Worldtraveller
Aerospace
- Sep 25, 2013
- 82
A colleague is working on a presentation that our company is putting together for basic stress analysis topics for our customer.
We are going through the presentation that was originally created by a previous engineer (who is no longer with the company) and discovered some discrepancies between different references.
For a ring doubler in a shear web (Nui only does this for non-buckling webs), there is a slight difference in methods, and seemingly in results, between Nui (1st Ed. Section 6). and Flabel.
The total stress in the ring doubler is calculated by Nui as bending stress plus tension stress:
fb = 2q(0.25R)R1/[tW^2/6] Where R is the hole, and R1 is the distance to the center of the doubler. W and t are the thickness and width of the doubler.
ft = 2qR/Wt <-- this is basic P/A
While Flabel goes about it slightly differently, the fb is the same. However, his ft is double what Nui has, namely:
ft = 4qR/Wt
I’m working through to see if there’s much in the way of how this is derived that causes the seeming discrepancy, or if there’s an actual error (I’m thinking the error is probably in my understanding, these books and procedures have been around for decades!) or typo in the text.
Anyone familiar enough with this to speak to the seeming discrepancy?
TIA.
