Estimating effect of an impact on a composite (sandwich) plate
Estimating effect of an impact on a composite (sandwich) plate
(OP)
To all
I’d like to know if there is a way of estimating the effect of an impact on a composite panel. I am not after some fancy FE analysis. Just a rough idea/back-of-the envelope calc type of approach
Given the mass (of the object) and its drop height I estimated the impact energy at 5J. To which “numbers” should one compare this impact energy too to get an idea what is happening to the panel? I suspect penetrating is unlikely (i.e. going through the panel) I suspect some sort of delamination is possible.
Is it just a matter of comparing the impact energy to some Critical energy release rate?
Thanks
Regards
I’d like to know if there is a way of estimating the effect of an impact on a composite panel. I am not after some fancy FE analysis. Just a rough idea/back-of-the envelope calc type of approach
Given the mass (of the object) and its drop height I estimated the impact energy at 5J. To which “numbers” should one compare this impact energy too to get an idea what is happening to the panel? I suspect penetrating is unlikely (i.e. going through the panel) I suspect some sort of delamination is possible.
Is it just a matter of comparing the impact energy to some Critical energy release rate?
Thanks
Regards





RE: Estimating effect of an impact on a composite (sandwich) plate
JAMS Impact Damage Formation on Composite Aircraft Structures, 2013 Technical Review, Hyonny Kim, FAA JAMS 2013 Technical Review Meeting, April 9-10, 2013, Everett WA
University of California San Diego
Thesis: DESIGNING COMPOSITE STRUCTURES FOR LOW-VELOCITY IMPACT http://www.dtic.mil/dtic/tr/fulltext/u2/a225217.pd...
ARC... many topics, this subject... https://arc.aiaa.org/action/doSearch?AllField=comp...++
NTRS... many topics, this subject... https://ntrs.nasa.gov/?N=0&Ntk=All&Ntt=com... matchallpartial
Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]
RE: Estimating effect of an impact on a composite (sandwich) plate
Just conduct some tests.
RE: Estimating effect of an impact on a composite (sandwich) plate
Impact Test is planned but not for a while. One could end up end up doing the test(s) and show that while the composite panel is meeting all the (other) requirements, it is damaged from a "minor" impact (BVD most likely) and the customer will have no choice but to replace it.
RE: Estimating effect of an impact on a composite (sandwich) plate
When I was working remotely in the 'field' we used one-side Ultrasonic NDI [US-NDI] or 'coin-tap-test' to ID suspected composite damage [area]. This only got-us in the ball-park.
IF cutout-repair was necessary... our rule-of-thumb...
We trimmed-out [routed] the area suggested by US-NDI + a margin [had to know local thickness], +~1T] all-around... then examined the laminate in-detail.
We trimmed-out [routed] the area suggested by tap-test + a margin [had to know local thickness, +~4T-to-6T] all-around... then examined the laminate in-detail.
Usually we were close... but added trimming was almost always necessary.
After the area was trimmed-out to 'solid/undamaged laminate' then we scarfed the edges for build-up patch repair.
A few [more] composite repair documents that include inspection.
AGARD-R-716 Composite Structure Repair
AGARD-CP-530 Debonding/Delamination of Composites
USAF T.O. 1-1-690 General Advanced Composite Repair Processes Manual
SAE R-336 Care and Repair of Advanced Composites
SAE AIR5719 Teaching Points for an Awareness Class on "Critical Issues in Composite Maintenance and Repair
SAE ARP5089 COMPOSITE REPAIR NDT/NDI HANDBOOK
SAE ARP6262 Basic Composite Repair Technician Certification Standard
and the list goes on... butgottagetbacktowork
Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]