DTIC ADA251767: Coupon and Birdstrike Testing of F-111 ADBIRT Windshields Which Have Been Subjected to Simulated Pressure/Thermal Service Life

58 Pages·1.8 MB·English

by  Defense Technical Information Center

AD-A251 767
WL-TR-91-3088
COUPON AND BIRDSTRIKE TESTING OF
F- II ADBIRT WINDSHIELDS WHICH HAVE
BEEN SUBJECTED TO SIMULATED PRESSURE/
THERMAL SERVICE LIFE
Daniel R. Bowman
University of Dayton
300 College Park Avenue
Dayton, Ohio 45469-0110
January 1992
JUN 19 19
Interim Report for Period February 1990 - October 1990
Approved for public release; distribution unlimited.
FLIGHT DYNAMICS DIRECTORATE 00
LI
WRIGHT LABORATORY
AIR FORCE SYSTEMS COMMAND
WRIGHT-PATTERSON AIR FORCE BASE, OHIO 45433-6553
922 , l 4in1>
NOTICE
When Government drawings, specifications, or other data are used for any purpose other
than in connection with a definitely Government-related procurement, the United States
Government incurs no responsibility or any obligation whatsoever. The fact that the government
may have formulated or in any way supplied the said drawings, specifications, or other data, is
not to be regarded by implication, or otherwise in any manner construed, as licensing the holder,
or any other person or corporation; or as conveying any rights or permission to manufacture,
use, or sell any patented invention that may in any way be related thereto.
This report is releasable to the National Technical Information Service (NTIS). At NTIS,
it will be available to the general public, including foreign nations.
This technical report has been reviewed and is approved for publication.
T.J. CHOE, ILt, USAF RALPH J., SPEE
Project Engineer Chief, Aircrew Protection Branch
Windshield Sys Prog Office Vehicle Subsystems Division
FOR THE COMMANDER
Chief
Vehicle Subsystems Division
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addressee is no longer employed by your organization please notify WL/FIVR, WPAFB, OH
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SECURITY CLASSIFICATION OF THIS PAGE
Form Approved
REPORT DOCUMENTATION PAGE OMBNo.0 704-0188
la. REPORT SECURITY CLASSIFICATION lb. RESTRICTIVE MARKINGS
Unclassified
2a. SECURITY CLASSIFICATION AUTHORITY 3. DISTRIBUTION /AVAILABILITY OF REPORT
Approved for public release; distribution
2b.' DECLASSIFICATION/DOWNGRADING SCHEDULE is unlimited
4. PERFORMING ORGANIZATION REPORT NUMBER(S) 5. MONITORING ORGANIZATION REPORT NUMBER(S)
UDR-TR-91-73 WL-TR-91-3088
'I
6a. NAME OF PERFORMING ORGANIZATION 6b. OFFICE SYMBOL 7a. NAME OF MONITORING ORGANIZATION
University of Dayton (Iafpp licable) Flight Dynamics Directorate (WL/FIVR)
Research Institute Wright Laboratory
6c. ADDRESS (City, State, and ZIP Code) 7b. ADDRESS(City, State, and ZIP Code)
300 College Park Avenue Wright-Patterson AFB, OH 45433-6553
Dayton, Ohio 45469
8a. NAME OF FUNDING /SPONSOR'.':, 8b. OFFICE SYMBOL 9 PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER
ORGANIZATION (If applicable)
I
_F33615-84-C-3404
8c ADDRESS (City, State, and ZIP Code) 10. SOURCE OF FUNDING NUMBERS
PROGRAM PROJECT TASK IWORK UNIT
ELEMENT NO. NO. NO ACCESSION NO.
64212F 1926 101 12
i1 . TITLE (Include Security Classification)
COUPON AND BIRDSTRIKE TESTING OF F-111 ADBIRT WINDSHIELDS WHICH HAVE BEEN SUBJECTED TO
SIMULATED PRESSURE/THERMAL SERVICE LIFE
12. PERSONAL AUTHOR(S)
Bowman, Daniel R.
13a. TYPE OF REPORT 13b- TIME COVERED 14. DATE OF REPORT (Year, Month, Day) 15. PAGE COUNT
Interim FROM FEB90 TO OCT9O January 1992 60
16. SUPPLEMENTARY NOTATION
17. COSATI CODES 18. SUBJECT TERMS (Continue on reverse if necessary and identify by block number)
F-111 Aircraft Coupon Testing
FIELD GROUP SUB-GROUP
ADBIRT Windshield Transparencies
Birdstrike Testing
19. ABSTRACT (Continue on reverse if necessary and identify by block number)
This program consisted of birdstrike testing, crack analysis, and coupon testing of
F-111 ADBIRT windshield transparencies which had been subjected to pressure/thermal
testing in the WPAFB Building 68 Transparency Durability Facility. Three pairs of F-111
ADBIRT windshield transparencies (left and right hand) were used in this program, one
pair each from Sierracin/Sylmar Corp., Swedlow, Inc., and PPG IndLstries, Inc. The
edges and bolt holes of all of the transparencies were examined for edge cracking.
The three rignt-hand windshields were birdstrike tested, and the three left hand
windshields were used for coupon testing. Dynamic mechanical analysis (DMA), gel
permeation chromatography (GPC), tensile, and edge attachment testing were conducted.
Simulated service life in the durability facility did not produce as much structural
degradation in terms of birdstrike resistance as in-service aging. A significant number of
cracks were found in the windshields in the vicinity of the edge attachments, similar to
crackinq from in-service aged windshields. Coupon testing revealed no bulk polycarbonate
deorada inon.
20. DISTRIBUTION /AVAILABILITY OF ABSTRACT 21. ABSTRACT SECURITY CLASSIFICATION
[MUNCLASSIFIED/UNLIMITED 0 SAME AS RPT -DTIC USERS Unclassified
22a NAME OF RESPONSIBLE INDIVIDUAL 22b TELEPHONE (Include Area Code) 22c OFFICE SYMBOL
Mr. Ruise~i E. Urzi 1 [phone] WL/FIVR
DD Form 1473, JUN 86 Previous editions are obsolete. - SECURITY CLASSIFICATION OF THIS PAGE
Unclassified
PREFACE
The efforts reported herein were performed by the Aerospace Mechanics Division of
the University of Dayton Research Institute (UDRI), Dayton, Ohio, under Air Force Contract
F33615-84-C-3404, modification P00011. The program was sponsored by the Wright
Laboratory, Flight Dynamics Directorate, Wright-Patterson Air Force Base, Ohio. Air Force
administrative direction and technical support were provided by Mr. Russ Urzi, of WLIFIVR.
The work described herein was conducted during the period February 1990 to October
1990. University of Dayton project supervision was provided by Mr. Dale H. Whitford,
Supervisor, Aerospace Mechanics Division, and Mr. Blaine S. West, Head, Structures Group.
Mr. Daniel R. Bowman was the principal investigator.
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TABLE OF CONTENTS
SECTION PAGE
I INTRODUCTION 1
1.1 Background 1
1.2 Objectives 2
1.3 Scope 2
2 TEST ARTICLE, COUPON TEST MATRIX, AND SPECIMEN PREPARATION 3
2.1 Test Article Procurement for Experimental Studies 3
2.2 Test Matrix 3
2.3 Specimen Layout and Fabrication 3
3 EXPERIMENTAL TESTS 7
3.1 Tensile Edge Attachment Tests 7
3.1.1 Test Objective 7
3.1.2 Specimen Configuration 7
3.1.3 Test Method 7
3.1.4 Test Data 7
3.1.5 Data Analysis/Correlation 7
3.2 Polycarbonate Tensile Test 11
3.2.1 Test Objective 11
3.2.2 Specimen Configuration 11
3.2.3 Test Method 11
3.2.4 Test Data 11
3.2.5 Data Analysis/Correlation 16
3.3 Dynamic Mechanical Analysis (DMA) Tests 16
3.3.1 Test Objective 16
3.3.2 Specimen Configuration 16
3.3.3 Test Method 16
3.3.4 Test Data 16
3.3.5 Data Analysis/Correlation 22
3.4 Gel Permeation Chromatography (GPC) Tests 23
3.4.1 Test Objective 23
3.4.2 Specimen Configuration 23
3.4.3 Test Method 23
3.4.4 Test Data 23
3.4.5 Data Analysis/Correlation 23
4 CRACK ANALYSIS 30
v
TABLE OF CONTENTS (continued)
PAGE
SECTION
32
5 FULL SCALE BIRDSTRIKE TESTING
32
5.1 Test Setup and Test Facility
32
5.2 Birdstrike Test Results
46
6 CONCLUSIONS/RECOMMENDATIONS
49
REFERENCES
vi
LIST OF ILLUSTRATIONS
PAGE
FIGURE
2.1 F-Ill ADBIRT Transparency Nominal Cross-Section 4
3.1 Tensile Edge Attachment Specimen 8
3.2 Tensile Edge Attachment Test Setup 9
3.3 Tensile Test Specimen 12
3.4 Tensile Test Setup 13
3.5 Typical Tensile Load-Displacement Curve 15
3.6 DMA Scan of Acrylic Surface Plies 17
3.7 DMA Scan of PPG SN-H-04-20-2380 Polycarbonate Plies 18
3.8 DMA Scan of Swedlow SN 027 Polycarbonate Plies 19
3.9 DMA Scan of Sierracin SN 057 Polycarbonate Plies 20
3.10 Polycarbonate Molecular Wcght Distribution from PPG Windshield,
25
SN 87-H-04-20-2380
3.11 Polycarbonate Molecular Weight Distribution from Swedlow Windshield,
26
SN 027
3.12 Polycarbonate Molecular Weight Distribution from Sierracin Windshield,
27
SN 057
3.13 Polycarbonate Composite Molecular Weight Distribution from PPG,
Swedlow, and Sierracin Windshields 28
5.1 UDRI Impact Physics Test Range 5 33
5.2 Aft Arch/Center Beam Assembly 34
5.3 Comparison of Cross-Section Properties Between Flight Hardware
and UDRI Test Hardware 35
vii
LIST OF ILLUSTRATIONS (continued)
FIGURE PAGE
5.4 Bird Impact Location 36
5.5 High Speed Camera Locations 37
5.6 Birdstrike Tested F- 11I ADBIRT Windshield and Test Summary,
Sierracin SN 082 38
5.7 Birdstrike Tested F-I II ADBIRT Windshield and Test Summary,
Swedlow 018 40
5.8 Birdstrike Tested F- 11I ADBIRT Windshield and Test Summary,
PPG SN 86-H-11-04-2010 42
5.9 Birdstrike Test Results of New, Service Aged, and Durability
Facility Aged F-Ill ADBIRT Windshields 45
viii
LIST OF TABLES
PAGE
TABLE
5
2.1 Test Transparencies
2.2 Coupon Test Matrix 6
3.1 Tensile Edge Attachment Test Results 10
3.2 Tensile Test Results 14
3.3 Glass Transition Temperatures from DMA 21
3.4 Gel Permeation Chromatography Results 24
ix
SECTION 1
INTRODUCTION
1.1 BACKGROUND
The U.S. Air Force, recognizing the importance of maintaining bird impact resistance
protection for its pilots and recognizing that high performance aircraft transparencies are a
high cost item, is committed to continued monitoring, testing, and evaluation of aircraft
transparencies.
In 1984, under contract No. F33615-84-C-3403, project 1926, the Wright Laboratory
contracted with the UDRI to conduct a program to test service-aged F-I II transparencies.
The main objective of that program was to determine the effect of in-service* aging on bird
impact resistance capability. The program was conducted from May 1985 to December 1987
and included 22 full-scale birdstrike tests of baseline and in-service aged windshields.
Reference 1 gives a complete discussion of this subject.
The structural integrity of in-service aged F-1I I ADBIRT windshields was found to be
significantly reduced by in-service aging. Results of the bird impact tests indicated that the
windshield capability is reduced from a 470 knot baseline capability (as tested on simulated
flight hardware) to 360 knots after 2 years in-service aging (40% in terms of impact energy),
and reaches an asymptotic minimum value of 325 knots at an installed age of 5 years.
Birdstrike risk assessment of the windshield indicated that, given a birdstrike, degradation
causes the likelihood of penetration to increase significantly with installed age.
The reduction of bird impact resistance capability with installed age caused Air Force
concern. As a result, the Air Force contracted with UDRI (Contract F33615-84-C-3404,
modification P00011) to conduct additional research of the F-I II windshield structural
degradation problem. The program consisted of laboratory coupon tests of in-service aged
and baseline F-I 11 ADBIRT windshield coupons; research of polycarbonate degradation and
craze testing; fractography; and finite element analysis of the windshield edge attachment.
* In-service age is defined as the amount of time the transparency was on the aircraft, also
referred to as installed age.
I