束从管子内表面到外表面穿过整个
In the field of aerospace, the axisymmetric composite structure has been widely used, and delamination and porosity are the most common categories of conventional process defects. It is well-known that the ideal flaky two-dimensional defects like delamination can not be detected by x-rays, but the delamination is in fact always of a certain thickness. At this point, tangential X-rays can be used to obtain a permanent record of defects in a part if ultrasound C-scan does not work. However, when applying this method, the stability of the detectability and the comparative relationship between the defects need careful statistics to get. The challenge is that the path length of a single beam of X-rays that passes through the part varies with the geometry of the part and with the ray source - the part - the position of the film. The purpose of this paper is to: (a) identify the limits and limitations of different sizes and locations of defects detectable when using the process. (b) How to choose the best radiographic parameters. Although the work in this paper is aimed at the specific dimensions of the axisymmetric carbon fiber reinforced plastic pipe, the proposed process can be applied well to any other part within its scope of application. 1 ray beam path calculation In our study, ray source - parts - the film position shown in Figure 1. The beam of rays (BD) that the X-ray beam passes through in the part body varies continuously, assuming that one of the beams passes through the entire inner to the outer surface of the tube