4. Impact threat

Now that we've described the different types of impact damage and the problems of detectability in more detail, let's return to the general concept of damage tolerance. We saw earlier that all undetectable damage, i.e. damage whose permanent indentation was less than the BVID, should hold the EC (figure 10 ). In reality, the problem is more complicated. This is true for a thin structure (figure 27 ), but not for a thick one. For a thick structure, the impact energy required to reach the BVID...