This slide presentation reviews non-destructive evaluation (NDE) techniques of Reinforced Carbon-Carbon (RCC) materials and the progress involved in bringing the technology to technological maturity. Included is information about the test specimens, thermographic, ultrasonic, eddy current, and radiographic inspection of RCC materials

Hernandez, Jose M.

NASA Technical Reports Server

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NASA - "Johnson Space Center 
Source of Acquisition 
NASA Johnson Space Center 
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RCC NDE Update 
Jose M. Hernandez 
NASA - Johnson Space Center 
March 9, 2004 
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https://ntrs.nasa.gov/search.jsp?R=20100042556 2019-08-30T13:40:27+00:00Z
______ . 0 
~s:t: Development NDE RCC 
Inspection S~m?""," ".... I~ 
Took a two-phase approach: 
• Phase 1: Quantitatively determine viability of each technique based 
on existing manufacturer acceptability testing capabilities and LESS 
localize convective oxidation NDE cnteria. (Initially given 3 months> 
Took 7 months) 
~Held a TIM May 8-9 at KSC 
~ Both long and near term technologies were identified 
~ Near term defined as ability to field technique <= 10 months (i.e. 
focused on mature technologies) 
~Everything else categorized as advanced NDE techniques 
~Held 2nd TIM November 20-21 at Sandia National Laboratories 
~Reached consensus on technologies to pursue 
• Phase 2: Develop selected techniques into "turn-key" systems. (12 
months) 
>Are presently atthe initial stage of phase 2 
~SJ': 
Results of 2~,,:,TIM I~ 
Selected the four most promising in-situ techniques with <12 
months total development time 
Thermography 
Short Term I Contact Ultrasonics 
<12 months Eddy Current 
Long T 
NASA-
* Not Selected 
Micro-Power Impulse Radar* 
Thermal Conductivity Msmts.* 
Digital Radiograpby 
Limited Angle CT 
X-ray transmission msmts. * 
Health Monitoring Sensors* 
Phased Array llitrasonics 
Radiography 
Non-contact Ultrasonics* 
Shearography * 
MRI* 
Tera-Hertz Imaging* 
Back Scatter X-ray 
Guided Wave Ultrasonics 
3-D microwave* 
Remote Acoustic Impact Doppl 
UltrasonicSpectroscopy* 
RCC Validation Test Specimeo_Set __________ -------, 
• Boeing disks wI arc jet exposure 
• 0.25" tho central section (coating) 
• 0.44" tho edge section (no coating) 
• 8L post impact - 4 panel round robin 
• 0.25" tho section with natural flaws (coating) 
• 8L "blind specimen" (Bill's Box) 
• Uncoated "blind specimen" (Sam's Box) RCC Blind Test Box (Bill's Box) 
• Complete RCC panel (manuf. reject) 
• Various other pieces 
.' . . 
. .' . 
. '. '. 
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_ RCC Puck 5 w ples: I~ 
Side A Side B 
Crack through 
Si-C layer 
followed by 
arc-jet 
exposure 
-- ----- --- ---- n ~ 
..... ... n/ _ 
.---~ ----------_._---. 
• Inspection from Side A 
Simulates Nearside 
(Surface) Flaw 
Detection 
• Inspection from Side 8 
Simulates Backside 
(Deep) Flaw Detection 
~~ Thermograp~!,c Ins.~~tion of Ree I~ 
• Principal Advantage: 
-No physical contact with RCC 
required 
• Expected Detection Capabilities: 
-Delaminations 
-Large Voids 
-Significant Porosity 
-M icrocracking 
• Primary Limitation: 
-Detectability of small deep flaws - flaws smaller than 
their depth 
• Estimation for timepfinspection on vehicle: 
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-2".h'outs;'tler~[panel 
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Thermography Data after 0.1 sec RCC Puck Sample 
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Ultrasonic In.§Rect!g!\ o{RCC I .... 
• Principal Advantage: 
-Inspections performed from one side. 
- Pulse-Echo technique seems most promising 
• Expected Detection Capabilities: 
-Sensitive to near-surface variations 
-Interply delaminations 
-Impact damage 
-Voids 
-Subsurface oxidation 
-Disbonds at the Si-C to C-C interface 
-UT niche: penetration for deep flaw detection 
• Primary Limitation: 
- Structure thickness & energy level excitation; 
- Att~nuation & neC!r-~urfaQe signal clarity; 
- Flaw size & depth sensitivity. 
- Need well characterized cal standards 
- ----
.-:'/-------1 W ater In let 
::::~ III (pumped in from reservoir) 
'· 1.. Captured W ater Column 
Excess W ater Flow 
(recovered into reservoir) 
---. 
.,. UT - 0.24" &H9~~4" ~~mel with Coating I~ 
t-
Back* Mid 
Side 
1/8" dia. 
'. '--'1 1/4" dia . 
., 3/8" dia. 
",'.I- i<: I 1/2" d· 3 ' ~",) . ~,J la . 
Front* 
Side 
. ~ j • • ~ 
P-E UT Optimum Coupling 
0.4" 
Mid Front 
0.22" Side 
0.04" 
~~ 
Eddy Curren,t.lnsp,e.:stion of RCC I~ 
• Principal Advantage: 
-Inspections performed from outer, exposed surfaces utilizing a 
multi-frequency mode that should allow for the measurement of SiC 
coating thicknesses and the detection of localized carbon-carbo/spring loaded 
mass loss due to carbon oxidation. foot 
• Expected Detection Capabilities: 
-SiC coating thickness measurements 
-localized mass loss due to oxidation 
• Primary Limitation: 
-Detectability of deep flaws a limitation - Primarily 
a surface and near-
surface inspection tool though preliminary work 
shows defects <0.25" deep can be detected. 
• Estimation for time' of inspection on vehicle: 
- 4 hOLJrsper panel 
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Cl. 
-
1/8" dia 
coil 
Referencel coil 
away froti part 
undbr tes 
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_ Eddy Current..pf RCS~amRles I~ 
12 
11 
10 
9 
8 
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7 
6 
5 
4 
Sam's Box 3 4 5 6 7 
01-13 01-21 01-24 
8 9 10 11 
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01-32 
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Ch1V-0.4 ' Ch2V 
0.21 
01-35 
0.15 
0.09 
0.03 
-0.04 
-0 .10 
-0.16 
-0 .22 
-0 .28 
-0 .34 
-0 .40 
-0 .47 
-0 .53 
-0 .59 
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RadiosraphipJnsR:ectigp of Ree I~ 
• Principal Advantage: 
- Inspections performed from outer, exposed surfaces will 
provide high resolution imaging capability through the 
entire structure including subsurface structures 
• Expected Detection Capabilities: 
-Large Voids 
-Mass Loss (when compared to previous images) 
-Cracks oriented parallel to the x-ray beam 
• Primary Limitation: 
-The RCC panels have an inherently high degree of local 
density variations. Differentiating natural variations 
or structural features from flaws will be the main challenge 
(digital image analysis may overcome this limitation). 
• Estimation for time of inspection on vehicle: 
- 2 hours per panel with additional time for post image analysis 
~~ 
_ Radioaraphi£9xida~(mSamRles I~ 
Enlarged X-ray Image 
Preliminarv System Design ,~ 
Preliminary technique for 
Radiographic inspection. 
In addition to the positions 
shown, the x-ray source may 
need to be moved in and out 
of plane 
Shuttle Wing 
Shuttle Wing 
X Ray 
Panel 
X Ray 
Panel 
X Ray 
Source 
N~~ 
- Volumetric Imfging R~sults I~ 
Cracks 
View of outer rim section. View of inner rim section. 
Vertical views for different slices (exactly 0.230 in. 
apart) show distinct- cracks in each rim section. 
N~~ 
Capabilities of Chosen Technigues 
Technique I Physical 
Thermal 
UT 
Eddy 
Current 
X-ray 
Contact 
Req'd 
X 
X 
Deep Cracks 
Delams 
X X 
x x 
X 
X 
Large Sig. Local 
Voids Porosity Mass 
I Loss 
X X XI 
x x x 
X 
X 
Impact Coat Inspect 
Damage Msmt Stem 
I I Fastener 
Area 
I 
X 
x 
X 
X 
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Ji'~ Detection Re.9.lj ireT _ents I~ 
The LESS PRT has stipulated the following flaw 
detection requirements: 
• Tubular voids> 0.05" diameter and 3" in length 
• Coating damage 
• Delams - TBD 
• Backside damage - TBD 
• Cracks - TBD 
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Inspection P':2cess ...... I~ 
'----.. ----
Though the inspection process has not been developed, one can 
envision a process similar to the following: 
Level I Inspection 
• Visual 
• Tactile 
• Thermography - exposed acreage 
• Ultrasoun/Eddy - exposed acreage 
• X-ray - T -seal flange, lugs & rib areas 
Level II Inspection 
• Eddy Current (coating thickness) 
• X-ray 
Level III Inspection 
• Panel removal 
• Two-side inspection using above techniques 
• Computed tomography .(CT) scans 
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_ Other Areas .t:f~e:;c;t~nQ Attention I~ 
• Advanced NDE techniques show promise 
Y Phased array UT, Guided Wave UT, EM Acoustic 
transducers, segmented and laser systems 
• Developing RCC standards 
Y Boeing has initiated development of generic standards 
y Need to develop technique specific standards 
y Need to agree on a robust validation process for 
each technique 
• Data storage, reduction and analysis 
• Systems integration and fielding of inspection systems 
• Developing a viable inspection procedure that minimizes 
disruptiq,n ofqrbiterprocessing activities 
I 


RCC NDE Update

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