论文部分内容阅读
为了检测船舶螺旋桨的内部缺陷,成功地发展了一种超声波检测缺陷的技术,当将这种技术应用于实际螺旋桨时,必須确定允許的缺陷尺寸,以及叶片需要加以检测的区域。本文已为达到此目的而提出了如下的分析和计算。 (1)用线弹性断裂力学和螺旋桨材料的⊿K_Φ值分析疲劳裂纹是否从桨叶的缺陷处进一步扩展。 (2)在干若种应力、桨叶厚度和纵横比条件下计算缺陷的最大容許尺寸。 (3)用不稳定升力面理论计算了螺旋桨上在尾件流区缺陷中的应力分布,根据每个螺旋桨的临界缺陷尺寸分布,确定出所要检测的区域。
In order to detect the internal defects of the ship’s propeller, a technique for the ultrasonic inspection of defects has been successfully developed. When this technique is applied to an actual propeller, the allowable defect size and the area to be detected by the blade must be determined. This article has made the following analysis and calculations for this purpose. (1) Analyze whether the fatigue crack is further expanded from the blade defect by using the linear elastic fracture mechanics and the ⊿K_Φ value of the propeller material. (2) Calculate the maximum allowable defect size under conditions of stress, paddle thickness and aspect ratio. (3) The unsteady lifting surface theory is used to calculate the stress distribution on the propeller in the tail flow area. According to the critical defect size distribution of each propeller, the area to be detected is determined.