Air Force Research Laboratory

Transcription

1 Air Force Research Laboratory Summary of Laser Eye Protection (LEP) Degradation Assessments DoE Laser Safety Officer Workshop, 9 May 2018 Integrity Service Excellence Major Ed Kelly 711th Human Performance Wing Airman Systems Directorate Bioeffects Division Optical Radiation Bioeffects Branch Department of Defense, or the United States Government.

2 Outline Canadian Study Overview Test Plan Accelerated Aging Data (1064 & 532 nm) Experimental Results Experimental Discussion Future Work USN Study Overview Purpose Test Set Up Results Follow-on Testing in 2018 Conclusions Acknowledgements Department of Defense, or the United States Government. 2

3 Canadian Study Overview Assessment of degradation of ballistic LEP from CAF inventory 1064nm protection [NSN: -9064, (1064 nm)] 532nm protection [NSN: -5626, (532 nm)] Department of Defense, or the United States Government. 3

4 Canadian Study Overview Test Plan Accelerated aging (Shelf life) Soak in controlled hot environment. Accelerated age is derived from Arrhenius equation. UV exposure Procedure ASTM G155-13: cycle 4 using the Atlas Ci4000 Xenon Weather-Ometer. Laser radiation exposure: 532nm and 1064nm Temperature shock Measurement Equipment Cary 6000i Spectrophotometer Used to measure the transmission of the LEP. 4 Department of Defense, or the United States Government. 4

5 Canadian Study Overview Accelerated Aging Data (1064 nm) -new test method nm protection (Green LEP) LEP accelerated years 23 to exhibits darker green in color has a noticeably different spectrum performance than the rest of the NSN group Department of Defense, or the United States Government. 5

6 Canadian Study Overview Accelerated Aging Data (532 nm) 532nm protection (orange LEP) Optical Density Time (years) new new new new Data for 532nm protection Consistently measuring ~ OD4 New test method data included from ~ 22 to 44 years No degradation up to ~ 44 years of accelerated aging Department of Defense, or the United States Government. 6

7 Canadian Study Overview Experimental Results Tests demonstrated color change 1064 nm Clear change in color of the dye Suspect UV actinic effects Resulting in a change in performance As received (0 hrs) OD = 5.5 After 524 hrs of exposure, equates to 196 days in field OD = 2.8 Department of Defense, or the United States Government. 7

8 Canadian Study Overview Experimental Results - Solar radiation degradation 1064nm protection UV degradation nm OD spec 820nm 850nm 1064nm Optical Density nm to 850nm OD spec Wavelength (nm) days days days days days days Exposure (days) OD (1064nm) OD (820nm to 850nm) to to to to Department of Defense, or the United States Government. 8

9 Canadian Study Overview Experimental Results - Solar radiation degradation - smaller steps Optical Density Ballistic LEP solar degradation nm Wavelength (nm) hrs hrs hrs hrs hrs 1064nm hrs hrs hrs Exposure(hrs) Days in Ottawa Days in Phoenix (OD) (OD) Taking a more frequent testing approach by lessening the solar exposure time between tests, the protective performance at 1064 nm degrades quickly & fails the OD 5 specification around the 100-hour mark (Equivalent of ~ 28 days in Ottawa or 15 days in a desert (Phoenix) type setting) Department of Defense, or the United States Government. 9

10 Canadian Study Overview Experimental Results Tests demonstrated color change 532 nm No visible change in color of dye Consistent with no change in the OD As received (0 hrs) OD = 4.1 After 524 hrs of exposure, equates to 196 days in field OD = Department of Defense, or the United States Government. 10

11 Canadian Study Overview Experimental Results - Solar radiation degradation 532nm protection UV degradation Optical Density nm nm OD limit Wavelength (nm) days days days days days days OD spec > 532 nm Exposure (Days in Ottawa) OD (at 532 nm) Department of Defense, or the United States Government. 11

12 Canadian Study Overview Experimental Discussion Solar radiation 1064 nm protection LEP are very sensitive to solar radiation After 168 hrs of radiant exposure (~ 49 days in the field) they fail their OD > 5 requirement 532 nm protective LEP don t exhibit solar radiation degradation Accelerated aging (shelf life) Up to 23 years of accelerated aging, no visible change in the OD performance Testing up to 30 years is underway Department of Defense, or the United States Government. 12

13 Canadian Study Overview Future Work 1064 nm laser radiation: Investigate Ground Laser Target Designator (GLTD) laser source radiation on LEP Real world UAE Notch 1 Visor testing 532 nm laser radiation: Investigate Firing continuous wave laser source on LEP Temperature shock effects Department of Defense, or the United States Government. 13

14 USN Study Overview PURPOSE Previous LEP solarization and ballistic testing showed LEP visors would last ~ 200 hours NISE / 219 Solar indicators projects 2013 & 2017 Giving wearers an simple indication end of life Solar indicators color change at the end of life cycle Department of Defense, or the United States Government. 14

15 USN Study Overview Test Set Up Solar Chamber: Q-Sun Xenon Test Chamber Model Xe-3-H MIL-STD-810G W curve, simulating actual sun rise and set, heat rise/fall 50% humidity Spectral Region UV A ( / nm) with irradiance 62.7 W/m 2 UV B ( nm) with irradiance of 5.6 W/m 2 Visible ( nm) with irradiance W/m 2 Infrared ( nm) with irradiance of Starting at 32 C (89 F) raising in 2 hr increments peaking at 52 C (125 F) then returning in 2 hr increments to 32 C at the completion of the test of 250 hrs (200 of actual solar) Department of Defense, or the United States Government. 15

16 USN Study Overview Test Set Up High Velocity Impact Tester (Ballistic): Skylark Machines MIL-STD-622F.22 Cal barrel / T37 frags Air pressure and nitrogen regulated feet per second 50% Andersen Head form for helmet mounting (Army method) Visor holder (Navy method) Department of Defense, or the United States Government. 16

17 USN Study Overview Test Set Up Army Method: Visor is mounted on helmet and head form Skylark Machines, High Velocity Impact Tester Navy Method: Visor mount for visors without attachments Department of Defense, or the United States Government. 17

18 USN Study Overview Test Set Up Neodymium HGU-55/P Full Up Assembly Neodymium MBU-12/P Mask Trim Only Neodymium JHMCS Step-In Full Up Assembly Department of Defense, or the United States Government. 18

19 USN Study Overview Results Trimmed only Laser Eye Protection Self Neodymium Performed as predicted - all shots were within spec 250 hrs 0 hours all passed 99 hours passed 250 hours failed Full up assemblies Laser Eye Protection Did not perform as expected - -all shots were within spec 0 hrs 198 hrs 250 hrs 0 hours failed 99 hours failed 198 hours failed 250 hours failed Department of Defense, or the United States Government. 19

20 UV Kills polycarbonate The blue spectrum kills dyes How much and when? USN Study Overview Follow-on Testing in 2018 More solarization and ballistics testing is needed to determine the most time a users is to expect their visor to last. The tentative plan: Consisting of solarizing three (3) Neutral Densities visors will be removed after the first cycle, then perform ballistic testing at V50. ( f/s) The next three (3) will be removed remove after the second cycle then ballistic test at V50 So on until failures occur 100% of the time. Testing will continue at the failure solarization cycle but using the V0 (a lower f/s ballistic shot) Department of Defense, or the United States Government. 20

21 Conclusions Certain LEP degrades with exposure to UV Light 1064 nm May need to test LEP to ensure OD requirements acceptable Future studies to look at recommending useful life Department of Defense, or the United States Government. 21

22 Acknowledgements Royal Canadian Air Force See next slide US Navy Human Systems Department See slide after next Department of Defense, or the United States Government. 22

23 Laser Eye Protection (LEP) Comprehensive Degradation Distribution A: Approved for public release; distribution unlimited. PA Case No: TSRL- PA The opinions expressed on this document, electronic or otherwise, are solely those of the author(s). They do not represent an endorsement by or the views of the United States Air Force, the Department of Defense, or the United States Government. Assessment Mr. Andrew Jacques Dr. Gholam Yousefi Capt. David Brookes, CD MSc

24 Ballistic Results; Solarized Clear, Neutral Density and LEP Visors Christine Stanley Adam Carlisle Department of Defense, or the United States Government.