锆-4合金低周疲劳断口SEM特征提取及断口分析

Feature extraction of Zr-4 low fatigue fracture images and fracture analysis

核材料断口大多复杂,并且具有断口差异小的特点,一般特征提取方法难以区分。本文比较了5种不同的小波分解及6种不同的能量或熵提取特征,找到提取锆-4合金低周疲劳断口(SEM)的纹理图像特征的方法,即用Db4小波提取L1能量能有效区分锆-4合金不同疲劳寿命断口的纹理特征及在裂纹扩展方向上的能量变化特征。最后,提取了不同疲劳寿命断口(放大倍数为4000和150)的能量、熵值分布,并分析了各方向小波频率分量与疲劳寿命的关系。

It is hard to distinguish the fracture images for the complicate texture structure of Zr-4 alloy, This article used 5 different wavelets to decompose the SEM images of the alloy Zr-4 to obtain its energy and entropy. With the data, we drew a conclusion that Db4 wavelet and energy norm LI were more effective to extract image characteristic of different life-span. Then an energy change at the direction of fracture extension was studied to find the relationship between them. With this result, an investigation between the fracture （4000X and 50X） under different life-span and energy at every frequency band was conducted.