KirbyWan
Aerospace
- Apr 18, 2008
- 583
Howdy all,
So we pull drum peel tests on honeycomb specimins all the time. I've reviewed three specs that cover this, ASTM D 1781, GE SPM 70-71-06, and Boeings BSS7207. They all have the same equipment requirements, the only difference being the speed of the cross head. ASTM and GE use a cross head speed of one inch per minute, while the Boeing standard uses three inchs per minute.
The odd thing is the drum peel results we get with the faster drum head speed of three inches per minute are two to three times better then when we run the cross head at the lower speed of one inch per minute. This bothers me because there should be no speed dependency in this test.
Has anyone else noticed this effect? Has anyone corrected this problem before? My only guess at this point is that at the one inch per minute speed the system hits a harmonic and bounces as it pulls. I was thinking of running a test at various cross head speeds around one inch per minute to see if a trend can be established. Any suggestions? Comments? Other drum peel specs I can reference? Should the drum peel values be affected by the cross head speed and the specs don't mention it because it is already accounted for with different target values for an acceptable bond?
Thanks for everyones help.
-Kirby
Kirby Wilkerson
Remember, first define the problem, then solve it.
So we pull drum peel tests on honeycomb specimins all the time. I've reviewed three specs that cover this, ASTM D 1781, GE SPM 70-71-06, and Boeings BSS7207. They all have the same equipment requirements, the only difference being the speed of the cross head. ASTM and GE use a cross head speed of one inch per minute, while the Boeing standard uses three inchs per minute.
The odd thing is the drum peel results we get with the faster drum head speed of three inches per minute are two to three times better then when we run the cross head at the lower speed of one inch per minute. This bothers me because there should be no speed dependency in this test.
Has anyone else noticed this effect? Has anyone corrected this problem before? My only guess at this point is that at the one inch per minute speed the system hits a harmonic and bounces as it pulls. I was thinking of running a test at various cross head speeds around one inch per minute to see if a trend can be established. Any suggestions? Comments? Other drum peel specs I can reference? Should the drum peel values be affected by the cross head speed and the specs don't mention it because it is already accounted for with different target values for an acceptable bond?
Thanks for everyones help.
-Kirby
Kirby Wilkerson
Remember, first define the problem, then solve it.
